Muscles & Movement (Edexcel A (SNAB) A Level Biology)

Exam Questions

54 mins5 questions
1a
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3 marks

The diagram below shows a transmission electron micrograph of a section of skeletal muscle. 
mammalian-muscle-under-the-microscope-1

Name structures A, Band C

1b
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4 marks

During intense exercise, the pH of the skeletal muscle tissue falls sharply. This decrease in pH reduces the ability of calcium ions to stimulate muscle contraction.

Describe how.

1c
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1 mark

The sliding filament mechanism of a muscle contraction is used to describe how muscle fibers contract and relax.

Which statements about the role of ATP are true? 

  1. ATP binds to the myosin heads producing a change in the shape that causes the myosin heads to release from the action filaments
  2. ATP binds to the myosin heads producing a change in shape that causes the myosin heads to bind to the actin filaments
  3. Calcium ions activate the enzyme ATPase which hydrolyses ATP to ADP
  4. Potassium ions activate the enzyme ATPase which hydrolyses ATP to ADP
  A I and IV 
  B II and III
  C I and III
  D II and IV

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2a
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6 marks

Slow and fast twitch skeletal muscle fibres differ in a number of ways.

Compare and contrast slow and fast twitch muscle fibres.

2b
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4 marks

A scientist investigated the proportions of slow and fast twitch muscle fibres in athletes and non-athletes.

The percentage of fast and slow twitch muscle fibres was analysed. The results are shown in the graph below.
htq7tmxg-image

Explain which athlete you would expect to find the greater density of mitochondria with their muscle fibre cells.

2c
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2 marks

Elite sprinters tend to be bulkier and more muscular than long distance runners. 

Use your knowledge of fast and slow twitch muscle fibre to explain why.

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3a
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3 marks

Muscles generate movement by antagonistic muscle action. 

Describe the action taken by muscles when a pair of antagonistic muscles work together.

Give a named example from human muscles as part of your answer.

3b
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1 mark

Muscle work together with tendons and ligaments

Which statements below describe the difference between tendons and ligaments? 

  A Tendons connect to the bone whereas ligaments connect to the muscle
  B Tendons connect muscles to bones whereas ligaments connect bones to bones
  C Tendons connect to bones only whereas ligaments connect to muscle only
  D Tendons connect to both ligaments and to muscle

3c
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3 marks

Explain how muscles maintain posture.

3d
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3 marks

The mass of muscle changes with age. Between the ages of 20 and 60, 15% of total muscle mass is lost. Between the ages of 60 and 80, a further 35% of the original total muscle mass is lost.

Plot a graph on the grid below to show the percentage of muscle mass remaining between the ages of 20 and 80. Assume that the rate of muscle loss in each age range is constant.

kn8lCftY_image

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4a
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2 marks

The diagram shows part of a relaxed myofibril. 

myofibril-labelled---sq

(i)

When the myofibril contracts, state which of the A-band, I-band and H-zone will decrease in length.

(1)

(ii)

When the myofibril contracts, state which of the A-band, I-band and H-zone will remain the same in length.

(1)

4b4 marks

The structure of a muscle is often referred to as light and dark. 

(i)

Identify and name the light and dark bands in the diagram from part (a).

(2)

(ii)

Describe the structure of the light and dark bands of a muscle.

(2)

4c
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4 marks

Explain the reason for your answer to part (a) (i)

4d
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3 marks

The whole myofibril is 21 mm long when relaxed.

Use the information given in the diagram in part (a) to calculate how many sarcomeres are in a myofibril. Give your answer to four significant figures.

4e
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1 mark
The graph shows information about the length of a sarcomere and the force of the contraction. 

EowhqwCA_sarcomere-length

Which of the statements regarding the relationship between force and length is false

  A Point C can generate less force than Point B since the sarcomere is lengthened and there are fewer cross bridges formed.
  B Point A can generate less force than Point B since the sarcomere is short and there are fewer cross bridges formed.
  C Force production in a muscle is proportional to the number of cross bridges (connection of actin and myosin) formed.
  D Point A can generate more force than Point C since the sarcomere is short.

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5a
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2 marks

Skeletal muscle is also known as striated muscle due to its striped appearance.

Use your knowledge of the protein filaments in muscle tissue to explain the striped appearance of skeletal muscle.

5b
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4 marks

Several different drugs exist that reduce the contraction of skeletal muscles. Two of these drugs are described in the table below.

Drug Mechanism of action
PBP Inhibits ATP hydrolysis
Dantrolene Inhibits the release of calcium ions from the sarcoplasmic reticulum

Explain how each of the drugs in the table reduce the contraction of skeletal muscles.

5c
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4 marks

A type of muscle disease is caused by a gene mutation. This leads to the production of disfigured myosin molecules that are unable to bind to other myosin molecules.

Use your knowledge of how muscles contract to predict the effect of this gene mutation.

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