Unit Test I: Control and Coordination

Name

The diagram shows part of a sarcomere in a striated muscle. To which labelled structure calcium ions bind during muscle contraction?

• A
• B
• C
• D

Tetanus toxin prevents fusion of acetylcholine vesicles with the presynaptic membrane. What effect does this have on muscle function?

• A) Increased release of acetylcholine causing paralysis
• B) No acetylcholine to stimulate muscle contraction causing paralysis
• C)Increased release of acetylcholine causing excessive stimulation of muscles leading to fatigue
• D) No acetylcholine in the synaptic cleft causing continuous muscle contraction

Characteristics of some muscle cells are listed. 1. have single nucleus 2. need nervous stimulus to contract 3. contain actin and myosin 4. have cylindrical and branched shape Which of these are true for skeletal muscle cells?

• A) 1 and 3
• B) 2 and 3
• C) 2 and 4
• D) 1 and 4

The graph shows different phases of an action in an axon. The phases are labelled A, B, C, D, E, F and G. In which labelled parts do voltage gated sodium channels open to let depolarisation happen?

• B and C
• D and E
• A and G
• F

What is the correct sequence of some of the events that occur in a neuromuscular junction and a muscle cell? 1. Acetylcholine is released from the motor neurone. 2. Calcium ions bind to troponin. 3. Calcium ions diffuse into the motor neurone. 4. Diffusion of sodium ions depolarises the sarcolemma. 5. Myosin binds to actin.

• A) 3, 1, 4, 2, 5
• B) 4, 3, 1, 2, 5
• C) 3, 1, 4, 5, 2
• D) 4, 1, 3, 5, 2

What happens during depolarisation stage of an action potential?

• A) There is a net diffusion of Na ions into the cell.
• B) The neuron's membrane voltage becomes more negative.
• C) The cell's inside becomes more negative than the outside.
• D) Voltage gated K ion channels are open.

The diagram shows events, labelled with numbers 1 to 10, happening during synaptic transmission of a nerve impulse. Which statement is correct?

• A) At 10, acetylcholinesterase enters the presynaptic cell.
• B) At 7, acetylcholine enters the postsynaptic cell through the ion channel.
• C) At 1, presynaptic membrane is depolarised.
• D) At 5, acetylcholine diffuses through the synaptic cleft.

The figure shows a cholinergic synapse. What causes the neurotransmitter vesicles to move towards and fuse with the presynaptic neurone membrane?

• A) diffusion of calcium ions into the neurone
• B) diffusion of calcium ions out of the neurone
• C) diffusion of sodium ions into the neurone
• D) diffusion of sodium ions out of the neurone

Human taste buds on the tongue contain receptor cells. Different receptor cells respond to different stimuli. The diagram shows receptor cells in a taste bud. What is the role of sensory receptor cells in the nervous system?

• A) to receive action potentials from motor neurones and produce responses
• B) to receive action potentials from sensory neurones and produce responses
• C) to detect stimuli and generate action potentials in sensory neurones
• D) to detect stimuli and generate action potentials in motor neurones