Question 1

Which of the following best describes the structure shown in the first image (four fused rings)?

Accepted Answer

A steroid

Question 2

Which molecule is represented in the second image, and what is its primary biological function?

Accepted Answer

Glycerol; serves as the backbone for triglycerides and phospholipids

Question 3

Based on the third image, which structural feature distinguishes a saturated fatty acid from an unsaturated fatty acid?

Accepted Answer

Presence of at least one C=C double bond in unsaturated fatty acids

Question 4

Referencing the fourth image, which statement is true about saturated and unsaturated fatty acids at room temperature (25°C)?

Accepted Answer

Saturated fatty acids are solid, unsaturated are liquid

Question 5

Given the general formula $\mathrm{CH_3(CH_2)_nCOOH}$ (fifth image), what does the value of $n$ determine?

Accepted Answer

The length of the fatty acid chain

Question 6

The sixth image shows the structure of lauric acid. What is its chemical formula?

Accepted Answer

$\mathrm{C_{12}H_{24}O_2}$

Question 7

Which fatty acid is shown in the seventh image, and what is its degree of saturation?

Accepted Answer

Stearic acid; saturated

Question 8

The eighth image shows myristic acid. What is its molecular formula and how many carbons does it contain?

Accepted Answer

$\mathrm{C_{14}H_{28}O_2}$; 14 carbons

Question 9

Which process is illustrated in the twelfth image, and what is its significance in lipid formation?

Accepted Answer

Dehydration synthesis; forming ester bonds in triglycerides

Question 10

How many ester linkages are present in a triglyceride molecule, as shown in the tenth image?

Accepted Answer

Three

Question 11

Which of the following best explains why triglycerides are nonpolar, despite their polar building blocks?

Accepted Answer

Dehydration synthesis removes polar groups, leaving only nonpolar hydrocarbon chains

Question 12

Which image best represents a phospholipid, and what is a key property of phospholipids in biological membranes?

Accepted Answer

Image 11; they are amphipathic, with hydrophilic heads and hydrophobic tails

Question 13

What is the main structural difference between a triglyceride and a phospholipid, as shown in images 10 and 11?

Accepted Answer

Triglycerides have three fatty acids; phospholipids have two fatty acids and a phosphate group

Question 14

Which of the following is true about the arrangement of phospholipids in the plasma membrane (see images 16 and 17)?

Accepted Answer

Phosphate heads face both the interior and exterior aqueous environments

Question 15

Which of the following molecules is NOT a steroid, based on the images provided?

Accepted Answer

Glycerol

Question 16

A triglyceride is synthesized from one glycerol and three fatty acids. If the fatty acids are lauric acid ($\mathrm{C_{12}H_{24}O_2}$), stearic acid ($\mathrm{C_{18}H_{36}O_2}$), and palmitoleic acid ($\mathrm{C_{16}H_{30}O_2}$), what is the molecular formula of the resulting triglyceride?

Accepted Answer

$\mathrm{C_{49}H_{92}O_6}$

Question 17

Which of the following statements about waxes is correct, based on the images and study materials?

Accepted Answer

Waxes are composed of one saturated fatty acid and one long-chain alcohol

Question 18

Why is acetic acid ($\mathrm{CH_3COOH}$) considered the most water-soluble fatty acid?

Accepted Answer

It has a short hydrocarbon chain, making the polar carboxyl group dominant

Question 19

Which of the following best explains why phospholipids are described as amphipathic?

Accepted Answer

They contain both hydrophilic (phosphate head) and hydrophobic (fatty acid tails) regions

Lipids: Structure, Types, and Biological Functions

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