B4.2 Respiration

Question 1

What is aerobic respiration and where does it occur in cells?

Answer 1

Respiration WITH oxygen, in the mitochondria.

Question 2

What is anaerobic respiration and where does it occur in cells?

Answer 2

Respiration WITHOUT oxygen, in the cytoplasm.

Question 3

Is respiration an endo- or exothermic reaction?

Answer 3

Exothermic.

Question 4

State the balanced chemical equation for aerobic respiration.

Answer 4

C6H12O6 + 6O2 -> 6CO2 + 6H2O

Question 5

State the word equation for anaerobic respiration in animal cells.

Answer 5

Glucose -> lactic acid

Question 6

State the word equation for anaerobic respiration in plant and yeast cells.

Answer 6

Glucose -> ethanol + carbon dioxide

Question 7

Is more or less energy transferred in anaerobic respiration compared to aerobic respiration?

Answer 7

Less, due to incomplete oxidation of glucose.

Question 8

How have humans used our understanding of anaerobic respiration in plant and yeast cells in manufacturing?

Answer 8

Production of bread and alcoholic drinks.

Question 9

Name three physical ways in which the human body reacts to an increased demand for energy.

Answer 9

Heart rate, breathing rate and breath volume all increase.

Question 10

Why do these increase?

Answer 10

To increase the oxygenation of the blood and to supply the muscles with more oxygenated blood.

Question 11

What does a build-up of lactic acid cause in muscles?

Answer 11

Muscle fatigue.

Question 12

What is an oxygen debt?

Answer 12

The amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells.

Question 13

Where is lactic acid converted back into glucose?

Answer 13

The liver.

Question 14

How is lactic acid transported to the liver?

Answer 14

Via the blood.

Question 15

What is produced when enzymes chemically break down carbohydrates?

Answer 15

Simple sugar monomers.

Question 16

What is produced when enzymes chemically break down lipids?

Answer 16

Fatty acids and glycerol.

Question 17

What is produced when enzymes chemically break down proteins?

Answer 17

Amino acids.

Question 18

What is “metabolism”?

Answer 18

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

Question 19

What is the energy released via respiration used for in cells?

Answer 19

The continual enzyme controlled processes of metabolism that synthesise new molecules.

Question 20

Name three cellular reactions which could be included under the term “metabolism”.

Answer 20

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 excretion.