Biology 🍃 | Respiration | 12

Question 1

What are the uses of energy in living organisms?

Answer 1

• Cell division
• Muscle contraction
• Protein synthesis
• Active transport
• Growth
• Passage of nerve impulses
• Maintaining constant body temperature

Question 2

Define aerobic respiration

Answer 2

The chemical reactions in cells that use oxygen to break down nutrient molecules to release energy.

Question 3

What is the word equation for aerobic respiration?

Answer 3

glucose + oxygen → carbon dioxide + water

Question 4

What is the chemical equation for aerobic respiration?

Answer 4

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Question 5

Define anaerobic respiration.

Answer 5

The chemical reactions in cells that break down nutrient molecules to release energy without using oxygen.

Question 6

What is the word equation for anaerobic respiration in yeast?

Answer 6

glucose → ethanol + carbon dioxide

Question 7

What is the word equation for anaerobic respiration in the muscles during exercise?

Answer 7

glucose → lactic acid

Question 8

What is the chemical equation for anaerobic respiration in yeast?

Answer 8

C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

Question 9

What is another word for anaerobic respiration in yeast?

Answer 9

Fermentation.

Question 10

When do we carry out anaerobic respiration?

Answer 10

When in vigorous exercise, and our lungs and heart cannot supply oxygen to muscles as fast as needed.

Question 11

What are the drawbacks of aerobic respiration?

Answer 11

• Requires oxygen
• Happens at a relatively slow pace

Question 12

When do humans anaerobically respire?

Answer 12

When we are exercising too strenuously to have enough oxygen to break down glucose into energy.

Question 13

What are the drawbacks of anaerobic respiration?

Answer 13

• It releases less energy per glucose molecule than with aerobic respiration.
• It causes a buildup of lactic acid in muscles, causing oxygen debt

Question 14

What is oxygen debt?

Answer 14

The extra oxygen we require after strenuous exercise to break down the lactic acid built up in our muscles.

Question 15

Why does our heart rate remain high for a few minutes after exercise?

Answer 15

So that we can supply enough oxygen to break down remaining lactic acid (pay back oxygen debt).

Question 16

Where is lactic acid broken down?

Answer 16

Our blood takes the lactic acid to the liver.

Question 17

How can we set up an investigation that looks at the effect of temperature on respiration in yeast?

Answer 17

• Two test tubes
• Corks with holes on both
• A pipe that can reach from the air in tube a to tube b’s indicator (limewater/hydrogen carbonate)
• Another pipe in tube B that connects air in the tube to atmospheric air.

Question 18

How can we investigate the effect of temperature on respiration in yeast?

Answer 18

1. Boil water, to drive off dissolved air
2. Dissolve small amount of sugar in boiled water
3. When cool, add yeast and stir with glass rod } in tube A
4. Trickle liquid paraffin into tube A
5. Set up an identical apparatus but with boiled yeast
6. Leave apparatus in warm place
7. After half an hour, observe changes in indicator.