Question 1

Which of the following best explains why saturated fatty acids are solid at room temperature?

Accepted Answer

Their hydrocarbon tails are straight, allowing molecules to pack closely together.

Question 2

A triglyceride molecule is formed by the bonding of which components?

Accepted Answer

Three fatty acids and one glycerol molecule

Question 3

Why are unsaturated fatty acids typically liquid at room temperature?

Accepted Answer

Their hydrocarbon tails contain double bonds, causing bends that prevent tight packing.

Question 4

Which of the following is a function of waxes in biological systems?

Accepted Answer

Forming waterproof barriers on leaves and feathers

Question 5

Phospholipids are essential components of cell membranes because:

Accepted Answer

They have both hydrophilic and hydrophobic regions, allowing them to form bilayers.

Question 6

Which structural feature distinguishes a steroid from other types of lipids?

Accepted Answer

A backbone of four fused carbon rings

Question 7

A scientist analyzes a lipid and finds it contains a long hydrocarbon chain and a carboxyl group, but no double bonds. What type of fatty acid is this?

Accepted Answer

Saturated fatty acid

Question 8

Which of the following best describes the amphipathic nature of phospholipids?

Accepted Answer

They have both hydrophilic phosphate heads and hydrophobic fatty acid tails.

Question 9

Which equation represents the general formula for a saturated fatty acid with $n$ carbon atoms?

Accepted Answer

$C_nH_{2n+1}COOH$

Question 10

A patient is advised to reduce their intake of saturated fats. Which food item should they avoid based on lipid structure?

Accepted Answer

Butter

Question 11

Which of the following statements about waxes is correct?

Accepted Answer

Waxes are made of long fatty acid tails bonded to long-chain alcohols or carbon rings.

Question 12

Which lipid type is most directly involved in hormone production and cell signaling?

Accepted Answer

Steroids

Question 13

If a fatty acid contains two double bonds in its hydrocarbon chain, it is classified as:

Accepted Answer

A polyunsaturated fatty acid

Question 14

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

Their hydrophilic heads interact with water while hydrophobic tails avoid water, resulting in a bilayer structure.

Question 15

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

Accepted Answer

Catalyzing chemical reactions

Question 16

A lipid molecule is found to have a phosphate group, two fatty acid tails, and a glycerol backbone. What type of lipid is this?

Accepted Answer

Phospholipid

Question 17

Which of the following best describes the difference between animal fats and most vegetable oils?

Accepted Answer

Animal fats are mostly saturated and solid at room temperature, while vegetable oils are mostly unsaturated and liquid.

Question 18

Which of the following is a real-world example of a biological function of waxes?

Accepted Answer

Making bird feathers waterproof

Question 19

Which of the following best describes the structure of a fatty acid?

Accepted Answer

A hydrocarbon chain with a carboxyl group at one end

Question 20

Which of the following is true regarding the solubility of lipids in water?

Accepted Answer

Lipids are generally nonpolar and hydrophobic, making them insoluble in water.

Lipids: Structure, Types, and Biological Functions

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