1. Biochemistry is the study of:
Answer: B. the composition and structure of chemical compounds in living organisms and the chemical processes in them
Biology Class 11 Unit 2: Molecular Biology (Biological Molecules) MCQs
235 multiple choice questions with the correct answer for each. Tap an option to check yourself, or switch on "Show all answers". This is page 1 of 5.
Tap an option to check your answer.
2. Molecular biology is a:
Answer: B. specialized branch of biochemistry
3. The most prevalent type of chemical bond in biological molecules is the:
Answer: C. covalent bond
4. Which of the following is NOT a covalent bond found in biomolecules?
Answer: D. Hydrogen bond
5. An ionic bond is formed when:
Answer: B. one atom donates electrons to another, forming oppositely charged ions that attract
6. Hydrogen bonds form between a hydrogen atom bonded to a highly electronegative atom and:
Answer: B. a lone pair of electrons on a neighbouring electronegative atom
7. In DNA, the number of hydrogen bonds between guanine and cytosine is:
Answer: C. three
8. In DNA, adenine and thymine are joined by:
Answer: B. two hydrogen bonds
9. Hydrophobic interactions occur between:
Answer: B. non-polar molecules or regions in the presence of water
10. In the cell membrane, phospholipid hydrophobic tails are oriented:
Answer: B. towards each other, away from water
11. Hydrophilic literally means:
Answer: C. water loving
12. The living mass of the cell and the organism is called:
Answer: C. protoplasm
13. Approximately how many bioelements are found in living organisms?
Answer: B. 25
14. The six major bioelements constituting about 99 percent of protoplasm include:
Answer: B. C, H, O, N, Ca, P
15. The most abundant element in the human body is:
Answer: C. oxygen
16. Which of the following is a minor bioelement?
Answer: C. Potassium
17. The percentage of water in both bacterial and mammalian cells is about:
Answer: C. 70 percent
18. The four fundamental biological molecules are:
Answer: B. carbohydrates, proteins, lipids, nucleic acids
19. A macromolecule made of many repeating units is called a:
Answer: C. polymer
20. In condensation reaction two monomers join with the release of:
Answer: B. water
21. When 20 monomers are condensed to form a polymer, the number of water molecules released is:
Answer: B. 19
22. Condensation is also called:
Answer: B. dehydration synthesis
23. Hydrolysis is:
Answer: B. breakdown of a polymer into monomers by the addition of water
24. All digestion reactions are examples of:
Answer: B. hydrolysis
25. The percentage of water in the jellyfish body is about:
Answer: C. 99 percent
26. The water molecule is polar because:
Answer: C. electrons are shared unequally between oxygen and hydrogen
27. Polarity makes water an excellent solvent for:
Answer: B. polar substances and ionic compounds
28. The attraction among water molecules themselves is called:
Answer: B. cohesion
29. The attraction between water molecules and polar surfaces is called:
Answer: B. adhesion
30. The specific heat capacity of water is:
Answer: C. 1 calorie per gram per degree Celsius
31. Water has a high specific heat because:
Answer: B. much of the absorbed heat is used to break hydrogen bonds
32. Heat of vapourization of water is about:
Answer: C. 574 calories per gram
33. Sweating cools an animal because of water's:
Answer: C. high heat of vapourization
34. When oil drops on water join into a single drop, the property shown is:
Answer: C. hydrophobic exclusion
35. When water ionizes it releases:
Answer: B. an equal number of hydrogen ions and hydroxyl ions
36. Ice floats on water because:
Answer: B. it is less dense, having a lattice with maximum hydrogen bonding
37. The word carbohydrate literally means:
Answer: B. hydrates of carbon
38. The general formula of a carbohydrate by the classic concept is:
Answer: B. Cn(H2O)n
39. Carbohydrates are now defined as:
Answer: B. polyhydroxy aldehydes or polyhydroxy ketones or their complex derivatives
40. Carbohydrates are classified on the basis of:
Answer: C. the number of saccharide units
41. Oligosaccharides are made of:
Answer: B. 2 to 10 saccharide units
42. The general formula of monosaccharides is:
Answer: B. (CH2O)n
43. Monosaccharides contain carbon atoms ranging from:
Answer: C. 3 to 7
44. Monosaccharides containing an aldehyde group are called:
Answer: B. aldoses
45. Fructose is a:
Answer: B. ketohexose
46. Ribose and deoxyribose belong to:
Answer: C. pentoses
47. Glyceraldehyde is a:
Answer: A. triose
48. Galactose is a component of:
Answer: C. milk sugar
49. The five-cornered ring structure of monosaccharides is called:
Answer: B. furanose
50. The six-cornered ring with one oxygen and five carbon atoms is called:
Answer: B. pyranose
About Biology Class 11 Unit 2 MCQs (Federal Board)
These 235 Biology MCQs cover Class 11 Unit 2: Molecular Biology (Biological Molecules) of the Federal Board (FBISE) HSSC-I (1st Year / Class 11) syllabus. They are SLO-based MCQs as per the new pattern for FBISE exams. Each question has four options and the correct answer is shown, so you can practise for the annual examination and find the topics you still need to revise. The questions are split over 5 pages of 50. Use the Print button to save this chapter as a PDF.