All Free Biology MCQs with Answers

4481. Lecithin contains_.

• A. Ethanolamine
• B. Choline
• C. Serine
• D. Betaine

Explanation: Lecithin contains choline as its phosphate head, hence option B is correct.

4482. Nitrogenous bases such as choline and serine are significant part of which of the following?

• A. Sphingolipids
• B. Phospholipids
• C. Phosphodiester
• D. None of these

Explanation: Choline and serine are phosphate heads and hence they are a part of phospholipids as phospholipids contain polar phosphate heads, glycerol and saturated fatty acid tails.

4483. Saponification number describes_.

• A. Unsaturation in fat
• B. Average molecular weight of fatty acid
• C. Acetyl number
• D. Acid number

Explanation: Saponification number describes acid number.

4484. Essential fatty acids show all the characteristics except _.

• A. Lipotropism
• B. Blood clotting factors
• C. Used for energy production
• D. None of these

Explanation: Lipotropism is not a characteristic or property of essential fatty acids. Lipotropism refers to the movement or attraction of fat cells or lipids towards a particular stimulus or location. It is not a characteristic typically associated with essential fatty acids, which are specific types of fatty acids that cannot be synthesized by the body and must be obtained through diet.

4485. A sample of RNA is sequenced and found to contain 22% adenine. Which of the following conclusions can also be drawn about the sample?

• A. 22% uracil
• B. 22% thymine
• C. 22% cytosine
• D. 22% guanine

Explanation: In RNA, Adenine forms 2 hydrogen bonds with Uracil and Cytosine bonds with Guanine. But in DNA, Adenine forms 2 hydrogen bonds with Thymine and Cytosine forms 3 hydrogen bonds with Guanine.

4486. For a protein molecule of 2000 amino acids, the mRNA will have a length of how many nucleotides?

• A. 3000
• B. 2000
• C. 6000
• D. 5000

Explanation: A amino acid is made of 3 nucleotides so 2000 multiply with 3, gives us 6000, hence option C is the correct answer.

4487. Most abundant intracellular free nucleotide is:

• A. UTP
• B. FAD
• C. NAD
• D. ATP

Explanation: ATP is most abdundant as it is used for almost every reaction in the body.

4488. Which of the following makes protective coatings around the plant organs?

• A. Lipids
• B. Waxes
• C. Glycerols
• D. Glycolipids

Explanation: Option B is correct because the cuticle is a waxy layer that reduces loss of excessive water during high temperatures in plants during transpiration.

4489. Which of the following is a water-soluble vitamin?

• A. Riboflavin
• B. Vitamin C
• C. Niacin
• D. All of these

Explanation: Option D is correct because the vitamins mentioned in option A, B and C, they are polar and can form bonds with water, making it water soluble.

4490. In DNA molecules, Adenine pairs with which of the following nucleic acid bases?

• A. Guanine
• B. Thymine
• C. Cytosine
• D. Uracil

Explanation: Adenine forms 2 hydrogen bonds with Thymine, therefore option B is correct