Topic 12

Question 1

Uses of energy transferred by respiration (7)

Answer 1

. Muscle contraction
. Protein synthesis
. Cell division
. Active transport
. Growth
. Passage of nerve impulses
. Maintenence of a constant body temperature

Question 2

What is aerobic respiration?

Answer 2

Chemical reactions in cells (mitochondria) that use oxygen to break down nutrient molecules (e.g glucose) to release energy -> most efficient in transferring energy from glucose

Question 3

Word equation for aerobic respiration

Answer 3

Oxygen + glucose -> carbon dioxide + water

Question 4

Chemical equation for aerobic respiration

Answer 4

C6H12O6 + 6O2 -> 6CO2 + 6H2O

Question 5

What is anaerobic respiration?

Answer 5

Chemical reactions in cells that break down nutrient molecules to release energy without using oxygen -> transfers much less energy/glucose molecules

Question 6

Word equation anaerobic respiration

Answer 6

Glucose -> lactic acid

Question 7

Oxygen debt

Answer 7

During really vigorous exercise your body can’t supply oxygen to your muscles quickly enough with aerobic respiration alone -> start respiring anaerobically

Question 8

Oxygen debt steps

Answer 8

1. Anaerboic respiration leads to build up of lactic acid in muscle cells and blood
2. After exercise you have an “oxygen debt” -> amount of extra oxygenyour body needs to eliminate lactic acid
3. Heart rate remains high to transport lactic acid in blood from muscles to liver
4. Breathing rate and depth remain high to supply oxygen for aerobic respiration of lactic acid in the liver -> break down of lactic acid using oxygen

Question 9

Respiration in yeast: higher temperature

Answer 9

More carbon dioxide released (greater amount of bubbles) -> above optimum temperature rate of respiration will decrease (enzymes denatured)

Question 10

Respiration in yeast: word equation

Answer 10

Glucose -> alcohol + carbon dioxide

Question 11

Respiration in yeast: chemical equation

Answer 11

C6H12O6 -> 2C2H5OH + 2CO2