Which one of the following statements is not correct?
1. Retinal is the light absorbing portion of visual photo pigments
2. In retina, the rods have the photo pigment rhodopsin, while cones have three different photo pigments
3. Retinal is a derivative of vitamin-C
4. Rhodopsin is the purplish red protein present in rods only

Which part of the human ear plays no role in hearing as such but is otherwise very much required?
1. Eustachian tube
2. Organ of Corti
3. Vestibular apparatus
4. Ear ossicles

A person entering an empty room suddenly finds a snake, right in front, on opening the door. Which one of the following is likely to happen in his neurohormonal control system?
1. Sympathetic nervous system is activated, releasing epinephrine and norepinephrine from adrenal medulla
2. Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse
3. Hypothalamus activates the parasympathetic division of brain
4. Sympathetic nervous system is activated, releasing epinephrine and norepinephrine from adrenal cortex

The purplish red pigment rhodopsin contained in the rods type of photoreceptor cells of the human eyes is a derivative of
1. vitamin-C
2. vitamin-D
3. vitamin-A
4. vitamin-B

When a neuron is at resting state, i.e., not conducting any impulse, the axonal membrane is

The nerve centres which control the body temperature and the urge for eating are contained in
1. hypothalamus
2. pons
3. cerebellum
4. thalamus

Alzheimer’s disease in humans is associated with the deficiency of
1. dopamine
2. glutamic acid
3. acetylcholine
4. Gamma Amino Butyric Acid (GABA)

Which one of the following does not act as a neurotransmitter?
1. Acetylcholine
2. Epinephrine
3. Norepinephrine
4. Cortisone

Which of the following pesticides is an acetylcholinesterase inhibitor?
1. Aldrin
2. BHC
3. Endosulfan
4. Malathion

Identify the correct statement:
1. In amniotes, last nerve is spinal accessory.
2. In non-amniotes, last nerve is vagus.
3. Optic is shortest nerve.
4. Olfactory nerves have mixed fibres.