Topic 2 Triple Respiration

Question 1

Describe cellular respiration as an

Answer 1

exothermic reaction (transfers energy to the environment) which is continuously occurring in living cells. The energy transferred supplies all the energy needed for living processes.

Question 2

Respiration in cells can take place

Answer 2

aerobically (using oxygen) or anaerobically (without oxygen) to transfer energy.

Question 3

Aerobic respiration

Answer 3

takes place in the mitochondria

Question 4

Organisms need energy for:

Answer 4

• chemical reactions to build larger molecules
• movement
• keeping warm.

Question 5

Aerobic respiration is represented by the equation:

Answer 5

glucose + oxygen → carbon dioxide + water + energy release
Recognise the chemical symbols: C6H12O6, CO2, O2 and H2O

Question 6

Anaerobic respiration in muscles is represented by the equation:

Answer 6

Glucose → lactic acid.

Question 7

As the oxidation of glucose is incomplete in anaerobic respiration much

Answer 7

less energy is transferred than in aerobic respiration.

Question 8

Anaerobic respiration in plant and yeast cells is represented by the equation:
glucose →

Answer 8

ethanol + carbon dioxide + energy release

Question 9

Anaerobic respiration in yeast cells is called
and has economic importance in the manufacture

Answer 9

fermentation

of alcoholic drinks and bread

Question 10

During exercise, the human body reacts to the increased demand for energy.

Answer 10

The heart rate, breathing rate and breath volume increase during exercise to supply the muscles with more oxygenated blood. This enables increased cellular respiration so more energy is transferred to meet the demands of the muscle cells.

Question 11

If insufficient oxygen is supplied

Answer 11

, anaerobic respiration takes place in muscles. The incomplete oxidation of glucose causes a build-up of lactic acid and creates an oxygen debt. During long periods of vigorous activity muscles become fatigued and stop contracting efficiently. Blood flowing through the muscles transports the lactic acid to the liver where it is converted back into glucose. Oxygen debt is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells.

Question 12

Metabolism is

Answer 12

the sum of all the reactions in a cell or the body.

Question 13

The energy transferred by respiration in cells is used by the organism for the

Answer 13

continual enzyme controlled processes of metabolism that synthesise new molecules.

Question 14

Metabolism includes:

Answer 14

conversion of glucose to starch, glycogen and cellulose
the formation of lipid molecules from a molecule of glycerol and three molecules of fatty acids
the use of glucose and nitrate ions to form amino acids which in turn are used to synthesise proteins
respiration
breakdown of excess proteins to form urea for excretio