Question 1

Which of the following best describes the chemical difference between DNA and RNA nucleotides, as shown in the images?

Accepted Answer

RNA nucleotides contain a ribose sugar with a hydroxyl group at the 2' carbon, while DNA nucleotides contain a deoxyribose sugar lacking the 2' hydroxyl group.

Question 2

Which type of bond links nucleotides together in a single strand of DNA or RNA?

Accepted Answer

Phosphodiester bond

Question 3

In the context of protein structure, what is the primary force stabilizing the secondary structure (such as α-helices and β-sheets)?

Accepted Answer

Hydrogen bonds between backbone amide and carbonyl groups

Question 4

Which of the following statements about the peptide bond is CORRECT?

Accepted Answer

It has partial double-bond character, restricting rotation around the bond.

Question 5

Which property of water is MOST responsible for its ability to dissolve ionic compounds such as NaCl?

Accepted Answer

High dielectric constant and polar nature

Question 6

Why are most animal cells unable to digest cellulose, as opposed to starch?

Accepted Answer

Cellulose is composed of β-1,4 glycosidic bonds, and animals lack the enzyme cellulase.

Question 7

Which of the following best explains the hydrophobic effect in protein folding?

Accepted Answer

Hydrophobic amino acids aggregate to minimize ordering of water molecules, increasing entropy of the solvent.

Question 8

Which of the following is a TRUE statement about the structure of phospholipids in biological membranes?

Accepted Answer

Phospholipids are amphipathic, with hydrophilic heads and hydrophobic tails, forming bilayers in water.

Question 9

Which of the following is a function of cholesterol in animal cell membranes?

Accepted Answer

It increases membrane fluidity and serves as a precursor for steroid hormones.

Question 10

Which of the following best describes the difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have their genetic material enclosed in a nucleus, while prokaryotic cells do not.

Question 11

Which of the following is a consequence of the partial double-bond character of the peptide bond?

Accepted Answer

The peptide bond is planar, restricting rotation and contributing to defined protein secondary structures.

Question 12

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

Accepted Answer

It refers to the spatial arrangement of multiple polypeptide subunits in a protein complex.

Question 13

Which of the following is a major function of immunoglobulins (antibodies) in the immune system?

Accepted Answer

They specifically bind to antigens, marking them for destruction by other immune cells.

Question 14

Which of the following best explains why hemoglobin exhibits a sigmoidal oxygen-binding curve?

Accepted Answer

Hemoglobin exhibits cooperative binding, where binding of one oxygen increases the affinity for additional oxygen molecules.

Question 15

Which of the following is a correct statement about the effect of a single amino acid substitution in a protein?

Accepted Answer

It can have little effect, or it can cause dramatic changes in protein stability or function, depending on the location and nature of the substitution.

Question 16

Which of the following is a key reason why noncovalent interactions are essential for biological macromolecule function?

Accepted Answer

They are weak and reversible, allowing dynamic molecular interactions necessary for life.

Question 17

Which of the following best describes the role of the hydrophobic effect in the formation of a phospholipid bilayer?

Accepted Answer

Hydrophobic tails cluster together away from water, while hydrophilic heads face the aqueous environment, forming a bilayer.

Question 18

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

Accepted Answer

Polysaccharide – monosaccharide – glycosidic bond

Question 19

Which of the following is a property of water that contributes to its high surface tension?

Accepted Answer

Its cohesive network of hydrogen bonds

Biological Macromolecules: Structure, Function, and Cellular Context

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