Respiration

Question 1

Aerobic respiration

Answer 1

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

36-38 ATP

20 chemical reactions, 4 phases

Question 2

Red blood cells

Answer 2

No organelles

Can’t respire aerobically

Question 3

Anaerobic respiration advantages

Answer 3

No need for mitochondria or oxygen

Question 4

Facultative/ obligate anaerobes

Answer 4

Prokaryotic

Rely on anaerobic resp.

Question 5

Why is there a rise in temp.?

Answer 5

Energy generated lost as heat

Question 6

Anaerobic respiration in animals

Answer 6

Glucose -> lactic acid

C6H12O6 -> 2C3H6O3

Question 7

Anaerobic respiration in fungi

Answer 7

Glucose -> ethanol + CO2

C6H12O6 -> C2H5OH + CO2

Question 8

Anaerobic respiration aka

Answer 8

Fermentation

Question 9

ATP

Answer 9

V soluble but doesn’t diffuse

Question 10

NAD

Answer 10

A coenzyme

A hydrogen carrier

Question 11

Glycolysis intro

Answer 11

Splitting glucose (occurs in cytoplasm)

Necessary because mitochondria have channel proteins for pyruvate and not glucose

Has to make glucose reactive, to overcome Ea

Question 12

Glycolysis details

Answer 12

• phosphorylation -> glucose-6-phosphate (traps inside cell)
• isomérisation (isomerise) -> fructose-6-phosphate
• phosphorylation (phosphofructokinase) -> fructose-1,6-diphosphate
• splits into 2x triose phosphate
• TP oxidised -> à series of intermediates -> pyruvate
• provides energy for substrate-level phosphorylation

Question 13

Phosphorylation

Answer 13

Uses ATP

Question 14

Glycolysis net products

Answer 14

2 pyruvate, 2ATP, 2NADH2

Question 15

Link reaction

Answer 15

• pyruvate diffuses/actively transported into the mitochondrial fluid matrix - needs a carrier (ATP)
• 2x pyruvate decarboxylated -> 2x acetyl
• acetyl associates with coenzyme A
• pyruvate is oxidised, NAD is reduced

Question 16

Mitochondrial fluid matrix

Answer 16

Gel- where all the enzymes are

Question 17

Coenzyme À

Answer 17

Acceptor molecules
Only take 2 molecules of pyruvate
Recycled

Question 18

Decarboxylation

Answer 18

Hence the CO2 product

Question 19

Krebs Cycle function

Answer 19

To regenerate acceptor molecule, extracting hydrogen for oxidative phosphorylation

Question 20

Krebs cycle details

Answer 20

• acetyl coA -> via a series of intermediates -> citrate
• citrate decarboxylated -> glutartic acid, NAD reduced
• glutartic acid decarboxylated -> ocyloacetate, FAD reduced
• substrate-level phosphorylation produces 2x ATP

Products: 4x CO2

Question 21

Oxidative phosphorylation details

Answer 21

1) NADH2 and FADH2 release hydrogen into inner mitochondrial membrane; oxidised
2) hydrogen splits into protons and electrons
3) electrons flow down electron carriers of decreasing energy levels; the electron transport chain - leaves energy
4) electron leaves proton electrically imbalanced; protons join from matrix to balance
5) electron moves, leaving chemical imbalance
6) energy used to pump protons across membrane after accumulation (electrochemical gradient; proton motive force)
7) protons flow through ATP synthase
8) energy translated into ADP substrate-level phosphorylation

Question 22

Where does oxidative phosphorylation occur?

Answer 22

At the cristae 
Many 
High SA 
Greater rate of flow 
More ATP production

Question 23

OXIDATIVE phosphorylation

Answer 23

• oxygen is the final electron acceptor in the matrix
• protons join to form water

1/2O2 + 2H+ + 2e- -> H2O
Catalyses by cytochrome oxidase

Question 24

Why is the yield not reached?

Answer 24

• transporting NADH2 into mito
• active transport of pyruvate
• leaky protons
• NADH2 used elsewhere

Question 25

Chemiosmosis

Answer 25

* proton motive force | * high -> low across a membrane

Question 26

Investigating respiration rate

Answer 26

Using yeast mitochondria to observe mitochondria at the cellular level Indicator: CO2

Question 27

Acclimation/équilibration

Answer 27

Yay

Question 28

Respirometers all contain:

Answer 28

* organism (+ control) * manometer tube (contains coloured liquid and scale) * soda lime/ KOH (absorbs CO2; allows tracking of oxygen usage) * cotton wool (allows O2 but not [...] * screws (airtight; open during équilibration) * syringe (push air back into system to push fluid back into measurable scale) * Barrier (separate organism from soda lime) * water-bath (constant temp.)

Question 29

Respiratory quotient definition

Answer 29

Measure of the ratio of CO2 given out compared to the O2 consumed by an organism over a given period

Question 30

Respiratory quotient examples

Answer 30

Glucose: 1.0 Lipids: 0.7 Protein: 0.9 Organisms rarely respire just one substrate; produces intermediate values Most organisms resting RQ: 0.8-0.9

Question 31

How does stage 2 (pyruvate -> ethanol and CO2) of anaerobic respiration allow stage 1 (glucose -> pyruvate) to continue

Answer 31

Regeneration of NAD allows continuation of glycolysis

Question 32

Acetyl CoA formation

Answer 32

Pyruvate is oxidised in a decarboxylation reaction; coenzyme A is added

Question 33

Why might glucose not be used in an investigation?

Answer 33

It is broken down during glycolysis in the cytoplasm - cannot cross the mitochondrial membrane

Question 34

Ice cold Isotonic

Answer 34

Reduce enzyme activity Prevents osmosis - no shrivel