Question 1

In mammals, the female secondary (accessory) sexual characters are developed by the hormone

Accepted Answer

Oestrogen is responsible for the appearance of secondary sexual characteristics (development of breasts, pubic and axillay hair) for females at puberty and for the maturation and maintenance of the reproductive organs in their mature functional state.Thus, the correct answer is the option (B).

Question 2

Which of the following is secreted at ends of nerve fibres?

Accepted Answer

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Question 3

Which one of the following statements is correct?

Accepted Answer

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Question 4

If both ovaries are removed from a rat, then which hormone will decrease in blood?

Accepted Answer

The ovary is a reproductive organ, found in pairs as part of the vertebrate reproductive system in females. Ovaries are gonads and are endocrine glands. They secrete the hormone oestrogen and in less quantity, testosterone and progesterone. Oestrogen is responsible for the appearance of secondary sex characteristics for females at puberty. So, if both the ovaries are removed, then there will be no production of oestrogen.Thus, the correct answer is the option (B).

Question 5

The name 'second messenger' is given to which of the following?

Accepted Answer

Second messengers are the low molecular weight molecules that serve to transmit and amplify the signal of hormones, the first messenger, to initiate the downstream enzyme cascade inside the cell. cAMP serves as the second messenger in almost all the cells while ATP and GTP are the energy currencies of the cell. Thus, the correct answer is option B.

Question 6

Which of the following hormones are produced in the hypothalamus and stored in the posterior pituitary?

Accepted Answer

$\textbf{Correct option:B}$ $\textbf{Solution:}$$\textbf{Option (A)}$$\bullet$  Gonadotropin releasing hormone from hypothalamus stimulates the anterior pituitary to secrete FSH and LH .$\bullet$ FSH helps the graafian follicle development and secretion of estrogens from them ,and sperm production in males.$\bullet$ LH stimulates androgens and progesterone secretion from leydig's cell and corpus luteum respectively.$\textbf{Option (B)}$$\bullet$ The neurosecretory cells of hypothalamus secretes two hormones which are known as neurohormone and they are stored in poterior lobe of pituitary; they are oxytocin and vasopressin or ADH .$\bullet$ Vasopressin increases the permeability of distal convoluted tubules and collecting duct to water in the nephrons. ADH or vasopressin promotes contraction of involuntary muscles in the walls of the intestine, gall bladder and blood vessels and urinary bladder which creates a pressure effect. $\bullet$ Oxytocin promotes the contraction of uterine muscle  as it becomes highly sensitive to oxytocin and helps inducing labour at the later stages of pregnancy and promotes parturition.It is also called milk ejecting hormone due to contraction of myoepithelial cells of the lactating breast ,bringing milk from the alveoli to mammary ducts. $\textbf{Option (C)}$$\bullet$ Thyroid stimulating hormone promotes the uptake of iodine by the thyroid glands and stimulates the growth and synthesis of thyroid hormones which are thyroxine and triiodothyronine.$\bullet$ Growth hormone or somatotropin promotes the growth of tissues by protein synthesis and glycogen breakdown.$\textbf{Option (D)}$$\bullet$ Adrenocorticotropic hormones promotes the growth and secretion of adrenal cortex which releases mineralocorticoids,glucacorticoid and sex corticoids.$\bullet$ The intermediate lobe of pituitary secretes melanotropin or melanocyte stimulating hormones which acts on pigmented cells(melanophores) to induce skin colour in certain animals.$\textbf{Hence, the correct option is (B)}$

Question 7

Action of endocrine glands is mediated through

Accepted Answer

Endocrine glands release hormones (chemical messengers) into the bloodstream to be transported to various organs and tissues throughout the body.

Question 8

Cell surface transmembrane receptors are ?

Accepted Answer

Receptor is a molecule usually found on the surface of a cell, that receives chemical signals from outside the cell. When such external substances bind to a receptor, they direct the cell to do something, such as divide, die, or allow specific substances to enter or exit the cell.Receptors are proteins embedded in either the cell's plasma membrane (cell surface receptors), in the cytoplasm, or in the cell's nucleus (nuclear receptors), to which specific signaling molecules may attach.So, the correct answer is option A.

Question 9

An example of endocrine gland is:

Accepted Answer

A gland that makes substances such as sweat, tears, saliva, milk, and digestive juices, and releases them through a duct or opening to a body surface are called the exocrine gland.Endocrine glands are ductless glands. These pour their secretion in blood.Sebaceous glands are exocrine glands in the skin, that secretes oily material called sebum.The pineal gland is a small endocrine gland, present in the brain that produces the hormone melatonin (which is responsible for the wake/sleep patterns).Salivary glands are exocrine glands in the mouth (with ducts) that produce saliva.Mammary glands are present in females; these produce milk to feed the young one.Thus, the correct answer is option B.

Question 10

T-cells are lymphocytes, which produce the cellular immunity. These are developed from

Accepted Answer

T cells or T lymphocytes are a type of lymphocytes that plays a central role in cell-mediated immunity. They are called as T-cells because they develop and mature in the thymus.Thus, the correct answer is option A.

Chemical Control And Integration

Biology
5928 Views

In mammals, the female secondary (accessory) sexual characters are developed by the hormone

Which of the following is secreted at ends of nerve fibres?

Which one of the following statements is correct?

If both ovaries are removed from a rat, then which hormone will decrease in blood?

The name 'second messenger' is given to which of the following?

Which of the following hormones are produced in the hypothalamus and stored in the posterior pituitary?

Action of endocrine glands is mediated through

Cell surface transmembrane receptors are ?

An example of endocrine gland is:

T-cells are lymphocytes, which produce the cellular immunity. These are developed from

Chemical Control And Integration

Biology 5928 Views

In mammals, the female secondary (accessory) sexual characters are developed by the hormone

Which of the following is secreted at ends of nerve fibres?

Which one of the following statements is correct?

If both ovaries are removed from a rat, then which hormone will decrease in blood?

The name 'second messenger' is given to which of the following?

Which of the following hormones are produced in the hypothalamus and stored in the posterior pituitary?

Action of endocrine glands is mediated through

Cell surface transmembrane receptors are ?

An example of endocrine gland is:

T-cells are lymphocytes, which produce the cellular immunity. These are developed from

Biology
5928 Views