Respiration

Question 1

What is respiration?

Answer 1

Exothermic reaction that releases
energy from glucose and oxygen.

Question 2

Define aerobic respiration

Answer 2

Glucose and oxygen → carbon
dioxide + water; energy released
C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 3

Where does aerobic respiration
take place?

Answer 3

Continuously inside the
mitochondria of animal and plant
cells

Question 4

The energy released during
respiration is used….

Answer 4

To build larger molecules from
smaller ones;
enable muscles to contract in
animals;
to maintain a steady body
temperature;
in plants, to build up sugars,
nitrates and other nutrients into
amino acids and then proteins.

Question 5

Describe and explain the
changes that take place during
exercise

Answer 5

The heart rate increases and the
rate and depth of breathing
increases to ensure blood flow to
muscles increases so the supply
of sugar and oxygen increases
and carbon dioxide is removed
quickly from the cells. Arteries
dilate to increase blood flow to
muscles.

Question 6

Muscles store glucose as…

Answer 6

Glycogen. Glycogen is converted
back to glucose in muscles during
exercise.

Question 7

Which type of respiration takes
place with insufficient oxygen?

Answer 7

Anaerobic respiration.

Question 8

Word equation for anaerobic
respiration in humans.

Answer 8

Glucose → lactic acid; less energy
released

Question 9

Define oxygen debt

Answer 9

The amount of oxygen needed to
break down the lactic acid produced
during anaerobic exercise

Question 10

Describe muscle fatigue

Answer 10

Muscles stop contracting efficiently
when they are subjected to long
periods of vigorous exercises. This is
due to the build up of lactic acid in the
muscles. Lactic acid is poisonous and
causes cramps.

Question 11

Where in the body is lactic
acid broken down?

Answer 11

Blood carries the lactic acid from the
muscles to the liver.
Lactic acid is converted to glucose
inside the liver.

Question 12

Why do you continue to
breathe heavily after
exercise?

Answer 12

To ensure oxygen is delivered to the
body to repay the O2 debt (to break
down the lactic acid).

Question 13

What is fermentation?

Answer 13

Anaerobic respiration in yeast cells:
Glucose → ethanol + carbon dioxide
This is how we make bread and
alcoholic drinks.

Question 14

What is metabolism?

Answer 14

The sum of all chemical reactions that happen in an organism.

Question 15

Give examples of chemical
reactions that happen in
plants or animals.

Answer 15

Glucose to starch/cellulose and vice
versa
Fatty acids + glycerol to lipids and vice
versa
Amino acids (in animals)/ nitrates (in
plants) to proteins and vice versa
Proteins broken down to urea.