Marking Scheme: Coordination and Response

This is the marking scheme for quiz: Coordination And Response

Section 1: Core Syllabus

Question 1

• An automatic [1]
• Rapid/unconscious response to a stimulus [1]

Question 2 (a) Muscle or gland that carries out the response [1] (b) Protects the organism from harm [1] by reacting quickly without waiting for brain processing [1]

Question 3

• Insulin [1]

Question 4 (a) Growth of a plant [1] in response to light [1] (b) Auxin [1]

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Section 2: Extended Syllabus

Question 5

• Sensory neuron: Carries impulses from receptor to CNS [1]; often has long dendrites/short axon [1]
• Motor neuron: Carries impulses from CNS to effector [1]; often has short dendrites/long axon [1]

Question 6

• Impulse reaches end of pre-synaptic neuron [1]
• Neurotransmitters are released into the synaptic cleft [1]
• Neurotransmitters diffuse across the gap and bind to receptors on post-synaptic membrane [1]
• This triggers a new electrical impulse (depolarization) in the next neuron [2]

Question 7

• Pancreas detects increase in blood glucose [1]
• Pancreas secretes insulin [1]
• Insulin causes glucose to move from blood into cells [1]
• Insulin stimulates liver/muscle cells to convert glucose to glycogen [1]
• Blood glucose levels return to normal/baseline [1]

Question 8

• Auxin is produced in the shoot tip [1]
• Auxin moves to the shaded side of the shoot [1]
• High concentration of auxin on shaded side causes cells to elongate faster than on the lighted side [1]
• This uneven growth causes the shoot to bend towards the light source [1]