Question 1

Which of the following best describes the difference between fibrous and globular proteins?

Accepted Answer

Fibrous proteins have a structural role, while globular proteins are typically involved in metabolic functions such as catalysis and transport.

Question 2

A single amino acid substitution in the primary structure of hemoglobin leads to sickle cell disease. Which amino acid is substituted, and what is the consequence for the protein's quaternary structure?

Accepted Answer

Glutamic acid is replaced by valine, causing hemoglobin molecules to stick together and form fibers.

Question 3

Which of the following statements about chaperonins is correct?

Accepted Answer

Chaperonins provide a hydrophilic environment that allows polypeptides to fold properly, isolated from the cytoplasm.

Question 4

Which of the following is NOT a component of a nucleotide?

Accepted Answer

A fatty acid

Question 5

Which of the following correctly matches the nitrogenous base with the type of nucleic acid in which it is found?

Accepted Answer

Adenine is found in both DNA and RNA.

Question 6

What is the main structural difference between DNA and RNA?

Accepted Answer

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

Question 7

Which of the following best describes the 'Central Dogma' of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 8

Which of the following is a purine base found in both DNA and RNA?

Accepted Answer

Adenine

Question 9

A polynucleotide strand has a directionality, with a 5' end and a 3' end. What chemical group is found at the 5' end?

Accepted Answer

A phosphate group ($-PO_4^{2-}$)

Question 10

Which of the following base pairs is correct for DNA?

Accepted Answer

Guanine pairs with cytosine

Question 11

A mutation changes a codon in mRNA from UAU to UAA. What is the likely effect on the resulting protein?

Accepted Answer

The protein will be prematurely terminated because UAA is a stop codon.

Question 12

Which of the following best explains why sickle cell hemoglobin forms fibers inside red blood cells?

Accepted Answer

A hydrophobic amino acid is exposed on the surface, causing hemoglobin molecules to stick together.

Question 13

Which of the following is a function of globular proteins?

Accepted Answer

Acting as enzymes to catalyze biochemical reactions

Question 14

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

Accepted Answer

It is formed by covalent bonds between the phosphate group of one nucleotide and the 3' carbon of the next sugar.

Question 15

Which of the following best describes the difference between a nucleoside and a nucleotide?

Accepted Answer

A nucleotide contains a nitrogenous base, a sugar, and a phosphate group, while a nucleoside lacks the phosphate group.

Question 16

Which of the following is a pyrimidine base found in RNA but not in DNA?

Accepted Answer

Uracil

Question 17

If a DNA strand has the sequence 5'-ATCGGTA-3', what is the complementary sequence on the other strand?

Accepted Answer

3'-TAGCCAT-5'

Question 18

Which of the following best explains why chaperonins are important in the cell?

Accepted Answer

They prevent the aggregation of misfolded proteins by providing an isolated environment for folding.

Question 19

Which of the following is a correct pairing of a purine and a pyrimidine in DNA?

Accepted Answer

Adenine and thymine

Question 20

A scientist isolates a nucleic acid from a virus and finds that it contains uracil, ribose, and is single-stranded. What type of nucleic acid is this?

Accepted Answer

Single-stranded RNA

The Structure and Function of Large Biological Molecules: Proteins and Nucleic Acids

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