Question 1

Which of the following statements best explains why lipids are not considered true polymers?

Accepted Answer

Lipids are not made from repeating monomer units, but are assembled from smaller molecules like glycerol and fatty acids.

Question 2

A patient is diagnosed with atherosclerosis, a condition linked to plaque buildup in arteries. Which dietary change would most likely reduce their risk, based on the structure of fats?

Accepted Answer

Replace saturated fats with unsaturated fats, which have one or more double bonds causing kinks in their hydrocarbon chains.

Question 3

Which of the following best describes the difference between starch and cellulose?

Accepted Answer

Starch is composed of glucose monomers with $\alpha$ glycosidic linkages, while cellulose is composed of glucose monomers with $\beta$ glycosidic linkages.

Question 4

During the synthesis of a fat molecule, what type of reaction occurs between glycerol and fatty acids, and what is the byproduct?

Accepted Answer

Dehydration reaction; byproduct is water ($H_2O$).

Question 5

A protein is exposed to high heat and extreme pH, causing it to lose its functional shape. What is this process called, and what is the likely consequence?

Accepted Answer

Denaturation; the protein will lose its biological activity.

Question 6

Which of the following best explains why enzymes are highly specific in their function?

Accepted Answer

The three-dimensional shape and charge of the enzyme's active site allows it to bind only to specific substrates.

Question 7

Which of the following is a correct pairing of a macromolecule with its monomer?

Accepted Answer

Carbohydrate – monosaccharide

Question 8

A DNA molecule is composed of two strands held together by hydrogen bonds. Which base pairs are correctly matched in DNA?

Accepted Answer

Adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).

Question 9

Which of the following best describes the structure of a phospholipid and its role in biological membranes?

Accepted Answer

A phospholipid has two hydrophobic fatty acid tails and a hydrophilic phosphate head, forming a bilayer in cell membranes.

Question 10

A mutation causes a single amino acid substitution in the primary structure of hemoglobin. What is the most likely consequence?

Accepted Answer

The protein may lose its normal shape and function, potentially causing diseases such as sickle-cell anemia.

Question 11

Which of the following best explains why cellulose cannot be digested by most animals, including humans?

Accepted Answer

Cellulose contains $\beta$-glycosidic linkages, and most animals lack the enzymes to break these bonds.

Question 12

Which of the following is a function of chitin in living organisms?

Accepted Answer

Structural support in the exoskeletons of arthropods and cell walls of fungi

Question 13

Which of the following best describes the process of hydrolysis in the breakdown of polymers?

Accepted Answer

Hydrolysis adds a water molecule, breaking the bond between monomers.

Question 14

Which of the following correctly matches a macromolecule with its primary function?

Accepted Answer

Carbohydrates – provide energy and structural support

Question 15

A scientist is studying a molecule with the formula $C_6H_{12}O_6$. Which class of biomolecule does this most likely represent, and what is its function?

Accepted Answer

It is a monosaccharide, serving as a major fuel for cells.

Question 16

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

DNA is usually double-stranded and contains thymine, while RNA is usually single-stranded and contains uracil.

Question 17

Which of the following is a correct description of the quaternary structure of a protein?

Accepted Answer

It is the overall shape formed by multiple polypeptide chains interacting.

Question 18

Which of the following best explains the amphipathic nature of phospholipids and its importance in cell membranes?

Accepted Answer

Phospholipids have both hydrophilic heads and hydrophobic tails, allowing them to form bilayers that create a selective barrier in cell membranes.

Chapter 5: Biomolecules – Structure and Function of Macromolecules in Biology

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