respiration

Question 1

What is the primary need for energy in living organisms?

Answer 1

To maintain their metabolism and perform work such as anabolic reactions, active transport, movement, and bioluminescence.

Question 2

Define anabolic reactions.

Answer 2

Synthesis of complex substances from simpler ones.

Question 3

List examples of anabolic reactions.

Answer 3

• DNA replication
• Protein synthesis
• Active transport
• Movement
• Maintenance of body temperature
• Making polysaccharides, triglycerides, polynucleotides.

Question 4

What are the features of ATP that make it suitable as the universal energy currency?

Answer 4

• Small
• Water-soluble
• Easily transported
• Easily hydrolysed to release energy
• Large quantity of energy released
• Rapid turnover rate
• Readily available in cells.

Question 5

What is the equation for the hydrolysis of ATP?

Answer 5

ATP + H2O ⇌ ADP + Pi (inorganic phosphate).

Question 6

Where does ATP synthesis occur?

Answer 6

In substrate-linked reactions during glycolysis and in the Krebs cycle.

Question 7

What is chemiosmosis?

Answer 7

The process by which ATP is synthesised.

Question 8

What role do coenzymes play in respiration?

Answer 8

They act as hydrogen carriers and facilitate reactions.

Question 9

What is the equation for the reduction of NAD?

Answer 9

NAD+ + H+ + 2e- ⇌ NADH.

Question 10

What is the role of coenzyme A in respiration?

Answer 10

It carries acetyl groups made from pyruvate during the link reaction to the Krebs cycle.

Question 11

What is the respiratory quotient (RQ)?

Answer 11

The ratio of carbon dioxide molecules produced to oxygen molecules taken in during respiration.

Question 12

Typical RQ for carbohydrate respiration?

Answer 12

1.0.

Question 13

Typical RQ for lipid respiration?

Answer 13

0.7.

Question 14

What is the net ATP produced in glycolysis?

Answer 14

2 ATP.

Question 15

What occurs during the link reaction?

Answer 15

Pyruvate is converted into acetyl coenzyme A (ACoA) and CO2 is released.

Question 16

What is produced during one turn of the Krebs cycle?

Answer 16

• 2 CO2
• 1 ATP
• 1 FAD
• 3 NAD.

Question 17

What drives ATP synthesis during oxidative phosphorylation?

Answer 17

The facilitated diffusion of protons (H+) through ATP synthase.

Question 18

What is the final electron acceptor in the electron transport chain?

Answer 18

Oxygen.

Question 19

Describe the effect of temperature on the rate of respiration in yeast.

Answer 19

Temperature affects the rate of hydrogen release and subsequently the rate of respiration.

Question 20

What are the controlled variables in the redox indicator experiment?

Answer 20

• Volume of dye added
• Volume of yeast suspension
• Type of substrate
• Concentration of substrate
• Temperature.

Question 21

What is the structure of the mitochondrion?

Answer 21

• Double membrane
• Inner membrane folded into cristae
• Matrix contains enzymes and circular DNA.

Question 22

What occurs in anaerobic respiration?

Answer 22

Reduced NAD cannot be oxidized due to the absence of oxygen.

Question 23

Fill in the blank: The primary energy source for aerobic respiration comes from the _______.

Answer 23

[oxidation of hydrogen to water].

Question 24

What is the role of cristae in mitochondria?

Answer 24

Cristae increase the surface area for ATP synthesis.

Question 25

How does the permeability of the outer membrane of mitochondria compare to the inner membrane?

Answer 25

The outer membrane is more permeable than the inner membrane.

Question 26

What is the pH level of the inner membrane compared to the matrix in mitochondria?

Answer 26

The inner membrane has a lower pH than the matrix due to H+ released by the ETC.

Question 27

What key components are found in the mitochondrial matrix?

Answer 27

Enzymes for the link reaction and Krebs cycle, 70S ribosomes, and circular DNA.

Question 28

What is the main function of mitochondria?

Answer 28

ATP synthesis and aerobic respiration.

Question 29

What happens during anaerobic respiration when free oxygen is not present?

Answer 29

Hydrogen cannot be removed, reducing NAD is not recycled, and the ETC stops working.

Question 30

What are the consequences of the ETC stopping during anaerobic respiration?

Answer 30

Oxidative phosphorylation cannot take place, and Krebs cycle and link reaction pause.

Question 31

What is the ethanol pathway in anaerobic respiration?

Answer 31

1) Pyruvate and reduced NAD formed from glycolysis 2) Pyruvate decarboxylated to ethanal 3) Ethanal accepts hydrogen from reduced NAD 4) Ethanol is formed by alcohol dehydrogenase 5) NAD is regenerated.

Question 32

What is the lactate pathway in anaerobic respiration?

Answer 32

Pyruvate accepts hydrogen and is converted to lactate by lactate dehydrogenase, allowing glycolysis to continue.

Question 33

True or False: The lactate pathway is reversible.

Answer 33

True.

Question 34

Why is less ATP synthesized during anaerobic respiration compared to aerobic respiration?

Answer 34

1) Glucose is not completely broken down 2) Pyruvate contains energy 3) ETC stops without oxygen 4) Krebs cycle and link reaction pause.

Question 35

What is oxygen debt?

Answer 35

The need for extra oxygen after exercise to convert lactate into glycogen and reoxygenate hemoglobin.

Question 36

How do rice plants adapt to wet environments?

Answer 36

1) Cells tolerate high ethanol concentrations 2) Stems have aerenchyma for oxygen diffusion 3) Some grow elongated stems to keep leaves above water.

Question 37

What is the purpose of using a respirometer?

Answer 37

To measure the rate of respiration by tracking oxygen uptake.

Question 38

Fill in the blank: The _______ pathway involves pyruvate being decarboxylated to produce ethanol.

Answer 38

ethanol

Question 39

What is the function of soda lime in a respirometer?

Answer 39

To absorb carbon dioxide.

Question 40

What is required for the calculation of oxygen uptake in a respirometer?

Answer 40

The diameter of the tube.

Question 41

What is produced when cells respire anaerobically and ethanol is formed?

Answer 41

Ethanol is produced and NAD is regenerated.