Q: Which of the following is a correct description of the central dogma of molecular biology?

$$\text{DNA} \to \text{RNA} \to \text{Protein}$$

Question 1

Which of the following best describes the process by which a protein polymer is synthesized from amino acid monomers?

Accepted Answer

Dehydration reaction, which removes a water molecule to form a peptide bond

Question 2

A sample of double-stranded DNA contains 30% adenine (A). According to Chargaff’s rules, what percentage of the DNA is guanine (G)?

Accepted Answer

$$20\%$$

Question 3

Which structural feature is unique to RNA compared to DNA?

Accepted Answer

RNA is usually single-stranded and contains uracil instead of thymine

Question 4

A mutation causes a single amino acid substitution in the primary structure of hemoglobin. Which of the following is a possible consequence?

Accepted Answer

The protein may misfold, leading to diseases such as sickle-cell anemia

Question 5

Which of the following interactions is responsible for the secondary structure of proteins?

Accepted Answer

Hydrogen bonds between the polypeptide backbone

Question 6

If a DNA strand has the sequence 5'-ATCGGCTA-3', what is the complementary sequence on the other strand (written 5' to 3')?

Accepted Answer

5'-TAGCCGAT-3'

Question 7

Which of the following best explains why DNA can store vast amounts of genetic information?

Accepted Answer

The sequence of four different nitrogenous bases allows for many possible combinations

Question 8

Which part of an amino acid determines its unique chemical properties and interactions in a protein?

Accepted Answer

The side chain (R group)

Question 9

A protein is exposed to high temperature and extreme pH. What is the most likely result?

Accepted Answer

The protein will denature, losing its three-dimensional structure and function

Question 10

Which of the following is a correct description of the central dogma of molecular biology?

Accepted Answer

$$	ext{DNA} 	o 	ext{RNA} 	o 	ext{Protein}$$

Question 11

Which of the following best describes a dehydration reaction in the context of macromolecule synthesis?

Accepted Answer

A reaction that removes a water molecule to form a new bond between monomers

Question 12

Which of the following statements about disulfide bridges is correct?

Accepted Answer

They are covalent bonds that stabilize tertiary and quaternary protein structure

Question 13

A scientist is analyzing a polypeptide and finds that it contains many hydrophobic side chains. Which of the following is most likely true about the protein’s tertiary structure?

Accepted Answer

Hydrophobic side chains will cluster together inside the protein, away from water

Question 14

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

Accepted Answer

Storing genetic information

Question 15

Which of the following best explains why a change in the primary structure of a protein can affect its function?

Accepted Answer

The sequence of amino acids determines the protein’s three-dimensional shape, which is critical for function

Question 16

Which of the following statements about nucleotides is correct?

Accepted Answer

A nucleotide consists of a nitrogenous base, a pentose sugar, and one or more phosphate groups

Question 17

Which of the following best describes the difference between the secondary and tertiary structure of a protein?

Accepted Answer

Secondary structure involves hydrogen bonding in the backbone, while tertiary structure involves interactions among side chains

Question 18

A patient has a genetic mutation that changes a hydrophilic amino acid to a hydrophobic one in a protein’s active site. What is the most likely effect on the protein’s function?

Accepted Answer

The protein’s active site may lose its ability to interact with water-soluble substrates, reducing its activity

Question 19

Which of the following best describes hydrolysis in the context of macromolecule breakdown?

Accepted Answer

Hydrolysis adds a water molecule to break a bond between monomers

Macromolecules: Structure and Function of DNA, RNA, and Proteins

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