Grade 11 : Biology - Neural (Set 1) | Concept of Maths

Question 1

1. Which of the following organelles are found in the cell body of a neuron as granular bodies called Nissl's granules?

A) Mitochondria and Lysosomes

B) Golgi Apparatus and Smooth ER

C) Ribosomes and Rough ER

D) Centrioles and Microtubules

Answer

Correct Answer: C

Nissl's granules are rich in RNA and are composed of free ribosomes and Rough Endoplasmic Reticulum ($RER$), facilitating protein synthesis within the neuron.

Question 2

2. In a resting neuron, the electrical potential difference across the plasma membrane is known as the resting potential. What is its typical approximate value?

A) $0 \text{ mV}$

B) $-70 \text{ mV}$

C) $+30 \text{ mV}$

D) $-90 \text{ mV}$

Answer

Correct Answer: B

The resting membrane potential is typically around $-70 \text{ mV}$, meaning the inside of the cell is more negative than the outside. This is maintained by the differential permeability of the membrane to ions like $K^+$ and $Na^+$.

Question 3

3. Bipolar neurons, characterized by having one axon and one dendrite, are typically located in which of the following tissues?

A) Cerebral Cortex

B) Retina of the Eye

C) Embryonic stage only

D) Spinal Cord

Answer

Correct Answer: B

Bipolar neurons are specialized sensory neurons. While multipolar neurons are found in the cerebral cortex, bipolar neurons are found in the retina of the eye, the olfactory epithelium, and the inner ear.

Question 4

Question 5

5. When an impulse reaches the axon terminal, it triggers the opening of voltage-gated channels for which ion, leading to neurotransmitter release?

A) $Cl^-$

B) $K^+$

C) $Na^+$

D) $Ca^{2+}$

Answer

Correct Answer: D

The arrival of the action potential at the synaptic knob causes voltage-gated $Ca^{2+}$ channels to open. The influx of $Ca^{2+}$ ions stimulates the fusion of synaptic vesicles with the pre-synaptic membrane.

Question 6

6. Which part of the human brain acts as the primary center for regulating body temperature, hunger, and thirst?

A) Hypothalamus

B) Cerebellum

C) Thalamus

D) Medulla Oblongata

Answer

Correct Answer: A

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

Question 7

7. In the peripheral nervous system ($PNS$), which cells are responsible for the formation of the myelin sheath around the axons?

A) Oligodendrocytes

B) Astrocytes

C) Schwann cells

D) Microglial cells

Answer

Correct Answer: C

In the $PNS$, Schwann cells wrap around the axon to form the myelin sheath. In the $CNS$, this function is performed by Oligodendrocytes.

Question 8

8. Which of the following represents the correct sequence of components in a simple reflex arc?

A) Effector $\rightarrow$ Motor Neuron $\rightarrow$ CNS $\rightarrow$ Sensory Neuron $\rightarrow$ Receptor

B) Receptor $\rightarrow$ Motor Neuron $\rightarrow$ CNS $\rightarrow$ Sensory Neuron $\rightarrow$ Effector

C) Receptor $\rightarrow$ Sensory Neuron $\rightarrow$ CNS $\rightarrow$ Motor Neuron $\rightarrow$ Effector

D) CNS $\rightarrow$ Receptor $\rightarrow$ Sensory Neuron $\rightarrow$ Motor Neuron $\rightarrow$ Effector

Answer

Correct Answer: C

The reflex arc pathway is: Receptor (detects stimulus) $\rightarrow$ Sensory (afferent) neuron $\rightarrow$ CNS (integration) $\rightarrow$ Motor (efferent) neuron $\rightarrow$ Effector (muscle/gland).

Question 9

9. In the human eye, the point of greatest visual acuity (resolution) where only cones are densely packed is called the:

A) Blind spot

B) Fovea centralis

C) Optic disc

D) Aqueous chamber

Answer

Correct Answer: B

The fovea is a thinned-out portion of the retina where only the cones are densely packed. It is the point where visual acuity (resolution) is the greatest.

Question 10

10. During the depolarization phase of an action potential, the axonal membrane becomes highly permeable to:

A) $K^+$ ions

B) $Cl^-$ ions

C) $Na^+$ ions

D) $Mg^{2+}$ ions

Answer

Correct Answer: C

Depolarization occurs because the stimulus causes the $Na^+$ channels to open, leading to a rapid influx of $Na^+$ ions into the cell, reversing the polarity of the membrane.

Accepted Answer

Correct Answer: B

The $Na^+-K^+$ ATPase pump actively transports $$3 Na^+$$ ions outwards for every $$2 K^+$$ ions transported inwards into the cell. This consumes one molecule of $ATP$.

Grade 11 : Biology - Neural (Set 1) | Concept of Maths