Respiration (Chapter 12)

Question 1

What is the equation for making ATP?

Answer 1

ADP + Pi > ATP

Question 2

Why is ATP useful?

Answer 2

• Releases energy in small suitable amounts.
• Broken down in one step.
• Makes energy available rapidly.
• Makes phosphorylated substances more reactive/lower activation energy.
• Can be reformed/made again.

Question 3

Why do plants make ATP in respiration as well as photosynthesis?

Answer 3

• In the dark no ATP is produced in photosynthesis.
• Some tissues unable to photosynthesis/ produce ATP.
• ATP cannot be moved from cell to cell/stored.
• Plants use more ATP than produced in photosynthesis.
• ATP needed for active transport.
• ATP for synthesis e.g. protein.

Question 4

What happens when there is oxidation during respiration?

Answer 4

Lose electrons, lose H, gain O2

Question 5

What happens when there is reduction during respiration?

Answer 5

Gains electrons, gains H, lose O2

Question 6

Where does glycolysis take place?

Answer 6

In the cytoplasm

Question 7

Describe the stages of glycolysis

Answer 7

1) Pi added to 6 glucose (ATP needed)
2) Glucose splits into 2x 3C triose phosphate (TP)
3) Triose phosphate is oxidised and gives H to NAD to form reduced NAD.
4) TPs are made into pyruvate (3C), releasing ATP

Question 8

Describe the stages of the Link Reaction

Answer 8

1) Pyruvate is oxidised and gives H to NAD.
2) Pyruvate loses CO2 and becomes 2C acetyl group.
3) 2C acetyl joins with co-enzyme A to form acetyl coenzyme A (2C)

Question 9

Where does the Link Reaction take place?

Answer 9

In the matrix of the mitochondria

Question 10

What is made in glycolysis?

Answer 10

Makes ATP, NADH, and Pyruvate (needs ATP).

Question 11

What is made in the Link Reaction?

Answer 11

Makes CO2, NADH, acytyl coenzyme A (no ATP)

Question 12

Where does the Krebs Cycle take place?

Answer 12

In the matrix of the mitochondria

Question 13

Describe the stages of the Krebs Cycle

Answer 13

1) Acetyl coenzyme A joins with 4C molecule (releases CoEnzyme A to form a 6 carbon molecule)
2) NAD and FAD are reduced,
3) Substrate level phosphorylation (makes 2 ATP).

Question 14

What is made in the Krebs Cycle?

Answer 14

ATP, NADH, FADH, CO2 (4C molecule recycled)

Question 15

Where does the Electron Transport Chain take place?

Answer 15

On the inner membrane of the mitochondria.

Question 16

Describe the process of the Electron Transfer Chain (Chemeosmotic Theory)

Answer 16

1) NADH and FADH release their H which splits into protons and electrons.
2) Electrons move along carrier in ELT using oxidation-reduction reactions which release energy.
3) Protein channels use this energy to actively transport H ions into intermembrane space.
4) These then diffuse back down concentration gradient through ATP synthase into matrix and release ATP in oxidative phosphorylation (combine ADP and Pi)

Question 17

Describe the process of Oxidative Phosphorylation

Answer 17

1) Protons and electrons combine with O2 to make water

2) O2 acts as terminal acceptor of electrons and stops build up of electrons.

Question 18

What is made from the ELT and Oxidative Phosphorylation together?

Answer 18

ATP, Water, NAD, FAD (needs ATP)

Question 19

What happens in anaerobic respiration?

Answer 19

There is no O2. NAD is regenerated/ pyruvate removed so glycolysis continues.

Question 20

What is the equation for anaerobic respiration in plants?

Answer 20

Pyruvate + Reduced NAD > Ethanol + CO2 + NAD

Question 21

What is the equation of anaerobic respiration in animals?

Answer 21

Pyruvate + Reduced NAD > Lactate + NAD

Question 22

What is used as an artificial electron acceptor in experiments and what is the positive result?

Answer 22

Methylene Blue which becomes colourless when reduced.

Question 23

Why are respiratory substances other than glucose used to investigate stages of respiration?

Answer 23

Glucose cannot cross the mitochondrial membrane and is usually broken down in glycolysis.

Question 24

How are manometers used?

Answer 24

They are used to measure the rate of gas exchange.

1) Organisms use O2 and release CO2 in respiration.
2) CO2 is absorbed by a substance such as potassium hydroxide.
3) Pressure in tube is lowered so level of liquid moves.

Question 25

What values are needed to calculate the rate of respiration?

Answer 25

• Volume of the tube
• The distance moved by the water
• Time taken
• Mass of respiring organisms

Question 26

Why is the manometer left for a while after setting up?

Answer 26

• Allows an equilibrium to be reached
• Allows for expansion/pressure change in apparatus
• Allow respiration rate of seed to stabilise.

Question 27

What order so the stages of respiration take place?

Answer 27

1) Glycolysis
2) Link Reaction
3) Krebs Cycle

Question 28

What is the equation for the Link Reaction?

Answer 28

Pyruvate + NAD + CoEnzyme A > Acetyle CoEnzyme A + NADH + CO2

Question 29

What happens between the Link Reaction and Krebs cycle?

Answer 29

Acetyl CoEnzyme A reacts with 4 carbon molecule and releases CoEnzyme A to form a 6 carbon molecule which enters the Krebs cycle.

Question 30

Why do we make such large amounts of ATP?

Answer 30

ATP is unstable

ATP cannot be stored/is an immediate source of energy

Named process uses ATP e.g. active transport, muscle contraction, glycolysis

ATP only releases a small amount of energy at a time

Question 31

Which process moves pyruvate into the mitochondria?

Answer 31

Active transport