3.5.2 respiration

Question 1

what is a phosphorylation reaction?

Answer 1

transfer of a phosphate group to make it more reactive

Question 2

what is a decarboxylation reaction?

Answer 2

removal of CO2

Question 3

outline aerobic respiration

Answer 3

uses oxygen
produces more ATP
glucose completely broken down
carbon dioxide and water produced

Question 4

outline anaerobic respiration

Answer 4

without oxygen
produces less ATP
glucose partially broken down
lactic acid produced

Question 5

what are the 4 stages of aerobic respiration?

Answer 5

glycolysis
link reaction
krebs cycle
oxidative phosphorylation

Question 6

where does glycolysis take place?

Answer 6

the cytoplasm

Question 7

what are the 2 stages in glycolysis?

Answer 7

phosphorylation
oxidation

Question 8

outline phosphorylation in glycolysis

Answer 8

glucose is phosphorylated by adding 2 phosphates from 2 molecules of ATP this produces 2 molecules of TP and 2 ADP

Question 9

outline oxidation in glycolysis

Answer 9

TP is oxidised forming 2 molecules of pyruvate
NAD is reduced forming 2NADH
4 ATP are produced

Question 10

why must glycolysis take place in the cytoplasm?

Answer 10

because glucose cannot cross the outer mitochondrial membrane
it breaks down into pyruvate because this can cross the membrane

Question 11

what are the products of glycolysis?

Answer 11

2 reduced NAD
2 pyruvate
2 ATP (net gain)

Question 12

where does the reduced NAD produced in glycolysis go?

Answer 12

to oxidative phosphorylation

Question 13

where does the pyruvate produced in glycolysis go?

Answer 13

actively transported into the mitochondrial matrix for use in the link reaction

Question 14

where does the ATP produced in glycolysis go?

Answer 14

used for energy

Question 15

how many C atoms are in pyruvate?

Answer 15

3 carbon atoms

Question 16

outline what happens during the link reaction

Answer 16

pyruvate is decarboxylated ( carbon dioxide is removed)
NAD is reduced it collects hydrogen from pyruvate
pyruvate is converted into acetate
no ATP is produced
acetate combines with coenzyme A to form acetyl coenzyme A

Question 17

where does the link reaction take place?

Answer 17

mitochondrial matrix

Question 18

in an anaerobic respiration what is the only stage that happens?

Answer 18

glycolysis

Question 19

what are the products of anaerobic respiration in plants and yeast?

Answer 19

carbon dioxide and ethanol

Question 20

what are the products of anaerobic respiration in animals and bacteria?

Answer 20

lactic acid

Question 21

how is anaerobic respiration able to continue?

Answer 21

production of lactic acid, CO2 and ethanol regenerate NAD
this means glycolysis can continue even when oxygen is in short supply

Question 22

how many carbon atoms are in acetyl coenzyme A?

Answer 22

2 carbon atoms

Question 23

what are the 2 types of reaction that occur in the link reaction?

Answer 23

oxidation
decarboxylation

Question 24

what are the products of the link reaction?

Answer 24

2 acetyl coenzyme A
2 carbon dioxide
2 reduced NAD

Question 25

where does the acetyl coenzyme A produced in the link reaction go?

Answer 25

to the krebs cycle

Question 26

where does the carbon dioxide produced in the link reaction go?

Answer 26

released as a waste product

Question 27

where does the reduced NAD produced in the link reaction go?

Answer 27

to oxidative phosphorylation

Question 28

outline the Krebs cycle

Answer 28

• acetyle coenzyme A (from the link reaction) joins with a 4C compound to form a 6C compound. Coenzyme A goes back to the link reaction
• decarboxylation occurs forming a 5C compound dehydrogenation also occurs, the hydrogen is used to form reduced NAD from NAD
• decarboxylation and dehydrogenation of the 5C compound occur to form a 4C compound
• ATP is made by the removal of a phosphate group, as the phosphate group is directly transferred from 1 molecule to another we say the ATP has been formed by substrate level phosphorylation

Question 29

what are the products from ONE Krebs cycle?

Answer 29

1 coenzyme A
oxaloacetate (4C)
2 carbon dioxide
1 ATP
3 reduced NAD
1 reduced FAD

Question 30

where does the coenzyme A produced in the Krebs cycle go?

Answer 30

reused in the next link reaction

Question 31

where does the oxaloacetate produced in the Krebs cycle go ?

Answer 31

regenerated for use in next Krebs cycle

Question 32

where does the carbon dioxide produced in the Krebs cycle go?

Answer 32

released as a waste product

Question 33

where does the ATP produced in the Krebs cycle go?

Answer 33

used for energy

Question 34

where does the reduced NAD produced in the Krebs cycle go ?

Answer 34

to oxidative phosphorylation

Question 35

where does the reduced FAD produced in the Krebs cycle go?

Answer 35

to oxidative phosphorylation

Question 36

where does the Krebs cycle take place?

Answer 36

mitochondrial matrix

Question 37

where does oxidative phosphorylation take place?

Answer 37

mitochondrial cristae

Question 38

what happens in oxidative phosphorylation?

Answer 38

the process wheee the energy carried by electrons, from reduced coenzymes is used to make ATP

Question 39

outline what happens in oxidative phosphorylation

Answer 39

• hydrogen atoms are released from reduced NAD and reduced FAD which are oxidised to NAD and FAD, hydrogen atoms split into protons and electrons
• electrons move down electron transport chain losing energy at each carrier
• energy used by the electron carriers to pump protons from the mitochondrial matrix into the intermembrane space
• conc. of protons is higher in the intermembrane space than in mitochondrial matrix forms an electrochemical gradient
• protons move down electrochemical gradient back across inner mitochondrial membrane and into mitochondrial matrix via ATP synthase
• process of ATP production driven by movement of H+ ions across the membrane
• in mitochondrial matrix the protons, electrons and oxygen combine to form water