Lipids: Structure, Properties, and Functions | Biochemistry Quizzes

Question 1

Which of the following is not a property of lipids?

Accepted Answer

Biologically inert

Answer

Insoluble in water

Answer

High energy value

Answer

Versatile structure and function

Question 2

What is the main functional group of fatty acids?

Accepted Answer

Carboxyl group

Answer

Amino group

Answer

Phosphate group

Answer

Glycerol group

Question 3

Which type of phospholipid is a major component of cell membranes?

Accepted Answer

Phosphatidylcholine

Answer

Cardiolipin

Answer

Sphingomyelin

Answer

Phosphatidylinositol

Question 4

What is the main role of steroids in the body?

Accepted Answer

Hormonal signaling

Answer

Energy storage

Answer

Cell membrane structure

Answer

Enzyme catalysis

Question 5

Which of the following fatty acids is an omega-6 fatty acid?

Accepted Answer

Arachidonic acid

Answer

Linolenic acid

Answer

Eicosapentaenoic acid

Answer

Palmitic acid

Question 6

What is the main function of lipoproteins?

Accepted Answer

Transport lipids in the blood

Answer

Facilitate hormone action

Answer

Provide energy for cellular processes

Answer

Regulate gene expression

Question 7

What is the key difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds, while unsaturated fatty acids have one or more.

Answer

Saturated fatty acids have double bonds, while unsaturated fatty acids do not.

Answer

Saturated fatty acids are more polar than unsaturated fatty acids.

Answer

Saturated fatty acids are liquid at room temperature, while unsaturated fatty acids are solid.

Question 8

Which of the following steroids is involved in cholesterol synthesis?

Accepted Answer

Lanosterol

Answer

Cholesterol

Answer

Estrogen

Answer

Testosterone

Question 9

Which molecule serves as the precursor for prostaglandin synthesis?

Accepted Answer

Arachidonic acid

Answer

Glycerol

Answer

Phosphatidylcholine

Answer

Sphingosine

Question 10

Which technique is used to separate lipids based on their polarity?

Accepted Answer

Thin-layer chromatography

Answer

Gel electrophoresis

Answer

High-performance liquid chromatography

Answer

Gas chromatography

Question 11

Which of the following is NOT a characteristic of fatty acids?

Accepted Answer

Are capable of forming hydrogen bonds with water molecules

Answer

Composed of a carboxylic acid group and a hydrocarbon chain

Answer

Can be saturated or unsaturated

Answer

Have polar and nonpolar regions

Question 12

Which type of phospholipid is the most abundant in cell membranes?

Accepted Answer

Phosphatidylcholine

Answer

Phosphatidylethanolamine

Answer

Phosphatidylserine

Answer

Phosphatidylinositol

Question 13

What is the characteristic structural feature of steroids?

Accepted Answer

A four-ring structure composed of three cyclohexane rings and one cyclopentane ring

Answer

A long hydrocarbon chain attached to a polar head group

Answer

A double bond between the first and second carbon atoms in the hydrocarbon chain

Answer

A hydroxyl group attached to the fourth carbon atom in the hydrocarbon chain

Question 14

Which of the following is NOT a function of lipids in the body?

Accepted Answer

Carbohydrate metabolism

Answer

Energy storage

Answer

Cell membrane formation

Answer

Hormone synthesis

Question 15

Which fatty acid is considered an essential fatty acid for humans?

Accepted Answer

Polyunsaturated linoleic acid

Answer

Saturated palmitic acid

Answer

Monounsaturated oleic acid

Answer

Trans-unsaturated elaidic acid

Question 16

Which enzyme is responsible for the breakdown of triglycerides?

Accepted Answer

Lipase

Answer

Protease

Answer

Amylase

Answer

Nuclease

Question 17

Which condition is characterized by a high level of LDL cholesterol in the blood?

Accepted Answer

Hypercholesterolemia

Answer

Hypertriglyceridemia

Answer

Atherosclerosis

Answer

Arterial embolism

Question 18

Which technique is commonly used to extract lipids from biological samples?

Accepted Answer

Soxhlet extraction

Answer

Gel electrophoresis

Answer

Chromatography

Answer

PCR

Question 19

Which type of lipid is a significant component of cell membranes, forming the lipid bilayer?

Accepted Answer

Phospholipids

Answer

Fatty acids

Answer

Steroids

Answer

Glycolipids

Question 20

Saturated fatty acids are primarily involved in which bodily function?

Accepted Answer

Energy storage

Answer

Cell membrane fluidity

Answer

Hormone production

Answer

Antioxidant defense

Question 21

Which characteristic is NOT associated with steroids?

Accepted Answer

Water solubility

Answer

Lipid structure

Answer

Ring structure

Answer

Hydrophobic nature

Question 22

Which type of chemical bond links the glycerol backbone to fatty acids in triglycerides?

Accepted Answer

Ester bonds

Answer

Glycosidic bonds

Answer

Phosphodiester bonds

Answer

Peptide bonds

Question 23

Which factor primarily influences the melting point of fatty acids?

Accepted Answer

Number of double bonds

Answer

Chain length

Answer

Degree of branching

Answer

Presence of functional groups

Question 24

Phospholipids in cell signaling primarily function to:

Accepted Answer

Generate second messengers

Answer

Act as receptors for hormones

Answer

Form ion channels

Answer

Transport molecules across membranes

Question 25

Lipid synthesis in the body primarily occurs in which organ?

Accepted Answer

Liver

Answer

Adipose tissue

Answer

Muscle

Answer

Pancreas

Question 26

Which type of fatty acid is essential for human health but cannot be synthesized by the body?

Accepted Answer

Linoleic acid

Answer

Palmitic acid

Answer

Stearic acid

Answer

Oleic acid

Question 27

The process of breaking down lipids to generate energy is known as:

Accepted Answer

Lipolysis

Answer

Glycolysis

Answer

Proteolysis

Answer

Gluconeogenesis

Question 28

What is the primary structural element of fatty acids?

Accepted Answer

Hydrocarbon chains

Answer

Glycerol

Answer

Phosphates

Answer

Amino acids

Question 29

Which type of phospholipid is predominant in cell membranes?

Accepted Answer

Phosphatidylcholine

Answer

Sphingomyelin

Answer

Cardiolipin

Answer

Phosphatidylinositol

Question 30

How does cholesterol contribute to the structure of cell membranes?

Accepted Answer

Enhances membrane rigidity and stability

Answer

Increases membrane permeability

Answer

Participates in signal transduction pathways

Answer

Reduces membrane fluidity

Question 31

Which process is responsible for the breakdown of lipids to generate energy?

Accepted Answer

Beta-oxidation

Answer

Lipolysis

Answer

Lipogenesis

Answer

Glycolysis

Question 32

What is the main function of lipoproteins in lipid transport?

Accepted Answer

Making lipids soluble in the bloodstream

Answer

Storing lipids for energy reserves

Answer

Synthesizing lipids for cellular use

Answer

Breaking down lipids into waste products

Question 33

Which of the following is not considered a type of lipid?

Accepted Answer

Carbohydrates

Answer

Fatty acids

Answer

Phospholipids

Answer

Steroids

Question 34

What functional group is essential in the structure of all fatty acids?

Accepted Answer

Carboxyl group

Answer

Alcohol group

Answer

Amine group

Answer

Ketone group

Question 35

Which type of fatty acid has been associated with increased cholesterol levels and risk of heart disease?

Accepted Answer

Saturated fatty acids

Answer

Unsaturated fatty acids

Answer

Omega-3 fatty acids

Answer

Omega-6 fatty acids

Question 36

Which steroid hormone plays a crucial role in regulating glucose metabolism?

Accepted Answer

Insulin

Answer

Testosterone

Answer

Estrogen

Answer

Cortisol

Question 37

Which of the following is a characteristic of unsaturated fatty acids?

Accepted Answer

They have double bonds between carbon atoms

Answer

They exclusively contain single bonds between carbon atoms

Answer

They tend to be more structurally rigid than saturated fatty acids

Answer

They are primarily found in animal fats

Question 38

What is the process by which triglycerides are broken down for energy utilization?

Accepted Answer

Hydrolysis

Answer

Dehydration synthesis

Answer

Oxidation

Answer

Polymerization

Question 39

Which organ is primarily responsible for cholesterol synthesis in the body?

Accepted Answer

Liver

Answer

Heart

Answer

Pancreas

Answer

Kidneys

Question 40

What is the primary role of steroids in the immune system?

Accepted Answer

Suppressing inflammation

Answer

Activating immune cells

Answer

Regulating hormone production

Answer

Fighting off infections