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

The fatty acid used as an additive in cigarettes is

  1. heptanoic acid

  2. caprylic acid

  3. nonanoic acid

  4. lauric acid

  5. tridecylic acid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Heptanoic acid is used to esterify steroids in the preparation of drugs such as testosterone enanthate, trenbolone enanthate, drostanolone enanthate and methenolone enanthate (Primobolan). It is also one of many additives in cigarettes.

Multiple choice

The fatty acid obtained from the cyanobacterium Spirulina is

  1. paullinic acid

  2. lignoceric acid

  3. α-linolenic acid

  4. stearidonic acid

  5. gamma-linolenic acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Stearidonic acid is a ω-3 fatty acid, sometimes called moroctic acid. It is biosynthesised from alpha-linolenic acid by the enzyme delta-6-desaturase. Natural sources of this fatty acid are the seed oils of hemp, blackcurrant, corn gromwell and echium, and the cyanobacterium Spirulina.

Multiple choice

Which of the following statements is incorrect regarding triglycerides?

  1. In triglyceride form, lipids can be absorbed by the jejunum.

  2. The process of lipolysis takes place in the intestine.

  3. Triglycerides form chylomicrons.

  4. Liver cells can synthesise and store triglycerides.

  5. Human brain cannot utilise fatty acids as an energy source.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The pancreatic lipase acts at the ester bond, hydrolysing the bond and releasing fatty acid.

Multiple choice

The algae capable to produce oil used in biofeeds and biofuels is

  1. Sagenista

  2. Schizochytrium

  3. Synurids

  4. Tribonema

  5. Vaucheria
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Schizochytrium is a genus of unicellular protists found in coastal marine habitats. They are assigned to the stramenopiles, a group which also contains kelp and various of micro-algae. Certain species produce large amounts of docosahexaenoic acid and are grown commercially for production of this oil for biofeeds, biomass and biofuels.

Multiple choice

Fats are __________.

  1. body building foods

  2. energy bank of the foods

  3. inorganic compounds

  4. fibrous components of the diet

  5. needed for repair of tissues
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Fats are rich in energy and are thus, called the energy bank of the foods.

Multiple choice

The calorific values of carbohydrates, proteins and fats respectively are

  1. 4.1 k cal/g, 5.65 k cal/g and 9.45 k cal/g

  2. 5.65 k cal/g, 10 k cal/g and 2.3 kcal/g

  3. 3.1 k cal/g, 9 k cal/g and 6 k cal/g

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Carbohydrates provide 4.1 kcal/g, proteins provide 5.65 kcal/g, and fats provide 9.45 kcal/g. This explains why fats are the most energy-dense macronutrients at over twice the caloric density of carbohydrates. Option D is incorrect as these are standard physiological fuel values.

Multiple choice

Which of the following statements are incorrect?

a. The chemical digestion of food is brought about by enzymes. b. Proteins are converted into amino acids after digestion. c. Fats are converted into fatty acids and glycerol. d. Glucose, fatty acids, amino acids and glycerol are water soluble molecules.

  1. a and b

  2. a, b and c

  3. b, c and d

  4. a, b and d

  5. All of the above
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct answer as all the statements are correct.

Multiple choice

In which of the following conditions it is said that certain types of lipids and proteins are essential?

  1. When a cell cannot synthesize them and dies in their absence.

  2. When cell needs them badly, and synthesizes them on its own.

  3. When cell needs them and obtains them from the diet.

  4. When cell needs them and obtains them from adjacent cells.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  These are not synthesized in the cell so, the cell has to obtain them from the food.