Lipids: Structure, Properties, and Metabolism - Chemistry for Biology Majors

Question 1

Lipids are a diverse group of biological molecules essential for life. Which of the following is NOT a characteristic of lipids?

Accepted Answer

They are polar molecules.

Answer

They are insoluble in water.

Answer

They are composed primarily of carbon, hydrogen, and oxygen.

Answer

They have a high energy content.

Question 2

Which of the following is the predominant type of lipid found in cell membranes?

Accepted Answer

Phospholipids

Answer

Triglycerides

Answer

Steroids

Answer

Waxes

Question 3

Which type of chemical bond contributes to the high energy content of lipids?

Accepted Answer

Covalent bonds

Answer

Ionic bonds

Answer

Hydrogen bonds

Answer

Van der Waals forces

Question 4

Which of the following enzymes plays a key role in the metabolism of fatty acids?

Accepted Answer

Lipase

Answer

Amylase

Answer

Protease

Answer

Lactase

Question 5

Which hormone is involved in the regulation of lipid metabolism?

Accepted Answer

Insulin

Answer

Glucagon

Answer

Epinephrine

Answer

Testosterone

Question 6

Which lipid serves as a precursor to vitamin D?

Accepted Answer

Cholesterol

Answer

Phosphatidylcholine

Answer

Triacylglycerol

Answer

Sphingolipid

Question 7

Which technique can be used to separate lipids based on their polarity?

Accepted Answer

Chromatography

Answer

Spectroscopy

Answer

Electrophoresis

Answer

Crystallization

Question 8

Which lipid is a major component of the myelin sheath surrounding nerve cells?

Accepted Answer

Sphingomyelin

Answer

Cholesterol

Answer

Phosphatidylserine

Answer

Triacylglycerol

Question 9

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

Accepted Answer

Muscle contraction

Answer

Energy storage

Answer

Membrane formation

Answer

Hormone synthesis

Question 10

Which of these is NOT a type of lipid?

Accepted Answer

Proteins

Answer

Triglycerides

Answer

Phospholipids

Question 11

What type of fatty acid is saturated?

Accepted Answer

With only single bonds between carbon atoms

Answer

With at least one double bond between carbon atoms

Answer

With a hydroxyl group attached to a carbon atom

Answer

With a carboxylic acid group at one end

Question 12

Which lipid class consists of glycerol, two fatty acids, and a phosphate group?

Accepted Answer

Phospholipids

Answer

Triacylglycerols

Answer

Steroids

Answer

Waxes

Question 13

What is the primary function of cholesterol in cell membranes??

Accepted Answer

Regulates membrane fluidity

Answer

Acts as a signaling molecule

Answer

Facilitates energy transport

Answer

Stores genetic information

Question 14

What enzyme catalyzes the hydrolysis of phospholipids?

Accepted Answer

Phospholipase

Answer

Lipase

Answer

Protease

Answer

Amylase

Question 15

Which of the following is a key difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have only single bonds between carbon atoms, while unsaturated fatty acids have at least one double bond.

Answer

Unsaturated fatty acids have only single bonds between carbon atoms, while saturated fatty acids have at least one double bond.

Answer

Saturated fatty acids are more polar than unsaturated fatty acids.

Answer

Unsaturated fatty acids are more solid at room temperature than saturated fatty acids.

Question 16

What type of lipid is primarily utilized for energy storage in the body?

Accepted Answer

Triglycerides

Answer

Phospholipids

Answer

Steroids

Answer

Fatty acids

Question 17

Which of the following is an essential fatty acid for human health?

Accepted Answer

Linoleic acid

Answer

Palmitic acid

Answer

Stearic acid

Answer

Butyric acid

Question 18

Which enzyme is responsible for breaking down triglycerides?

Accepted Answer

Lipase

Answer

Amylase

Answer

Protease

Answer

Sucrase

Question 19

What is the name of the condition that impairs the digestion of fats?

Accepted Answer

Cystic fibrosis

Answer

Anorexia nervosa

Answer

Lactose intolerance

Answer

Phenylketonuria

Question 20

Which lipid type is involved in hormone production?

Accepted Answer

Steroids

Answer

Phospholipids

Answer

Fatty acids

Answer

Triglycerides

Question 21

Which technique is commonly used for the separation of lipids?

Accepted Answer

Thin-layer chromatography

Answer

Paper chromatography

Answer

Gel electrophoresis

Answer

Atomic absorption spectroscopy

Question 22

Which of the following is not a characteristic of lipids?

Accepted Answer

Composed of carbon, hydrogen, oxygen, and nitrogen

Answer

Insoluble in water

Answer

High energy density

Answer

Essential for membrane structure

Question 23

What type of lipids has a glycerol backbone esterified to three fatty acids?

Accepted Answer

Triglycerides

Answer

Phospholipids

Answer

Steroids

Answer

Sphingolipids

Question 24

Which of the following is an omega-3 fatty acid?

Accepted Answer

Alpha-linolenic acid

Answer

Palmitic acid

Answer

Oleic acid

Answer

Stearic acid

Question 25

What is the primary role of cholesterol in biological membranes?

Accepted Answer

To maintain membrane fluidity and rigidity

Answer

To regulate membrane permeability

Answer

To act as a signaling molecule

Answer

To provide energy for cellular processes

Question 26

Which of the following processes is involved in lipid catabolism?

Accepted Answer

Beta-oxidation

Answer

Glycolysis

Answer

Photosynthesis

Answer

Transcription

Question 27

Which type of lipids is composed of a polar head group and two nonpolar fatty acid tails?

Accepted Answer

Phospholipids

Answer

Triglycerides

Answer

Fatty acids

Answer

Sterols

Question 28

Which of the following lipids serves as a precursor for the synthesis of steroid hormones?

Accepted Answer

Cholesterol

Answer

Phosphatidylcholine

Answer

Sphingomyelin

Answer

Triglycerides

Question 29

What is the function of lipoproteins in lipid metabolism?

Accepted Answer

To transport lipid-soluble molecules in the bloodstream

Answer

To regulate blood sugar levels

Answer

To provide energy for cellular processes

Answer

To synthesize new lipids

Question 30

What structural feature makes triglycerides insoluble in water?

Accepted Answer

Long, nonpolar hydrocarbon tails

Answer

Polar ester bonds

Answer

Glycerol backbone

Question 31

The primary function of phospholipids in biological membranes is to:

Accepted Answer

Provide a barrier to water-soluble molecules

Answer

Transport ions and other molecules across the membrane

Answer

Generate ATP for cellular energy

Answer

Store genetic information

Question 32

Which of the following is a type of saturated fatty acid?

Accepted Answer

Palmitic acid

Answer

Oleic acid

Answer

Linoleic acid

Answer

Arachidonic acid

Question 33

The process by which lipids are broken down to release energy is called:

Accepted Answer

Lipolysis

Answer

Glycolysis

Answer

Proteolysis

Answer

Gluconeogenesis

Question 34

The presence of a double bond in a fatty acid molecule results in:

Accepted Answer

A decrease in melting point

Answer

An increase in melting point

Answer

No change in melting point

Answer

Formation of a cis isomer

Question 35

Which of the following is NOT a function of lipids?

Accepted Answer

Transcription

Answer

Energy storage

Answer

Cellular signaling

Answer

Vitamin absorption

Question 36

The synthesis of lipids occurs primarily in the:

Accepted Answer

Endoplasmic reticulum

Answer

Mitochondria

Answer

Golgi apparatus

Answer

Lysosomes

Question 37

Which of the following lipids is a major component of plant cell membranes?

Accepted Answer

Phospholipids

Answer

Sphingolipids

Answer

Sterols

Answer

Triacylglycerols

Question 38

The most prevalent type of fatty acid in animal fats is:

Accepted Answer

Saturated fatty acid

Answer

Unsaturated fatty acid

Answer

Polyunsaturated fatty acid

Answer

Trans fatty acid

Question 39

Which of the following is not a function of lipids in biological systems?

Accepted Answer

Protein synthesis

Answer

Energy storage

Answer

Membrane formation

Answer

Hormone production

Question 40

The process of breaking down triglycerides into glycerol and fatty acids is known as:

Accepted Answer

Lipolysis

Answer

Lipogenesis

Answer

Gluconeogenesis

Answer

Glycogenesis

Question 41

Among the following, which is a type of hydrophobic lipid?

Accepted Answer

Cholesterol

Answer

Phospholipid

Answer

Glycolipid

Answer

Triglyceride

Question 42

Lipids known as phospholipids have a glycerol backbone with two fatty acids and a phosphate group. What is their primary function?

Accepted Answer

Cell membrane formation

Answer

Energy storage

Answer

Hormone synthesis

Answer

Enzyme activation

Question 43

The primary role of cholesterol in biological systems is:

Accepted Answer

Cell membrane rigidity

Answer

Energy storage

Answer

Hormone synthesis

Answer

Enzyme activation

Question 44

Which of the following compounds belongs to the category of eicosanoids?

Accepted Answer

Prostaglandin

Answer

Testosterone

Answer

Thyroxine

Answer

Insulin

Question 45

Lipid synthesis primarily occurs in which organs/tissues?

Accepted Answer

Liver and adipose tissue

Answer

Stomach and kidneys

Answer

Brain and heart

Answer

Pancreas and spleen

Question 46

Which of the following factors does NOT influence the solubility of lipids?

Accepted Answer

pH

Answer

Chain length

Answer

Degree of unsaturation

Answer

Polarity

Question 47

Which of the following properties characterizes phospholipids?

Accepted Answer

They consist of both polar head groups and nonpolar tail groups.

Answer

They have a glycerol backbone.

Answer

They are completely insoluble in water.

Question 48

Which of the following fatty acids is considered saturated?

Accepted Answer

Palmitic acid

Answer

Oleic acid

Answer

Linoleic acid

Answer

Eicosapentaenoic acid

Question 49

Which of the following is a type of eicosanoid?

Accepted Answer

Prostaglandin

Answer

Triacylglycerol

Answer

Phospholipid

Answer

Fatty acid

Question 50

What is the primary function of the hydrophobic tail of a phospholipid?

Accepted Answer

It interacts with the cell membrane's hydrophobic interior

Answer

It anchors the phospholipid to the membrane surface

Answer

It interacts with the polar head group

Question 51

Which of the following enzymes is responsible for catalyzing the hydrolysis of triacylglycerols?

Accepted Answer

Lipase

Answer

Kinase

Answer

Polymerase

Answer

Dehydrogenase

Question 52

What is the key structural difference that distinguishes saturated from unsaturated fatty acids?

Accepted Answer

The presence of double bonds

Answer

The number of carbon atoms in the chain

Answer

The type of head group

Answer

The number of hydroxyl groups

Question 53

What is the primary role of apolipoproteins in lipid metabolism?

Accepted Answer

They facilitate the solubilization of lipids in the bloodstream

Answer

They synthesize lipids in the liver

Answer

They break down lipids in cells

Answer

They activate lipid-metabolizing enzymes