Chapter 12

Question 1

What are the two different types of respiration?

Answer 1

Aerobic

Anaerobic

Question 2

When does Aerobic respiration take place and what are the products?

Answer 2

Requires O2

Produces CO2 + H2O and much ATP

Question 3

When does anaerobic respiration take place and what are the products?

Answer 3

Absence of O2

Produces: Lactate, Ethanol + CO2 + Little ATP

Question 4

What are the four stages of aerobic respiration?

Answer 4

1) Glycolysis
2) Links Reaction
3) Krebs Cycle
4) Oxidative Phosphorylation

Question 5

Summarise the process of Glycolysis

Answer 5

The splitting of 6-carbon molecule into two 3-pyruvate molecule

Question 6

Summarise the process of Links Reaction

Answer 6

3-carbon pyruvate molecules enter a series of reaction which leads to the formation of acetyl-coenzyme A

Question 7

Summarise the process of Krebs Cycle

Answer 7

Introduction of acetyl coenzyme A into a cycle of oxidation-reduction reactions that yield some ATP + Large quantity of NAD + FAD

Question 8

Summarise the process of Oxidative Phosphorylation

Answer 8

Use of electrons, associated with Reduced NAD and FAD, released from the Krebs cycle to synthesize ATP with water produced as a by-product

Question 9

Where does glycolysis occur within the cell?

Answer 9

Cytoplasm

Question 10

State the four stages of glycolysis?

Answer 10

Stage 1: Phosphorylation of gluscose to glucose phosphate
Stage 2: Splitting of the phosphorylated glucose
Stage 3: Oxidation of triose phosphate
Stage 4: the production of ATP

Question 11

What is the overall yield from glycolysis?

Answer 11

• 2 molecules of ATP
• 2 molecules of reduced NAD
• 2 Molecules of pyruvate

Question 12

In what way are pyruvate molecules oxidized, Before the Krebs cycle?

Answer 12

Through Links Reaction

Question 13

In eukaryotic cells where do the Krebs cycle and links reaction take place?

Answer 13

Mitochondria

matrix

Question 14

What series of reactions does pyruvate go through during links reaction?

Answer 14

• Pyruvate is oxidized to acetate

- 2-carbon acetate combines with a Coenzyme A to produce acetyl-coenzyme A

Question 15

What is the overall reaction of pyruvate during links reaction?

Answer 15

Pyruvate

Question 16

Summarise the Krebs cycle?

Answer 16

• 2-carbon acetyl coenzyme combines with a 4-carbon molecule to produce ab 6-carbon molecule
• In a series of reactions the 6-carbon molecule loses CO2 + Hydrogen to give a 4-carbon molecule + a single molecule of ATP produce as a result of SUBSTRATE LEVEL PHOSPHORYLATION
• The 4-carbon molecule can now combine with a new molecule of acetyl coenzyme A to begin the cycle again

Question 17

For each pyruvate what do the links reaction and Krebs cycle produce?

Answer 17

• Reduced Coenzymes (NAD, FAD)
• 1 molecule of ATP
• 3 molecules of CO2

Question 18

Are coenzymes enzymes?

Answer 18

NO

Question 19

What are coenzymes?

Answer 19

Molecules that some enzymes require in order tio function

Coenzymes play a major role in photosynthesis where they carry H atom from 1 molecule to another?

Question 20

Give an example of when coenzymes carry H atom from 1 molecule to another?

Answer 20

• NAD (Respiration)
• FAD (Krebs Cycle)
• NADH (Photosynthesis)

Question 21

Why does the Krebs cycle perform an important role in cells?

Answer 21

• Breaks down macromolecules into smaller ones
  -Produce H atoms that are carried by NAD to electron transfer chain + provide energy for oxidative phosphorylation
  leads to the production of ATP provides energy for the cell
  -Regenerates 4-carbon molecule that combines with acetyle coenzyme A, which would toherwise accumulate
  -Source of intermediate compounds used by cells

Question 22

What coenzymes carry H atoms to oxidative phosphorylation?

Answer 22

NAD

FAD

Question 23

What is oxidative phosphorylation?

Answer 23

The mechanism by which some energy of the energy electrons within H atoms is conserved in the formation of ATP

Question 24

Where does oxidative phosphorylation take place?

Answer 24

Mitochondria

Question 25

What is within the cristae that are involved in oxidative phosphorylation and hence ATP synthesis?

Answer 25

enzymes and other protein

Question 26

The synthesis of ATP by oxidative phosphorylation involves the transfer of electrons down a series of electron carrier molecules which together form the

Answer 26

Electron transfer chain

Question 27

Describe the process of the synthesis of ATP and oxidative phosphorylation?

Answer 27

• H atoms (from glycolysis + krebs cycle) combine with coenzymes NAD + FAD
• Reduced NAD and FAD donate the electrons of the H atoms they are carrying to the first molecule in the Electron Transfer Carrier
• electrons pass along a chain of ETC molecules in a series of OXIDATION-REDUCTION reactions
• As electrons flow along the chains, the energy they release causes the active transport of protons across the inner mitochondrial + inner intermembrane space
• Protons accumulate in the Intermembranal space before they diffuse back into the mitochondrial matrix through ATP synthase channels embedded in the inner mitochondrial membrane
• At the end of the chain the e- combine with these protons + o2 TO FORM H2O
• O2 is, therefore, the final acceptor of e- in the ETC

Question 28

What is the theory called for the synthesis of ATP and oxidative phosphorylation?

Answer 28

Chemiosmotic theory of oxidative phosphorylation

Question 29

What is the importance of oxygen in respiration?

Answer 29

Is to act as a final acceptor of the H atoms produced in glycolysis + Krebs cycle

Without it Ha atoms + electrons would ‘back up’ along the chain + the process of respiration would come to a halt

Question 30

How is energy released in stages? how is it useful?

Answer 30

The energy released little at a time, more can be harvested for the benefit of the organism

• therefore, electrons carried by NAD and FAD are not transferred in one explosive step
• They are carried along with a series of ETC molecules each of which is slightly lower energy level
• therefore electrons move down a gradient
• Transfer of gradient allows their energy + therefore more useful

Question 31

What are alternative respiratory substances?

Answer 31

Lipids + proteins

Question 32

What must be done to the lipids before respiration?

Answer 32

Lipids are hydrolyzed to glycerol + fatty acids

Question 33

Describe how lipids are used to be respired?

Answer 33

• Glycerol is then phosphorylated + converted to triose phosphate which enters the glycolysis pathway and subsequently the Krebs cycle
• Fatty acid component is broken down into 2 carbon fragments of carb + many H atoms
• H atoms are used to produce ATP during oxidative phosphorylation

Question 34

Describe how proteins are used for respiration?

Answer 34

• Hydrolyzed to AA
• They have their amino group removed (deamination) entering the respiratory pathway at different points depending on C atoms they contain 2-c compound converted to pyruvate
• 4 and 5 carbon compounds are converted to intermediates in the Krebs Cycle

Question 35

Why is it that during the absence of O2 The Krebs cycle and electron transfer chain cannot continue?

Answer 35

FAD and Nad will be reduced

nor will be available to take up H+ produced during K cycle + o enzymes stop working

Question 36

During the absence of O2, how do you produce ATP?

Answer 36

Aerobic respiration is the only potential way of producing ATP