Tag: biology

Questions Related to biology

Identify the correct match from the column I, II & III:-

Column-I Column-II Column-II
1) Dendron a) Myelinogesis i) transduction
2) Cell body b) Receptor ii) P.N.S
3) Myelinated Axon c) Grey matter iii) Information co-ordination
4) Schwann cell d) White matter iv) Fast conduction
biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. $1-b-i, \quad 2-c-iii, \quad 3-d-ii, \quad 4-a-iv$

  2. $1-b-i, \quad 2-c-iii, \quad 3-d-iv, \quad 4-a-ii$

  3. $1-a-i, \quad 2-d-iv, \quad 3-c-iii, \quad 4-b-ii$

  4. $1-d-iv, \quad 2-a-i, \quad 3 - c-ii, \quad 4-b-iii$

Show answer
Correct Option: B
Explanation:

The correct match can be represented as-

   Column-I    Column-II    Column-III
 1)  Dendron  b)  Receptor I)  transduction 
 2)  Cell body  c)  Grey matter iii)   information co-ordinator
 3)  Myelinated Axon d)   White matter iv)  fast - conduction
 4)  Schwann cell  a)  Myelinogenesis  ii)  P.N.S.

So, the correct option is '1-b-i, 2-c-iii, 3-d-iv, 4-a-ii'.

When the person is alert, with open eyes and actively trying to solve some complex problem, the EEG shows ............ waves.

biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. Alpha

  2. Beta

  3. Delta

  4. Gamma

Show answer
Correct Option: B
Explanation:

An electroencephalogram (EEG) is a test, that measures and records the electrical activity of the brain. Beta waves have a frequency of 13 to 30 cycles per second. These waves are normally found, when person is alert or have taken high doses of certain medicines, such as benzodiazepines.

When the direction of nerve impulse is reversed, the condition is

biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. Axo - Axonic synapse

  2. Axo - Dendritic synapse

  3. Both of the above

  4. None of the above

Show answer
Correct Option: A
Explanation:

There are different forms of synapse depending on the position of the synapse. When the synapse occurs in the axon, the synapse is known as the axoaxonic synapse. The nerve impulse conduction takes place from one axon to the other axon. The nerve impulse is transferred from the axon of one neuron to the axon of the other neuron. In this process, the direction of nerve impulse is reversed from axon to dendron to the axon to axon. 

Thus,l the correct answer is option A. 

Waves emitted in brain during deep sleep is

biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. Alpha

  2. Beta

  3. Delta

  4. Gamma

Show answer
Correct Option: C
Explanation:

A delta wave is a high amplitude brain wave. Delta waves are usually associated with the deep stage 3 of NREM sleep, also known as slow-wave sleep (SWS) and aid in characterizing the depth of sleep.

Which of the following statements about the transmission of the nerve impulse is correct? 
(a) A nerve impulse travels from the dendritic end towards the axonal end.
(b) At the dendritic end, electrical impulses bring about the release of some chemicals which generate an electrical impulse at the axonal end of another neuron.
(c) The chemicals released from the axonal end of one neuron cross the synapse and generate a similar electrical impulse in a dendrite of another neuron.
(d) A neuron transmits electrical impulses not only to another neuron but also to muscle and gland cells.

biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. (a) and (c)

  2. (b) and (d)

  3. (a), (c) and (d)

  4. (b), (c) and (d)

Show answer
Correct Option: C
Explanation:

A nerve impulse is a way nerve cells (neurons) communicate with one another. Nerve impulses are mostly electrical signals along the dendrites to produce a nerve impulse or action potential. The action potential is the result of ions moving in and out of the cell.
A nerve impulse travels from the dendritic end towards the axonal end. The chemicals released from the axonal end of one neuron cross the synapse and generate a similar electrical impulse in a dendrite of another neuron. A neuron transmits electrical impulses not only to another neuron but also to muscle and gland cells.

Therefore, the correct answer is option C.

Speed of nerve impulse in mammals is 

biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. 1 meter /sec

  2. 100 meter/sec

  3. 1000 meter /sec

  4. None of the above

Show answer
Correct Option: B
Explanation:

Nerve impulses are conducted with great velocity. In mammalian nerve, the speed of conduction may be as high as 100 meters per second.

The rate at which a nerve impulse travels along a nerve fiber is dependent up on 

biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. Length of the nerve fibre

  2. Diameter of the nerve fibre

  3. Presence of connective tissue sheath

  4. None of the above

Show answer
Correct Option: B
Explanation:

Increased axon diameter in axons leads to increase action potential velocity. As there is an increase in diameter of a fibre, its internal resistance decreases. The internal resistance decreases faster relative to the membrane resistance - therefore the distance the membrane potential can travel is increased by an increased diameter. So, the correct answer is option B.

If myelin sheath is continued in myelinated nerve fibre then what will happen in a neuronal conduction?

biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. Velocity will be increased.

  2. Conduction will be slow.

  3. Conduction will be stopped.

  4. No effect is seen.

Show answer
Correct Option: C
Explanation:

Myelin is an insulating layer or sheath, that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. The purpose of the myelin sheath is to allow electrical impulses to transmit quickly and efficiently along the nerve cells. Nerve impulses cannot pass through the myelination, so they jump from one node of Ranvier to the next. If the whole nerve becomes myelinated then the conduction will be stopped.

The speed of nerve impulse depends on the diameter of the axon.
biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

The speed with which the nerve impulse is conducted by axon is known as nerve conduction velocity. The speed of nerve conduction does not depend on the diameter of axon only rather it depends on the diameter of the nerve fibre. The diameter of nerve fibre is axon, neurilemma, and myelin sheath in myelinated axons while axon and neurilemma in unmyelinated fibre. Conduction velocity is high in myelinated nerve fibre with the greater diameter. So, the given statement is false.

The propagation of a nerve impulse is due to changes in the permeability of the nerve cell membrane that allow for a voltage difference across the membrane.

biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Neurons send messages through electrical impulses called as nerve impulses. The nerve impulse is due to the changes occurring across the cell membrane. Cell membranes contain a sodium-potassium pump. The concentration of sodium and potassium ions is different across the membrane. This difference causes a voltage difference between the inside of the neuron and its surroundings. This is called as the resting membrane potential. The membrane potential is always negative inside the cell. The sodium and potassium channels in the cells are voltage-gated, meaning they can open and close depending on the voltage across the membrane. During action potential, permeability of the nerve cell membrane changes for both sodium and potassium ions. During depolarization, there is influx of sodium ions which makes inside of the cell positive. Depolarization is followed by repolarization during which the outflux of potassium ions takes place which makes inside of the cell negative. The whole process results in the propagation of a nerve impulse.

Thus, the correct answer is option A.