Explanation

Acetylcholine is the neurotransmitter lying outside the central nervous system.

It plays a key role in transmitting signals between nerves and muscles in the peripheral nervous system.

Explanation

During the non-conducting state, the neuron membrane is permeable to the efflux of K⁺ (potassium ions).

This outward movement of potassium helps maintain the resting membrane potential by keeping the inside of the neuron negatively charged compared to the outside.

Explanation

Nissl's granules are groups of ribosomes.

They are found in the neuron’s cytoplasm.

They are involved in protein synthesis.

They essential for neuron growth and repair.

Explanation

In human myelinated fibers, nerve impulses travel at 100-120 meters per second.

Myelination increases conduction speed by allowing the impulse to jump between nodes of Ranvier in a process called saltatory conduction.

Explanation

The posterior lobe of the pituitary produces Antidiuretic Hormone (ADH).

ADH helps regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys.

Explanation

The organelles only found at the seeding stage in oil seed plants are glyoxiosomes. They are specialized peroxisomes involved in the conversion of stored fats into sugars during seed germination.

Explanation

The nucleus takes dyes due to the presence of chromatin.

It is a complex of DNA and proteins that make up the chromosome.

Chromatin is responsible for staining with basic dyes, such as hematoxylin and eosin.

They are commonly used in histology and cytology to visualize cell nuclei.

Chromatin is composed of:

• DNA (the genetic material)
• Histone proteins (which form a structure called a nucleosome)
• Non-histone proteins (which regulate gene expression and chromatin structure)

Explanation

In a relaxed muscle fiber,  Tropomyosin blocks the myosin binding site on the thin filament, preventing the thick filaments from binding, thus preventing muscle contraction. 

Tropomyosin:

This protein sits on the actin filament and covers the myosin binding sites, effectively blocking them from interacting with myosin heads in a relaxed muscle. 

Role of Calcium:

When calcium ions are present, they bind to troponin, which then causes a conformational change in tropomyosin, exposing the myosin binding sites on actin, allowing for muscle contraction. 

Explanation

The secondary structure of proteins is stabilized by Hydrogen bonds. 

The secondary structure of proteins, like the α-helix and β-pleated sheet, is primarily held together by hydrogen bonds formed between the carbonyl oxygen of one amino acid and the amide nitrogen of another amino acid in the polypeptide backbone. 

Explanation