Question 1

Which structural feature distinguishes saturated fatty acids from unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have only single bonds between carbon atoms in their hydrocarbon tails.

Question 2

Why are unsaturated fatty acids typically liquid at room temperature?

Accepted Answer

The presence of double bonds causes bends in the tails, preventing tight packing.

Question 3

Which of the following best explains why animal fats are usually solid at room temperature?

Accepted Answer

Animal fats are composed mainly of saturated fatty acids, which stack tightly.

Question 4

A triglyceride is formed by the bonding of which molecules?

Accepted Answer

Three fatty acids and a glycerol

Question 5

Which type of lipid is primarily responsible for forming waterproof barriers on plant leaves?

Accepted Answer

Waxes

Question 6

What is the main structural difference between a phospholipid and a triglyceride?

Accepted Answer

Phospholipids have two fatty acids and a phosphate group attached to glycerol.

Question 7

Which of the following is a function of steroids in animal cells?

Accepted Answer

Regulating reproductive system development

Question 8

Which statement correctly describes the solubility of fatty acids in water?

Accepted Answer

Fatty acids are insoluble in water because their hydrocarbon tails are nonpolar.

Question 9

Which of the following best describes the role of the carboxyl group in fatty acids?

Accepted Answer

It allows the fatty acid to form bonds with glycerol.

Question 10

Which of the following lipids contains a rigid backbone of four carbon rings?

Accepted Answer

Steroids

Question 11

A scientist analyzes a lipid and finds it is solid at room temperature, contains only single bonds in its hydrocarbon tails, and is derived from animal tissue. What type of lipid is this most likely to be?

Accepted Answer

Saturated fatty acid

Question 12

Which of the following is a real-world example of a wax’s biological function?

Accepted Answer

Making bird feathers waterproof

Question 13

Which of the following best explains why vegetable oils are liquid at room temperature?

Accepted Answer

They contain fatty acids with double bonds that prevent tight packing.

Question 14

Which of the following is NOT a function of lipids in living organisms?

Accepted Answer

Catalyzing chemical reactions

Question 15

Which of the following correctly matches the lipid type with its function?

Accepted Answer

Steroids – act as hormones

Question 16

Which chemical formula represents a saturated fatty acid with 16 carbon atoms?

Accepted Answer

$\mathrm{C_{16}H_{32}O_2}$

Question 17

Which of the following statements about phospholipids is correct?

Accepted Answer

They contain a hydrophilic phosphate head and two hydrophobic fatty acid tails.

Question 18

Which lipid type is most likely to be found in honeycomb structures made by bees?

Accepted Answer

Waxes

Question 19

Which of the following is a consequence of the presence of double bonds in unsaturated fatty acids?

Accepted Answer

The fatty acid tails are bent, preventing tight packing.

Question 20

Which of the following best describes the molecular structure of cholesterol?

Accepted Answer

A rigid backbone of four carbon rings

Lipids: Structure, Types, and Biological Functions

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