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 LysosomesB) Golgi Apparatus and Smooth ERC) Ribosomes and Rough ERD) Centrioles and Microtubules

Answer

✓ Correct Answer: Option C

Explanation: 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 mVB) -70 mV +30 mV

Question 3

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

A) Cerebral CortexB) Retina of the EyeC) Embryonic stage onlyD) Spinal Cord

Answer

✓ Correct Answer: Option B

Explanation: 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

4. For the active transport of ions across the axonal membrane, the $Na^+-K^+$ pump transports how many ions in which direction?

A) $2 Na^+ out for 3 K^+ in$B) $3 Na^+ out for 2 K^+ in$C) $3 Na^+ in for 2 K^+ out$D) $1 Na^+ out for 1 K^+ in$

Answer

✓ Correct Answer: Option B

Explanation: 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 ofATP$.

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: Option D

Explanation: 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) HypothalamusB) CerebellumC) ThalamusD) Medulla Oblongata

Answer

✓ Correct Answer: Option A

Explanation: 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) OligodendrocytesB) AstrocytesC) Schwann cellsD) Microglial cells

Answer

✓ Correct Answer: Option C

Explanation: 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 ReceptorB) Receptor \rightarrow Motor Neuron \rightarrow CNS \rightarrow Sensory Neuron \rightarrow EffectorC) Receptor \rightarrow Sensory Neuron \rightarrow CNS \rightarrow Motor Neuron \rightarrow EffectorD) CNS \rightarrow Receptor \rightarrow Sensory Neuron \rightarrow Motor Neuron \rightarrow Effector

Answer

✓ Correct Answer: Option C

Explanation: 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 spotB) Fovea centralisC) Optic discD) Aqueous chamber

Answer

✓ Correct Answer: Option B

Explanation: 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) $K^+$ ionsB) $Cl^-$ ionsC) $Na^+$ ionsD) $Mg^{2+}$ ions

Answer

✓ Correct Answer: Option C

Explanation: 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: Option B

Explanation: The resting membrane potential is typically around -70 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 $Na^+$.

Grade 11 : Biology - Neural (Set 1)

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

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?

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

4. For the active transport of ions across the axonal membrane, the $Na^+-K^+$ pump transports how many ions in which direction?

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

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

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

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

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

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