Tag: zoology

Questions Related to zoology

Hormones are produced at a particular centralized site and transported throughout the organism by means of 

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

  1. a series of synapses

  2. an integrated neural pathway system.

  3. cellular communication

  4. an internal transport system

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Correct Option: C

Steroid-based hormones are able to act inside the cell. This is possible because

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

  1. there are no receptors for hormones on the cell surface

  2. hormones must interact with the nucleus to have an effect.

  3. proteins carry them into the cell

  4. steroid-based hormones are hydrophobic molecules that can pass through the cell membrane.

Show answer
Correct Option: D
Explanation:
Steroid based hormones are fat soluble so they can enter the cell easily after which they bind to the specific steroid receptors and perform the required activities on the cell. And because they are lipids(hydrophobic molecules)  so they can enter the cell membrane.
So, the correct option is 'steroid-based hormones are hydrophobic molecules that can pass through the cell membrane'

The mode of action of steroid hormones involves

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

  1. a second messenger.

  2. modification of enzyme activity.

  3. stimulation of DNA replication.

  4. stimulation of mRNA transcription

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Correct Option: A

All of the following statements are true about hormones except

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

  1. They are transporated by the circulatory system

  2. They bind to receptors on target cells

  3. They must be present in large quantities to have an effect

  4. They are secreted by endocrine glands

  5. They can affect organs of the body that are far removed from their site of synthesis

Show answer
Correct Option: C
Explanation:
1. Hormones are produced by specialized glands(endocrine glands) and are secreted directly into the bloodstream.
2. Hormones are transported by the bloodstream from the endocrine cells to serve as ‘chemi­cal messenger’ which act on target cells or organs by regulating the rates of specific metabolic reactions. 
3. Hormones exert their effects not where they are locally produced, but on other tissues of the body. 
4. Hormones are required in very small amounts and their effect may be excitatory or inhibitory depending upon their concentration and the physiological state of the responding tissue. Hence, All of the following statements are true about hormones except They must be present in large quantities to have an effect. 
So, the correct answer is 'They must be present in large quantities to have an effect'.  

Choose the peptide hormone from the following

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

  1. adrenaline

  2. Insulin

  3. Testosterone

  4. Progesterone

Show answer
Correct Option: B
Explanation:

Peptide hormones are the one which have single or multiple long amino acid chain/s. Insulin is a peptide hormone with two amino acid chains, one with 21 and other with 30 amino acids. This makes option B correct. 

Identify the incorrect pair.

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

  1. Fatty acid- Insulin

  2. Glucose- Chitin

  3. Thymine- Nucleotide

  4. Amino acid- Hemoglobin

  5. Nitrogen- Uric acid

Show answer
Correct Option: A
Explanation:

Chitin is a polymer of N-acetyl glucosamine which in turn is a derivative of glucose. 

Thymine one of the purine (nitrogenous base) that makes deoxyribonucleotide units of DNA. 
Hemoglobin has four protein subunits, two alpha-globin and two beta-globin. Uric acid is a heterocyclic compound of CHON. 
Insulin is a protein hormone secreted by the pancreas.
So, the correct answer is option A.

Chemically hormones are

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

  1. Biogenetic amines only

  2. Proteins, steroids and biogenetic amines

  3. Proteins only

  4. Steroids only

Show answer
Correct Option: B
Explanation:

Hormones are certain essential substances in our bodies that are released by our body's endocrine system.  They are chemical messengers in our bodies that transmit messages for the action of various glands in our bodies and their secretions. 

Hormones are made up of certain chemical substances like proteins,  steroids and biogenetic amines. So, option B " proteins, steroids and biogenetic amine" is the correct option.

With increasing age, secretion of which of the following reduces to almost half?

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

  1. GTH

  2. Melatonin

  3. Estrogen

  4. ADH

Show answer
Correct Option: C
Explanation:
The primary function of estrogen is development of female secondary sexual characters. These include breasts, endometrium, regulation of the menstrual cycle, etc. In males, estrogen regulates certain functions of the reproductive system important for maturation of sperms. The loss of estrogen is a central feature of menopause, which usually occurs around age 50. However, estrogen production begins to decline in most women before they turn 40. 
So, the correct option is 'Estrogen'.

Which hormone promotes cell division, protein synthesis
and bone growth

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

  1. GH (STH)

  2. PTH

  3. ADH

  4. ACTH

Show answer
Correct Option: A
Explanation:

The chief function of STH (GH) is to promote synthesis and secretion of small protein hormone called insulin like growth factors (IGFs).

Epinepherine is

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

  1. Nephrostomal part of mesoderm

  2. Clusters of glomeruli in mammalian kidney

  3. Hormone of the adrenal gland

  4. Frontal lobe of nephritides

Show answer
Correct Option: C
Explanation:

The chromatin cells of adrenal medulla synthesize two hormones adrenaline or epinephrine (80%) and noradrenaline or norepinephrine (20%).