electron transport chain

Question 1

what happens in the final stage of respiration

Answer 1

reduced NAD or FAD from glycolysis and the krebs cycle is used with oxygen to make ATP in process called oxidative phosphorylation

Question 2

what does oxidative phosphorylation involve

Answer 2

an electron transport chain

Question 3

what is an electron transport chain

Answer 3

series of electron carrier molecules down which electron from reduced NAD or FAD are passed

Question 4

what also happens the same time as the electron chain transport

Answer 4

the hydrogen ions protons left behind are used in chemiosmosis to supply the energy to synthesise ATP

Question 5

thinking of the electron transport chain as being at different energy levels

Answer 5

-the first member of the chain is the highest level with steps down
-each electron is passed down from one energy level to another driving production of ATP

Question 6

what is ATP production know as

Answer 6

oxidative phosphorylation because ADP is phosphorylated in process that depends on presence of oxygen

Question 7

first hydrogen acceptor in electron transport chain

Answer 7

coenzymes NAD and FAD
-act as hydrogen acceptors for hydrogen released in krebs cycle
-one molecule of ATP produced when FAD is reduced and accepts hydrogen from NADH which becomes oxidised

Question 8

second hydrogen acceptor

Answer 8

oxygen
-when oxygen is reduced water if formed and the chain is at its end

Question 9

what are cytochromes

Answer 9

protein pigments with iron group like heamoglobin

Question 10

what are cytochromes involved in

Answer 10

in electron transport and are reduced by electrons from reduced FAD and reduced NAD which is oxidised again
- molecule of ATP is produced at this stage

Question 11

what is cytochrome oxidase

Answer 11

-enzyme that receives electrons from cytochromes and is reduced as cytochromes are oxidised
-molecule of ATP also produced at this stage

Question 12

hydrogen entering from reduced NAD

Answer 12

each molecule of hydrogen passing along electron transport chain from reduced NAD enough energy released to make 3 molecules of ATP

Question 13

hydrogen entering from reduced FAD

Answer 13

-when hydrogen enters chain from reduced FAD only 2 molecules of ATP reduced

Question 14

where do link reaction and krebs cycle take place

Answer 14

matrix of the mitochondria

Question 15

where do the electron transport chain and ATP production take place

Answer 15

the inner membrane of the mitochondria

Question 16

site of ATPase enzymes

Answer 16

-closely packed stalked particles

Question 17

what did Peter Mitchell describe

Answer 17

the link between electrons that are passed down the electron transport chain and the production of ATP

Question 18

what does the chemiosmotic theory explain

Answer 18

explains what happens to the hydrogen ions that are left behind when electrons are passed along the electron transport chain and how the movement of hydrogen ions is coupled to the actual production of ATP

Question 19

what does Mitchell propose

Answer 19

that hydrogen ions are actively transported into the space between the inner and outer mitochondrial membranes using the energy provides as the electrons pass along the transport chain

Question 20

what does active transport of hydrogen ions across inner membrane result in

Answer 20

a different hydrogen ion concentration on each side of the membrane

Question 21

consequences of having a concentration gradient of hydrogen ions across membranes

Answer 21

the membrane space has a higher concentration of hydrogen ions that the matrix so there is a concentration gradient across the membrane
-also pH gradient
-because positive ions concentrated in membrane space there is electrochemical gradient

Question 22

consequences of various hydrogen concentration across membranes

Answer 22

mean there is tendency for hydrogen ions to move back into the matrix

Question 23

whats the only way hydrogen ions can move back into the matrix

Answer 23

-through special pores found on stalked particles and have ATPase enzymes associated with them

Question 24

what happens as hydrogen ions move across different concentration gradients

Answer 24

-as they move along electrical, concentration and pH gradients their energy is used to drive synthesis of ATP

Question 25

1960 accepted model of formation of ATP

Answer 25

was that a high energy phosphate group was directly transferred to ADP from another intermediate- like end of glycolysis when pyruvate formed
-but intermediate not found and chemiosmotic theory accepted

Question 26

evolution of cellular respiration

Answer 26

-evolved to produce energy in form of ATP for use in cells
-fact that same process in almost all living organisms means it evolved at early stages of development of organisms and very effective

Question 27

how much ATP is gained during its oxidation of one molecule of glucose

Answer 27

-38 molecules but 2 molecules used to transport reduced NAD molecules produced by glycolysis through mitochondrial membrane leaving 36 for body cells

Question 28

how much ATP molecules does oxidation of 2 molecules of reduced NAD provide energy for

Answer 28

process makes about 5 molecules of ATP

Question 29

how much ATP does oxidation of 2 molecules of reduced FAD make

Answer 29

3 molecules of ATP

Question 30

overall yield of ATP in aerobic respiration

Answer 30

31 molecules