Question 1

Which of the following best explains why cats do not taste sweetness?

Accepted Answer

Cats have a defective gene for one of the two proteins that form the sweet receptor complex.

Question 2

Which atom is represented by the question mark in the molecular diagram, given that it shares two electrons to satisfy its outer shell?

Accepted Answer

Sulfur

Question 3

Which of the following is a correct formula for a carbohydrate, based on the ratio of hydrogen to oxygen atoms?

Accepted Answer

$$\mathrm{C}_n(\mathrm{H}_2\mathrm{O})_n$$

Question 4

Why are starch and glycogen easily digested by humans, but cellulose is not?

Accepted Answer

Cellulose has a different glycosidic bond configuration that human enzymes cannot hydrolyze.

Question 5

Which of the following amino acids would dissolve most easily in water?

Accepted Answer

Serine

Question 6

What is the main function of phospholipids in biological membranes?

Accepted Answer

They form a bilayer with hydrophilic heads and hydrophobic tails, creating a selective barrier.

Question 7

Which statement best describes the role of functional groups in organic molecules?

Accepted Answer

Functional groups determine the chemical properties and reactivity of organic molecules.

Question 8

A protein is formed by joining amino acids through which type of reaction?

Accepted Answer

Dehydration reaction

Question 9

If a protein is composed of 400 amino acids, how many peptide bonds are present in its primary structure?

Accepted Answer

$$399$$

Question 10

Which of the following best explains why burning hair smells like sulfur?

Accepted Answer

Hair contains high levels of the amino acid cysteine, which has sulfur atoms that form disulfide bonds.

Question 11

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

Accepted Answer

Storing genetic information

Question 12

Which statement about the sweet receptor in cats is correct?

Accepted Answer

Cats have a defective gene, so they lack a functional sweet receptor and cannot taste sweetness.

Question 13

Which of the following best describes the structure of DNA?

Accepted Answer

A double helix composed of two strands held together by hydrogen bonds between base pairs

Question 14

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

Accepted Answer

$$\mathrm{A} - \mathrm{T}$$ and $$\mathrm{C} - \mathrm{G}$$

Question 15

Which of the following is true about the sweetness index of aspartame compared to glucose?

Accepted Answer

Aspartame has a much higher sweetness index than glucose.

Question 16

Which of the following statements about polysaccharides is correct?

Accepted Answer

Starch and glycogen are easily digested by humans, but cellulose is not.

Question 17

Which of the following is a real-world example of a protein acting as a transporter?

Accepted Answer

A fructose transporter moving sugar across a cell membrane

Question 18

Which of the following best describes the process by which termites digest cellulose?

Accepted Answer

Termites rely on microorganisms in their digestive tracts to hydrolyze cellulose.

Question 19

Which of the following is a correct statement about the protein structure prediction by AlphaFold 3?

Accepted Answer

AlphaFold 3 can accurately predict the tertiary and quaternary structures of proteins from their amino acid sequences.

Question 20

Which of the following is true about the protein Growth/Differentiation Factor 15 (GDF15) and morning sickness?

Accepted Answer

GDF15 is a protein with 112 amino acids that forms a homodimer and is a major cause of nausea during early pregnancy.

Cell Chemistry and Biological Molecules: Why Cats Can't Taste Sweet

Study Guide - Practice Questions