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Biology for IGCSE & O level - Coordination And Response (Section 4)

1
When focusing on a near object, what happens to the lens?
Answer
(B)
It becomes more rounded.
2
Which part of the eye is responsible for focusing light onto the retina?
Answer
(A)
Cornea and lens
3
If a plant seedling is placed horizontally, which part of the plant will exhibit positive geotropism?
Answer
(C)
The roots
4
Which part of the nervous system is responsible for the fight-or-flight response?
Answer
(C)
The sympathetic nervous system
5
What would happen to a plant's roots if they were placed in a horizontal position?
Answer
(C)
They would grow downwards.
6
Which division of the nervous system is responsible for voluntary control of skeletal muscles?
Answer
(B)
Somatic nervous system
7
What is the effect of the plant hormone auxin?
Answer
(B)
It promotes cell elongation.
8
What structures are involved in the sense of touch?
Answer
A
B
9
What is the name of the transparent layer at the front of the eye?
Answer
(B)
Cornea
10
What part of the eye is responsible for detecting low-intensity light?
Answer
(B)
Rods
11
What is the main role of the skin in thermoregulation?
Answer
(C)
To regulate body temperature.
12
What happens to the pupil in bright light?
Answer
(B)
It constricts
13
Which nervous system division is responsible for conscious control of movement?
Answer
(B)
Somatic nervous system
14
Which part of the plant is described by the term, 'positively gravitropic'?
Answer
(C)
The roots
15
What structure in the eye is responsible for focusing light onto the retina?
Answer
(B)
Lens
16
What is the role of the rods in the eye?
Answer
(C)
To see in dim light.
17
Which of the following is NOT a function of the skin?
Answer
(D)
Digestion of food
18
What structure regulates the size of the pupil?
Answer
(B)
The iris
19
Which part of the neuron is responsible for receiving signals from other neurons or sensory receptors?
Answer
(B)
Dendrite
20
During a 'fight or flight' situation, which of the following is NOT likely to occur?
Answer
(C)
Decreased blood flow to muscles
21
What type of cell provides insulation for neurons in the central nervous system?
Answer
(B)
Oligodendrocytes
22
What structure is responsible for carrying impulses from the eye to the brain?
Answer
(A)
Optic nerve
23
Which plant structure is primarily responsible for absorbing water and minerals from the soil?
Answer
(D)
The root
24
What is the primary goal of homeostasis?
Answer
(B)
To maintain a stable internal environment.
25
What part of the eye is affected by the pupil reflex?
Answer
(B)
The iris
26
What is the difference between a hormone and a target cell?
Answer
(B)
Hormones are chemical substances, and target cells have specific receptors that bind with them.
27
In a plant, what is the advantage of positive phototropism?
Answer
(B)
The plant can absorb more light for photosynthesis.
28
Which part of the eye refracts light to help focus it on the retina?
Answer
(B)
Lens
29
What is the relationship between hormones and target cells?
Answer
(C)
Hormones affect target cells with specific receptors.
30
What is the main function of the endocrine system?
Answer
(C)
To regulate body functions using hormones.
31
What is the response of roots to gravity?
Answer
(A)
Positive geotropism
32
What is a key difference between the nervous and endocrine systems?
Answer
(B)
The nervous system uses electrical impulses for rapid communication, while the endocrine system uses hormones for slower, longer-lasting effects.
33
What best describes how hormones travel throughout the body?
Answer
(C)
Through the bloodstream.
34
What happens to the body's blood vessels during vasoconstriction in response to cold?
Answer
(B)
They constrict to conserve heat.
35
What is the effect of vasoconstriction?
Answer
(B)
Decreased blood flow.
36
What type of signal travels across the synapse?
Answer
(B)
Chemical signal
37
What is the correct sequence of the events in a simple reflex arc?
Answer
(A)
Receptor -> Sensory neuron -> Relay neuron -> Motor neuron -> Effector
38
What changes occur in the eye when focusing on a distant object?
Answer
(B)
The ciliary muscles relax, and the suspensory ligaments tighten, making the lens flatter.
39
What components are involved in the transmission of a nerve impulse across a synapse?
Answer
A
B
C
40
What are the functions of the ciliary muscles?
Answer
B
C
41
What is the role of the rods in the retina?
Answer
(B)
To detect light intensity in dim conditions
42
What best describes the function of the motor neurons?
Answer
(B)
Carry impulses to effectors
43
What part of the brain is responsible for processing sensory information and initiating voluntary actions?
Answer
(C)
Cerebrum
44
In a plant, what is the growth response called when a stem grows upwards?
Answer
(C)
Negative geotropism
45
Which of the following is NOT a function of the myelin sheath?
Answer
(C)
To generate action potentials
46
What is the name of the insulating layer around the axon of a neuron?
Answer
(C)
Myelin sheath
47
What happens to the body when blood vessels constrict?
Answer
(A)
Blood flow decreases.
48
Which parts of the eye are involved in the process of accommodation?
Answer
A
B
49
What term describes the widening of blood vessels?
Answer
(B)
Vasodilation
50
What is the stimulus that triggers the 'fight or flight' response?
Answer
(C)
A perceived threat or danger