Respiration

Question 1

Aerobic respiration equation

Answer 1

Glucose + oxygen → carbon dioxide + water (+ energy)

C₆H₁₂ O₆+ → 6CO₂ + 6H ₂O

Question 2

Demonstrating CO2 production

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Answer 2

(See diagram)
Air → A: sodalime → B: Lime water → C: germinating seeds → D: lime water

• Air comes in through the left, test tube A absorbs CO2 from air
• The limewater at B wouldn’t turn cloudy as the air doesn’t contain CO2
• At C the seeds respire and produce CO2 as waste product
• At D lime water becomes cloudy due to presence of CO2

Question 3

Demonstrating energy release

Answer 3

(See diagram)

2 jar with one germinating seed and one boiled seed
Thermometer and wet cotton

-The Germinating seed produces thermal energy and ATP from respiration. This means that temp is higher than other
jar

-The boiled seeds have denatured enzymes so cannot respire or produce energy. It acts as a comparison to the germinating seeds

Question 4

Respiration in cells

Answer 4

In mitochondria:

• contains many enzymes required in respiration
• respiration takes place in the inner membrane
• inner membrane are folded so there’s more space for enzymes to attach
• muscle + sperm cell have many mitochondria due to their high energy requirements

Question 5

What is respiration?

Answer 5

A reaction that occurs in living things to create energy. It breaks down glucose into energy

Question 6

What is aerobic respiration?

Answer 6

In this form all energy is released from the glucose as it is fully broken down. It’s used for day to day processes like movement and keeping warm

Question 7

What is anaerobic respiration?

Answer 7

Respiration without O₂

Question 8

Effects of exercise on the body

Answer 8

1. breathing rate increases
2. depth of breath increases
   - more O2 taken in to allow more O2 in blood
   - more CO2 exhaled
3. heart rate increase
   - increase blood flow to muscles
   - more O2 + glucose delivered
   - allows increase in respiration + energy release
4. feeling hotter
   - not all energy in respiration covered to KE
   - some lost as heat

Question 9

Benefits of exercise

Answer 9

• more blood pumped per heart beat
• more heart volume
• lower breathing/pulse rate:
  1. higher lung capacity means you take in more O2 per breath
  2. pulse rates drop because of a higher heart volume and more blood pumped per beat

Question 10

Equation for anaerobic respiration

Answer 10

glucose → lactic acid + energy

C₆H₁₂ O₆ → 2C ₃ H ₆ O ₃

(Aerobic respiration has 16x more energy)

Question 11

Oxygen debt in anaerobic respiration

Answer 11

-The additional O2 that must be taken in after rigorous exercise for the body to ‘respire’ the lactic acid made in anaerobic respiration

Question 12

Breaking down lactic acid in anaerobic respiration

Answer 12

lactic acid + oxygen→ carbon dioxide + water

C₃H₆ O₃ + 3O₂ → 3CO₂ + 3 H₂O

Question 13

Respiration in yeast

Answer 13

aerobic:
glucose + oxygen → carbon dioxide + water

anaerobic:
glucose → ethanol + carbon dioxide

Question 14

Describe an experiment to investigate the effect of exercise on breathing in humans

Answer 14

During exercise cells respire more quickly, this means O2 has to be delivered and CO2 taken away more quickly. As a result the lung muscles contract and relax faster and the heart beats faster.

Measure a person’s breath per 10s when stationary.
Then after 1 minute of running at 5mph then at 2 minutes etc.
You will find a linear relationship as described above between the two