Cellular Respiration

Question 1

Why do autotrophic organisms need to respire?

Answer 1

Cannot rely solely on photosynthesis as an energy source

Question 2

What do autotrophic organisms do?

Answer 2

They can fix carbon as complex organic molecules, which are used as an energy source

Question 3

What advantage do autotrophic organisms have over heterotrophic organisms?

Answer 3

Autotrophic organisms can create their own energy source to use when dark (no photosynthesis occurring)

Question 4

How do heterotrophs gain their supply of energy?

Answer 4

By eating plants or organisms which have derived their energy from autotrophs (complex organic compounds)

Question 5

What does ‘the energy currency of cells’ refer to?

Answer 5

ATP

Question 6

Which types of organisms respire, transferring energy from carbon compounds into ATP?

Answer 6

Animals, plants, microorganisms

Question 7

What processes require ATP?

Answer 7

Activation of chemicals/active transport/transport of molecules across cell membrane/movement/protein synthesis/cell division

Question 8

What is the role of ATP?

Answer 8

Short term and immediate energy supply

Question 9

How does ATP differ from carbs/fats?

Answer 9

Carbs and fats act as a long term energy storage

Question 10

How does ATP turn into ADP?

Answer 10

The ATP is hydrolysed by the removal of one of its inorganic phosphates

Question 11

How much energy is released through the hydrolysation of ATP to ADP?

Answer 11

30.5 kj of energy is released for immediate use by cells

Question 12

What is crucial about the release of energy, as a result of the hydrolysation?

Answer 12

It is important energy is not released in large bursts otherwise there is risk of energy wastage and damage to cells

Question 13

What is ATP?

Answer 13

A triphosphate nucleoside composed of; the base: adenine; the pentose sugar: ribose; and three phosphate groups

Question 14

What is ADP?

Answer 14

A diphosphate nucleoside composed of; the base: adenine; the pentose sugar: ribose; and two phosphate groups

Question 15

ADP + Pi and energy added =

Answer 15

ATP

Question 16

Why are enzymes important in respiration?

Answer 16

Each step in respiration is an enzyme-catalysed reaction

Question 17

What is the basic description of a coenzyme?

Answer 17

An additional molecule, to the enzyme, which assists the enzyme in carrying out its function

Question 18

Why might hydrogenase enzymes require a coenzyme?

Answer 18

In oxidation/reduction reactions, they require another molecule to act as the acceptor or donor, of the hydrogen atoms removed by the enzyme

Question 19

Oxidation?

Answer 19

A chemical reaction, in which, hydrogen atoms or electrons are lost; or oxygen atoms are gained

Question 20

Reduction?

Answer 20

A chemical reaction, in which, hydrogen atoms or electrons are gained, or oxygen atoms are lost

Question 21

What actually is a coenzyme?

Answer 21

A non-protein, organic molecule, which binds to an enzymes AS

Question 22

What is NAD (nicotinamide adenine dinucleotide)?

Answer 22

A hydrogen carrier molecule, made in the body, it is an important molecule involved in all stages of respiration

Question 23

What does the nicotinamide part of an NAD molecule do?

Answer 23

Accepts a pair of hydrogen atoms, becoming reduced as it does so. When it loses the hydrogen atoms it becomes reduced

Question 24

What is FAD (flavin adenine dinucleotide)?

Answer 24

Similar molecule to NAD and also acts as a hydrogen carrier

Question 25

How does FAD differ from NAD?

Answer 25

Contains riboflavin instead of nicotinamide; FAD is tightly bound to a dehydrogenase enzyme (embedded in the mitochondrial inner membrane), so only pumps hydrogens back into the matrix

Question 26

How is coenzyme A similar to other co-enzymes?

Answer 26

Also an organic molecule