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

Which of the following components constitute plasma membrane?

  1. Proteins only

  2. Lipids only

  3. Proteins, carbohydrate and lipids

  4. Protein, Lipids, iron
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The plasma membrane (cell membrane) has a fluid mosaic structure composed of phospholipids (lipids), embedded proteins, and carbohydrates attached to proteins (glycoproteins) and lipids (glycolipids). These carbohydrates form the glycocalyx on the cell surface and are important for cell recognition.

Multiple choice

Maximum energy is liberated during the breakdown of ____________.

  1. nucleic acid

  2. fat

  3. protein

  4. carbohydrates

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A fat molecule has more carbon-hydrogen bonds than a sugar molecule. Thus, a large amount of energy can be obtained by the breakdown of fat molecules as compare to the same amount of carbohydrates. 

Multiple choice

A pound of butter contains more usable energy than a pound of sugar for a human, because

  1. sugar contains much more water than butter

  2. a fat molecule has more carbonhydrogen bonds than a sugar molecule

  3. butter is an animal product, whereas the sugar is a plant product

  4. there is much more waste in digestion and absorption of sugar than of butter
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Fat molecules contain more carbon-hydrogen bonds per gram than carbohydrates, and each C-H bond stores significant chemical energy. This is why fats yield approximately 9 kcal/g while sugars yield only 4 kcal/g. The difference is not due to water content, animal vs plant source, or digestive waste.

Multiple choice

Free fatty acids are unesterified form of fatty acids found in the blood plasma.

The number of milligrams of potassium hydroxide required to neutralize the free fatty acids in 1 g of fat is called ___________.

  1. iodine number

  2. acid number

  3. acetyl number

  4. coordination number

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

Acid number or acid value refers to the number of milligrams of potassium hydroxide required to neutralize the free fatty acids in 1 g of fat.

Multiple choice

Cell wall is made up of

  1. protein

  2. lipids

  3. cellulose

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

Cellulose is the primary structural component of plant cell walls, forming a rigid network that provides mechanical support. While cell walls also contain hemicellulose, pectin, and proteins like lignin in some plants, cellulose is the dominant material. Proteins, lipids, and starch are not major wall components.

Multiple choice

Which of the following does not provide energy?

  1. Glucose

  2. Pulses

  3. Oil

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

Vitamins are essential micronutrients required for various metabolic processes, but they do not provide energy when broken down. Glucose and pulses (proteins) provide 4 kcal/g, while oil (fats) provides 9 kcal/g. Only the macronutrients - carbohydrates, proteins, and fats - supply calories.

Multiple choice

The body tissue filled with fat droplets is

  1. skeletal tissue

  2. adipose tissue

  3. areolar tissue

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

These are fat cells. They are oval or rounded cells filled with fat droplets. This tissue is found below the skin and in the bone marrow. The function of this tissue is to store fat and conserve body heat.