Tag: mechanism of hormone action

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Questions Related to mechanism of hormone action

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Steroid hormones easily pass through plasma membrane by simple diffusion because they

  1. Are lipid soluble

  2. Are water soluble

  3. Enter through pores

  4. Contain carbon and hydrogen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Steroid hormones are made up of fats and they are not soluble in water. They are hydro phobic in nature. Hence they can easily pass through the plasma membrane by simple diffusion. 

So, the answer is 'Are lipid soluble'. 

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which one of the following pairs of hormones are the examples of those that can easily pass through the cell membrane of the target cell and bind to a receptor inside it(mostly in nucleus)?

  1. Insulin, glucagon

  2. Thyroxine, insulin

  3. Somatostatin, oxytocin

  4. Cortisol, testosterone
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cortisol and testosterone are lipid soluble hormones, which can directly pass through the cell membrane of the target cell and bind with intracellular receptors. So, the correct answer is option D.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of these is not a secondary messenger?

  1. cAMP

  2. cGMP

  3. Calcium

  4. Sodium/Mg
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Secondary messengers are intracellular signalling molecules released by the cell in response to exposure of extracellular signalling molecules-the first messengers. Second messengers trigger physiological changes such as proliferation, migration, survival, etc. Some common secondary messengers are cAMP(Cyclic Adenosine Mono Phosphate), cGMP(Cyclic Guanosine Mono Phosphate), Calcium ion, IP$ _3$, etc. So all the given options serve as secondary messengers except the Sodium/Mg ions.

So, the correct answer is 'Sodium/Mg'.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Steroid hormones 

  1. Work via second messenger

  2. Trigger rapid, short term response in cells

  3. Alter the activity of genes

  4. Initiate open channels in plasma membrane
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Steroid hormones are derived from cholesterol. They are in the form of lipids. Their receptors are intracellular i.e. located inside the cell. These hormones are lipid soluble and hence, cross the cell membrane easily to enter the cell. The hormone binds to receptor and a hormone-receptor complex is formed. The complex then binds to transcription factors which then bind to DNA and this causes activation and transcription of a particular gene. This leads to synthesis of specific proteins that affect the metabolism of cells.
Hence, steroid hormones alter the activity of genes.
So, the correct answer is 'Alter the activity of genes'.
Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Signalling between cells usually results in activation of protein by

  1. Kinases

  2. Proteases

  3. Lipases

  4. Nucleases
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Signalling is the communication between cells by means of signalling molecules. When a ligand binds to its receptor, ligand-receptor complex is formed which activate protein kinases. Kinases are the enzymes that transfer phosphate group to the target cells. Phosphorylation of target cells cause different changes in the cell.
So, the correct answer is 'Kinases'.
Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of these can pass easily through cell membrane of target cells and bind to internal receptors?

  1. Thyroxine, insulin

  2. Somatostatin, Oxytocin

  3. Insulin, glucagon

  4. Cortisol, testosterone
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A. Thyroxine, insulin hormones are protein hormones. 

B. Somatostatin, oxytocin are protein hormones. 
C. Insulin, glucagon are protein hormones.
D. Cortisol, testosterone are steroid hormones. 
Steroid hormones are made up of fats and are not soluble in water, hence they can easily pass through the cell membrane.
So, the answer is Cortisol, testosterone. 

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

(A) Every receptor is unique for a hormone
(B) Every hormone is unique for a receptor.

  1. Both true

  2. Both false

  3. A true B false

  4. B true B false
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the human body, every receptor is specific for a hormone and every hormone is specific for a receptor.

So, the correct option is ‘Both true’.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which one of the following is proteinaceous in chemical nature?

  1. Thyroxine

  2. Insulin

  3. Progesterone

  4. Oxytocin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Thyroxine is a proteinaceous hormone, formed by the addition of iodine to amino acid tyrosine which is then combined with protein thyroglobulin

So, the correct answer is 'Thyroxine'

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

A dehydration synthesis reaction is also known as

  1. A condensation reaction

  2. A hydrolysis reaction

  3. An isomeric reaction

  4. An energy-releasing reaction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Dehydration means removal of water. It is a synthesis reaction where polymerization occurs in which the monomers are bound together which releases water as the end product or byproduct.

Hence, the correct answer is 'A condensation reaction'.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Choose the correct answer from the alternatives given.
Pick out the false statement pertaining to acromegaly:

  1. oversecretion of somatotropin after adolescence causes this disease

  2. the person gets a giant stature

  3. long bones of the limbs elongate

  4. the person looks like a gorilla
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

GH or STH (Growth or Somatotropin Hormone) stimulates body growth, protein, fat and carbohydrate metabolism. Hypersecretion of this hormone during the period of skeleteal growth causes gigantism characterized by excessive growth of bones, with the enlargement of internal organs as well. Hypersecretion in adulthood causes acromegaly. Here thr, bones become abnormally thick due to ossification of periosteum and thickening of soft tissues as well. 

So the correct answer is the person gets a giant structure.