Question 1

Which property of carbon atoms allows them to form large, complex molecules essential for life?

Accepted Answer

Their ability to form four covalent bonds due to four valence electrons

Question 2

Which functional group is most likely to act as an acid by donating a proton ($$H^+) in $$aqueous solution?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 3

A dehydration reaction is important in the synthesis of biological polymers. What is the result of a dehydration reaction between two glucose molecules?

Accepted Answer

Formation of a glycosidic linkage and release of a water molecule ($$H_2O)$$

Question 4

Which statement best explains why saturated fats are solid at room temperature while unsaturated fats are liquid?

Accepted Answer

Saturated fats have no double bonds, allowing their hydrocarbon chains to pack tightly

Question 5

Which level of protein structure is directly affected by a single amino acid substitution, such as in sickle-cell disease?

Accepted Answer

Primary structure

Question 6

What type of bond is responsible for the secondary structure of proteins, such as alpha helices and beta pleated sheets?

Accepted Answer

Hydrogen bonds between backbone atoms

Question 7

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

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded

Question 8

Which process breaks down polymers into monomers by adding water?

Accepted Answer

Hydrolysis

Question 9

A phospholipid molecule is amphipathic. What does this mean in the context of cell membranes?

Accepted Answer

It contains both hydrophilic and hydrophobic regions

Question 10

Which of the following is a correct complementary base pairing in DNA?

Accepted Answer

Adenine (A) pairs with thymine (T)

Question 11

Which type of isomerism is responsible for the difference in biological activity between left-handed and right-handed versions of a molecule?

Accepted Answer

Enantiomerism

Question 12

Which polysaccharide is the main structural component of plant cell walls and is difficult for most animals to digest?

Accepted Answer

Cellulose

Question 13

What is the main function of ATP in cells?

Accepted Answer

To provide energy for cellular processes

Question 14

Which of the following best explains why trans fats are considered unhealthy?

Accepted Answer

They contribute to coronary heart disease by raising LDL cholesterol

Question 15

Which of the following is a correct description of a peptide bond?

Accepted Answer

A covalent bond formed between the carboxyl group of one amino acid and the amino group of another

Question 16

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

Accepted Answer

The association of multiple polypeptide chains into a functional protein

Question 17

Which of the following is a real-world consequence of protein denaturation?

Accepted Answer

A cooked egg white turns solid due to loss of protein structure

Question 18

Which of the following equations correctly represents the hydrolysis of ATP to ADP?

Accepted Answer

$$ATP + H_2O \rightarrow ADP + P_i + energy$$

Question 19

Which of the following best describes the backbone of a DNA molecule?

Accepted Answer

Alternating sugar and phosphate groups joined by phosphodiester bonds

Question 20

A scientist compares the DNA sequences of two species and finds that they share 98% similarity. What does this suggest about their evolutionary relationship?

Accepted Answer

They are closely related and share a recent common ancestor

Carbon and the Molecular Diversity of Life: Biological Molecules and Their Properties

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