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GCSE Biology: Year 9 Respiration & Exercise

How does the body change when it is exercising?

Respiration is a c _ _ _ _ _ _ reaction which releases the e _ _ _ _ _ trapped in food (sugar).

Respiration can be aerobic (with o _ _ _ _ _) or anaerobic (without o _ _ _ _ _)

Aerobic respiration takes place 24 hours a day in all l _ _ _ _ _ c _ _ _ _ (plants and animals).

Most of the reactions happen inside m _ _ _ _ _ _ _ _ _ _ _.

Because respiration gives out energy, it is described as an e _ _ _ _ _ _ _ _ reaction.

Energy that is released during respiration is used by the organism for:

• Moving (contracting _ _ _ _ _ _ _)

• Keeping _ _ _ _

• Doing chemical reactions that build up _ _ _ _ _ _ molecules

Different processes in my body – commonly confused!Process What is it? Where is happens When it happensRespiration

Breathing

Circulation

Aerobic Respiration

Word Equation

Symbol Equation

Anaerobic Respiration in AnimalsDuring exercise, if insufficient o _ _ _ _ _ reaches the m _ _ _ _ _ they use anaerobic respiration to obtain e _ _ _ _ _.

This is the incomplete oxidisation of g _ _ _ _ _ _ and produces a small amount of e _ _ _ _ _ and l _ _ _ _ _ acid.

Anaerobic respiration results in an o _ _ _ _ _ d _ _ _ that has to be repaid in order to breakdown the lactic acid. You do this by breathing deeply once exercise stops.

If muscles are subjected to long periods of vigorous activity they become f _ _ _ _ _ _ _, i.e. they stop c _ _ _ _ _ _ _ _ _ efficiently. This is caused by a build-up of l _ _ _ _ _ a _ _ _ in the muscles.

Lactic acid is transported to the l _ _ _ _ where it is converted back to g _ _ _ _ _ _.

Practical: does the rate of hand clasping affect the length of time the muscles can work for without getting fatigued

You are going to investigate the hypothesis that ‘The harder muscles work, the sooner the muscles become fatigued’.

Equipment: Stopwatch

Method

• Sit down and rest your elbow on the desk.

• Clasp and unclasp the hand on your stronger arm at the rate of once every three seconds.

• Record how long it takes to feel fatigued (until it becomes too painful to continue the action).

• Switch hands and repeat for faster rates of hand clasping

Write down:

• IV and DV (2 marks).

• Control variables (2 marks)

• Table (2 marks)

• Graph (4 marks)

Differences Between Aerobic and Anaerobic Respiration in Animals

Both of these chemical reactions are controlled by tiny chemicals called

_ _ _ _ _ _ _ which speed up reactions in the cell.

Aerobic Respiration Anaerobic RespirationWhen does it happen?

Does oxygen react with sugar?

How much energy is released?

What are the products (chemicals formed)?

Where in the cell does it happen?

Anaerobic Respiration in Plants and YeastAnaerobic respiration in plant and yeast cells is represented by the equations:

Anaerobic respiration in yeast cells is called fermentation and has economic importance in the manufacture of bread and alcoholic drinks.

Practical: does the temperature affect the rate of anaerobic respiration in yeast?

Write down:

• IV and DV (2 marks).

• Control variables (2 marks)

• Table (2 marks)

• Graph (4 marks)

Revision Crossword

Across2. The amount of oxygen you need to take in to break down lactic acid9. Energy from respiration is used to maintain body temperature in these10. This type of respiration happens when oxygen is absent12. Energy from respiration is used to allow muscles __________13. The toxic product of respiration17. The useful product from respiration18. Amino acids can be built into these using energy from respiration20. The product of anaerobic respiration which makes muscles feel cramped.Down1. Energy from respiration is used to maintain body temperature in these3. Tiny chemicals which control the chemical reactions in cells.4. The ‘fuel’ burnt by the body during respiration5. This beats faster when you exercise to circulate oxygen and sugar to muscles6. Where aerobic respiration happens in the cell7. Energy from respiration is used to build _____ molecules from small ones8. The type of sugar burnt during respiration11. This happens faster when you exercise to take in more oxygen and remove carbon dioxide14. Required for aerobic respiration15. This type of respiration happens when oxygen is present.16. How much energy is released during aerobic respiration?19. Animals convert excess sugar as this21. Plants use the energy from respiration to convert sugars into these

Aerobic Respiration Exam QuestionsQuestion 1:

Describe what happens to sugars during respiration (2 marks)

Question 2:

Each day a boy ate food containing 12 000 kilojoules of energy. The boy used 80% of this energy to maintain his core body temperature.

(a) Name the process which releases energy from food (1 mark)

(b) Calculate the amount of energy that the boy would need each day to maintain his core temperature. Show clearly how you worked out your final answer (2 marks)

Question 3:

Give the full name of the process that occurs in mitochondria (1 marks)

Question 4:

Copy and complete the equation for aerobic respiration (2 marks)

Sugar + ____________ → Carbon dioxide + ___________ + ENERGY

Anaerobic Respiration Exam QuestionsQ1)