Tag: zoology

Questions Related to zoology

Hormones can be composed of

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Amino acid derivatives

  2. Polypeptide proteins

  3. Steroid

  4. All of the above

Show answer
Correct Option: D
Explanation:

Hormones are also grouped into three general structures as follows:

  1. Steroid hormones are fat-soluble molecules made from cholesterol. Among these are the three major sex hormones groups: estrogens, androgens and progesterones. Males and females make all three, just in different amounts. Steroids pass into a cell's nucleus, bind to specific receptors and genes and trigger the cell to make proteins.
  2. Amino acid derivatives, such as epinephrine, are water-soluble molecules derived from amino acids (the building blocks of protein). These hormones are stored in endocrine cells until needed. They act by binding to protein receptors on the outside surface of the cell. The binding alerts a second messenger molecule inside the cell that activates enzymes and other cellular proteins or influences gene expression.
  3. Insulin, growth hormone, prolactin and other water-soluble polypeptide hormones consist of long chains of amino acids, from several to 200 amino acids long. They are stored in endocrine cells until needed to regulate such processes as metabolism, lactation, growth and reproduction.

Hormones of adrenal cortex are synthesised from

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Tyrosine

  2. Tryptophan

  3. Cholesterol

  4. Glycoproteins

Show answer
Correct Option: C
Explanation:
A. Tyrosine is the precursor for thyroxine hormone.
B. Tryptophan is the precursor for melatonin and serotonin hormone.
C. Cholesterol is used in the synthesis of steroid hormones.
D. Glycoproteins are the proteins having carbohydrate group.
Hormones of adrenal cortex are steroid hormones. They are derived from cholesterol.
So, the correct answer is 'Cholesterol'.

Steroid hormones are derived from 

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Cholesterol

  2. Corticoid

  3. NAD

  4. Protein

Show answer
Correct Option: A
Explanation:
Steroid hormones are derived from cholesterol. They are in the form of lipids and synthesised by gonads and adrenal glands. For example. testosterone and estrogen are steroid sex hormones synthesised by gonads and corticoids (glucocorticoids, mineralocorticoids and sexocorticoids) are synthesised by adrenal cortex. The receptors for steroid hormones are located inside the cells i.e. intracellular receptors. 
So, the correct answer is 'Cholesterol'.

Steroid hormones have a _______ effect.

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Slow and short term

  2. Fast and short term

  3. Fast and long lasting

  4. Slow and long lasting

Show answer
Correct Option: D
Explanation:
Steroid hormones are derived from cholesterol. They are in the form of lipids. The receptors for steroid hormones are located in the cell i.e. they are intracellular receptors. Steroid hormones cross the cell membrane as they are lipid soluble and enter the cell where they bind with the receptors and hormone-receptor complex is formed. Thus, steroid hormones act slowly but they have along lasting effect on metabolism.
So, the correct answer is 'Slow and long lasting'.

Which one is not involved as secondary messenger in $Ca^{2+}$ mediated hormone

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. cAMP

  2. DAG

  3. $IP _3$

  4. Phospholipase

Show answer
Correct Option: D

Which of these is a steroid hormone? 

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Epinephrine

  2. Thyroxine

  3. Estrogen

  4. Gonadotropin

Show answer
Correct Option: C
Explanation:
Estrogen is a steroid hormone secreted from ovarian follicles and stimulates the development of secondary sex organs and sexual characters in females. Steroid hormones are synthesised from cholesterol. They are in the form of lipids and their receptors are located inside the cell.
Epinephrine is derived from amino acid tyrosine, thyroxine is a peptide hormone and gonadotropin is a glycoprotein.
So, the correct answer is 'Estrogen'.

Which of these is not a steroid hormone? 

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Aldosterone

  2. Androgen

  3. Estrogen

  4. Thyroxine

Show answer
Correct Option: D
Explanation:
A. Aldosterone is a mineralocorticoid hormone secreted from the adrenal cortex. It maintains the electrolyte balance in the body by reducing the loss of sodium through urine and sweat.
B. Androgen is a sexocorticoid produced by adrenal cortex. It stimulates the deposition of protein in muscles and nitrogen retention in males.
C. Estrogen is the female sex hormone secreted from ovarian follicles and stimulate the development of female secondary sex organs.
D. Thyroxine is secreted from thyroid gland. It stimulates the consumption of oxygen by metabolically active tissues and also increases the oxidation of glucose in tissues. 
Out of all these hormones, thyroxine is not a steroid hormone. Instead, it is derived from amino acid tyrosine.
So, the correct answer is 'Thyroxine'.

Which of these is a glycoprotein?

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Erythropoietin

  2. Insulin

  3. Oxytocin

  4. Vasopressin

Show answer
Correct Option: A
Explanation:
Erythropoietin is a glycoprotein hormone secreted by juxtaglomerular cells of kidneys. It acts on bone marrow and stimulates the formation of red blood cells (RBCs). This process is known as erythropoiesis. Erythropoietin is secreted in response to hypoxic conditions in body as RBC carry oxygen and transport it to different parts of the body.
Insulin, oxytocin and vasopressin are peptide hormones and are composed of amino acids.
So, the correct answer is 'Erythropoietin'. 

When all the peptide bonds of a protein have been broken down, the result would be

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Polypeptides

  2. Oligopeptides

  3. Peptides

  4. Amino acids

Show answer
Correct Option: D

Name the chemical, deficiency of which causes Parkinson's disease while excess production may lead to schizophrenia.

zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. Dopamine

  2. Acetylcholine

  3. Endorphins

  4. Glycine

Show answer
Correct Option: A
Explanation:
Dopamine is a catecholamine secreted from adrenal gland. It acts as a neurotransmitter and precursor for norepinephrine. Deficiency of dopamine causes Parkinson's disease in which muscles become rigid. The neurons that secrete dopamine degenerate in this disease. Excess amounts of dopamine cause schizophrenia in which a person's ability to think and feel is affected. The patient loses his ability to concentrate and the memory is also affected.
So, the correct answer is 'Dopamine'.