Grade 11 : Biology - Neural (Set 2) | Concept of Maths

Question 1

1. While cooking, Rohan accidentally touches a hot pan. He immediately pulls his hand away before even feeling the pain. Which part of the nervous system primarily coordinates this rapid response?

A) Spinal Cord (Reflex Arc)

B) Cerebral Cortex

C) Cerebellum

D) Medulla Oblongata

Answer

Correct Answer: A

This is a reflex action. The stimulus (heat) travels via sensory neurons to the Spinal Cord, which immediately sends a motor command back to the muscles. This bypasses the conscious brain (Cerebral Cortex) initially to minimize injury.

Question 2

2. In a resting neuron, the concentration gradient is maintained by the $Na^+ - K^+$ pump. For every $1$ molecule of ATP consumed, how many ions are moved across the membrane?

A) $2 Na^+$ out and $3 K^+$ in

B) $3 Na^+$ in and $2 K^+$ out

C) $3 Na^+$ out and $2 K^+$ in

D) $2 Na^+$ in and $3 K^+$ out

Answer

Correct Answer: C

The active transport mechanism (Sodium-Potassium Pump) utilizes $1$ ATP to transport $3 Na^+$ ions out of the cell and $2 K^+$ ions into the cell, helping maintain the negative resting potential.

Question 3

3. A scientist observes that a specific nerve fiber has a high conduction velocity due to "Saltatory Conduction". This process is characterized by the impulse jumping between which structures?

A) Dendrites

B) Nodes of Ranvier

C) Myelin Sheaths

D) Synaptic Knobs

Answer

Correct Answer: B

Saltatory conduction occurs in myelinated neurons where the action potential "jumps" from one Node of Ranvier to the next, significantly increasing the speed of transmission compared to unmyelinated fibers.

Question 4

4. When a person enters a dark movie theater from bright sunlight, they are initially unable to see, but vision gradually improves. This "Dark Adaptation" is primarily due to the regeneration of which pigment in the rods?

A) Iodopsin

B) Rhodopsin

C) Melanin

D) Hemoglobin

Answer

Correct Answer: B

Rods are responsible for scotopic (twilight/dark) vision. They contain a purplish-red protein called Rhodopsin (Visual Purple), which contains a derivative of Vitamin A. It bleaches in light and regenerates in the dark.

Question 5

5. During an intense football match, a player’s heart rate and breathing rate increase significantly. Which division of the Autonomic Nervous System (ANS) is primarily responsible for this "fight or flight" response?

A) Somatic Nervous System

B) Central Nervous System

C) Parasympathetic Nervous System

D) Sympathetic Nervous System

Answer

Correct Answer: D

The Sympathetic Nervous System prepares the body for emergency or high-stress situations by increasing heart rate, dilating bronchioles, and redirecting blood flow to muscles.

Question 6

6. An gymnast is able to maintain perfect body posture and balance while walking on a narrow beam. Which part of the brain is the main center for such motor coordination and equilibrium?

A) Cerebrum

B) Hypothalamus

C) Cerebellum

D) Corpus Callosum

Answer

Correct Answer: C

The Cerebellum (often called the "little brain") is responsible for coordinating voluntary movements, maintaining posture, and ensuring body balance/equilibrium.

Question 7

7. At a chemical synapse, when an action potential reaches the axon terminal, it triggers the opening of voltage-gated channels for which specific ion to facilitate neurotransmitter release?

A) $Ca^{2+}$

B) $K^{+}$

C) $Cl^{-}$

D) $Mg^{2+}$

Answer

Correct Answer: A

The arrival of the impulse at the axon terminal opens voltage-gated Calcium ($Ca^{2+}$) channels. The influx of calcium ions stimulates synaptic vesicles to fuse with the plasma membrane and release neurotransmitters into the synaptic cleft.

Question 8

8. A patient complains of difficulty in hearing. The doctor finds that the vibrations are not being transmitted effectively from the ear drum to the inner ear. Which set of bones (Ear Ossicles) is involved in this transmission?

A) Femur, Tibia, Fibula

B) Malleus, Incus, Stapes

C) Radius, Ulna, Humerus

D) Atlas, Axis, Sacrum

Answer

Correct Answer: B

The middle ear contains three tiny bones called ear ossicles: Malleus (hammer), Incus (anvil), and Stapes (stirrup). They amplify sound waves and transmit them to the oval window of the cochlea.

Question 9

9. The master control center for body temperature, hunger, and thirst is located in which part of the forebrain?

A) Hypothalamus

B) Thalamus

C) Hippocampus

D) Amygdala

Answer

Correct Answer: A

The Hypothalamus contains centers which control body temperature, urge for eating (hunger), and drinking (thirst). It also secretes various hypothalamic hormones.

Question 10

10. In the human eye, the point of greatest visual acuity (sharpness) where only cones are densely packed is known as the:

A) Blind Spot

B) Optic Disc

C) Fovea Centralis

D) Aqueous Humor

Answer

Correct Answer: C

The Fovea Centralis (a thinned-out portion of the macula lutea) contains only cones and is the area where visual resolution (acuity) is the highest.

Grade 11 : Biology - Neural (Set 2) | Concept of Maths