Biology · Chemistry

Lipids, Fats, and Biochemistry

1,009 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 biology food for health fats fats and their test different nutrients in food

Fats in the body are formed when

  1. Glycogen is formed from glucose.

  2. Sugar level becomes stable in blood.

  3. Extra glycogen storage in liver and muscles is stopped.

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

Carbohydrates are the preferred fuel for cellular respiration. Excess carbohydrates are stored as glycogen in muscles and liver. Glycogen storage is for short duration only. Glycogen reserves meet energy demand between meals and during intense physical exercises. Long term storage of carbohydrates occurs as fats. After storing glycogen, still extra carbohydrates available are converted to fats for long term storage in the body.

Multiple choice biology food for health fats fats and their test different nutrients in food

The molecule used by most animals for long term energy storage is

  1. Starch

  2. Fat

  3. Protein

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

The fats contain more energy per gram than carbohydrates and as a result of this, the body tends to use fat to store energy over long periods of time and uses carbohydrates to store energy short-term.
Therefore, the correct answer is option B.

Multiple choice biology food for health fats fats and their test different nutrients in food

Fats and carbohydrates are together called as 

  1. Protective foods

  2. Harmful foods

  3. Body building foods

  4. Energy giving foods
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

We need energy for doing work. Energy is provided by carbohydrates and fats. Carbohydrates and fats on oxidation liberate energy. As compared to fats, carbohydrates get easily oxidized and converted into glucose and provide energy. One gram of carbohydrate yields about 17 kilo-joule of energy, whereas one gram of fat produces 37 kilo-joule of energy. This is the reason why carbohydrates and fats are called as energy food.

Multiple choice biology food for health fats fats and their test different nutrients in food

Cholesterol is synthesised in

  1. Brunner's gland

  2. Pancreas

  3. Liver

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

Slightly less than half of the cholesterol in the body derives from biosynthesis de novo. Biosynthesis in the liver accounts for approximately 10% and in the intestines approximately 15%, of the amount produced each day. The cholesterol biosynthesis pathway involves enzymes that are in the cytoplasm, microsomes (ER), and peroxisomes. Synthesis of cholesterol, like that of most biological lipids, begins from the two-carbon acetate group of acetyl-CoA. Cholesterol synthesis does not occurs in pancreas, spleen and Brunner's gland. 

So, the correct answer is 'Liver'

Multiple choice biology food for health fats fats and their test different nutrients in food

Oxidation of which of the following substances in the body yields more amount of calories?

  1. Glucose

  2. Glycogen

  3. Protein

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

Oxidation refers to the direct breakdown of nutrients for energy. Fats or lipids have the highest energy content of 9 kcal/gm while proteins and carbohydrates have 4 kcal/gm.
Therefore, the correct answer is option D.

Multiple choice biology food for health fats fats and their test different nutrients in food

Which category of compound is most concentrated energy source?

  1. Lipid

  2. Carbohydrates

  3. Proteins

  4. Vitamins
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Lipids are a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, phospholipids, and others. The main biological functions of lipids include storing energy, signaling, and acting as structural components of cell membranes.
Triglycerides, stored in adipose tissue, are a major form of energy storage both in animals and plants. The adipocyte, or fat cell, is designed for continuous synthesis and breakdown of triglycerides in animals, with breakdown controlled mainly by the activation of hormone-sensitive enzyme lipase. The complete oxidation of fatty acids provides high caloric content, about 9 kcal/g, compared with 4 kcal/g for the breakdown of carbohydrates and proteins. Migratory birds that must fly long distances without eating use stored energy of triglycerides to fuel their flights.
Multiple choice biology food for health fats fats and their test different nutrients in food

Fats 

  1. Are building blocks of our body

  2. Maintain metabolic rate

  3. Keep body temperature in the normal range

  4. Are stored to give energy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Although, the main source of energy for our bodies is carbohydrates, fat is used as a source of backup energy in cases when carbohydrates are not available. This is a concentrated energy source but it is important to remember that each gram of fat has nine calories (over double the calories from protein and carbohydrates) so you should avoid having more than 20 to 35% of your daily calories from fat. In a 1,800 calorie diet, you should only consume 40-70 grams of fat.

Multiple choice biology food for health fats fats and their test different nutrients in food

Number of essential fatty acids is

  1. $6$
  2. $4$
  3. $3$
  4. $2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Non-essential fatty acids are those fatty acids that the body can synthesize on its own. Essential fatty acids are those fatty acids that are required by the body but it cannot synthesize. There are two essential fatty acids, linoleic and alpha-linolenic acid. These must be obtained from food. 

Thus, the correct answer is option D.

Multiple choice biology food for health fats fats and their test different nutrients in food

Which is least harmful?

  1. Saturated fat

  2. Oils

  3. Chloresterol

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

Unsaturated fats are liquid at room temperature as they have double bonds. Saturated fatty acids have single bond and are solid at room temperature. Polyunstaurated fats are good for health as they boost up the good cholestrol level. As they are liquid so they do not choke the blood vessels and they are easily metabolized. Polyunsaturated fats include omega-3 and omega-6 fats. These are essential fatty acids that the body needs for brain function and cell growth.

So, the correct answer is option D.

Multiple choice biology food for health fats fats and their test different nutrients in food

Bile salts help in

  1. Absorption of fats

  2. Digestion of fats

  3. Both A and B

  4. Excretion of fats
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Bile salts emulsify fats (a physical process aiding digestion) and also form micelles, which are necessary for the absorption of fatty acids and monoglycerides across the intestinal wall.

Multiple choice biology food for health fats fats and their test different nutrients in food

Excess carbohydrates and proteins are stored in body as

  1. Amino acids

  2. Fats

  3. Monosaccharides

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

The excess carbohydrates and proteins are stored in the body as fats. It gets converted into energy during excessive physical work. Essential fatty acids are those fatty acids which play an important role in the biological process and they can be metabolized easily. These acts as a fuel rather getting deposited as fat in the body. The human body cannot synthesize essential fatty acids. Unsaturated fats are liquid at room temperature as they have double bonds. The essential fatty acids are unsaturated as they have double bonds. Saturated fatty acids have the single bond and are solid at room temperature.

So, the correct answer is option B.

Multiple choice biology food for health fats fats and their test different nutrients in food

Fatty substances are emulsified by

  1. Lipase

  2. Bilirubin and biliverdin

  3. HCl

  4. Sodium salts of glycoholic and taurocholic acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Bile salts, specifically sodium glycocholate and sodium taurocholate, act as detergents to emulsify fats, increasing the surface area for lipase action.