Question 1

Which of the following best explains why butter is solid at room temperature while vegetable oil is liquid?

Accepted Answer

Butter contains more saturated fatty acids, which allow molecules to pack closely together, making it solid.

Question 2

A triglyceride is formed by the reaction of glycerol with three fatty acids. What type of reaction is this, and what is a byproduct?

Accepted Answer

Dehydration synthesis; water is produced.

Question 3

Which of the following fatty acids is most likely to be found in coconut oil based on the provided table?

Accepted Answer

Lauric acid ($CH_3(CH_2)_{10}COOH$)

Question 4

Which structural feature distinguishes a saturated fatty acid from an unsaturated fatty acid?

Accepted Answer

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

Question 5

If a triglyceride is composed of three palmitic acid molecules and one glycerol, what is its molecular formula? (Palmitic acid: $C_{16}H_{32}O_2$, Glycerol: $C_3H_8O_3$; remember that three water molecules are lost during formation)

Accepted Answer

$C_{51}H_{98}O_6$

Question 6

Which of the following statements about phospholipids is correct?

Accepted Answer

Phospholipids have a hydrophilic head and two hydrophobic tails.

Question 7

Which of the following best describes the role of lipids in biological systems?

Accepted Answer

Lipids are the primary long-term energy storage molecules.

Question 8

A fatty acid with the formula $CH_3(CH_2)_{16}COOH$ is classified as which type of fatty acid?

Accepted Answer

Saturated fatty acid

Question 9

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

Accepted Answer

The fatty acid chains are bent, preventing tight packing and resulting in a liquid state at room temperature.

Question 10

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.

Question 11

Which fatty acid is most likely to be found in animal fats and is solid at room temperature?

Accepted Answer

Stearic acid

Question 12

Which of the following is a correct description of the structure of a triglyceride?

Accepted Answer

Three fatty acids attached to a glycerol backbone via ester bonds.

Question 13

Which of the following is a correct statement about the difference between cis and trans unsaturated fatty acids?

Accepted Answer

Trans fatty acids have hydrogen atoms on opposite sides of the double bond, resulting in a straighter chain.

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 best describes the chemical reaction that links fatty acids to glycerol in triglyceride formation?

Accepted Answer

Esterification, which involves the removal of water ($H_2O$)

Question 16

Which of the following fatty acids has the shortest hydrocarbon chain?

Accepted Answer

Butyric acid ($CH_3CH_2COOH$)

Question 17

Which of the following is a correct statement about the solubility of fatty acids in water?

Accepted Answer

Fatty acids are insoluble in water because their hydrocarbon chains are hydrophobic.

Question 18

Which of the following best explains why unsaturated fats are considered healthier than saturated fats?

Accepted Answer

Unsaturated fats decrease LDL cholesterol and increase HDL cholesterol.

Question 19

Which of the following is a correct description of the amphipathic nature of phospholipids?

Accepted Answer

Phospholipids have both hydrophilic and hydrophobic regions.

Lipids and Proteins: Structure and Function in General Biology

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