respiration SLOP

Question 1

State 5 processes that ATP is used in

Answer 1

Active transport, DNA replication, cell division, endocytosis and exocytosis, protein synthesis, movement of bacterial flagella, phosphorylation of glucose in glycolysis

Question 2

Describe the structure of ATP

Answer 2

Ribose (pentose) sugar, 3 phosphate groups (phosphoester bond attaches ribose to first phosphate; phosphoanhydride attaches adjacent phosphates), adenine base

Question 3

State the name of two processes used to produce ATP in aerobic respiration

Answer 3

Substrate-level phosphorylation and oxidative phosphorylation

Question 4

State all the stages of aerobic respiration in which ATP is produced

Answer 4

Glycolysis, Krebs cycle, oxidative phosphorylation

Question 5

Describe how energy is released from ATP

Answer 5

ATP is hydrolysed to ADP, releasing an inorganic phosphate molecule

Question 6

State the location of glycolysis

Answer 6

Cytoplasm

Question 7

Describe how glucose is phosphorylated in glycolysis

Answer 7

2 x ATP molecules are broken down and their phosphate groups added to glucose to form hexose bisphosphate

Question 8

Describe what happens to hexose bisphosphate in glycolysis

Answer 8

It splits into 2 x triose phosphate molecules

Question 9

Describe how pyruvate is produced in glycolysis from triose phosphate

Answer 9

TP oxidised and H atom added to NAD to produce NADH; 2 x Pi group removed from TP and added to 2 x ADP molecules to form 2 x ATP

Question 10

State the yield of ATP, NADH and pyruvate in glycolysis per glucose molecule

Answer 10

4 x ATP produced (net 2); 2 x NADH; 2 x pyruvate

Question 11

Describe the process by which ATP is produced in glycolysis

Answer 11

Substrate-level phosphorylation - enzyme with 2 active sites (pyruvate kinase) takes Pi off phosphorylated compound (TBP) and adds them directly to ADP to make ATP

Question 12

Describe how pyruvate and NADH reach the mitochondrion

Answer 12

Mitochondrial shunt mechanism - actively transported into mitochondrion

Question 13

glycolysis involves oxidation despite it being an anaerobic reaction

Answer 13

Hydrogen atoms are being removed from TBP

Question 14

Describe how the inner mitochondrial membrane is adapted for oxidative phosphorylation

Answer 14

Folded into cristae to provide a larger SA for electron carriers, ATP synthase enzymes, NADH dehydrogenase enzymes

Question 15

State 3 things found in the mitochondrial matrix

Answer 15

Mitochondrial DNA, 70s ribosomes, enzymes for link reaction and Krebs cycle

Question 16

Explain how the proton gradient is maintained in the intermembrane space

Answer 16

Phospholipid bilayer impermeable to protons (charged particles); they must pass through a hydrophilic channel protein or be pumped by active transport through a carrier protein

Question 17

Suggest why the synaptic knobs of neurones contain many mitochondria

Answer 17

They need to synthesise many molecules of neurotransmitter and export them, via exocytosis, into the synaptic cleft. The mitochondria supply the energy needed to do this.

Question 18

How are mitochondria replicated?

Answer 18

Divide by binary fission

Question 19

Which stages of respiration take place in the mitochondrial matrix?

Answer 19

Link reaction and Krebs cycle

Question 20

In what ways is the structure of the mitochondrion similar to that of a chloroplast?

Answer 20

For example, has envelope; folded inner membrane to give large surface area; ATP synthase enzymes and proton channels; electron transport chains; matrix; both have prokaryote-type ribosomes; both have loops of DNA.

Question 21

In what ways is the structure of the mitochondrion different from that of a chloroplast?

Answer 21

For example, chloroplasts have chlorophyll; coenzymes in chloroplasts are NADP, in mitochondria NAD and FAD; different enzymes; chloroplast usually a bit larger, but both in region of 2–10 μm

Question 22

Define the terms decarboxylation and dehydrogenation

Answer 22

Decarboxylation - removal of a CO2 molecule; dehydrogenation - removal of H atom(s)

Question 23

Describe what happens to pyruvate in the Link reaction

Answer 23

Pyruvate is decarboxylated and dehydrogenated by pyruvate decarboxylase enzyme –> this produces carbon dioxide, reduced NAD and acetate. The acetate (acetyl group) is added to coenzyme A to form Acetyl CoA.

Question 24

State the yield of ATP, NADH, acetate and CO2 in the Link reaction per glucose molecules

Answer 24

0 ATP produced, 2 x NADH, 2 x CO2, 2 x acetate

Question 25

How is the acetyl group carried to the Krebs cycle?

Answer 25

It is added to coenzyme A to form acetyl CoA

Question 26

How many ATP molecules are produced PER TURN of the Krebs cycle, and by what process?

Answer 26

1; substrate-level phosphorylation

Question 27

Describe how the acetyl group is used in the Krebs cycle

Answer 27

It is added to oxaloacetate (4C) to become citrate (6C)

Question 28

How many reduced NAD molecules are produced per glucose molecule in the Krebs

Answer 28

6

Question 29

How many reduced FAD molecules are produced per glucose molecule in the Krebs cycle

Answer 29

2

Question 30

How many CO2 molecules are produced PER TURN of the Krebs cycle?

Answer 30

2

Question 31

Which is the only stage of aerobic respiration that does NOT produce ATP

Answer 31

link reaction

Question 32

Define chemiosmosis

Answer 32

The flow of protons down their electrochemical gradient, through channels associated with ATP synthase

Question 33

Describe the roles of NADH and FADH in oxidative phosphorylation

Answer 33

They release their H atoms, which split into protons and electrons. The protons are pumped across the inner mitochondrial membrane, the electrons enter the electron transport chain

Question 34

State the names of three enzymes found in the inner mitochondrial membrane

Answer 34

ATP synthase, NADH dehydrogenase, FADH dehydrogenase

Question 35

Explain why oxygen is described as the final electron acceptor in aerobic respiration

Answer 35

It accepts electrons that are released from the last membrane-embedded electron carrier.

Question 35

State the name of the final electron acceptor in oxidative phosphorylation

Answer 35

oxygen

Question 36

Explain why the pH measured within the intermembrane space of mitochondria, is lower than that of both the mitochondrial matrix and the cytoplasm

Answer 36

The accumulation/high concentration of protons lowers the pH.

Question 37

State the process by which animals and plants respire anaerobically

Answer 37

Animals - lactate fermentation; plants - ethanol fermentation

Question 38

Describe the ethanol fermentation pathway

Answer 38

Pyruvate is decarboxylated (pyruvate decarboxylase) to form ethanal; ethanal is reduced (ethanol dehydrogenase) to ethanol using H atoms from NADH. NAD is therefore free to accept more H atoms allowing glycolysis to continue

Question 39

Describe the lactate fermentation pathway

Answer 39

Pyruvate is reduced (gains H atoms from NADH) (catalysed by lactate dehydrogenase) to form lactate, freeing up NAD to accept more H atoms in glycolysis

Question 40

Describe the fate of lactate

Answer 40

Carried to the liver where it is reconverted to pyruvate (which can then enter Link reaction) OR converted back into glucose/glycogen

Question 41

How many ATP molecules per glucose are produced in both lactate and ethanol fermentation?

Answer 41

4 (net 2)

Question 42

State the equation for RQ

Answer 42

CO2 produced/O2 absorbed

Question 43

Explain why lipids produce more energy per g than carbohydrates

Answer 43

More C - H bonds = more H atoms, = more protons can be formed, = steeper proton gradient, therefore more ATP via oxidative phosphorylation

Question 44

State the RQ values of proteins, carbohydrates and lipids

Answer 44

Proteins - 0.8; lipids - 0.7; carbohydrates - 1

Question 45

What is the purpose of sodium hydroxide in respirometer tubes?

Answer 45

Absorbs CO2 produced