Tag: biology

Questions Related to biology

In the resting state of the neural membrane, diffusion due to concentration gradients, if allowed would drive

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

  1. $Na^{+}$ into the cell

  2. $Na^{+}$ out of the cell

  3. $K^{+}$ into the cell

  4. $K^{+}$ and $Na^{+}$ out of the cell

Show answer
Correct Option: A
Explanation:

Answer is option A i.e. "Na+ into the cell"
In the resting state of the nerve cell, the cytoplasm inside the axon has a high concentration of K+ and a low concentration of Na+. While, the surrounding fluid outside the axon and cytoplasm, has a low concentration of K+ and a high concentration of Na+. Thus, if diffusion occurs, then through concentration gradient the Na+ enters into the nerve cell.

The dark bands (Black bands) (A-bands) of a skeletal
muscle are known as

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

  1. Isotropic bands

  2. Anisotropic bands

  3. Intercalated disc

  4. Cross bridges

Show answer
Correct Option: B
Explanation:

Each myofibril shows dark and light bands' The dark bands of the myofibril are termed as A-bands or anisotropic bands.

The muscle fatigue occurs due to accumulation of

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

  1. Pyruvic acid

  2. ATP

  3. Lactic acid

  4. Eroman $CO _{2}$

Show answer
Correct Option: C
Explanation:

During muscle fatigue due to deposition of lactic acid, cytoplasm becomes acidic thereby enzyme activity stops and food is not oxidised and as the energy is not available, muscular contraction stops.

The function of the gap junction is to

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

  1. Performing cementing to keep neighbouring cells together

  2. Facilitate communication between adjoining cells by connecting the cytoplasm for rapid transfer of ions, small molecules and some large molecules

  3. Separates two cells from each other

  4. Stop substance from leaking across a tissue

Show answer
Correct Option: B
Explanation:
A. Desmosomes perform cementing to keep the neighbouring cells together. It serve anchoring function.
B. Gap junctions facilitate the cells to communicate with each other by connecting the cytoplasm of adjoining cells for rapid transfer of ions, small molecules and sometimes big molecules,
C. No such junction is present.
D. Tight junctions help to stop substances from leaking across the tissue. 
So, the correct answer is 'Facilitate communication between adjoining cells by connecting the cytoplasm for rapid transfer of ions, small molecules and some large molecules'.

Which one of the following is a correct match?

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

  1. Nerve impulses - Transmitted from axon towards dendron

  2. Synaptic knob - Dendron

  3. Neuron - Endocrine system

  4. Nerve - Excretory system

Show answer
Correct Option: A
Explanation:

The nerve impulses are generated at the sensory receptor and are carried towards the CNS through the sensory neuron. The The nerve impulse is transmitted through the axon of one neuron to the dendrite of the other neuron. At the axonic end, there are telodendrons which release the neurotransmitters which flow through the synapse to the dendrite of the other neuron. 

Thus, the correct answer is option A. 

A spinal nerve takes nerve impulses:

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

  1. to the CNS

  2. away from the CNS

  3. both to and away from the CNS

  4. only inside the CNS

Show answer
Correct Option: C
Explanation:

A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body.  We have 31 pairs of spinal nerves and they are named after the section of the spine they come out of.

8 pairs of cervical nerves (C1-C8)
12 pairs of thoracic nerves (T1 – T12)
5 pairs of lumbar nerves (L1-L5)
5 pairs of sacral nerves (S1-S5)
1 pair of coccygeal nerves (Co1)

So, the correct answer is 'both to and away from the CNS'.

The nervous system uses .............. to transmit messages.

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

  1. Chemical impulses

  2. Electrical impulses

  3. Mechanical impulses

  4. All of the above

Show answer
Correct Option: B
Explanation:

The nervous system uses electrical impulses to transmit messages. Neurons conduct electrical impulses by generating the action potential. Action potential is generated through the flow of positively charged ions across the neuronal membrane.

An axon terminal passes the electrical stimulus to a dendrite of next neuron through .............. reaction.

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

  1. Chemical

  2. Electrical

  3. Mechanical

  4. None of the above

Show answer
Correct Option: A
Explanation:

A nerve impulse travels in a form of electrical charge from a neuronal axon end to the synapse. Here, the electrical impulse is converted to the chemical impulse in the synaptic cleft. Further, this nerve impulse flows from synaptic cleft to dendritic tips, converting the chemical impulse to electrical impulse. The neurotransmitters required is synthesised only by axon terminals and the receptors required to detect these chemical transmitters are only present on the dendritic ends. Thus, the impulse always flows from one axonal end of a neuron to another dendron head of a neuron. 

So, the correct answer is option A.

A nerve impulse leaves a neuron via the

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

  1. Dendrites

  2. Cyton

  3. Axon

  4. Nucleus

Show answer
Correct Option: C
Explanation:

Dendrites are the small extension of nerve cells that receives signals from sensory receptors or other neurons.

The long extension of the cell body of the nerve cell is called as axon that serves to conduct the nerve impulse away from the cell body. 
Cyton /soma is the metabolic center of the nerve cell where the metabolic contents are manufactured. It is not involved in nerve impulse conduction. The nucleus is present in the soma. 
Therefore, the correct answer is option C.

There are certain special nerves which are insulated by myelin sheaths around them. The nerve impulse travels very fast along these nerves because it "leaps" along certain special points on these nerves. What is this special mode of conduction known as?

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

  1. Superconduction

  2. Saltatory conduction

  3. Ultrasonic conduction

  4. Hyperconduction

Show answer
Correct Option: B
Explanation:

Saltatory conduction is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials.

So, the correct option is 'Saltatory conduction'.