AP Bio Ch 8

cellular respiration equation

C6H12O6+6O2--->6CO2+6H2O+ATP

energy in glucose is stored in the

carbon to hydrogen bonds

energy from glucose gets transferred to

ATP

when energy is transferred from glucose to ATP about

60% is lost as heat

cellular respiration

the step by step oxidation of glucose into CO2 and H2O

in cellular respiration O2 is the

final electron acceptor

glucose is a

high energy molecule

carbon to hydrogen bonds in glucose contain

high energy electrons

cellular respiration is very

exergonic

approximately 40% of energy from cellular respiration is

stored in 36 to 38 molecules of ATP

glycolysis

the breakdown of 6 carbon glucose to two molecules of 3 carbon pyruvate

during glycolysis oxidation results in

NADH and provides enough energy for the net gain of two ATP molecules

preparatory step

pyruvate is broken down from a 3 carbon to a 2 carbon acetyl group and CO2 is released

the prep step takes place in the

matrix of the mitochondria

since glycolysis ends with two molecules of pyruvate

the prep step occurs twice for every glucose molecule

citric acid cycle (krebs cycle)

completes the breakdown of glucose

electron transport chain (ETC)

series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions

glycolysis takes place in the

cytoplasm

substrate-level phosphorylation

a phosphate group is directly transferred from a high energy compound to ADP to form ATP with the help of an enzyme

the splitting of glucose into 2 3 carbon molecules is a

coupling reaction

the breaking down of glucose into 3 carbon molecules during glycolysis is an

endergonic reaction that relies on energy released from the exergonic breaking apart of 2 ATP molecules

after glucose is broken down during glycolysis

2 NAD+ molecules are reduced to become NADH due to the addition of a phosphate and the oxidation of the 3 carbon molecules

the NADH molecules produced during glycolysis go

to the ETC only if oxygen is present

after NADH is made during glycolysis a

phosphate group is added onto the 3 carbon molecules so each molecule has 2 phosphates

after an additional phosphate group is added onto each 3 carbon molecule during glycolysis

two rounds of substrate level phosphorylation per molecule occur which rips off all of the phosphates and combines each with an ADP molecule to form 4 ATP molecules

the molecules left after substrate level phosphorylation are the

two pyruvate molecules (3 carbon molecules without any phosphates)

how many ATP molecules are used during glycolysis

2 ATP molecules

how many ATP molecules are created during glycolysis

4 ATP molecules

the net gain of ATP molecules from glycolysis is

2 ATP molecules

NAD+ is also known as

vitamin B3

inputs of glycolysis

6 carbon glucose, 2 NAD+, 2 ATP, 4 ADP, and 4 phosphate groups

outputs of glycolysis

2 3 carbon pyruvate, 2 NADH, 2 ADP, and 4 total ATP (net gain of 2 ATP)

anaerobic respiration (fermentation) is used when there is

little to no oxygen

anaerobic respiration stops the process of

cellular respiration except for the glycolysis portion

anaerobic respiration has to use a different

pathway for NADH to dump their electrons since the ETC cannnot work without oxygen

the ETC cannot work without oxygen because

oxygen is the final electron acceptor and transporter

anaerobic respiration requires NADH to dump its electrons back to

pyruvate which is the end product of glycolysis

when pyruvate accepts the electrons from NADH during fermentation (anaerobic respiration) it is reduced to either

lactic acid or ethanol (alcohol) and carbon dioxide

fermentation that results in lactic acid is called

lactic acid fermentation

fermentation that results in ethanol and CO2 is called

alcoholic fermentation

anaerobic respiration is the same as glycolysis except once NADH is produced and there is no oxygen

an enzyme puts the electrons from NADH on to pyruvate which either makes lactic acid or alcohol and CO2

after NADH loses its electrons to pyruvate during fermentation

it is oxidized back to NAD+ which can be reused and allows glycolysis to keep going

because glycolysis does not require oxygen it is believed to be

a conserved biochemical process from the beginning of life on earth when there was little oxygen

advantages of anaerobic respiration

glycolysis and substrate level phosphorylation generate enough ATP to keep simpler organisms (bacteria and yeast) alive and enough to keep animals alive when exercising

disadvantages of anaerobic respiration

generates much less ATP than full cellular respiration

structure of the mitochondria

outer membrane, intermembrane space, cristae (inner membrane), matrix (inner compartment)

in the prep step the 3 carbon pyruvate molecules from glycolysis are

oxidized to a 2 carbon acetyl group

acetyl groups are the

entrance to the citric acid cycle

during the prep step a carbon atom is

taken from pyruvate and combined with oxygen to form CO2

the electrons taken from when a carbon atom is removed from pyruvate during the prep step are used to

reduce NAD+ to NADH

NADH created during the prep step goes to

the ETC when there is oxygen

the removal of a carbon atom from pyruvate turns it into a

2 carbon acetyl group

the 2 carbon acetyl group formed during the prep step is escorted by

CoA (coenzyme A) into the matrix and the citric acid cycle

two prep steps occur for every

one glucose molecule because there are two pyruvates

another name for FAD+ is

vitamin B2

the first step in the citric acid cycle is

the 2 carbon acetyl group combines with a 4 carbon molecule to produce 6 carbon citrate (citric acid)

the first step of the citric acid cycle is performed with the help of

an enzyme

the second step of the citric acid cycle is

the oxidation of the 6 carbon citrate which produces 2 CO2, 3 NADH, and makes the 6 carbon citrate back into a 4 carbon molecule

the third step of the citric acid cycle is

the production of one ATP molecule due to substrate level phosphorylation using the 4 carbon molecule

the fourth step of the citric acid cycle is

additional oxidation reactions occur which produce one FADH2 molecule from FAD+, another NADH, and regenerate a 4 carbon molecule that is reused at the beginning of the next cycle

the total products from one acetyl group in the citric acid cycle

3 NADH, 1 FADH2, 1 ATP

since 2 acetyl groups are created at the end of the prep step

the citric acid cycle is done twice for one glucose molecule

FADH2 and NADH produced from the citric acid cycle go to

the ETC when there is oxygen

the reactions in the citric acid cycle are very

exergonic reactions

the first step of the ETC

NADH and FADH2 dump their high energy electrons into the ETC

the citric acid cycle takes place in the

matrix of mitochondria

the ETC takes place in the

cristae of mitochondria

the second step of the ETC is the

electrons are transported down the different protein complexes (electron carriers)

the third step of the ETC

the electrons' energy is transferred to the protein complexes as they are transported through which results in hydrogen ions being pumped through into the intermembrane space which builds up a concentration gradient

the fourth step of the ETC

the hydrogen ions flow through ATP synthase proteins which put a phosphate onto ADP to create ATP as the hydrogen ions move through

during the ETC oxygen takes

hydrogen ions and electrons as they flow through the concentration gradient and forms water

every one molecule of NADH that is used in the ETC produces

3 ATP molecules

every one molecule of FADH2 that is used in the ETC produces

2 ATP molecules

factors that can lower the maximum yield of ATP during cellular respiration

in some cells NADH cannot cross the mitochondrial membranes without the help of a shuttle protein which lowers the ATP produced by NADH to 2 and the exact yield of ATP from NADH is technically a little less than 3 ATP

when fat is used as an energy source it is broken down into

glycerol and 3 fatty acids

glycerol from broken down fat is converted into

pyruvate and enters the prep step

the fatty acids from broken down fat are broken into

acetyl CoA and can enter the citric acid cycle

the problem with breaking down fat for energy is that there are lots of 2 carbon groups in fatty acids meaning

it takes constant aerobic exercise and lowering fat intake to burn it off

people who are starving will resort to breaking down

the proteins that make up their muscle cells

the amino acids in proteins can be broken into

acetyl groups that can enter the citric acid cycle when escorted by CoA

excessive carbohydrate intake results in

the formation of fat (glycerol and 3 fatty acids synthesized together)

the ultimate goal of mitochondrial respiration is

to produce energy

in the ETC cyanide and carbon monoxide act as

non-competitive inhibitors for a cytochrome protein which leads to a backup of electrons resulting in death

during glycolysis specific enzymes are used

between each of the steps in order to lower the energy of activation

one of the enzymes during glycolysis has

an allosteric site for ATP which means large quantities of ATP can slow down cellular respiration (negative feedback and enzyme inhibition)