Topic 2.8: Cell Respiration

Question 1

Define cell respiration

Answer 1

Cell respiration is the controlled release of energy from organic compounds to produce ATP

Question 2

What are the two main types of cell respiration?

Answer 2

anaerobic respiration and aerobic respiration

Question 3

Define anaerobic respiration

Answer 3

Anaerobic respiration involves the partial breakdown of glucose in the cytosol for a small yield of ATP

Question 4

Define aerobic respiration

Answer 4

Aerobic respiration utilises oxygen to completely break down glucose in the mitochondria for a larger ATP yield

Question 5

Define ATP

Answer 5

ATP (adenosine triphosphate) is a high energy molecule that functions as an immediate source of power for cell processes

Question 6

What is the first step of anaerobic respiration?

Answer 6

Glycolysis breaks down glucose (6-C) into two molecules of pyruvate (3C), and also produces:

Hydrogen carriers (NADH) from an oxidised precursor (NAD+)
A small yield of ATP (net gain of 2 molecules)

Question 7

After Glycolysis breaks down glucose (6-C) into two molecules of pyruvate (3C) what is the last step of anaerobic respiration?

Answer 7

Anaerobic respiration proceeds in the absence of oxygen and does not result in the production of any further ATP molecules

In animals, the pyruvate is converted into lactic acid (or lactate)
In plants and yeasts, the pyruvate is converted into ethanol and carbon dioxide

Question 8

Where does glycolysis occur?

Answer 8

cytoplasm

Question 9

Where does aerobic respiration occur?

Answer 9

mitochondria

Question 10

What happens during aerobic respiration?

Answer 10

Pyruvate is broken down into carbon dioxide and water, and a large amount of ATP is produced (~34 – 36 molecules)

Question 11

What does aerobic respiration consist of?

Answer 11

Aerobic respiration consists of the link reaction, citric acid cycle (or Krebs cycle) and the electron transport chain

Question 12

Define respirometer

Answer 12

A respirometer is a device that determines an organism’s respiration rate by measuring the rate of exchange of O2 and CO2

Question 13

What is the difference between anaerobic and aerobic respiration in terms of reactants?

Answer 13

Anaerobic: glucose

Aerobic: glucose and oxygen

Question 14

What is the difference between anaerobic and aerobic respiration in terms of combustion?

Answer 14

Anaerobic: incomplete

Aerobic: complete

Question 15

What is the difference between anaerobic and aerobic respiration in terms of energy yield?

Answer 15

Anaerobic: low (2 ATP)

Aerobic: High (36-38 ATP)

Question 16

What is the difference between anaerobic and aerobic respiration in terms of products?

Answer 16

Anaerobic: Animals: lactic acid
Yeast: Ethanol + CO2

Aerobic: CO2 and H2O

Question 17

What is the difference between anaerobic and aerobic respiration in terms of location?

Answer 17

Anaerobic: cytoplasm

Aerobic: cytoplasm and mitochondria

Question 18

What is the difference between anaerobic and aerobic respiration in terms of stages?

Answer 18

Anaerobic: glycolysis, fermentation

Aerobic: glycolysis, link reaction, Krebs cycle, and electron transport chain