5 Respiration

Question 1

What do cells use as their immediate source of energy?

Answer 1

ATP.

Question 2

What are the 2 different forms of cellular respiration?

Answer 2

Aerobic respiration-needs oxygen and produces carbon dioxide, water and ATP.
Anaerobic respiration- no oxygen, produces lactate in animals, ethanol carbon dioxide in plants and fungi.

Question 3

List the 4 stages of aerobic respiration.

Answer 3

Glysolysis, Link reaction, Krebs cycle, Oxidative phosphorylation.

Question 4

What is the initial stage of both aerobic and anaerobic respiration?

Answer 4

Glycolysis.

Question 5

Where does the first stage of respiration take place? and what is produced at the end of it?

Answer 5

Glycolysis takes place in the cytoplasm and produces two 3 carbon Pyruvate molecules.

Question 6

What needs to be done to Glucose before it is split in Glycolysis?

Answer 6

It needs to be made more reactive by adding 2 phosphate molecules .

Question 7

As well as 2 Pyruvate molecules what else is produced when one glucose molecule undergoes glycolysis?

Answer 7

2 molecules of ATP( initially 4 are produced, but 2 are used up)
2 molecules of reduced NAD.

Question 8

When pyruvate is produced in the absence of oxygen what can it be converted to.

Answer 8

Lactate or Ethanol.

Question 9

Where does the krebs cycle and link reaction both take place?

Answer 9

Inside mitochondria.

Question 10

Briefly describe what takes place during the link reaction.

Answer 10

Pyruvate is oxidised to acetate. 3 carbon, pyruvate loses a carbon dioxide molecule and 2 hydrogen molecules. Hydrogen molecule are accepted by NAD, forms reduced NAD, and later used to produce ATP. 2 acetate combines with coenzyme A and produces acetylocoenzyme A.

Question 11

How is the acetylocoenzyme A incorporated in the krebs cycle?

Answer 11

2 acetylocoenzyme A combines with 4 carbon molecule to produce 6 carbon molecule.

Question 12

What is produced from the krebs cycle?

Answer 12

Reduced coenzymes, One ATP, 3 carbon dioxide molecules.

Question 13

What is a coenzyme and give some examples.

Answer 13

Coenzymes are molecules that some enzymes require in order to function. Examples: NAD-in respiration, FAD- in krebs cycle, NADP-in photosynthesis.

Question 14

Significance of the krebs cycle.

Answer 14

Breaks down macro-molecules int smaller ones.
Produces hydrogen atoms.
Regenerates 4 Carbon molecule.
Source of intermediate compounds.

Question 15

Where does oxidative phosphorylation take place?

Answer 15

Mitochondria.

Question 16

state the importance of oxygen in the final stage of aerobic respiration.

Answer 16

oxygen acts as the final receptor of the hydrogen atoms produced in glycolysis and krebs cycle. without this role, the process of respiration would come to a halt.

Question 17

Why in Anaerobic respiration can the krebs cycle and electron transfer chain not continue.

Answer 17

because the FAD and NAD will be reduced, so no FAD and NAD will will be available to take up hydrogen iond during kreb cycle and so enzymes will stop working.

Question 18

equation of the production of ethanol in plants.

Answer 18

Pyruvate + reduced NAD =ethanol + Carbon dioxide+ oxidised NAD

Question 19

What does anaerobic respiration form in animals?

Answer 19

Lactate

Question 20

How is energy from Cellular respiration derived?

Answer 20

1. Substrate level phosphorolation in glycolysis and krebs cycle.
2. Oxidative phosphorolation in electron transfer chain.