iGCSE Biology (0610)-14.2 Sense organs - iGCSE Style Questions Paper 3

Question

(a) Complete the sentences using words from the list. Each word may be used once, more than once or not at all.

movement, muscles, nerve, organisms, receptor, reflex, sense, tissues

The eye is a ………………………….. organ. The eye is made from a group of ………………………….. . The ………………………….. cells in the retina detect light.

(b) Fig. 4.1 is a diagram of the parts of the eye.

(i) Draw an X on Fig. 4.1 to show the position of the blind spot.

(ii) Identify the letters on Fig. 4.1 that represent the:

cornea ……………………………………

iris ……………………………………

retina ……………………………………

optic nerve. ……………………………………

(iii) Complete the table by describing the function of some of the structures of the eye.

▶️ Answer/Explanation

Solution

(a) The eye is a sense organ. The eye is made from a group of tissues. The receptor cells in the retina detect light.

Explanation: The eye detects light (sense organ), consists of multiple tissues (e.g., cornea, retina), and contains photoreceptor cells (rods/cones) in the retina.

(b)(i) The blind spot is where the optic nerve exits the eye (no photoreceptors). X is marked at this location.

(b)(ii)
– Cornea: B (transparent outer layer).
– Iris: C (controls pupil size).
– Retina: E (contains light-sensitive cells).
– Optic nerve: D (transmits visual signals to the brain).

(b)(iii)
– Iris: Controls the amount of light entering the eye by adjusting pupil size.
– Lens: Focuses light onto the retina for clear vision.

Question

(a) The eye is a sense organ that contains receptor cells that respond to light.

State three other stimuli that sense organs respond to.

(b) Fig. 6.1 shows a section through the human eye.

(i) State the names of the structures labelled on Fig. 6.1.

Write your answers in the spaces provided.

(ii) Draw an X on Fig. 6.1 to show the location of the blind spot.

Complete the sentences using the words from the list.

Each word may be used once, more than once or not at all.

Rays of light reach the front of the eye. Light is …… through the cornea and the …… focuses light on the retina. Light …… in the retina detect light and the optic nerve carries impulses to the …… .

(ii) State what happens to the pupil’s diameter in a person’s eye when they move from a bright room to a dark room.

▶️ Answer/Explanation

Solution

(a)

Any three from:

Chemical (e.g., taste or smell)
Sound (hearing)
Touch/pressure/pain (tactile sensations)
Temperature (thermal sensations)

Explanation: Our body has various sense organs that detect different stimuli. The nose detects chemical stimuli (smell), ears detect sound waves, skin detects touch/pressure/pain and temperature changes, while the eyes specifically detect light stimuli.

(b)(i)

Explanation: The retina is the light-sensitive layer at the back of the eye. The pupil is the opening that allows light to enter the eye, and the iris is the colored part that controls the size of the pupil.

(b)(ii)

X should be placed where the optic nerve meets the retina (the optic disc).

Explanation: The blind spot is located at the optic disc where the optic nerve exits the eye. There are no photoreceptor cells in this area, so it’s insensitive to light.

(c)(i)

Rays of light reach the front of the eye. Light is refracted through the cornea and the lens focuses light on the retina. Light receptors in the retina detect light and the optic nerve carries impulses to the brain.

Explanation: Light entering the eye is first refracted (bent) by the cornea. The lens then fine-tunes this refraction to focus the light precisely on the retina. Specialized receptor cells (rods and cones) in the retina detect the light and convert it into neural signals that travel via the optic nerve to the brain for processing.

(c)(ii)

The pupil diameter increases (dilates).

Explanation: In dark conditions, the pupil dilates (gets larger) to allow more light to enter the eye and reach the retina. This is an automatic reflex controlled by the iris muscles to optimize vision in different lighting conditions.

iGCSE Biology (0610)-14.2 Sense organs – iGCSE Style Questions Paper 3

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