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Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow?

(a)

Nitric oxide*

(b)

Nitrous oxide

(c)

Nitrogen dioxide

(d)

Nitrogen pentoxide

Correct Answer

(a)

Explanation

Answer: A The gasotransmitters are a family of gaseous signaling molecules which are produced endogenously and act at specific receptors to play imperative roles in physiologic and pathophysiologic processes. As a well-known gasotransmitter along with hydrogen sulfide and carbon monoxide, nitric oxide (NO) has earned repute as a potent vasodilator also known as endothelium-derived vasorelaxant factor (EDRF). Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164974/ https://www.civilsdaily.com/news/india-is-the-worlds-second-largest-emitter-of-nitrous-oxide/

Microtheme: "Biology,Human Physiology" —
21 questions asked in Prelims in the past.

  1. [2025] Consider the following statements :
    I. No virus can survive in/ocean waters.
    II. No virus can infect bacteria.
    III. No virus can change the cellular transcriptional activity in host cells.
    Which of the statements given above are correct?

    • (a) Only one
    • (b) Only two
    • (c) All the three
    • (d) None
    Correct Answer: (D) None
  2. [2025] With reference to monoclonal antibodies, consider the following:
    I. They are man-made proteins.
    II. They stimulate the patient’s immune system to fight the specific disease.
    III. They are produced using animal cells only.
    Which of the statements given above are correct?

    • (a) I and II only
    • (b) II and III only
    • (c) I and III only
    • (d) All the three
    Correct Answer: (D) All the three
  3. [2024] Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow?

    • (a) Nitric oxide*
    • (b) Nitrous oxide
    • (c) Nitrogen dioxide
    • (d) Nitrogen pentoxide
    Correct Answer: (A) Nitric oxide*
  4. [2022] Consider the following statements in respect of probiotics :
    1. Probiotics are made of both bacteria and yeast.
    2. The organisms in probiotics are found in foods we ingest but they do not naturally occur in our gut.
    3. Probiotics help in the digestion of milk sugars.
    Which of the statements given above is/are correct?

    • (a) 1 only
    • (b) 2 only
    • (c) 1 and 3
    • (d) 2 and 3
    Correct Answer: (C) 1 and 3
  5. [2020] Which of the following statements are correct regarding the general difference between
    plant and animal cells?
    (1) Plant cells have cellulose cell walls whilst animal cells do not.
    (2) Plant cells do not have plasma membrane unlike animal cells which do.
    (3) Mature plant cell has one large vacuole vacuoles.
    Select the correct answer using the code given below:

    • (a) 1 and 2 only
    • (b) 2 and 3 only
    • (c) 1 and 3 only
    • (d) 1, 2 and 3
    Correct Answer: (C) 1 and 3 only
  6. [2016] Which of the following statements is/are correct? Viruses can infect
    1. Bacteria
    2. Fungi
    3. Plants
    Select the correct answer using the code given below.

    • (a) 1 and 2 only
    • (b) 3 only
    • (c) 1 and 3 only
    • (d) 1, 2 and 3
    Correct Answer: (D) 1, 2 and 3
  7. [2014] Consider the following techniques/phenomena:
    1. Budding and grafting in fruit plants
    2. Cytoplasmic male sterility
    3. Gene silencing
    Which of the above is/are used to create transgenic crops?

    • (a) 1 only
    • (b) 2 and 3 only
    • (c) 1 and 3 only
    • (d) None
    Correct Answer: (B) 2 and 3 only
  8. [2013] Consider the following minerals :
    (1). Calcium
    (2). Iron
    (3). Sodium
    Which of the minerals given above is/are required by human body for the contraction of
    muscles?

    • (a) 1 only
    • (b) 2 and 3 only
    • (c) 1 and 3 only
    • (d) 1, 2 and 3
    Correct Answer: (D) 1, 2 and 3
  9. [2013] Which of the following statements is/are correct?
    (1). Viruses lack enzymes necessary for the generation of energy.
    (2). Viruses can be cultured in any synthetic medium.
    (3). Viruses are transmitted from one organism to another by biological vectors only.
    Select the correct answer using the codes given below.

    • (a) 1 only
    • (b) 2 and 3 only
    • (c) 1 and 3 only
    • (d) 1, 2 and 3
    Correct Answer: (A) 1 only
  10. [2013] Many transplanted seedlings do not grow because

    • (a) the new soil does not contain favourable minerals
    • (b) most of the root hairs grip the new soil too hard
    • (c) most of the root hairs are lost during transplantation
    • (d) leaves get damaged during transplantation
    Correct Answer: (C) most of the root hairs are lost during transplantation
  11. [2011] Regular intake of fresh fruits and vegetables is recommended in the diet since they are a good source of antioxidants. How do antioxidants help a person maintain health and promote longevity?

    • (a) They activate the enzyme necessary for vitamin synthesis in the body and help prevent vitamin deficiency.
    • (b) They prevent excessive oxidation of carbohydrates, fats and protein in the body and help avoid unnecessary wastage of energy.
    • (c) They neutralize the free radical produced in the body during metabolism.
    • (d) They activate certain genes in the cells of the body and help delay the ageing process.
    Correct Answer: (C) They neutralize the free radical produced in the body during metabolism.
  12. [2011] A married couple adopted a male child. A few years later, twin boys were born to them. The blood group of the couple is AB positive and O negative. The blood group of the three sons is A positive, B positive, and O positive. The blood group of the adopted son is?

    • (a) O positive
    • (b) A positive
    • (c) B positive
    • (d) Cannot be determined on the basis of the given data
    Correct Answer: (A) O positive
  13. [2010] Which one of the following processes in the bodies of living organisms is a digestive process?

    • (a) Breakdown of proteins into amino acids
    • (b) Breakdown of glucose into CO2 and H2O
    • (c) Conversion of glucose into glycogen
    • (d) Conversion of amino acids into proteins
    Correct Answer: (A) Breakdown of proteins into amino acids
  14. [2008] Assertion (A): In the human body, liver has an important role in fat digestion.
    Reason (R): Liver produces two important fat-digesting enzymes.

    • (a) Both A and R are individually true and R is the correct explanation of A
    • (b) Both A and R are individually true and R is not the correct explanation of A
    • (c) A is true but R is false
    • (d) A is false but R is true
    Correct Answer: (C) A is true but R is false
  15. [2008] Consider the following statements about probiotic food:
    1. Probiotic food contains live bacteria which are considered beneficial to humans.
    2. Probiotic food helps in maintaining gut flora.

    • (a) 1 only
    • (b) 2 only
    • (c) Both 1 and 2
    • (d) Neither 1 nor 2
    Correct Answer: (C) Both 1 and 2
  16. [2007] Which one of the following is not a digestive enzyme in the human system?

    • (a) Trypsin
    • (b) Gastrin
    • (c) Pepsin
    • (d) Amylase
    Correct Answer: (B) Gastrin
  17. [2007] Production of which one of the following is a function of the liver?

    • (a) Lipase
    • (b) Urea
    • (c) Mucus
    • (d) Hydrochloric Acid
    Correct Answer: (B) Urea
  18. [2007] Which one of the following parts of the human brain is the regulating center for swallowing and vomiting?

    • (a) Cerebellum
    • (b) Cerebrum
    • (c) Medulla oblongata
    • (d) Pons
    Correct Answer: (C) Medulla oblongata
  19. [2007] In the human being, normally in which one of the following parts does a sperm fertilize the ovum?

    • (a) Cervix
    • (b) Fallopian Tube
    • (c) Lower part of the uterus
    • (d) Upper part of the uterus
    Correct Answer: (B) Fallopian Tube
  20. [2007] In the human body, which one of the following hormones regulates blood calcium and phosphate?

    • (a) Glucagon
    • (b) Growth Hormone
    • (c) Parathyroid Hormone
    • (d) Thyroxine
    Correct Answer: (C) Parathyroid Hormone
  21. [2007] Which one of the following is the correct sequence in the order of decreasing length of the three structural parts given below of the small intestine in the human body?

    • (a) Jejunum – Duodenum – Ileum
    • (b) Ileum – Duodenum – Jejunum
    • (c) Jejunum – Ileum – Duodenum
    • (d) Ileum – Jejunum – Duodenum
    Correct Answer: (D) Ileum – Jejunum – Duodenum