document_title: Check (chess)

question_text: when do you have to say check in chess

question_tokens: when do you have to say check in chess

text: Check (chess)

text: Introduction[edit]

text: A check is the result of a move that places the opposing king under an immediate threat of capture by at least one of the player's pieces. Making a move that checks is sometimes called "giving check". If the king is in check and the checked player has no legal move to get his king out of check, the king is checkmated and the player loses.

text: Under the standard rules of chess, a player may not make any move which places or leaves their king in check. A player may move the king, capture the threatening piece, or block the check with another piece.[1]

text: Some variations of chess, such as Losing chess, allow a player to move into check, and in fast chess a player is permitted to leave their king in check, which results in them losing the game.

text: A king cannot itself directly check the opposing king, since this would place the first king in check as well. However a move of the king could expose the opposing king to a discovered check by another piece.

text: In informal games, it is customary to announce "check" when making a move that puts the opponent's king in check. However, in formal competitions, check is rarely announced.[2]

text: Getting out of check[edit]

text:
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White is in check. The king can get out of check by three methods.

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White is in checkmate. The king cannot escape anywhere and White has lost the game.

text: There may be up to three possible ways to get a king out of a single check on the following move:

text:
Capturing the checking piece, with either the king or another piece. If the checking piece is on a square next to the king, the king can capture the piece if the king does not move into a new check, i.e. if the piece is not protected by another enemy piece. Note that the piece which is pinned to the king cannot capture the checking piece because such a move will place the king in a check from the pinning piece.
Moving the king to an adjacent square where it will not be in check. The king is not allowed to castle when it is in check. The king may capture an enemy piece in a move to get out of check, as long as the piece is not protected.
Blocking the check. This will only work if the checking piece is a queen, rook or bishop and there is at least one empty square in the line between this checking piece and the checked king. Blocking a check is done by moving a piece to a square in line in between the checking piece and the checked king. (The blocking piece is then pinned to the king by the attacking piece.)[3]

text: In the position in the first diagram, White can get out of check by three methods:

text:
The move Nxa2, capturing the attacking piece.
Moving the king to any unattacked square (marked with "x"), namely Kd6, Ke5, or Ke7.
Blocking the check by the move Rc4 or Nd5.

text: If a king is placed in double check, the king must get out of both checks on the following move. Since it is impossible to capture both checking pieces or block both lines of attack in a single move, a double check can be escaped only by moving the king out of check.

text: If none of these possibilities can get the king out of check, then it is checkmated and the game is lost by the player being checkmated.

text: Types of checks[edit]

text: A simple and very common type of check is when a piece moves to directly attack the opposing king only by itself. Sometimes such a check is part of a chess tactic such as a fork, a skewer, or a discovered attack on another piece. In some cases, a check can be used to defend against such tactics.

text: There are also a few more special types of check:

text:
Discovered check. A discovered check is similar to any other type of discovered attack except that it is a discovered attack on the opposing king. In a discovered check, a piece moves out of the line of attack by another piece so that this other piece (which can be a queen, rook, or bishop) is then checking the opponent's king. The piece that actually moved in the discovered check move could possibly be any type of piece belonging to the same player as the checking piece except queen or the same type of piece administering the check. A discovered check could be a tactic in itself because the piece that moved could attack or otherwise create a threat to another piece on the checked king's side. The opponent has to get out of the discovered check on the following move and may not get a chance to thwart the attack by the other piece that moved.
Double check. A double check is a check from two pieces to the opponent's king in a single move. This happens when a moved piece attacks the king, resulting in a second piece giving check by discovered check. It can also happen, though very rarely, when an en passant capture opens two lines of attack simultaneously. In algebraic chess notation, a double check move is sometimes noted with a "++" after the written move in place of the usual "+", although "++" has been used to indicate checkmate (along with "#").[4] A double check cannot be blocked, nor can it be met by capturing one of the checking pieces (unless the king itself makes the capture), because there is check from two directions.
Cross-check. When a check is answered by a check, particularly when this second check is delivered by a piece blocking the first, it is called a cross-check. In fact, a "cross-checkmate" is also possible in that way (that is, to answer a check with a checkmate) but since no such term exists, it would be called cross-check as well. Cross-checks are rather rare but are a popular theme in chess problems.

text: Announcing check and notation[edit]

text: In friendly games, the checking player customarily says "check" when making a checking move. Announcing "check" is not required under the rules of chess and it is usually not done in formal games. Until the early 20th century a player was expected to announce "check", and some sources of rules even required it (Hooper & Whyld 1992:74).

text: In algebraic chess notation, a checking move is recorded like any other move, except that a "+" is normally written after the move.

text: In the FIDE rules for rapid chess, if a player leaves their king in check or commits any other illegal move their opponent cannot

text: Historical[edit]

text: Less commonly (and obsolete), the warning garde can be said when a player directly attacks the opponent's queen in a similar way. This was mostly abandoned in the 19th century (Hooper & Whyld 1992:74). The same move can be both check and garde simultaneously. Before the queen acquired its current move (about 1495) the rook was the most powerful piece. At that time the term check-rook was used for a move that checked the king and attacked a rook at the same time (Hooper & Whyld 1992:75).

text: Checking in tactics and strategy[edit]

text: Sometimes checking an opponent provides no benefit to the checking player. This is called a "useless check" and it may even provide the checked opponent with a tempo (move opportunity) to move the king into a safer position (Hooper & Whyld 1992:437). For example, 1.e4 e6 2.d4 Bb4+? does nothing for Black and in fact causes them to lose a tempo after 3.c3! A check given with the sole intention of delaying an inevitable defeat by one move is referred to as a "spite check", and may be considered somewhat unsporting (Eade 2005:65).

text: There are many instances, however, when checking the opponent's king may be a useful tactic or part of a tactic, either in attacking or in defense. Checking is often used in combinations with many other tactics or simply to force an opponent into a position where the opposing king can be checkmated, otherwise taken advantage of, or is otherwise worse for the opponent. Some attacks involve numerous checks to force an opponent into a losing position, especially when the king is exposed. An unexpected check in a forced combination or an overlooked cross-check in a planned series of checks may serve as sort of a zwischenzug, foiling the plan.

text: Some uses of checking:

text:
Repetitive checking to prevent losing a game going poorly (i.e. to draw the game by perpetual check).
Royal fork (knight fork of king and queen) or other forks involving the king.
Checks to force an exchange.
A double check could be especially bad for the opponent since there are likely to be fewer options to get out of check. A double check is often more likely to lead to checkmate or loss of material.
A check might force a king to move so that it cannot castle later.
Moving a piece to give check can sometimes open a line of attack on another piece. The opponent must escape the check, and therefore cannot (in general) prevent the other piece from being captured (discovered attack).
Similarly, the piece moved to create a discovered check may attack another enemy piece, leading to the same scenario.
The king may also, by being forced to move out of check, enable the checking piece to capture another piece (an absolute skewer).
A check might force some piece to block it and therefore pose an absolute pin on that piece.
A check might deflect the king from protecting some other piece (particularly in an endgame, to capture opponent's pawns).
A check could sometimes be used to foil an opponent's trap which would otherwise lead to loss of material. For example, if an opponent forks two of a player's pieces, the attacked player may be able to move one of the forked pieces to check the opponent's king requiring the opponent to save it on his/her next move, thus allowing the player to then move the other forked piece to also save it from attack.

text: History[edit]

text: In early Sanskrit chess (c. 500–700) the king could be captured and this ended the game. The Persians (c. 700–800) introduced the idea of warning that the king was under attack (announcing check in modern terminology). This was done to avoid the early and accidental end of a game. Later the Persians added the additional rule that a king could not be moved into check or left in check. As a result, the king could not be captured (Davidson 1949:22).

text: In this usage, the words "check" and "chess" come via Arabic from Persian shāh, meaning "king"[6] or "monarch" (Murray 2012:159).


document_title: Big Brother 20 (U.S.)

question_text: how many episodes of big brother season 20 have aired

root

text: Big Brother 20 (U.S.)

text: Production

text: Development

text: The series was announced in August 2016 as part of a double renewal for Big Brother 19 and Big Brother 20.[5] Along with the series the 24/7 live feeds returned with a CBS All Access subscription and Big Brother: After Dark is also returned on Pop.[6] The season is produced by Endemol Shine North America and Fly on the Wall Entertainment. Julie Chen returned as host and Allison Grodner as well as Rich Meehan returned as Executive Producers.[7] CBS began allowing online applications in September 2017, however open casting calls did not begin until March 2018.[8][9] Celebrity Big Brother winner and runner up Marissa Jaret Winokur and Ross Mathews host a new companion show known as Off the Block with Ross and Marissa following the end of former HouseGuest Jeff Schroeder's Big Brother Live Chat.[10]

tag: p

text: Prize

text: The last remaining HouseGuest is set to receive a prize of $500,000.[11]

text: Twists

text: This season's main theme and twists centered on technology.

text: BB App Store

text: For the first three weeks, viewers were asked a series of questions about their opinions on the remaining HouseGuests. The HouseGuest who was named in the most overall answers was deemed the "top trending" HouseGuest of the week and earned a "Power App", which would give them an advantage in the game, while the HouseGuest who was answered the least was deemed "least trending" was given a "Crap App", which gave them a punishment. Once HouseGuests received an app, they were no longer eligible to receive one in the future.

text:
Week

Top trending

Power App

Least trending

Crap App

Punishment

Name

Ability

Used?

1

Sam

Bonus Life

To be used immediately after a HouseGuest is evicted from the house, this power will give that HouseGuest a chance to return to the game via a competition. This power must be used in the first three evictions, or else the fourth evicted HouseGuest will automatically be given the chance to return.

Used

Faysal

Hamazon

The HouseGuest will routinely be given packages of ham, which they must consume on arrival. (As Faysal is Muslim, a vegetarian ham substitute was used instead.)

2

Tyler

The Cloud

The HouseGuest has the power to make themselves immune from nomination during one Nomination or Veto Ceremony of their choice over the following eight weeks.

Pending

Rachel

Yell!

For 24 hours, an angry reviewer was unleashed into the house at random times to loudly give the HouseGuest feedback on their game.

3

Bayleigh

Identity Theft

The HouseGuest can secretly replace the HoH's nominations with two of their own. This does not affect replacement nominations and can be used until eight players remain.

Not used

Haleigh

Read It!

Periodically throughout the week, the HouseGuest must wear a costume and read Hamlet in a Shakespearean accent. This punishment will continue until the entire play has been read.

tag: table

text: H@cker Competition

text: On Day 44, following Rachel's eviction, a new twist was unleashed on the HouseGuests called the "H@cker Competition". It lets one HouseGuest hack the game for a week. After the nominations, all of the HouseGuests compete in a competition at the same time in different rooms, making the winner anonymous to the other HouseGuests. The winner of the competition is able to "hack" the game in three different ways. First, they can replace one of the Head of Household's nominations and change it to someone of their choosing. Second, they get to select one of the three participants chosen for the Power of Veto competition. Finally, they can nullify one vote at the live eviction.

text:
Week

H@cker

Ability

Action

6

Haleigh

1. Replace one nomination2. Pick one veto player3. Nullify one eviction vote

1. Took Scottie off the Block and nominated Tyler in his place2. Picked Kaycee to play in the veto3. Nullified Tyler's vote during the live eviction

7

Kaycee

1. Took herself off the Block and nominated Rockstar in her place2. Picked Tyler to play in the veto3. Nullified TBA's vote during the live eviction

text: HouseGuests

text: The HouseGuests were announced on Monday, June 18 at 7 AM PDT through the CBS website.[12]

text:
Name

Age on entry

Occupation

Residence

Angela Rummans

26

Fitness model

Playa Vista, California

Angie "Rockstar" Lantry

34

Stay-at-home mom

Columbia, Maryland

Bayleigh Dayton

25

Flight attendant

Atlanta, Georgia

Brett Robinson

25

Cybersecurity engineer

Charlestown, Massachusetts

Chris "Swaggy C" Williams

23

Day trader

Bridgeport, Connecticut

Faysal Shafaat

26

Substitute teacher

Orlando, Florida

Haleigh Broucher

21

College student

College Station, Texas

JC Mounduix

28

Professional dancer

West Hollywood, California

Kaitlyn Herman

24

Life coach

Encino, California

Kaycee Clark

30

Pro-football player

Tempe, Arizona

Rachel Swindler

29

Vegas entertainer

Las Vegas, Nevada

Samantha "Sam" Bledsoe

27

Welder

Stuarts Draft, Virginia

Scottie Salton

26

Shipping manager

Chicago, Illinois

Steve Arienta

40

Former undercover cop

Wanaque, New Jersey

Tyler Crispen

23

Lifeguard

Hilton Head, South Carolina

Winston Hines

28

Medical sales rep

Bowling Green, Kentucky

text: Other appearances

text: All evicted HouseGuests appear on the Facebook Watch exclusive Off the Block with Ross and Marissa for an extended interview following their evictions.[13] Tyler Crispen appeared in the second episode of TKO: Total Knock Out as a contestant.[14] Crispen finished in third place and received $2,500.[15]

text: Episodes

text:
No.overallNo. inseasonTitleDay(s)Original air dateUS viewers(millions)Rating/share (18-49)Week 1
6671"Episode 1"Day 1June 27, 2018 (2018-06-27)5.33[16]1.5/7[16]
Sixteen new HouseGuests entered the newest version of the Big Brother House. After getting settled in the HouseGuests began formal introductions. Following formal introductions Julie informed the HouseGuests that the theme for the summer is "Big Brother Technology" and the first competition of the summer began.

Safety Competition – Part 1 ("The Trash Folder"):[a] There are 7 folders hidden inside of the "supercomputer". 6 of the folders are labeled "escape" however, 1 of them is labeled "escape and play". Each HouseGuest must collect a folder as fast as possible. The one who finds the "escape and play" folder will moved on to face the winner of part 2 in part 3 of the competition. The  HouseGuest who does not collect a folder will suffer a punishment. Angela was the winner and Kaycee was the loser.
Safety Competition – Part 2 ("HouseGuest CAPTCHA"):[a] The HouseGuests must collect block letters from the pit below their tether which is constantly raising and lowering. Each HouseGuest must collect the correct letters and be the first one to spell "HouseGuest" on their platform. The first HouseGuest to correctly collect and spell "HouseGuest" moved on to face the winner of part 1 in part 3 of the competition. The last remaining HouseGuest will suffer a punishment. Swaggy C was the winner and Sam was the loser.
Safety Competition – Part 3 ("Surfing the BB Web"): [b] The winners of part 1 and part 2 faced off in this competition and must "surf" the web. The winner of this competition will have the opportunity to keep 8 HouseGuests including themselves safe from the first eviction. Swaggy C was the winner.
Following the competitions Julie informed Swaggy C that of the four original groups that moved into the Big Brother house he must keep two of the groups safe. The punishments for the two losing HouseGuests were revealed. Kaycee received the "Pinwheel of Doom" punishment and is forced to wear a pinwheel unitard. Whenever the pinwheel spins she must stay in the room she is currently in until it stops spinning. Sam is forced to occasionally play the game as a robot, when the words "Robot online" are announced she plays the game as a robot, but when the words "Robot offline" are announced she plays the game as a human. Both punishments are in effect until the first live eviction. Swaggy C chose to keep groups 3 and 4 safe from eviction.

6682"Episode 2"Days 2-5June 28, 2018 (2018-06-28)5.13[17]1.4/6[17]

Head of Household ("Microchip Mayhem"): [a] When the competition starts HouseGuests must cross their beam and collect a "deletion dot". Once they have collected one they must cross back, place it inside another HouseGuests tube, and repeat. When a HouseGuest has 10 deletion dots inside their tube they are eliminated from the competition. Tyler was the winner and became the first HoH of the season.
On Day 5, Tyler nominated Sam and Steve for eviction.

6693"Episode 3"Days 5-9July 1, 2018 (2018-07-01)4.78[18]1.2/6[18]
Following nominations Sam has a one on one conversation with the other HouseGuests. As the HoH, Tyler was forced to chose the first four Have-Nots of the season. Kaitlyn volunteered and Tyler chose Brett, Scottie, and Winston to be the remaining Have-Nots. Each week in the new BB App Store the most trending HouseGuest will receive a power to help them in the Big Brother game. However, the least trending HouseGuest each week will receive a punishment. Each HouseGuest may only receive a power in the BB App Store once. Faysal was the least trending HouseGuest and received the Hamazon punishment, throughout the week Hamazon will deliver a fresh plate of ham which Faysal must eat in full. Meanwhile, Sam was the top trending HouseGuest and received Bonus Life power, this gives Sam or a HouseGuest of her choice the chance to return to the game if evicted. The power is only good through the first four evictions and if Sam does not use it by the third eviction then the fourth evicted HouseGuest automatically has the chance to return to the game.
6704"Episode 4"Days 9-12July 4, 2018 (2018-07-04)3.95[19]0.9/5[19]
The HouseGuests begin speculating who received the Power App as Faysal receives non-stop delivery's of Hamazon Swine.

Power of Veto ("VimeBro Studios"): The competition was played in five rounds. In each round the losing competitor is eliminated from the competition. The competitors were Tyler, Sam, Steve, Scottie, Swaggy C, and Faysal.
Stage 1 ("Snake Bite Pit"): When "action" is said the competitors must reach into a snake pit and pull out a like icon. Once they have a like icon they must place it in their corresponding score card. When a HouseGuest has three like icons in their score card they are finished with that stage. The last HouseGuest who does not have three like icons or the HouseGuest with the least amount of like icons after five minutes is eliminated. Scottie was eliminated following Stage 1.
Stage 2 ("Polar Plunge"): When the competition begins the HouseGuests must plunge to the bottom of an arctic pool and retrieve a like icon. Once they have a like icon they must place it in their corresponding score card. When a HouseGuest has ten like icons in their score card they are finished with that stage. The last HouseGuest who does not have ten like icons is eliminated. Swaggy C was eliminated following Stage 2.
Stage 3 ("Human Canvas"): When "action" is said the HouseGuests must stand on a post as they are fired at with paint balls. When told to do so they must move forward to a smaller post. The first HouseGuest to touch the ground is eliminated from the competition. Steve was eliminated following Stage 3.
Stage 4 ("Electricity in the Air"): When the competition starts HouseGuests must transfer balls one at a time using their device from the start to their scoreboard. However, the HouseGuests are schocked with shocking collars while attempting to transport their balls. When a HouseGuest collects ten balls they are finished. The last HouseGuest remaining is eliminated from the competition. Sam was eliminated following Stage 4.
Stage 5 ("Sloda"): When the competition begins the HouseGuests goal are to find and match the top three flavors to "Sloda", a soda version of slop. Once done they must place them in the corresponding order. The first HouseGuest to place the three flavors in the corresponding order will win the Power of Veto. Faysal was the winner and received the Power of Veto.
At the Veto Meeting, Faysal chose not to use the PoV, thus keeping the nominations the same.

6715"Episode 5"Days 12-16July 5, 2018 (2018-07-05)4.96[20]1.3/6[20]
Ahead of the first eviction, with a split house, alliances begin attempting to secure votes for their side. On Day 16, by a vote of 7-6, Steve was the first to be evicted from the Big Brother house.

Head of Household ("Land a Job"): When the competition starts HouseGuests must step up to the launch pad and launch their ball into the new town of "San Brosé" The building the ball lands on has a corresponding salary. The HouseGuest with the highest salary after everyone has launched their balls became the new HoH. Kaitlyn was the winner and became the second HoH of the season.

Week 2
6726"Episode 6"Days 16-17July 8, 2018 (2018-07-08)5.11[21]1.3/6[21]
Following the HoH competition Kaitlyn begins strategizing her nominations. The BB App Store opens for business again. Rachel was the least trending while Tyler was the most trending HouseGuest. Rachel received the "Yell!" Crap App, periodically throughout the next twenty-four hours an angry reviewer was released into the house to give her feedback. Tyler received "The Cloud" Power App, this gives him the opportunity to make himself immune from one nomination ceremony of veto meeting throughout the next eight weeks. Kaitlyn nominated Scottie and Winston for eviction
6737"Episode 7"Days 17-20July 11, 2018 (2018-07-11)5.43[22]1.5/7[22]
Following nominations the HouseGuests prepared to compete in the Power of Veto competition  The HouseGuests picked to compete in the Veto competition were Kaitlyn, Scottie, Winston, Faysal, Rachel, and Tyler. The HouseGuests then received a visit from Big Brother 19 HouseGuests and winners of the 30th season of The Amazing Race, Jessica Graf and Cody Nickson, who hosted the Power of Veto competition.

Power of Veto ("HouseGuestsOnly.com"): When the competition begins players must review dating profiles of former HouseGuests. Once reviewed they must place the former HouseGuests in their ideal dating location. Once all former HouseGuests are placed they must hit the buzzer. If all former HouseGuests are correctly placed their time gets locked in however, if they are incorrect they must try again until they are all correctly placed. If a HouseGuest takes longer than twenty minutes to correctly place all HouseGuests tey are automatically eliminated. The HouseGuest with the fastest time won the Power of Veto. Tyler was the winner with a time of 5 minutes and 29 seconds.
Rachel then begins receiving visits from her angry reviewer as a result of her Crap App from the BB App Store. At the Veto Ceremony Tyler chose to use the PoV to remove Scottie from the block. On Day 20, Kaitlyn then named Swaggy C as the replacement nominee.

6748"Episode 8"Days 20-23July 12, 2018 (2018-07-12)5.32[23]1.5/6[23]
Following the Veto Ceremony Swaggy C and Winston both begin campaigning for votes. The HouseGuests then cast their votes on who the want to evict. On Day 23, by a vote of 8-4, Swaggy C was the second to be evicted from the Big Brother house.

Head of Household ("Product Launch"): The competing HouseGuests watched a two videos about product launches for "Pineapple, Inc.". Julie then asked the HouseGuests a series of questions where the answer is either true or false. If a HouseGuest answered incorrectly they were eliminated from the competition. The last HouseGuest remaining became the next Head of Household. If two HouseGuests remain at the end the game would enter tiebreaker mode. Rachel and Scottie remained at the end. Both HouseGuests were given whiteboards and the answer to the final question was a number. The HouseGuest who came closest to the correct answer without going over would become the next HoH. If both HouseGuests went over the who was closest to the number would be the winner. Scottie was the winner and became the third HoH of the season.

Week 3
6759"Episode 9"Days 23-24July 15, 2018 (2018-07-15)5.19[24]1.4/6[24]
Following Swaggy's eviction the BB App Store opened for the final time. Inside, Haleigh was the least trending HouseGuest and received the "Read It!" Crap App. When told to read Haleigh must dress up in a costume, report to a specified room, and read Hamlet until told to stop. This punishment will continue until the entire book is read. Meanwhile, Bayleigh was the most trending HouseGuest and received the "Identity Theft" Power App. This power allows her to secretly chose the nominees for the week. On Day 24, Scottie nominated Brett and Winston for eviction.
67610"Episode 10"Days 24-27July 18, 2018 (2018-07-18)5.24[25]1.4/6[25]
Following nominations the HouseGuests picked players for the Veto Competition. The competitors were Scottie, Brett, Winston, Tyler, Rachel, and Rockstar.

Power of Veto ("Mamma Mia! Madness"): When the competition starts the HouseGuests must grab onto their disco ball and spin 15 times to set 30 seconds on their clock. They must then run acros the playing field and build a tower of champagne glasses. Before the clock runs out they must run back and spin again to get another 30 seconds. If their clock runs out before they make it back they are eliminated from the competition. However, if they volunteer to be a have-not for the week they may re-enter the competition. The first HouseGuest to successfully build their tower won the Power of Veto and a trip for 2 to the Greek islands. Scottie was the winner and received the PoV.
Meanwhile, Haleigh begins suffering from her Crap App punishment. Brett and Winston begin campaigning to Scottie in an attempt to get him to take one of them off of the block. Scottie informs Kaitlyn of their secret meeting causing confrontation throughout the house. At the Veto Ceremony, Scottie chose not to use the PoV thus keeping his nominations the same.

67711"Episode 11"Days 27-30July 19, 2018 (2018-07-19)5.58[26]1.6/7[26]
Following the Veto Ceremony each side of the house begins looking for votes. The HouseGuests voted in the live vote and eviction. On Day 30, by a vote of 6-5, Winston was the third to be evicted from the Big Brother house. Following Winston's eviction, a major confrontation occurs between Rockstar and Brett due to his eviction speech.

Head of Household ("Out On A Limb"):[c] In this competition each participating HouseGuest must stand on a peg attached to their tree and hold on as long as possible. Throughout the competition the trees move and water is sprayed on the HouseGuests. The last HouseGuest to remain on their tree will become the next Head of Household.

Week 4
67812"Episode 12"Days 27, 30-31July 22, 2018 (2018-07-22)5.45[27]1.5/6[27]

Head of Household ("Out On A Limb"):[c] During the competition honey and feathers also begin to spray at the HouseGuests. Sam was the last HouseGuest remaining on their tree and became the fourth HoH of the season.
Tensions begin to flare throughout the house between different HouseGuests following the eviction.
The episode also covered a major controversy between HouseGuests JC and Bayleigh following an incident where JC used the n-word in a conversation which Bayleigh took as offensive.
On Day 31, Sam nominated Haleigh and Kaitlyn for eviction.

67913"Episode 13"Days 31-34July 25, 2018 (2018-07-25)5.69[28]1.5/6[28]
Sam's nomination reasoning begins causing friction throughout the house. The HouseGuests then picked players for the Power of Veto competition. The competitors were Sam, Haleigh, Kaitlyn, JC, Rockstar, and Faysal. Former Big Brother HouseGuest, Rachel Reilly, entered the house to host the PoV competition.

Power of Veto ("Chop Bonk Spank"): Inspired by Big Brother 19's  "Punch, Slap, Kick" and sponsored by the fictional "Bro Fund Me", HouseGuests must stand on their target as Rachel randomly played sequences which Chomped, Bonked, and Spanked them. Rachel then asked the HouseGuests a question based on the sequence. Each correct answer earned the HouseGuest a point. The HouseGuest with the most points at the end of the game was the winner. After 7 rounds, Faysal was the winner with 7 points and received the Power of Veto.
At the Veto Ceremony, Fessy chose to use the PoV on Haleigh. Sam chose Rockstar to become the replacement nominee. She then informed the rest of the HouseGuests about her Bonus Life Power App.

68014"Episode 14"Days 34-37July 26, 2018 (2018-07-26)5.44[29]1.5/6[29]
Following the Veto Ceremony, Faysal gets caught in the middle of Haleigh and Kaitlyn. The HouseGuests then participated in the live vote eviction by voting on who they wished to evict from the house. On Day 37, by a vote of 9-1, Kaitlyn was the fourth to be evicted from the Big Brother house. However, due to Sam not using her Bonus Life Power App the evictee was automatically offered chance to win re-entry into the game.

Bonus Life Competition ("Outside The House"): In the Bonus Life Competition Kaitlyn must disassemble the life-sized puzzle of herself and must reassemble the puzzle on the opposite side of the fictional house within two minutes and thirty seconds. When she believes the puzzle is correctly built she must hit the buzzer. If the puzzle is correctly built she will win re-enter into the game however, if it is incorrectly built she will have the opportunity to continue working until her time is up. Kaitlyn did not correctly build the puzzle and was the officially evicted from the house.

Week 5
68115"Episode 15"Days 37-38July 29, 2018 (2018-07-29)5.40[30]1.5/6[30]

Head of Household ("Perfect Timing"): In the Head of Household competition, the HouseGuests must sit on an email and slide from their outbox to their inbox. The HouseGuest with the closest time to 8 seconds will be the new Head of Household. Bayleigh, with a time of 8.08 seconds, was the winner.
On Day 38, Bayleigh nominated Brett and Rachel for eviction.

68216"Episode 16"Days 38-41August 1, 2018 (2018-08-01)5.55[31]1.5/6[31]

Power of Veto ("Goober Driver"): In the Power of Veto competition, HouseGuests had to pave a road so they can give the four evicted HouseGuests a ride across town. The player who paves the road and gets the evicted HouseGuests to the other side of town the fastest wins the Power of Veto. Rachel, JC, and Sam timed out while Tyler won.
Bayleigh shares with Rachel the fact that she has a Power App.
After Tyler asks if Bayleigh would put Angela up if he uses the veto, Bayleigh tells Rachel that Tyler's targetting Angela. Then, Rachel tells Angela about Tyler targetting her which she doesn't believe. Angela tells Kaycee and she also thinks it's false. Kaycee tells Tyler about this, Tyler talks with Angela, who all agree Rachel should be the target, not Brett.
At the Veto Ceremony, Tyler chose to not use the PoV, thus keeping the nominations the same.

68317"Episode 17"Days 41-44August 2, 2018 (2018-08-02)5.61[32]1.5/6[32]
Ahead of eviction the show gives an update on Bayleigh's family which includes Swaggy C meeting Bayleigh's parents. The HouseGuests then participated in the live vote eviction by voting on who they wished to evict from the house. On Day 44, by a vote of 5-4, Rachel was the fifth to be evicted from the Big Brother house.

Head of Household ("GIF That Keeps on Giving"): Throughout the past week HouseGuests were shown gif's of themselves at predetermined times. In the competition Julie asked HouseGuests true or false questions about the gif's they viewed. Following the question the HouseGuests must lock in their answers. If they answer incorrectly they are eliminated from the competition. The last HouseGuest standing becomes the new Head of Household. If there are two HouseGuests remaining there will be a tie-breaker. Angela and Rockstar were the last two HouseGuest's standing and participated in the tie-breaker. Julie asked a question to which the answer was a number. The HouseGuest with the closest answer without going over would be the next HoH. If both HouseGuests went over the one closest to the answer would become the HoH. Angela provided the closest answer without going over and became the sixth HoH of the season.
Julie Chen announced after the Head of Household Competition about the "H@cker Comp". Each week, the HouseGuests will compete to "hack" the week. She also announces the first competition will be on Sunday night's nomination episode.

Week 6
68418"Episode 18"Days 44-45August 5, 2018 (2018-08-05)5.57[33]1.6/7[33]
On Day 45, Angela nominated Rockstar and Scottie for eviction and planned to backdoor Bayleigh.

H@cker Competition ("Crack The Code"): Over seven rounds, HouseGuests had to unscramble notorious Big Brother words in a certain amount of time. If a HouseGuest unscrambles a word correctly, they get one point. Haleigh became the first H@cker with four points.
Haleigh took Scottie off the block and nominated Tyler in his place.

68519"Episode 19"Days 45-48August 8, 2018 (2018-08-08)5.63[34]1.6/8[34]
The H@cker, Haleigh, picked Kaycee to play in the Power of Veto competition.

Power of Veto ("Boom Power Trip"): In an elimination style, HouseGuests had to roll a ball back and forth for a set number of times. The HouseGuest who was not able to finish before everyone else was eliminated and received a prize or a punishment. After someone was eliminated, they could keep their prize or exchange it for anyone else's prize. This went on until only one person remained. The HouseGuest who ended up with the Power of Veto was the winner. Angela ended up with the Power of Veto.
Angela took Tyler off the block and put up Bayleigh.

68620"Episode 20"Days 48-51August 9, 2018 (2018-08-09)4.99[35]1.4/7[35]
Haleigh calls a house meeting and tells everyone she was the H@cker. This sparks a fight between Bayleigh and Tyler. As part of the H@cker's abilities, Haleigh chose to nullify Tyler's vote during the live evictionThe HouseGuests then participated in the live vote eviction by voting on who they wished to evict from the house. On Day 51, by a vote of 6-1, Bayleigh was the sixth to be evicted from the Big Brother house and became the first member of the jury.

Head of Household ("#HashtagTooLong"): In a knockout elimination style, two players were challenged against each other to a multiple choice question. If the HouseGuest who rang in got it wrong, they were eliminated. If the HouseGuest was correct, the competitor was eliminated. The last remaining HouseGuest won the Head of Household. It came down to Haleigh and JC. Haleigh beat JC to become the next Head of Household.

Week 7
68721"Episode 21"Days 51-52August 12, 2018 (2018-08-12)TBDTBA
Following the HoH competition, Haleigh and Rockstar discussed who should be nominated. They decided on putting Angela and Kaycee on the block in order to eventually backdoor Tyler.
The Level 6 alliance tried to pursuade Haleigh to nominate Sam instead of one of them. Then, Sam went to Haleigh after hearing that her closest allies were conspiring against her, so Haleigh spilled how Level 6 wanted Sam nominated.
On Day 59, Haleigh nominated Angela and Kaycee for eviction.

H@cker Competition ("Hack the House"): The HouseGuests are shown fragments of an image from cameras around the house. Then they have to identify which room the camera is from by examining the image it's producing. If they correctly identify the room, they get one point. The HouseGuest who gets the most points after seven rounds becomes the final H@cker. Kaycee became the final H@cker with four points.
Kaycee took herself off the block and nominated Rockstar in her place.

68822"Episode 22"Days 52-55August 15, 2018 (2018-08-15)TBDTBA
68923"Episode 23"Days 55-58August 16, 2018 (2018-08-16)TBDTBA

text: Notes

text:
^ Jump up to: a b c Only eight HouseGuests participated in this competition

Jump up ^ Only two HouseGuests participated in this competition

^ Jump up to: a b This Head of Household competition began in Episode 11 on Day 30. However, completion was not broadcast on television until episode 12.

tag: ol

text: Have-Nots

text:
Week 1

Week 2

Week 3

Week 4

Week 5

Week 6

Week 7

Week 8

Week 9

Week 10

Week 11

Week 12

Week 13

Brett,Kaitlyn,Scottie,Winston

Faysal,Haleigh,JC,Rockstar

Angela,Brett,Sam,Tyler

Bayleigh,Kaycee,Rachel,Scottie

Faysal, Scottie,Tyler

none

text: Voting history

text:
Week 1

Week 2

Week 3

Week 4

Week 5

Week 6

Week 7

Week 8

Week 9

Week 10

Week 11

Week 12

Week 13

Day 99

Finale

Head of Household

Tyler

Kaitlyn

Scottie

Sam

Bayleigh

Angela

Haleigh

(none)

Technology Winner

SamFaysal

TylerRachel

BayleighHaleigh

(none)

Haleigh

Kaycee

(none)

Nominations(pre-veto)

SamSteve

ScottieWinston

BrettWinston

HaleighKaitlyn

BrettRachel

RockstarScottieTyler

AngelaKayceeRockstar

Veto Winner

Faysal

Tyler

Scottie

Faysal

Tyler

Angela

Tyler

(none)

Nominations(post-veto)

SamSteve

Swaggy CWinston

BrettWinston

KaitlynRockstar

BrettRachel

BayleighRockstar

Angela

Steve

Swaggy C

Winston

Kaitlyn

Rachel

Head ofHousehold

Nominated

Brett

Steve

Swaggy C

Nominated

Kaitlyn

Nominated

Bayleigh

Faysal

Sam

Winston

Brett

Kaitlyn

Brett

Bayleigh

Haleigh

Sam

Winston

Brett

Kaitlyn

Brett

Bayleigh

Head ofHousehold

JC

Steve

Swaggy C

Winston

Rockstar

Rachel

Bayleigh

Kaycee

Steve

Swaggy C

Winston

Kaitlyn

Rachel

Bayleigh

Rockstar

Sam

Winston

Brett

Nominated

Brett

Nominated

Nominated

Sam

Nominated

Swaggy C

Winston

Head ofHousehold

Rachel

Rockstar

Scottie

Sam

Swaggy C

Head ofHousehold

Kaitlyn

Brett

Bayleigh

Tyler

Head ofHousehold

Swaggy C

Winston

Kaitlyn

Rachel

Noteligible

Bayleigh

Sam

Winston

Brett

Kaitlyn

Head ofHousehold

Nominated

Evicted(Day 51)

JuryMember

Rachel

Steve

Swaggy C

Winston

Kaitlyn

Nominated

Evicted(Day 44)

Kaitlyn

Steve

Head ofHousehold

Brett

Nominated

Evicted(Day 37)

Winston

Steve

Nominated

Nominated

Evicted(Day 30)

Swaggy C

Sam

Nominated

Evicted(Day 23)

Steve

Nominated

Evicted(Day 16)

Notes

1, 2

2

3

none

4

Evicted

Steve7 of 13 votesto evict

Swaggy C8 of 12 votesto evict

Winston6 of 11 votesto evict

Kaitlyn9 of 10 votesto evict

Rachel5 of 9 votes to evict

Bayleigh6 of 7 votes to evict

KaitlynLost re-entryinto game

text: Notes

text:
^Note 1 :      As the winner of the first safety competition, Swaggy C had the opportunity to save eight HouseGuests, including himself. He and the seven other safe HouseGuests were not able to compete in the Head of Household competition.
^Note 2 : Each week in the BB App Store a power app and crap app were released into the game. The winner of the crap app is represented in italics.
^Note 3 :      Due to Sam not using her Bonus Life Power App, Kaitlyn automatically received a chance to re-enter the house. However, she was unable to complete the challenge and was ultimately evicted.
^Note 4 :      The H@cker earned the power to remove one of the HoH's nominations (represented by strikethrough font) and secretly replace it with their own (represented by bold font).  The H@cker was also able to nullify one vote at the live eviction.

tag: ul

text: Controversies and criticisms

text: JC Mounduix received criticism after he was shown using an ice cream scooper on the genitals of his other HouseGuests. Mounduix later told fellow HouseGuest Kaycee Clark to open up her vagina, saying it "feels good".[36]

text: Viewers questioned Angela Rummans and Rachel Swindler after they were caught on the live feeds making racist remarks, referencing fellow HouseGuest, Bayleigh Dayton. Rummans called her tan "ghetto", while Swindler compared her skin tone to Dayton's, who is African American. CBS later released a statement and warned Rummans and Swindler with future consequences.[37]

text: Since the start of the live feeds, Kaitlyn Herman has been criticized from viewers for her feelings and actions towards several men in the Big Brother House, while being in a 5 year relationship outside of the house. In Week 3, Herman's then boyfriend released a statement on Twitter, stating that he wanted to distance himself from the show and situation.[38]

text: Kaitlyn Herman and JC Mounduix both came under fire after they used n-word in separate occasions.[39] Herman used the word as she was singing the lyrics of a Drake song. Mounduix used the word after fellow HouseGuest Bayleigh Dayton, who is African American, asked Mounduix if there is a "difference between a midget and a dwarf". Offended, Mounduix said that the word "midget" is a derogatory term and then compared it to the n-word.[40][41] Many came to the defense of the two, saying that they didn't use the word towards someone.[42]

text: During a live eviction episode, HouseGuest Brett Robinson called out Angie "Rockstar" Lantry in his eviction speech for "strategic purposes".[43] Lantry responded by confronting Robinson in his face claiming that it was her daughter's birthday.[44] Lantry later called Robinson a "rich, snobby, white-privileged-ass dude".[45] Later that night, Lantry confronted Robinson with pots and pans[46] during which she exclaimed that Robinson has a "micropenis".[47] Upon confrontation, Lantry sat between Robinson's legs whom repeatedly asked her to get off of him.[48]

text: JC Mounduix was criticized by fans after he asked Rachel Swindler if she was transgender, stating that she has "a big Adam's apple." Mounduix proceeded to feel Swindler's neck, but she told him to stop. Moments later, he began to touch Swindler's neck again before being stopped by her.[49]

text: Viewers perceived some of Bayleigh Dayton's comments about Faysal "Fessy" Shafaat as being anti-Muslim. After Shafaat, a Muslim, complained about his in-house crush Haleigh Broucher talking about her past sexual experiences, Dayton claimed in private that Shafaat should "go find a virgin" and that he should "go to Pakistan and [get himself] one" because "that's what they do." Many viewers interpreted "they" as meaning Muslims.[50]

text: During a conversation between Bayleigh Dayton and Angela "Rockstar" Lantry, Dayton claimed that Lantry was the only white person who she knew that didn't like white people. Dayton then said that Lantry dislikes "normal white people" more than she does.[51] Days later, in a conversation with Haleigh Broucher, Dayton referred to her housemates as "crazy-ass white people."[52] Many viewers saw Dayton's statements as racist.[53]

text: Reception

text: Viewing figures

text:
#

Air Date

United States

Source

18–49(rating/share)

Viewers(millions)

Rank(timeslot)

Rank(night)

1

Wednesday, June 27, 2018

1.5/7

5.33

1

1

[16]

2

Thursday, June 28, 2018

1.4/6

5.13

1

1

[17]

3

Sunday, July 1, 2018

1.2/6

4.78

1

1

[18]

4

Wednesday, July 4, 2018

0.9/5

3.95

1

2

[19]

5

Thursday, July 5, 2018

1.3/6

4.96

1

1

[20]

6

Sunday, July 8, 2018

1.3/6

5.11

1

1

[21]

7

Wednesday, July 11, 2018

1.5/7

5.43

1

1

[22]

8

Thursday, July 12, 2018

1.5/6

5.32

1

1

[23]

9

Sunday, July 15, 2018

1.4/6

5.19

1

1

[24]

10

Wednesday, July 18, 2018

1.4/6

5.24

1

1

[25]

11

Thursday, July 19, 2018

1.6/7

5.58

1

1

[26]

12

Sunday, July 22, 2018

1.5/6

5.45

1

1

[27]

13

Wednesday, July 25, 2018

1.5/6

5.69

1

1

[28]

14

Thursday, July 26, 2018

1.5/6

5.44

1

1

[29]

15

Sunday, July 29, 2018

1.5/6

5.40

1

1

[30]

16

Wednesday, August 1, 2018

1.5/6

5.55

1

1

[31]

17

Thursday, August 2, 2018

1.5/6

5.61

1

2

[32]

18

Sunday, August 5, 2018

1.6/7

5.57

1

1

[33]

19

Wednesday, August 8, 2018

1.6/8

5.63

1

1

[34]

20

Thursday, August 9, 2018

1.4/7

4.99

1

1

[35]

211

Sunday, August 12, 2018

22

Wednesday, August 15, 2018

23

Thursday, August 16, 2018

text: ^Note 1 : Episode 21 was delayed to 8:20 PM ET (7:20 PM CT) due to the 2018 PGA Championship golf event running long.[54]


document_title: Cellular respiration

question_text: for each glucose molecule broken down in aerobic respiration approximately how may atps are produced

text: Cellular respiration

text: Aerobic respiration

text: Aerobic respiration requires oxygen (O2) in order to create ATP. Although carbohydrates, fats, and proteins are consumed as reactants, it is the preferred method of pyruvate breakdown in glycolysis and requires that pyruvate enter the mitochondria in order to be fully oxidized by the Krebs cycle. The products of this process are carbon dioxide and water, but the energy transferred is used to break bonds in ADP as the third phosphate group is added to form ATP (adenosine triphosphate), by substrate-level phosphorylation, NADH and FADH2

text:
Simplified reaction:
C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l) + heat

ΔG = −2880 kJ per mol of C6H12O6

text: The negative ΔG indicates that the reaction can occur spontaneously.

text: The potential of NADH and FADH2 is converted to more ATP through an electron transport chain with oxygen as the "terminal electron acceptor". Most of the ATP produced by aerobic cellular respiration is made by oxidative phosphorylation. This works by the energy released in the consumption of pyruvate being used to create a chemiosmotic potential by pumping protons across a membrane. This potential is then used to drive ATP synthase and produce ATP from ADP and a phosphate group. Biology textbooks often state that 38 ATP molecules can be made per oxidised glucose molecule during cellular respiration (2 from glycolysis, 2 from the Krebs cycle, and about 34 from the electron transport system).[2] However, this maximum yield is never quite reached because of losses due to leaky membranes as well as the cost of moving pyruvate and ADP into the mitochondrial matrix, and current estimates range around 29 to 30 ATP per glucose.[2]

text: Aerobic metabolism is up to 15 times more efficient than anaerobic metabolism (which yields 2 molecules ATP per 1 molecule glucose). However some anaerobic organisms, such as methanogens are able to continue with anaerobic respiration, yielding more ATP by using other inorganic molecules (not oxygen) as final electron acceptors in the electron transport chain. They share the initial pathway of glycolysis but aerobic metabolism continues with the Krebs cycle and oxidative phosphorylation. The post-glycolytic reactions take place in the mitochondria in eukaryotic cells, and in the cytoplasm in prokaryotic cells.

text: Aerobic respiration summed up

text: 1. Glycolysis:

text: --- 2 ATPs + Glucose → 2 Pyruvic Acid + 4 Hydrogen + 4 ATPs

text: 2. Formation of Acetyl CoA:

text: --- 2 Pyruvic Acid + 2 CoA → 2 Acetyl CoA + 2 Carbon Dioxide + 2 Hydrogen

text: 3. Krebs Cycle:

text: --- 2 Acetyl CoA + 3 O2 → 6 Hydrogen + 4 Carbon Dioxide + 2 ATPs

text: 4. Electron Transport System:

text: --- 12 Hydrogen + 3 O2 → 6 Water + 32 ATPs

text: Overall Reaction:

text: --- Glucose + 6 O2 → 6 Carbon Dioxide + 6 Water + 36 ATPs

text: Glycolysis

text: Glycolysis is a metabolic pathway that takes place in the cytosol of cells in all living organisms. This pathway can function with or without the presence of oxygen. In humans, aerobic conditions produce pyruvate and anaerobic conditions produce lactate. In aerobic conditions, the process converts one molecule of glucose into two molecules of pyruvate (pyruvic acid), generating energy in the form of two net molecules of ATP. Four molecules of ATP per glucose are actually produced, however, two are consumed as part of the preparatory phase. The initial phosphorylation of glucose is required to increase the reactivity (decrease its stability) in order for the molecule to be cleaved into two pyruvate molecules by the enzyme aldolase. During the pay-off phase of glycolysis, four phosphate groups are transferred to ADP by substrate-level phosphorylation to make four ATP, and two NADH are produced when the pyruvate are oxidized. The overall reaction can be expressed this way:

text: Starting with glucose, 1 ATP is used to donate a phosphate to glucose to produce glucose 6-phosphate. Glycogen can be converted into glucose 6-phosphate as well with the help of glycogen phosphorylase. During energy metabolism, glucose 6-phosphate becomes fructose 6-phosphate. An additional ATP is used to phosphorylate fructose 6-phosphate into fructose 1,6-disphosphate by the help of phosphofructokinase. Fructose 1,6-diphosphate then splits into two phosphorylated molecules with three carbon chains which later degrades into pyruvate.

text: Glycolysis can be literally translated as "sugar splitting".[3]

text: Oxidative decarboxylation of pyruvate

text: Pyruvate is oxidized to acetyl-CoA and CO2 by the pyruvate dehydrogenase complex (PDC). The PDC contains multiple copies of three enzymes and is located in the mitochondria of eukaryotic cells and in the cytosol of prokaryotes. In the conversion of pyruvate to acetyl-CoA, one molecule of NADH and one molecule of CO2 is formed.

text: Citric acid cycle

text: This is also called the Krebs cycle or the tricarboxylic acid cycle. When oxygen is present, acetyl-CoA is produced from the pyruvate molecules created from glycolysis. Once acetyl-CoA is formed, aerobic or anaerobic respiration can occur.[4] When oxygen is present, the mitochondria will undergo aerobic respiration which leads to the Krebs cycle. However, if oxygen is not present, fermentation of the pyruvate molecule will occur. In the presence of oxygen, when acetyl-CoA is produced, the molecule then enters the citric acid cycle (Krebs cycle) inside the mitochondrial matrix, and is oxidized to CO2 while at the same time reducing NAD to NADH. NADH can be used by the electron transport chain to create further ATP as part of oxidative phosphorylation. To fully oxidize the equivalent of one glucose molecule, two acetyl-CoA must be metabolized by the Krebs cycle. Two waste products, H2O and CO2, are created during this cycle.

text: The citric acid cycle is an 8-step process involving 18 different enzymes and co-enzymes.[4] During the cycle, acetyl-CoA (2 carbons) + oxaloacetate (4 carbons) yields citrate (6 carbons), which is rearranged to a more reactive form called isocitrate (6 carbons). Isocitrate is modified to become α-ketoglutarate (5 carbons), succinyl-CoA, succinate, fumarate, malate, and, finally, oxaloacetate.

text: The net gain of high-energy compounds from one cycle is 3 NADH, 1 FADH2, and 1 GTP; the GTP may subsequently be used to produce ATP. Thus, the total yield from 1 glucose molecule (2 pyruvate molecules) is 6 NADH, 2 FADH2, and 2 ATP.

text: Oxidative phosphorylation

text: In eukaryotes, oxidative phosphorylation occurs in the mitochondrial cristae. It comprises the electron transport chain that establishes a proton gradient (chemiosmotic potential) across the boundary of inner membrane by oxidizing the NADH produced from the Krebs cycle. ATP is synthesized by the ATP synthase enzyme when the chemiosmotic gradient is used to drive the phosphorylation of ADP. The electrons are finally transferred to exogenous oxygen and, with the addition of two protons, water is formed.

text: Efficiency of ATP production

text: The table below describes the reactions involved when one glucose molecule is fully oxidized into carbon dioxide. It is assumed that all the reduced coenzymes are oxidized by the electron transport chain and used for oxidative phosphorylation.

text:
Step
coenzyme yield
ATP yield
Source of ATP

Glycolysis preparatory phase

−2
Phosphorylation of glucose and fructose 6-phosphate uses two ATP from the cytoplasm.

Glycolysis pay-off phase

4
Substrate-level phosphorylation

2 NADH
3 or 5
Oxidative phosphorylation : Each NADH produces net 1.5 ATP (instead of usual 2.5) due to NADH transport over the mitochondrial membrane

Oxidative decarboxylation of pyruvate
2 NADH
5
Oxidative phosphorylation

Krebs cycle

2
Substrate-level phosphorylation

6 NADH
15
Oxidative phosphorylation

2 FADH2
3
Oxidative phosphorylation

Total yield
30 or 32 ATP
From the complete oxidation of one glucose molecule to carbon dioxide and oxidation of all the reduced coenzymes.

text: Although there is a theoretical yield of 38 ATP molecules per glucose during cellular respiration, such conditions are generally not realized because of losses such as the cost of moving pyruvate (from glycolysis), phosphate, and ADP (substrates for ATP synthesis) into the mitochondria. All are actively transported using carriers that utilize the stored energy in the proton electrochemical gradient.

text:
Pyruvate is taken up by a specific, low Km transporter to bring it into the mitochondrial matrix for oxidation by the pyruvate dehydrogenase complex.
The phosphate carrier (PiC) mediates the electroneutral exchange (antiport) of phosphate (H2PO4−; Pi) for OH− or symport of phosphate and protons (H+) across the inner membrane, and the driving force for moving phosphate ions into the mitochondria is the proton motive force.
The ATP-ADP translocase (also called adenine nucleotide translocase, ANT) is an antiporter and exchanges ADP and ATP across the inner membrane. The driving force is due to the ATP (−4) having a more negative charge than the ADP (−3), and thus it dissipates some of the electrical component of the proton electrochemical gradient.

text: The outcome of these transport processes using the proton electrochemical gradient is that more than 3 H+ are needed to make 1 ATP. Obviously this reduces the theoretical efficiency of the whole process and the likely maximum is closer to 28–30 ATP molecules.[2] In practice the efficiency may be even lower because the inner membrane of the mitochondria is slightly leaky to protons.[5] Other factors may also dissipate the proton gradient creating an apparently leaky mitochondria. An uncoupling protein known as thermogenin is expressed in some cell types and is a channel that can transport protons. When this protein is active in the inner membrane it short circuits the coupling between the electron transport chain and ATP synthesis. The potential energy from the proton gradient is not used to make ATP but generates heat. This is particularly important in brown fat thermogenesis of newborn and hibernating mammals.

text: According to some of newer sources the ATP yield during aerobic respiration is not 36–38, but only about 30–32 ATP molecules / 1 molecule of glucose [6], because:

text:
ATP : NADH+H+ and ATP : FADH2 ratios during the oxidative phosphorylation appear to be not 3 and 2, but 2.5 and 1.5 respectively. Unlike in the substrate-level phosphorylation, the stoichiometry here is difficult to establish.

ATP synthase produces 1 ATP / 3 H+. However the exchange of matrix ATP for cytosolic ADP and Pi (antiport with OH− or symport with H+) mediated by ATP–ADP translocase and phosphate carrier consumes 1 H+ / 1 ATP as a result of regeneration of the transmembrane potential changed during this transfer, so the net ratio is 1 ATP : 4 H+.
The mitochondrial electron transport chain proton pump transfers across the inner membrane 10 H+ / 1 NADH+H+ (4 + 2 + 4) or 6 H+ / 1 FADH2 (2 + 4).

text:
ATP : NADH+H+ coming from glycolysis ratio during the oxidative phosphorylation is

1.5, as for FADH2, if hydrogen atoms (2H++2e−) are transferred from cytosolic NADH+H+ to mitochondrial FAD by the glycerol phosphate shuttle located in the inner mitochondrial membrane.
2.5 in case of malate-aspartate shuttle transferring hydrogen atoms from cytosolic NADH+H+ to mitochondrial NAD+

text: So finally we have, per molecule of glucose

text:
Substrate-level phosphorylation: 2 ATP from glycolysis + 2 ATP (directly GTP) from Krebs cycle
Oxidative phosphorylation

2 NADH+H+ from glycolysis: 2 × 1.5 ATP (if glycerol phosphate shuttle transfers hydrogen atoms) or 2 × 2.5 ATP (malate-aspartate shuttle)
2 NADH+H+ from the oxidative decarboxylation of pyruvate and 6 from Krebs cycle: 8 × 2.5 ATP
2 FADH2 from the Krebs cycle: 2 × 1.5 ATP

text: Altogether this gives 4 + 3 (or 5) + 20 + 3 = 30 (or 32) ATP per molecule of glucose

text: The total ATP yield in ethanol or lactic acid fermentation is only 2 molecules coming from glycolysis, because pyruvate is not transferred to the mitochondrion and finally oxidized to the carbon dioxide (CO2), but reduced to ethanol or lactic acid in the cytoplasm.[6]

text: Fermentation

text: Without oxygen, pyruvate (pyruvic acid) is not metabolized by cellular respiration but undergoes a process of fermentation. The pyruvate is not transported into the mitochondrion, but remains in the cytoplasm, where it is converted to waste products that may be removed from the cell. This serves the purpose of oxidizing the electron carriers so that they can perform glycolysis again and removing the excess pyruvate. Fermentation oxidizes NADH to NAD+ so it can be re-used in glycolysis. In the absence of oxygen, fermentation prevents the buildup of NADH in the cytoplasm and provides NAD+ for glycolysis. This waste product varies depending on the organism. In skeletal muscles, the waste product is lactic acid. This type of fermentation is called lactic acid fermentation. In strenuous exercise, when energy demands exceed energy supply, the respiratory chain cannot process all of the hydrogen atoms joined by NADH. During anaerobic glycolysis, NAD+ regenerates when pairs of hydrogen combine with pyruvate to form lactate. Lactate formation is catalyzed by lactate dehydrogenase in a reversible reaction. Lactate can also be used as an indirect precursor for liver glycogen. During recovery, when oxygen becomes available, NAD+ attaches to hydrogen from lactate to form ATP. In yeast, the waste products are ethanol and carbon dioxide. This type of fermentation is known as alcoholic or ethanol fermentation. The ATP generated in this process is made by substrate-level phosphorylation, which does not require oxygen.

text: Fermentation is less efficient at using the energy from glucose: only 2 ATP are produced per glucose, compared to the 38 ATP per glucose nominally produced by aerobic respiration. This is because the waste products of fermentation still contain chemical potential energy that can be released by oxidation. Ethanol, for example, can be burned in an internal combustion engine like gasoline. Glycolytic ATP, however, is created more quickly. For prokaryotes to continue a rapid growth rate when they are shifted from an aerobic environment to an anaerobic environment, they must increase the rate of the glycolytic reactions. For multicellular organisms, during short bursts of strenuous activity, muscle cells use fermentation to supplement the ATP production from the slower aerobic respiration, so fermentation may be used by a cell even before the oxygen levels are depleted, as is the case in sports that do not require athletes to pace themselves, such as sprinting.

text: Anaerobic respiration

text: Cellular respiration is the process by which biological fuels are oxidised in the presence of an inorganic electron acceptor (such as oxygen) to produce large amounts of energy, to drive the bulk production of ATP.

text: Anaerobic respiration is used by some microorganisms in which neither oxygen (aerobic respiration) nor pyruvate derivatives (fermentation) is the final electron acceptor. Rather, an inorganic acceptor such as sulfate or nitrate is used. Such organisms are typically found in unusual places such as underwater caves or near hydrothermal vents at the bottom of the ocean.


document_title: Lithosphere

question_text: layers of the earth with lithosphere and asthenosphere

text: Lithosphere

text: Earth's lithosphere

text: Earth's lithosphere includes the crust and the uppermost mantle, which constitute the hard and rigid outer layer of the Earth. The lithosphere is subdivided into tectonic plates. The uppermost part of the lithosphere that chemically reacts to the atmosphere, hydrosphere and biosphere through the soil forming process is called the pedosphere. The lithosphere is underlain by the asthenosphere which is the weaker, hotter, and deeper part of the upper mantle. The Lithosphere-Asthenosphere boundary is defined by a difference in response to stress: the lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle failure, while the asthenosphere deforms viscously and accommodates strain through plastic deformation. The study of past and current formations of landscapes is called geomorphology.

text: History

text: The concept of the lithosphere as Earth’s strong outer layer was described by A.E.H. Love in his 1911 monograph "Some problems of Geodynamics" and further developed by Joseph Barrell, who wrote a series of papers about the concept and introduced the term "lithosphere".[2][3][4][5] The concept was based on the presence of significant gravity anomalies over continental crust, from which he inferred that there must exist a strong upper layer (which he called the lithosphere) above a weaker layer which could flow (which he called the asthenosphere). These ideas were expanded by Reginald Aldworth Daly in 1940 with his seminal work "Strength and Structure of the Earth"[6] and have been broadly accepted by geologists and geophysicists. Although these ideas about lithosphere and asthenosphere were developed long before plate tectonic theory was articulated in the 1960s, the concepts that a strong lithosphere exists and that this rests on a weak asthenosphere are essential to that theory.

text: Types

text: There are two types of lithosphere:

text:
Oceanic lithosphere, which is associated with oceanic crust and exists in the ocean basins (mean density of about 2.9 grams per cubic centimeter)
Continental lithosphere, which is associated with continental crust (mean density of about 2.7 grams per cubic centimeter)

text: The thickness of the lithosphere is considered to be the depth to the isotherm associated with the transition between brittle and viscous behavior.[7] The temperature at which olivine begins to deform viscously (~1000 °C) is often used to set this isotherm because olivine is generally the weakest mineral in the upper mantle. Oceanic lithosphere is typically about 50–140 km thick [8](but beneath the mid-ocean ridges is no thicker than the crust), while continental lithosphere has a range in thickness from about 40 km to perhaps 280 km;[8] the upper ~30 to ~50 km of typical continental lithosphere is crust. The mantle part of the lithosphere consists largely of peridotite. The crust is distinguished from the upper mantle by the change in chemical composition that takes place at the Moho discontinuity.

text: Oceanic lithosphere

text: Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle (peridotite) and is denser than continental lithosphere, for which the mantle is associated with crust made of felsic rocks. Oceanic lithosphere thickens as it ages and moves away from the mid-ocean ridge. This thickening occurs by conductive cooling, which converts hot asthenosphere into lithospheric mantle and causes the oceanic lithosphere to become increasingly thick and dense with age. In fact, oceanic lithosphere is a thermal boundary layer for the convection[9] in the mantle. The thickness of the mantle part of the oceanic lithosphere can be approximated as a thermal boundary layer that thickens as the square root of time.

text:
Here,

h

{\displaystyle h}

 is the thickness of the oceanic mantle lithosphere,

κ

{\displaystyle \kappa }

 is the thermal diffusivity (approximately 10−6 m2/s) for silicate rocks, and

t

{\displaystyle t}

 is the age of the given part of the lithosphere. The age is often equal to L/V, where L is the distance from the spreading centre of mid-oceanic ridge, and V is velocity of the lithospheric plate.

text: Oceanic lithosphere is less dense than asthenosphere for a few tens of millions of years but after this becomes increasingly denser than asthenosphere. This is because the chemically differentiated oceanic crust is lighter than asthenosphere, but thermal contraction of the mantle lithosphere makes it more dense than the asthenosphere. The gravitational instability of mature oceanic lithosphere has the effect that at subduction zones, oceanic lithosphere invariably sinks underneath the overriding lithosphere, which can be oceanic or continental. New oceanic lithosphere is constantly being produced at mid-ocean ridges and is recycled back to the mantle at subduction zones. As a result, oceanic lithosphere is much younger than continental lithosphere: the oldest oceanic lithosphere is about 170 million years old, while parts of the continental lithosphere are billions of years old. The oldest parts of continental lithosphere underlie cratons, and the mantle lithosphere there is thicker and less dense than typical; the relatively low density of such mantle "roots of cratons" helps to stabilize these regions.[10][11]

text: Subducted lithosphere

text: Geophysical studies in the early 21st century posit that large pieces of the lithosphere have been subducted into the mantle as deep as 2900 km to near the core-mantle boundary,[12] while others "float" in the upper mantle,[13][14] while some stick down into the mantle as far as 400 km but remain "attached" to the continental plate above,[11] similar to the extent of the "tectosphere" proposed by Jordan in 1988.[15]

text: Mantle xenoliths

text: Geoscientists can directly study the nature of the subcontinental mantle by examining mantle xenoliths[16] brought up in kimberlite, lamproite, and other volcanic pipes. The histories of these xenoliths have been investigated by many methods, including analyses of abundances of isotopes of osmium and rhenium. Such studies have confirmed that mantle lithospheres below some cratons have persisted for periods in excess of 3 billion years, despite the mantle flow that accompanies plate tectonics.[17]