2.6.1 Aerobic respiration

Question 1

What are chemical reactions in cells controlled by?

Answer 1

The chemical reactions inside cells are controlled

by enzymes.

Question 2

Where do most of the reactions take place in aerobic respiration?

Answer 2

Most of the reactions in aerobic respiration take

place inside mitochondria.

Question 3

What is the word equation for aerobic respiration?

Answer 3

glucose + oxygen ➞ carbon dioxide + water (+ energy)

Question 4

Energy that is released during respiration is used by

the organism. The energy may be used:

Answer 4

■ to build larger molecules from smaller ones
■ in animals, to enable muscles to contract
■ in mammals and birds, to maintain a steady
body temperature in colder surroundings
■ in plants, to build up sugars, nitrates and other
nutrients into amino acids which are then
built up into proteins.

Question 5

What changes take place during exercise?

Answer 5

■ the heart rate increases

■ the rate and depth of breathing increases.

Question 6

What do these changes do?

Answer 6

These changes increase the blood flow to the
muscles and so increase the supply of sugar and
oxygen and increase the rate of removal of
carbon dioxide.

Question 7

How do muscles help during exercise?

Answer 7

Muscles store glucose as glycogen, which can then

be converted back to glucose for use during exercise.