11. Which of the following statement(s) about acids is/are correct?
- They change the colour of red litmus to blue.
- They change the colour of blue litmus to red.
- They have pH value less than 7.
Select the correct answer from the codes given below:
[A] Only 1 and 3
[B] Only 2 and 3
[C] Only 1
[D] Only 2
Show Answer
Correct Answer: B [Only 2 and 3]
Notes:
Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5 – 8.3 at 25 °C.
12. Which of the following statement(s) is/are correct?
- Acids are sour in taste and generate H+ ions.
- Acids are sour in taste and generate OH– ions.
- Bases are bitter in taste and generate OH– ions.
Select the correct answer from the codes given below:
[A] Only 1 and 3
[B] Only 1 and 2
[C] Only 2 and 3
[D] All of the above
Show Answer
Correct Answer: A [Only 1 and 3]
Notes:
Acids are sour in taste, turn blue litmus to red, dissolve in water to release H+ or hydrogen ions. Acids include compounds such as HCl, HCN, and H2SO4 that ionize in water to give the H+ ion. Bases produce hydroxyl ions (OH-) when mixed with water.
13. Consider the following statements:
- It is a major constituent of biological membranes, nucleic acids and cellular energy transfer systems.
- It is needed to make shells, bones and teeth.
Which of the following elements has been described in above statements?
[A] Carbon
[B] Nitrogen
[C] Phosphorus
[D] Sulphur
Show Answer
Correct Answer: C [Phosphorus]
Notes:
Phosphorus is a major constituent of biological membranes, nucleic acids and cellular energy transfer systems. Many animals also need large quantities of this element to make shells, bones and teeth.
14. Which of the fol lowing statement(s) is/are correct?
I. Oils containing unsaturated fatty acids should be used for cooking
II. Animal fats have saturated carbon chains
III. Saturated fatty acids are generally harmful for health
[A] Only I and II
[B] Only I and III
[C] Only II and III
[D] All of the above
Show Answer
Correct Answer: D [All of the above ]
Notes:
Oils are unsaturated carbon compounds that have double or triple bonds. Double and triple bonds are easy to be digested or to be broken down into simpler substances. But if a saturated compounds like Vanaspati Ghee are used, it becomes difficult for our body to digest the food as single bonds are not easily broken down into simpler substances by the acids present in our body. Animal fat is a saturated fat in which the fatty acid chains have all or predominantly single bonds. It is made of long chains of carbon (C) atoms. Saturated fatty acids are straight-chain organic acids with an even number of carbon atoms. They raise the serum LDL cholesterol concentration when they are consumed in the diet. So, they are harmful for our health.
15. Amino acids are required for the synthesis of ____:
[A] Proteins
[B] Alkaloids
[C] Lipids
[D] Carbohydrates
Show Answer
Correct Answer: A [Proteins]
Notes:
Amino acids are required for the synthesis of body protein and other important nitrogen-containing compounds. Amino acids are constituents of protein and act as precursors for many coenzymes, hormones, nucleic acid, etc. Adult humans are unable to synthesize all twenty amino acids needed for protein synthesis; those which cannot be synthesized and which must then be acquired via the diet are referred to as essential.
16. Consider the following functions of bile juice released from the liver:
- It makes the food coming from the stomach alkaline
- It converts proteins into amino acids
- It breaks down fats into smaller globules
Which of the above statements is / are correct?
[A] Only 1
[B] Only 2 and 3
[C] Only 1 and 3
[D] All Are Correct Statements
Show Answer
Correct Answer: C [Only 1 and 3]
Notes:
Bile or gall is a dark green to yellowish brown fluid, produced by the liver that aids the digestion of lipids in the small intestine. It neutralizes the acid in food to provide the alkaline conditions needed in the small intestine. Besides, it breaks down large fat globules into smaller globules so that the pancreatic enzymes can easily act on them. This process is known as emulsification of fats. It does not convert proteins into amino acids.
17. Which of the following acids is synthesized in human stomach?
[A] Hydrochloric acid
[B] Sulphuric acid
[C] Nitric acid
[D] Phosphoric acid
Show Answer
Correct Answer: A [Hydrochloric acid]
Notes:
A typical adult human stomach will secrete about 1.5 liters of gastric acid daily. The best-known component of gastric juice is hydrochloric acid, the secretory product of the parietal, or oxyntic cell. It is known that the capacity of the stomach to secrete HCl is almost linearly related to parietal cell numbers.
18. A method for the delivery of nucleic acids to cells by high-speed particle bombardment is called?
[A] Transformation
[B] Biolistics
Biolistics
[C] Sequencing
[D] None of these
Show Answer
Correct Answer: B [Biolistics
Biolistics]
Notes:
A method for the delivery of nucleic acids to cells by high-speed particle bombardment is called Biolistics.
19. Amino acids are used to make new proteins, this is an example of which of the following?
[A] Egestion
[B] Absorption
[C] Assimilation
[D] None of the above
Show Answer
Correct Answer: C [Assimilation]
Notes:
Assimilation is the movement of digested food molecules into the cells of the body. For example, Amino acids are used to make new proteins.
20. Which of the following can affect proteins and nucleic acids, but not viruses?
[A] Denaturation
[B] Enzyme treatment
[C] Pressure
[D] All of these
Show Answer
Correct Answer: D [All of these]
Notes:
Because it affects proteins upon denaturation, this nuclease enzymes affect nucleic acids and the pressure will affect the structure but not the virus.
