Q: Which of the following best describes the monomer of a protein, and which functional groups are always present in this monomer?

Amino acid; contains a carboxyl group ($$\mathrm{\text{-}COOH}) $$and an amino group ($$\mathrm{\text{-}NH_2$})$$

Q: Which functional group is present in both proteins and nucleic acids, and what is its chemical formula?

Phosphate group; $$\mathrm{\text{-}PO_4$^{3-}}$$

Q: Which of the following diagrams would best represent the backbone of a polypeptide chain?

$$\mathrm{\text{-}N\text{-}C\text{-}C\text{-}N\text{-}C\text{-}C\text{-}}$$

Question 1

Which of the following best describes the monomer of a protein, and which functional groups are always present in this monomer?

Accepted Answer

Amino acid; contains a carboxyl group ($$\mathrm{	ext{-}COOH}) $$and an amino group ($$\mathrm{	ext{-}NH_2$})$$

Question 2

Which bond is formed between two amino acids during protein synthesis, and what is the chemical reaction called?

Accepted Answer

Peptide bond; dehydration synthesis ($$\mathrm{C-N}$$ bond formed by removal of $$\mathrm{H_2O})$$

Question 3

Which part of an amino acid determines its unique properties and how it interacts within a protein's 3D structure?

Accepted Answer

The side chain (R group)

Question 4

A protein is found embedded in a cell membrane, with many of its amino acids exposed to the watery environment outside the cell. Which type of amino acid side chains are most likely to be found on the surface of this protein?

Accepted Answer

Polar and charged side chains

Question 5

Which level of protein structure is primarily stabilized by hydrogen bonds between backbone atoms, and what is a common example of this structure?

Accepted Answer

Secondary structure; alpha helix ($$\alpha-$$helix) and beta sheet ($$\beta-$$sheet)

Question 6

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

Accepted Answer

Storing genetic information

Question 7

Which of the following correctly matches the three components of a nucleotide, the monomer of nucleic acids?

Accepted Answer

Phosphate group, pentose sugar, nitrogenous base

Question 8

Which of the following nitrogenous bases is a purine?

Accepted Answer

Adenine

Question 9

What is the key structural difference between DNA and RNA nucleotides?

Accepted Answer

DNA contains deoxyribose sugar, while RNA contains ribose sugar

Question 10

Which functional group is present in both proteins and nucleic acids, and what is its chemical formula?

Accepted Answer

Phosphate group; $$\mathrm{	ext{-}PO_4$^{3-}}$$

Question 11

A mutation causes a nonpolar amino acid to be replaced by a polar amino acid in the interior of a protein. What is the most likely effect on the protein's structure?

Accepted Answer

The protein may misfold because the polar side chain prefers to be exposed to water

Question 12

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

Accepted Answer

The arrangement of multiple polypeptide chains into a functional complex

Question 13

Which element is found in all amino acids but not in carbohydrates?

Accepted Answer

Nitrogen

Question 14

Which of the following diagrams would best represent the backbone of a polypeptide chain?

Accepted Answer

$$\mathrm{	ext{-}N	ext{-}C	ext{-}C	ext{-}N	ext{-}C	ext{-}C	ext{-}}$$

Question 15

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

Accepted Answer

Uracil

Question 16

A scientist is analyzing a molecule with the formula $$\mathrm{C_5H_{10}O_5$}$$, a phosphate group, and a nitrogenous base. What type of molecule is this?

Accepted Answer

RNA nucleotide

Question 17

Which of the following statements about peptide bonds is correct?

Accepted Answer

They form between the carboxyl group of one amino acid and the amino group of another

Question 18

Which of the following is a function of nucleic acids in living organisms?

Accepted Answer

Storing and transmitting genetic information

Question 19

Which of the following best explains why hydrophobic amino acids are typically found in the interior of globular proteins?

Accepted Answer

They avoid contact with water, stabilizing the protein's folded structure

Proteins and Nucleic Acids: Structure, Function, and Classification

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