Question 1

The first image shows two glucose molecules joining to form a disaccharide and water. What type of reaction is this, and what is the general equation for this process?

Accepted Answer

Dehydration synthesis; $$\mathrm{C_6H_{12}O_6$ + C_6H_{12}O_6$ \rightarrow C$$_{12}$$H_{22}O$$_{11} + H_2O}$

Question 2

Which of the following best explains why triglycerides are an efficient form of long-term energy storage in animals?

Accepted Answer

They contain more energy per gram than carbohydrates due to their high proportion of C-H bonds.

Question 3

Refer to the image showing saturated and unsaturated fatty acids. Which structural feature distinguishes unsaturated fatty acids from saturated fatty acids?

Accepted Answer

Presence of double bonds between carbon atoms in the hydrocarbon chain.

Question 4

Why are saturated fats typically solid at room temperature, while unsaturated fats are liquid?

Accepted Answer

Saturated fats have straight chains that pack closely together, while unsaturated fats have kinks from double bonds that prevent tight packing.

Question 5

Trans fats are produced by hydrogenating unsaturated oils. What is a major health concern associated with trans fats?

Accepted Answer

They increase the risk of cardiovascular disease by raising LDL cholesterol.

Question 6

Which of the following foods is most likely to be high in unsaturated fats?

Accepted Answer

Olive oil

Question 7

The phospholipid bilayer forms the basis of cell membranes. What property of phospholipids allows them to form this structure?

Accepted Answer

They have both hydrophilic heads and hydrophobic tails.

Question 8

Steroids, such as cholesterol, have a characteristic structure. Which of the following best describes this structure?

Accepted Answer

Four fused carbon rings

Question 9

Waxes are important for preventing water loss in plants and animals. What is the basic structure of a wax molecule?

Accepted Answer

A fatty acid linked to an alcohol by an ester bond

Question 10

A person is running a marathon and needs a quick source of energy. Which macromolecule will their body use first, and why?

Accepted Answer

Carbohydrates, because they are rapidly broken down into glucose for immediate energy.

Question 11

Why did early humans evolve a preference for fatty foods, as suggested by the image of ancient humans eating meat?

Accepted Answer

Fatty foods provided a dense source of energy that was scarce in their environment.

Question 12

Which of the following statements about phospholipids is correct?

Accepted Answer

They contain a glycerol backbone, two fatty acid tails, and a phosphate group.

Question 13

Which of the following best explains why cholesterol is important in animal cell membranes?

Accepted Answer

It helps maintain membrane fluidity and stability.

Question 14

A food scientist is analyzing a sample of butter and olive oil. Which test result would indicate the presence of unsaturated fats in olive oil?

Accepted Answer

A higher proportion of double bonds in the fatty acid chains.

Question 15

Which of the following is a function of steroid hormones in the human body?

Accepted Answer

Regulation of metabolism, immune response, and reproduction.

Question 16

Which of the following best describes the difference between cis and trans unsaturated fatty acids?

Accepted Answer

Cis fatty acids have hydrogen atoms on the same side of the double bond, causing a kink; trans fatty acids have hydrogens on opposite sides, making the chain straighter.

Question 17

Which of the following is NOT a function of triglycerides in animals?

Accepted Answer

Catalyzing metabolic reactions

Question 18

A plant leaf is coated with a waxy layer. What is the primary function of this wax?

Accepted Answer

To prevent water loss by evaporation

Question 19

Which of the following statements about milk is correct based on the study materials?

Accepted Answer

Milk is produced by mammals to nourish their young and contains water, proteins, fats, and sugars.

Question 20

Which of the following best explains why trans fats are solid at room temperature, unlike most unsaturated fats?

Accepted Answer

Trans double bonds allow fatty acid chains to pack more tightly, similar to saturated fats.

Lipids: Structure, Types, and Biological Functions

Study Guide - Practice Questions

Study Guide - Flashcards