Question 1

Which type of bond is primarily responsible for stabilizing the secondary structure (such as α-helix and β-pleated sheet) of a polypeptide chain?

Accepted Answer

Hydrogen bonds

Question 2

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids in the polypeptide chain

Question 3

A mutation changes a single amino acid in the primary structure of hemoglobin. Which level(s) of protein structure could be affected as a result?

Accepted Answer

All levels: primary, secondary, tertiary, and quaternary

Question 4

Which of the following is a function of chaperone proteins in cells?

Accepted Answer

Assisting newly-formed proteins in folding into their correct three-dimensional shapes

Question 5

Which carbohydrate is the primary energy source for most living organisms?

Accepted Answer

Glucose

Question 6

What type of reaction forms a glycosidic bond between two monosaccharides?

Accepted Answer

Dehydration synthesis

Question 7

Which polysaccharide is used for structural support in plant cell walls?

Accepted Answer

Cellulose

Question 8

A triglyceride is formed from which components?

Accepted Answer

One glycerol molecule and three fatty acids

Question 9

Which feature distinguishes a phospholipid from a triglyceride?

Accepted Answer

Phospholipids contain a phosphate group and two fatty acids; triglycerides contain three fatty acids and no phosphate group

Question 10

Which of the following best explains why unsaturated fatty acids are typically liquid at room temperature?

Accepted Answer

Their cis double bonds create kinks, preventing tight packing

Question 11

Which of the following is a steroid molecule important for membrane structure in animal cells?

Accepted Answer

Cholesterol

Question 12

Which of the following is NOT a component of a nucleotide?

Accepted Answer

A fatty acid

Question 13

Which statement correctly compares DNA and RNA?

Accepted Answer

DNA contains thymine; RNA contains uracil

Question 14

Which formula represents the general chemical formula for monosaccharides?

Accepted Answer

$$C_nH_{2n}O_n$$

Question 15

Which type of interaction is most important for stabilizing the tertiary structure of a protein?

Accepted Answer

Interactions between side chains, including hydrophobic interactions, ionic bonds, and disulfide bridges

Question 16

A patient is diagnosed with a genetic disorder that affects the formation of disulfide bridges in proteins. Which amino acid is most likely mutated?

Accepted Answer

Cysteine

Question 17

Which of the following best describes the quaternary structure of a protein?

Accepted Answer

The association of multiple polypeptide subunits

Question 18

Which of the following molecules is a disaccharide formed from glucose and fructose?

Accepted Answer

Sucrose

Question 19

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 20

Which nitrogenous base is found in RNA but not in DNA?

Accepted Answer

Uracil

Structure and Function of Large Biological Molecules: Proteins

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