5.2.2- Respiration

Question 1

what is the need for cellular respiration

Answer 1

to release energy for cells, that is used as a temporary energy store (ATP)

Question 2

what is ATP seen as, hint currency?

Answer 2

the universal energy currency

Question 3

what are the 8 biological processes that cells use ATP for?

Answer 3

-active transport
-exocytosis
-endocytosis
-DNA replication
-protein synthesis
-polysaccharide synthesis
-cell division
-muscle contraction

Question 4

what are the 4 key main features of a mitochondrion?

Answer 4

-outer membrane
-inner membrane/cristae
-matrix
-mitochondrial DNA

Question 5

why is the cristae in mitochondrion folded?

Answer 5

to increase the surface area

Question 6

where in a cell does glycolysis occur?

Answer 6

the cytoplasm

Question 7

what is glycolysis?

Answer 7

the phosphorylation of glucose, energy is extracted from glucose with no oxygen needed

Question 8

what are the two distinct phases in glycolysis?

Answer 8

-phosphorylation (phosphate added)
-dehydrogenation (pyruvate is formed, and ATP and reduced NAD are released)

Question 9

what occurs in glycolysis?

Answer 9

-glucose
+2 ATP
= hexose biphosphate
-splits
= 2 triose phosphates
+ Pi to both
= 2 triose biophosphate
-4 ATP released
-2 reduced NAD released
= 2 pyruvates

Question 10

what is the net primary productivity of glycolysis?

Answer 10

2 (start with 2, end with 4)

Question 11

what is the link reaction?

Answer 11

when the pyruvate is oxidised to acetate

Question 12

where does the link reaction occur?

Answer 12

the matrix of the mitochondria

Question 13

what happens during the link reaction?

Answer 13

pyruvate
- carbon dioxide released
-reduced NAD released
= acetyl group + coenzyme A
= acetylcoenzymeA

Question 14

what is the Krebs Cycle?

Answer 14

the Citric Acid Cycle, where 4 carbon citric acid is produced
it is when acetyl CoA combines with a oxoloacetate to make citrate, dehydrogenation and decarboxylation

Question 15

where does the Kreb’s Cycle occur?

Answer 15

the matrix of the mitochondria

Question 16

what does AcetylecoenzymeA combine with within the Krebs Cycle?

Answer 16

oxoloacetate

Question 17

how many cycles occur for one glucose molecule?

Answer 17

2

Question 18

what is oxidative phosphorylation?

Answer 18

the production of ATP using H atoms removed during glycolysis, link reaction and the Kreb’s Cycle
it involves oxidation-reduction reactions, as electrons from the H atoms are passed down a series of electron carriers, energy for making ATP is realised

Question 19

what occurs during oxidative phosphorylation?

Answer 19

-high energy electrons are passed down the electron carriers, but they lose energy as they are passed down.
-energy released is used to allow H+ ions across the membrane via the electron carriers
-protons can only move back through the membrane across the ATP synthase
-this movement caused the bottom of the ATP synthase to spin and ADP and Pi attach to make ATP.

Question 20

what does chemiosmosis mean?

Answer 20

the flow of H+ ions through ATP synthase during oxidative phosphorylation

Question 21

where does oxidative phosphorylation occur?

Answer 21

across the cristae

Question 22

what is anaerobic respiration?

Answer 22

the release of energy from substrates, in the absence of oxygen

Question 23

what are the 3 coenzymes involved in aerobic respiration?

Answer 23

-NAD
-FAD
-coenzyme A

Question 24

what is the role of NAD in aerobic respiration?

Answer 24

role in energy metabolism by accepting and donating electrons

Question 25

what is the role of FAD in aerobic respiration?

Answer 25

an electron carrier, deceivers electrons to electron transport chain after being reduced in the Krebs Cycle

Question 26

what is the role of Coenzyme A in aerobic respiration?

Answer 26

it is used to transfer aceyl groups a reactant for reaction, it releases a molecule of CO2 and reduces NAD and FAD

Question 27

what is the first step of aerobic respiration?

Answer 27

glycolysis, where 2 ATP, 2 reduced NAD and 2 pyruvate are produced per glucose

Question 28

what is produced from pyruvate in animal cells during anaerobic respiration?

Answer 28

lactate

Question 29

what occurs during anaerobic respiration in muscle cells?

Answer 29

-lactate fermentation -pyruvate accepts H atoms from reduced NAD to form lactate -lactate hydrogenase catalyses this reaction -NAD is regenerated and is now available to accept more H atoms from glucose, allowing glycolysis to continue?

Question 30

what is produced from pyruvate during anaerobic respiration of plant and microbe cells?

Answer 30

carbon dioxide and ethanol

Question 31

what occurs during anaerobic respiration of yeast cells?

Answer 31

-alcohol fermentation -pyruvate decarboxylase catalyses the removal of C02 from pyruvate to produce ethanal -ethanal accepts the H atoms from reduced NAD forming ethanol -ethanol dehydrogenase catalyses this reaction -NAD is regenerated and is available to accept more H atoms from glucose, allowing glycolysis to continue.

Question 32

what is the benefit of anaerobic respiration in muscles and yeast?

Answer 32

muscles= allows muscle contraction to continue yeast= allows yeast cells to continue growing

Question 33

what is a respiratory substrate?

Answer 33

any organic substance that can be used for respiration

Question 34

what are the 3 types of respiratory substrate?

Answer 34

-carbohydrates -proteins -lipids

Question 35

what do different respiratory substrates yield?

Answer 35

they yield different amounts of ATP and so they have different energy content

Question 36

why do respiratory substrates have different energy content?

Answer 36

because they each have different proportions of H atoms per gram -the more H atoms per gram, the more reduced NAD and FAD, so more ATP is generated in oxidative phosphorylation, meaning they have more energy per gram.

Question 37

what is the energy content of carbohydrates?

Answer 37

16 kJg -1

Question 38

what is the energy content of proteins?

Answer 38

17 kJg -1

Question 39

what is the energy content of lipids?

Answer 39

39 kJg -1

Question 40

give some details on carbohydrates as a respiratory substrate?

Answer 40

-they are the first substrate a cell uses, but stores are used up quickly -all cells respire glucose, which comes from hydrolysis of stored starch or glycogen

Question 41

give some details on proteins as a respiratory substrate?

Answer 41

-not normally respired, except during starvation -amino acids are released by digestion are respired -excess amino acids are deaminated to urea and carbohydrate

Question 42

give some details on lipids as a respiratory substrate?

Answer 42

-lipids are hydrolysed into glycerol and fatty acids (contain a high proportion of H atoms) -glycerol is converted into carbohydrate, which is used in glycolysis -fatty acids are converted to acetate, into Kreb's Cycle

Question 43

what is the RQ calculation?

Answer 43

RQ= respiration quotient RQ = CO2 produced / O2 consumed

Question 44

what is the RQ for carbohydrates?

Answer 44

1

Question 45

what is the RQ for protein?

Answer 45

0.9

Question 46

what is the RQ code for lipids?

Answer 46

0.7

Question 47

what is used to measure the respiratory quotent?

Answer 47

a respirometer

Question 48

why is the RQ value for carbohydrates 1?

Answer 48

it takes 6 oxygen molecules to completely respire one glucose molecule, which results in the production of 6 carbon dioxide molecules

Question 49

why is the RQ value for protein 0.9?

Answer 49

the structure of amino acids leads to an RQ between carbohydrates and lipids

Question 50

why is the RQ value for lipids 0.7?

Answer 50

lipids contain a greater proportion of carbon-hydrogen bonds so they produce more ATP in respiration the greater number of carbon-hydrogen bonds, more oxygen is required to break them down and so less carbon dioxide is released

Question 51

what is a respirometer?

Answer 51

a device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and carbon dioxide.

Question 52

what is the equation used to calculate respiration rate in a given time?

Answer 52

pi x r2 x h / t

Question 53

what units are used for respiration rate?

Answer 53

cm3/min

Question 54

why does anaerobic respiration produce a lower yield of ATP than aerobic respiration?

Answer 54

as there is no oxygen, glucose is not completely broken down and so less energy is released

Question 55

how much energy is released in the reaction of converting ATP into ADP and Pi?

Answer 55

30.6 kJ

Question 56

what is the last acceptor in oxidative phosphorylation?

Answer 56

oxygen

Question 57

how much ATP is released in glycolysis?

Answer 57

2

Question 58

how much ATP is released during the KREB'S CYCLE?

Answer 58

2

Question 59

how much ATP is released during oxidative phosphorylation?

Answer 59

28

Question 60

in total, how much reduced NAD is released during respiration?

Answer 60

10

Question 61

in total, how much reduced FAD is released during respiration?

Answer 61

2