Co-ordination & Response

Question 1

Name the organs of the Central Nervous System (CNS) (2)

Answer 1

The brain(1) and the spinal cord(1)

Question 2

Give one example of an effector organ. (1)

Answer 2

Gland(s) (1) or Muscle (1)

Question 3

Describe the journey taken by the nerve impulse between the sharp pin and the relay neuron (3

Answer 3

) The stimulus which is the pin is detected by the pain receptors in the skin(1) Then, an impulse is sent (1) from the receptor along to the sensory neuron (1). The nerve impulse crosses a synapse (1)

Question 4

Explain the importance of the reflex arc for living organisms. (2)

Answer 4

Reflex arcs are important because they allow for fast responses (1). This means that it will help you to survive as they minimize the damage made to the body (1)

Question 5

Name one hormone released by the pancreas (1)

Answer 5

insulin (1)

Question 6

Describe how the pancreas regulates blood glucose when levels rise above normal limits (2)

Answer 6

It detects an increase in blood glucose levels and releases insulin (1). Insulin increases the removal of glucose from the blood as it causes glucose to be converted into glycogen (1)

Question 7

(d) The diagram in part (b) identifies the testes.

(i) Name a hormone produced by the testes.

(ii) State one role of the hormone identified in part (i)

Answer 7

(i) testosterone (1)

(ii) State one role of the hormone identified in part (i) (1) Development of male secondary sexual characteristics such as experiencing changes to the voice box. (1)

Question 8

Name the chemical produced by plants that are responsible for both phototropism and geotropism. (1)

Answer 8

Auxin (1)

Question 9

Explain the importance of the phototropism response for plant survival (3)

Answer 9

It’s important because plants would be able to maximise their rate of photosynthesis (1) and the absorption of light energy (1) and response to light (1)

Question 10

State the term used to describe tropism responses that occur towards a stimulus (1)

Answer 10

Positive (tropisms) (1)

Question 11

Explain the role of the neurons in the withdrawal reflex of a finger from a hot object. (3)

Answer 11

The sensory neurone carries an impulse from a receptor to the relay neurone (1). The sensory neurone joins to the relay neuron by a synapse and carries the impulse to the motor neurone (1) the motor neurone carries the impulse to an effector. (1)

Question 12

State the term used to describe the control of an organism’s internal environment (1)

Answer 12

Homeostasis (1)

Question 13

Describe the structure and functioning of the withdrawal reflex of a finger from a hot object (4)

Answer 13

The receptors in the skin detect the stimulus (1) and then an impulse is generated (1). The impulse travels along a sensory neuron to a relay neuron(1) through the diffusion of neurotransmitters(1) across a synapse.(1) The relay neuron will pass it on to the motor neuron to an effector(1) which will cause the muscle to contract and make you pull away the finger. (1)

Question 14

(c) (i) Explain the changes that take place in the skin as a person enters a cold environment. (2)

(ii) Explain the changes that take place in the blood capillaries when a person enters a cold environment (3)

Answer 14

(i) less sweat will be released (1) which will lead to less heat loss (1).

(ii) The blood vessels constrict which will lead to less blood flow to the surface of the skin resulting in less heat loss.

Question 15

Explain how structure Y(iris) in the diagram controls the light entering the eye when someone walks into a dark room (2)

Answer 15

The iris controls the light entering the eyes when someone walks into a dark room by making the pupil widen (1) where the radial muscles contract (1) whereas the circular muscles (relax) (1)