Part 6: Sense Organs – Eye (Structure, Physiology of Vision, Photoreceptors)
Part 6 (25 MCQs) on Sense Organs – Eye: Structure, Physiology of Vision, Photoreceptors from Chapter 21 – Neural Control and Coordination (NCERT Class 11 + NEET UG).
Part 6: Sense Organs – Eye (Structure, Physiology of Vision, Photoreceptors)
Q1. The eye is an organ of:
a) Hearing
b) Balance
c) Vision
d) Smell
Answer: c) Vision
Explanation:
- ✅ (c) Eye = photoreceptor organ, detects light for vision.
Q2. The transparent front part of the eye that refracts light is:
a) Iris
b) Lens
c) Cornea
d) Retina
Answer: c) Cornea
Explanation:
- ✅ (c) Cornea = transparent layer → major refraction of light.
Q3. The coloured part of the eye is:
a) Lens
b) Cornea
c) Iris
d) Retina
Answer: c) Iris
Explanation:
- ✅ (c) Iris controls pupil size, gives eye its colour.
Q4. Which structure regulates the amount of light entering the eye?
a) Retina
b) Iris
c) Cornea
d) Lens
Answer: b) Iris
Explanation:
- ✅ (b) Iris muscles adjust pupil → control light entry.
Q5. The eye lens is held in position by:
a) Iris muscles
b) Suspensory ligaments
c) Ciliary body
d) Retina
Answer: b) Suspensory ligaments
Explanation:
- ✅ (b) Lens attached to ciliary body by suspensory ligaments.
Q6. The innermost light-sensitive layer of the eye is:
a) Cornea
b) Retina
c) Sclera
d) Iris
Answer: b) Retina
Explanation:
- ✅ (b) Retina has rods & cones (photoreceptors).
Q7. Rod cells are responsible for:
a) Colour vision
b) Night vision (dim light)
c) Sharp vision
d) Binocular vision
Answer: b) Night vision (dim light)
Explanation:
- ✅ (b) Rods → sensitive to low light (scotopic vision).
Q8. Cone cells are responsible for:
a) Dim light vision
b) Colour vision and acuity
c) Peripheral vision only
d) Night blindness
Answer: b) Colour vision and acuity
Explanation:
- ✅ (b) Cones detect colours & sharp vision.
Q9. Which pigment is present in rods?
a) Iodopsin
b) Rhodopsin
c) Hemoglobin
d) Melanin
Answer: b) Rhodopsin
Explanation:
- ✅ (b) Rods contain rhodopsin (visual purple).
Q10. Which pigment is present in cones?
a) Rhodopsin
b) Iodopsin (photopsin)
c) Melanin
d) Carotene
Answer: b) Iodopsin (photopsin)
Explanation:
- ✅ (b) Cones contain iodopsin for colour vision.
Q11. The fovea centralis has:
a) Only rods
b) Only cones
c) Both rods and cones
d) No photoreceptors
Answer: b) Only cones
Explanation:
- ✅ (b) Fovea = high cone density → sharpest vision.
Q12. Blind spot in retina is due to:
a) No cones
b) No rods
c) No photoreceptors
d) Excess cones
Answer: c) No photoreceptors
Explanation:
- ✅ (c) Optic disc = no rods or cones → blind spot.
Q13. The vitreous chamber is filled with:
a) Aqueous humour
b) Vitreous humour
c) CSF
d) Plasma
Answer: b) Vitreous humour
Explanation:
- ✅ (b) Vitreous humour = jelly-like fluid in posterior cavity.
Q14. The anterior chamber of eye is filled with:
a) Aqueous humour
b) Vitreous humour
c) Plasma
d) CSF
Answer: a) Aqueous humour
Explanation:
- ✅ (a) Aqueous humour = watery fluid between cornea & lens.
Q15. Which part of eye focuses light on retina?
a) Cornea and lens
b) Iris only
c) Retina only
d) Pupil only
Answer: a) Cornea and lens
Explanation:
- ✅ (a) Cornea = major refraction, lens = fine adjustment.
Q16. Accommodation of lens is controlled by:
a) Retina
b) Iris
c) Ciliary muscles
d) Suspensory ligaments
Answer: c) Ciliary muscles
Explanation:
- ✅ (c) Ciliary muscles change lens curvature for near/far vision.
Q17. Night blindness is caused by deficiency of:
a) Vitamin A
b) Vitamin D
c) Vitamin E
d) Vitamin K
Answer: a) Vitamin A
Explanation:
- ✅ (a) Vitamin A → rhodopsin synthesis; deficiency = night blindness.
Q18. Colour blindness is due to defect in:
a) Rods
b) Cones
c) Cornea
d) Lens
Answer: b) Cones
Explanation:
- ✅ (b) Cones defective → inability to perceive some colours.
Q19. The optic nerve is cranial nerve:
a) I
b) II
c) III
d) IV
Answer: b) II
Explanation:
- ✅ (b) Optic nerve (II) transmits visual signals to brain.
Q20. Which structure prevents internal reflection in eye?
a) Retina
b) Iris
c) Choroid
d) Cornea
Answer: c) Choroid
Explanation:
- ✅ (c) Choroid = pigmented layer, absorbs extra light.
Q21. The sharpest image in eye is formed at:
a) Blind spot
b) Fovea centralis
c) Peripheral retina
d) Iris
Answer: b) Fovea centralis
Explanation:
- ✅ (b) Fovea = highest cone density → sharpest vision.
Q22. Which structure acts as diaphragm of the eye?
a) Cornea
b) Lens
c) Iris
d) Retina
Answer: c) Iris
Explanation:
- ✅ (c) Iris controls pupil size → like camera diaphragm.
Q23. Which layer forms “white of the eye”?
a) Cornea
b) Sclera
c) Retina
d) Choroid
Answer: b) Sclera
Explanation:
- ✅ (b) Sclera = tough white outer coat.
Q24. Hypermetropia (long-sightedness) is corrected by:
a) Concave lens
b) Convex lens
c) Cylindrical lens
d) Bifocal lens
Answer: b) Convex lens
Explanation:
- ✅ (b) Convex lens brings near objects into focus.
Q25. Myopia (short-sightedness) is corrected by:
a) Convex lens
b) Concave lens
c) Cylindrical lens
d) Bifocal lens
Answer: b) Concave lens
Explanation:
- ✅ (b) Concave lens diverges rays → corrects myopia.
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