Question 1

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds in ice are more ordered, creating more open space.

Question 2

A scientist is studying a molecule with the formula $$C_{6}H$$_{12}$$O_{6}$. This molecule is most likely a:

Accepted Answer

Monosaccharide

Question 3

Which of the following statements about saturated and unsaturated fats is CORRECT?

Accepted Answer

Saturated fats have no double bonds between carbon atoms and are solid at room temperature.

Question 4

Which type of chemical bond is the strongest in biological systems?

Accepted Answer

Covalent bond

Question 5

What is the main function of phospholipids in cells?

Accepted Answer

They form the lipid bilayer of cell membranes.

Question 6

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

Accepted Answer

The linear sequence of amino acids joined by peptide bonds.

Question 7

A DNA sample contains 20% adenine. According to Chargaff’s rules, what percentage of the sample is cytosine?

Accepted Answer

$$30\%$$

Question 8

Which experiment provided direct evidence that DNA, not protein, is the genetic material in viruses?

Accepted Answer

Hershey-Chase experiment using radioactive phosphorus and sulfur

Question 9

During DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

Helicase

Question 10

Which of the following is a function of the 5’ cap and poly-A tail added to eukaryotic mRNA?

Accepted Answer

They protect mRNA from degradation and help ribosomes attach for translation.

Question 11

A mutation changes a codon from UAU to UAA. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 12

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each daughter DNA molecule consists of one parental strand and one newly synthesized strand.

Question 13

Which of the following is a property of water that helps moderate Earth’s climate and stabilize temperatures in organisms?

Accepted Answer

High specific heat capacity

Question 14

Which of the following is a correct complementary DNA sequence for 5’-ATGCCGTA-3’?

Accepted Answer

3’-TACGGCAT-5’

Question 15

Which of the following best explains why enzymes are specific to their substrates?

Accepted Answer

The three-dimensional shape of the enzyme’s active site is complementary to the substrate.

Question 16

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

Accepted Answer

Energy storage and structural support

Question 17

Which of the following is true about the structure of DNA?

Accepted Answer

The two strands are antiparallel and held together by hydrogen bonds between complementary bases.

Question 18

Which of the following best describes the role of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome based on the codon sequence of mRNA.

Question 19

Which of the following is a real-world application of recombinant DNA technology?

Accepted Answer

Production of human insulin in bacteria for diabetes treatment

Question 20

Which of the following is a property of unsaturated fats that distinguishes them from saturated fats?

Accepted Answer

They contain one or more double bonds and are usually liquid at room temperature.

Foundations of Biology: Chemical Bonds, Macromolecules, and Molecular Genetics

Study Guide - Practice Questions