NEET MCQ Test 3 — Questions and Answers
Question 1: Which enzyme is responsible for unwinding the DNA double helix during replication?
- DNA polymerase
- RNA polymerase
- Helicase (Correct answer)
- Ligase
Correct answer: Helicase
Helicase breaks hydrogen bonds between base pairs to unwind the double helix at the replication fork.
Question 2: The pH of a neutral solution at 25°C is:
- 0
- 7 (Correct answer)
- 10
- 14
Correct answer: 7
A neutral solution has equal concentrations of H+ and OH- ions, giving a pH of exactly 7 at 25°C.
Question 3: Newton's second law of motion states that force equals:
- mass × velocity
- mass × acceleration (Correct answer)
- mass / acceleration
- velocity / time
Correct answer: mass × acceleration
Newton's second law is expressed as F = ma, where force equals mass multiplied by acceleration.
Question 4: Which part of the human brain controls voluntary muscle movements?
- Cerebellum
- Medulla oblongata
- Cerebrum (Correct answer)
- Hypothalamus
Correct answer: Cerebrum
The cerebral cortex of the cerebrum controls voluntary muscle movements and higher cognitive functions.
Question 5: Ozone (O3) is an allotrope of which element?
- Carbon
- Nitrogen
- Oxygen (Correct answer)
- Sulfur
Correct answer: Oxygen
Ozone (O3) is an allotropic form of oxygen, differing from the common diatomic O2 molecule.
Question 6: Which vitamin is synthesized by the human body upon exposure to sunlight?
- Vitamin A
- Vitamin B12
- Vitamin C
- Vitamin D (Correct answer)
Correct answer: Vitamin D
UV-B radiation converts 7-dehydrocholesterol in skin to Vitamin D3 (cholecalciferol) upon sun exposure.
Question 7: The phenomenon of light bending around obstacles is called:
- Reflection
- Refraction
- Diffraction (Correct answer)
- Dispersion
Correct answer: Diffraction
Diffraction is the bending of waves, including light, around the edges of obstacles or through slits.
NEET MCQ Test 3
Which enzyme is responsible for unwinding the DNA double helix during replication?