Biology · Chemistry

Lipids, Fats, and Biochemistry

1,130 Questions

Lipids, fats, and biochemistry explore the structure and function of biological molecules. This includes fatty acids, cholesterol, trans-fats, and cellular membranes. Questions on this topic frequently appear in science sections of competitive government exams.

Types of fats and lipidsCholesterol and human bodyFatty acidsCellular membranes

Lipids, Fats, and Biochemistry Questions

Multiple choice

Which of the following statements about fats is incorrect?

  1. Fats can be a cell structure.

  2. Fats can be component of hormones.

  3. Fats are a more efficient form of energy storage than the proteins.

  4. Fats are a less efficient form of energy storage than carbohydrate.

  5. Fats are a type of lipids.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fats are a more efficient form of energy storage than carbohydrates and proteins.

Multiple choice

Based on the structural insights of the following compounds, mark the one that does not fit in the group of amphipathic compounds.

  1. Oleic acid

  2. Phosphatidylcholine

  3. Cholesterol

  4. Succinate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Oleic acid and cholesterol are uncharged species but have components, which are hydrophobic and others which are hydrophillic. Phosphatidylcholine has a +ve charge on N and a -ve on P, which makes it an amphipathic compound.

Multiple choice

Cell membranes are dynamic structures constituted of various biochemical entities. Many models have been proposed for defining the structure and constitution of membranes. The most accepted of these is the Singer and Nicholsons’ fluid mosaic model. Based on the knowledge of Singer and Nicholsons’ model, answer the following:

Which of the following biochemical moieties are proposed to be biological constituents of plasma membrane?

  1. Glycoproteins and glycolipids

  2. Phospholipids and chitin

  3. Proteins, lipids, carbohydrates and their collaborative derivates

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Singer and Nicholson's fluid mosaic model states that plasma membranes are composed of proteins, lipids (phospholipids, cholesterol), and carbohydrates (as glycoproteins and glycolipids). Option C correctly lists all major constituents.

Multiple choice

Consider the following statements regarding omega-3 fatty acids. Which of these statements is/are correct?

  1. Fish oil has become famous for its omega-3 fatty acid content but fish doesn't actually produce omega-3s.
  2. Their consumption may reduce the risk of coronary heart disease.
  3. They are essential fatty acids.

  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 1, 2 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

N−3 fatty acids (popularly referred to as ù−3 fatty acids or omega-3 fatty acids) are essential unsaturated fatty acids with a double bond (C=C) starting after the third carbon atom from the end of the carbon chain. The omega-3 fatty acids are "essential" fatty acids because they are vital for normal metabolism and cannot be synthesized by the human body. (Hence, statement 3 is correct.) Omega-3 fatty acids are made by marine microalgae. These are then consumed by fish and accumulate to high levels in their internal organs. (Hence, statement 1 is correct.)  Some evidences suggest that people with certain circulatory problems, such as varicose veins, may benefit from their dietary consumption, which may stimulate blood circulation, increase the breakdown of fibrin, a compound involved in clot and scar formation, and may reduce blood pressure. Evidently, Omega-3 fatty acids reduce blood triglyceride levels and regular intake may reduce the risk of secondary and primary heart attack. (Hence, statement 2 is also correct.)

Multiple choice

Identify the TRUE statements.

  1. The site for lipid synthesis is RER.
  2. The most abundant intracellular cation is K+.
  3. The first stable product of fixation of atmospheric nitrogen in leguminous plants is ammonia.
  4. A phosphoglyceride is always made up of a saturated or unsaturated fatty acid esterified to a phosphate group which is also attached to a glycerol molecule.

  1. 1 and 2

  2. 1 and 4

  3. 2 and 3

  4. 2 and 4

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct answer. Both statements are true. K+ is most abundant ion of intracellular fluid while Na+ is extra cellular fluid. The first stable product of fixation of atmospheric nitrogen in leguminous plants is ammonia.

Multiple choice

Which of the following excretory substances is not present in sebum?

  1. Wax

  2. Keratin

  3. Fatty acid

  4. Sterol
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Keratin is an extremely strong protein, which is a major component in skin, hair, nails, hooves, horns and teeth. The amino acids which combine to form keratin have several unique properties, and depending on the levels of the various amino acids, keratin can be inflexible and hard, like hooves, or soft, as is the case with skin.

Multiple choice

The primary source(s) of carbohydrates is/are

  1. marine animals

  2. plants

  3. coal tar

  4. crude oil
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plants produce carbohydrates through photosynthesis, converting light energy, water, and carbon dioxide into glucose and other carbohydrate molecules. This makes plants the primary producers of carbohydrates in virtually all ecosystems, forming the base of food chains. Marine animals, coal tar, and crude oil either consume carbohydrates or are derived from ancient plant matter, but only plants actively synthesize carbohydrates from inorganic sources.

Multiple choice

What is a cocoon made up of?

  1. Fats

  2. Carbohydrates

  3. Proteins

  4. Minerals
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Caterpillar in its next stage, called pupa, secretes protein fibres which harden on exposure to air and become silk fibres, which is soon fully formed and the covering is known as cocoon.