Question 1

Which of the following statements best explains why carbon is able to form such a wide variety of molecules in living organisms?

Accepted Answer

Carbon has a valence of 4, enabling it to form up to four covalent bonds with other atoms, resulting in chains, rings, and branching patterns.

Question 2

A scientist is studying a molecule with the formula $$C_6H_{12}O_6$. She finds that it can exist in both straight-chain and ring forms in aqueous solution. What type of molecule is she most likely studying?

Accepted Answer

A carbohydrate, specifically a monosaccharide like glucose

Question 3

Which process is responsible for assembling polymers such as proteins and carbohydrates in cells?

Accepted Answer

Dehydration synthesis, which removes water to form covalent bonds between monomers

Question 4

Which of the following best describes the structure and function of phospholipids in biological membranes?

Accepted Answer

Phospholipids have a hydrophilic head and two hydrophobic tails, forming a bilayer that separates the cell from its environment.

Question 5

A mutation changes a single amino acid in the primary structure of a protein. Which of the following is the most likely consequence?

Accepted Answer

The change may alter the protein's three-dimensional shape and function, depending on the role of the affected amino acid.

Question 6

Which of the following functional groups is directly involved in the formation of peptide bonds between amino acids?

Accepted Answer

Carboxyl group

Question 7

A patient is found to have a deficiency in enzymes that catalyze hydrolysis reactions. Which cellular process would be most directly affected?

Accepted Answer

Breakdown of starch into glucose monomers

Question 8

Which of the following statements about DNA and RNA is correct?

Accepted Answer

RNA contains ribose sugar and uracil, and is usually single-stranded.

Question 9

Which of the following best explains why saturated fats are solid at room temperature while unsaturated fats are liquid?

Accepted Answer

Saturated fats have no double bonds in their hydrocarbon chains, allowing them to pack tightly together.

Question 10

Which of the following is a real-world application of genomics and proteomics in biology?

Accepted Answer

Determining the evolutionary relationships between species by comparing DNA and protein sequences

Question 11

Which chemical group is found in all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 12

A researcher compares the amino acid sequences of hemoglobin from humans, gorillas, and frogs. She finds that the human and gorilla sequences differ by only one amino acid, while the frog sequence differs by 67 amino acids. What does this suggest?

Accepted Answer

Humans and gorillas share a more recent common ancestor than humans and frogs.

Question 13

Which of the following best describes the role of ATP in cellular processes?

Accepted Answer

ATP provides energy for cellular work by releasing energy when its terminal phosphate bond is hydrolyzed.

Question 14

Which of the following is NOT a function performed by proteins in living organisms?

Accepted Answer

Storing genetic information

Question 15

Which type of isomer differs in the spatial arrangement of atoms around a double bond, resulting in cis and trans forms?

Accepted Answer

Cis-trans isomer

Question 16

Which of the following statements about the sugar-phosphate backbone of DNA is correct?

Accepted Answer

The sugar-phosphate backbone runs antiparallel along the outside of the DNA double helix.

Question 17

Which of the following best explains the importance of functional groups in organic molecules?

Accepted Answer

Functional groups determine the solubility and reactivity of organic molecules, influencing their biological roles.

Question 18

A cell is observed to have a high concentration of unsaturated fats in its membranes. What property would this impart to the cell membrane?

Accepted Answer

The membrane would be more fluid and flexible due to the kinks in unsaturated fatty acid tails.

Question 19

Which of the following best describes the relationship between monomers and polymers in biological macromolecules?

Accepted Answer

Polymers are formed by linking monomers through dehydration reactions.

Molecular Diversity of Life: Biological Macromolecules and Carbon Chemistry

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