Tag: endocrine system and hormone

Questions Related to endocrine system and hormone

A major difference in the mechanism of action between steroid hormones and peptide hormones is that

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

  1. Steroid hormones do not affect the synthesis of proteins whereas peptide hormones affect the activity of proteins already in the cell

  2. Target cells react more rapidly to steroid hormones than they do to peptide hormones

  3. Steroid hormones bind to a receptor protein whereas peptide hormones bind to G protein

  4. Steroid proteins affect metabolism, whereas peptide hormones affect the membrane permeability

Show answer
Correct Option: A
Explanation:
 Steroids hormone Peptide hormones 
 It does not affect the synthesis of protein  Peptide hormone affect only protein 
 Target cell react more rapidly under the action of steroid hormone Target cell react slowly 
 Steroid hormones bind the nuclear receptors (protein receptor)  Peptide hormone can bind to G protein
 Steroid hormones affect metabolism.  Peptide hormone affects the membrane permeability. Because peptide hormone binds only on the receptor which is present on the plasma membrane.

So, the correct answer is ' Option A '

Which of the following conditions is not linked to deficiency of thyroid hormone?

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

  1. Cretinism

  2. Goitre

  3. Myxoedema

  4. Exopthalmia

Show answer
Correct Option: D
Explanation:

Hypothyroidism is a disorder caused due to deficiency of thyroid hormone. It may lead to cretinism, myxoedema, simple goitre, Hashimoto's disease. Exopthalamic goitre is thyroid enlargement in which thyroid secretes excessive amount of thyroid hormone. It is caused due to hypersecretion of thyroid hormone.

Which one of the following is proteinaceous in chemical nature?

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

  1. oxytocin

  2. Estrogen

  3. Progesterone

  4. Testosterone

Show answer
Correct Option: A
Explanation:

The oxytocin  is a G protein coupled receptor which requires Mg2+ and cholesterol. It belongs to the rhodopsin-type group of G protein coupled  receptors. The peripheral actions of oxytocin mainly reflect secretion from the pituitary gland. Chemical nature of oxytocin is proteinaceous . So the correct answer is 'Oxytocin' 

Which of the following hormones is a polypeptide? 

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

  1. LH

  2. Thyroxine

  3. Insulin

  4. Both B and C

Show answer
Correct Option: C
Explanation:

Polypeptide hormones are hormones made up of amino acids that are secreted by the endocrine system and distributed to end organs through the circulating blood. Endocrine organs that secrete peptide hormones include the hypothalamus, pituitary gland, thyroid gland, adrenals, ovaries, endocrine pancreas, and adipose tissues.

How many of these hormones are lipid soluble?
Progesterone, Estrogen, Epinephrine, Cortisol, Norepinephrine, Thyroxine, Prolactin, Aldosterone.

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

  1. Three

  2. Five

  3. Eight

  4. Four

Show answer
Correct Option: A
Explanation:
Dissolve in fats rather than in water. These are usually formed from cholesterol. Therefore fat-soluble hormones can pass through cell membranes.
Sex hormones or gonadal steroids are examples of the lipid-soluble hormone, like, Testosterone, Progesterone & Oestrogen. Other steroids, including Glucocorticoids such as cortisone &Mineralocorticoids such as Aldosterone, are the types of lipid-soluble hormones.
So the correct option is ' Three '.

The given table enlists various hormones and their chemical nature. Select the option which completes the table.

Hormone Chemical composition
(i) Peptide
Testosterone (ii)
Thyroxine (iii)
(iv) Amino-acid derivative
zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

  1. (i)-Cortisol, (ii)-Steroid, (iii)-Polypeptide, (iv)-Estradiol

  2. (i)-Oxytocin, (ii)-Protein, (iii)-Iodothyronin, (iv)-Epinephrine

  3. (i)-Cortical, (ii)-Protein, (iii)-Amine, (iv)-Estradiol

  4. (i)-Oxytocin, (ii)-Steroid, (iii)-Iodothyronine, (iv)-Epinephrine

Show answer
Correct Option: D
Explanation:

(i) Peptides: These hormones are further of two types: Short peptide and long peptide.

Short peptide: The hormones oxytocin and vasopressin from the posterior lobe of the pituitary gland.
Long peptide: The hormones insulin and glucagon from the pancreas.
(ii) Steroid: The hormones from adrenal cortex, testes, ovaries and placenta are steroids. So, testosterone is a steroid.
(iii) Amino acid derivative: The hormones epinephrine and norepinephrine from the adrenal medulla and thyroxine from the thyroid gland are derived from the amino acid tyrosine.
So, the correct answer is '(i)- Oxytocin, (ii)- Steroid, (iii)- Iodothyronine, (iv)- Epinephrine'.