Tag: zoology

Questions Related to zoology

Steroid hormones transmit their information by 

zoology control and coordination in living organisms mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

  1. Stimulating the receptors present on cellmembrane

  2. Entering into the cell and modifying cellular contents

  3. Entering into the cell and modifying nuclear organisation

  4. The help of an intracellular second messenger

Show answer
Correct Option: C
Explanation:

There are specific receptors for the binding of hormones. Steroid hormones have nuclear receptors. These steroid hormones are composed of cholesterol a dare hydrophobic in nature. They enter the cells through cell membranes. They move towards the nucleus and bind to the respective receptor. They have the activity like repression, initiation or transcription of certain genes and products. 

So, the correct answer is option C. 

Epinephrine and eicosanoids finds their receptors on

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

  1. Cell wall

  2. Plasma membrane

  3. Inner matrix

  4. None of these

Show answer
Correct Option: B
Explanation:
  •  Eicosanoids are compounds that include prostaglandins, prostacyclins, leukotrienes, and thromboxanes.
  • Lipid insoluble hormones such as eicosanoids bind to receptors on the outer surface of the plasma membrane, via plasma membrane hormone receptors.
  • The amino acid-derived hormones epinephrine and norepinephrine bind to beta-adrenergic receptors on the plasma membrane of cells.
  • Hence the Epinephrine and eicosanoids find their receptors on the plasma membrane.
  • So, the correct answer is 'Plasma membrane'.

Read the following carefully to give the correct answer 

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

  1. Protein hormone interact with the intra cellular receptor

  2. Iodothyronine hormone generate secondary messenger after interaction with receptor

  3. Hormone is a cell specific

  4. Somatostatin hormone secrete only by hypothalamus

Show answer
Correct Option: A

Tyrosine act as a precursor for which of the following hormones?

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

  1. Thyroid

  2. Adrenal

  3. Prolactin

  4. FSH

Show answer
Correct Option: A
Explanation:
  • Thyroxine (3,5,3',5'-tetraiodothyronine) is the thyroid hormone produced by follicular cells of the thyroid gland.
  • Thyroxine hormone is produced in the thyroid gland from tyrosine and iodine.
  • Hence the precursor for the synthesis of thyroid hormone is amino acid Throne.
  • Tyrosine (symbol Tyr or Y) or 4-dihydroxyphenylalanine is one of the 20 standard amino acids.
  • So, the correct answer is 'Thyroid'.

The stomach pain impulses are received by receptors known as

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

  1. Proprioreceptors

  2. Exteroreceptors

  3. Visceral receptors

  4. Chemoreceptors

Show answer
Correct Option: C
Explanation:

a) Proprioceptors are the mechanoceptors which are activated by changes in pressure or movement and are involved in maintaining muscle tone, body equilibrium and posture. 

b) Exteroreceptors are the one that is activated by stimulus from external environments. This includes photoreceptors of eye and mechanoreceptors of inner ear. Stomach pain is an internal stimulus. 
c) Receptors which are present in internal organs and are activated by internal stimuli are known as visceral receptors. 
d) Chemoceptors are the specialized receptors for taste and smell which are activated by changes in the chemical concentration of the substances. 

Intracellular receptors are mostly ?

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

  1. cytoplasmic receptors

  2. membrane receptors

  3. nuclear receptors

  4. ER receptors

Show answer
Correct Option: A

The signal transduction of steroid hormone across cell is through

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

  1. Binding of hormone to the cytoplasmic receptor and the complex binds to hormone response element on DNA with promoter DNA

  2. Binding of hormone to the transmembrane receptor which initiates the production of second messenger that activates enzymes which further activates transcription factors

  3. Binding of hormone to the transmembrane receptor which diffuse inside the cell cytoplasm and then activates the enzyme necessary for the activation of transcription factors

  4. Binding of hormone to the cytoplasmic receptor that initiates the production of second messenger which activates enzymes that further activates transcription factors

Show answer
Correct Option: C
Explanation:

Steroid hormones, i.e., androgens, estrogens, glucocorticoids, mineralocorticoids, and progestins, bind with high affinity to their respective steroid hormone receptors (SR).


Steroid hormone receptors are found in the nucleus, cytosol, and also on the plasma membrane of target cells. They are generally intracellular receptors (typically cytoplasmic or nuclear) and initiate signal transduction for steroid hormone which leads to changes in gene expression over a time period of hours to days.

So the correct answer is ' binding of hormone to the transmembrane receptor which diffuse inside the cell cytoplasm and then activates the enzyme necessary for the activation of transcription factors'.

Membrane bound receptors and hormones produce second messengers like _____.

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

  1. Renin

  2. $IP _3$

  3. ANF

  4. GHRF

Show answer
Correct Option: B

The elevated concentrations of cAMP indicates

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

  1. The activation of a cAMP-dependent protein kinase called protein Kinase A

  2. The activation of membrane receptors

  3. The splitting of ATP

  4. None of these

Show answer
Correct Option: A

The ions which plays major role in generating hormone action

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

  1. Calcium ions

  2. Magnesium ions

  3. Sodium ions

  4. None of these

Show answer
Correct Option: A
Explanation:

The ions which plays major role in generating hormone action is calcium ions. They make bones strong and powerful.