Question 1

Which of the following best explains why humans and elephants have nearly indistinguishable DNA structures, yet are vastly different organisms?

Accepted Answer

The sequence of nucleotides in DNA determines the differences between species.

Question 2

A dehydration reaction is essential for which of the following biological processes?

Accepted Answer

Linking two monosaccharides to form a disaccharide.

Question 3

Which of the following statements about saturated and unsaturated fats is correct?

Accepted Answer

Saturated fats have no double bonds in their fatty acid chains and are solid at room temperature.

Question 4

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

Accepted Answer

Storing genetic information.

Question 5

A person with sickle-cell disease has a single amino acid substitution in their hemoglobin protein. This is an example of which biological concept?

Accepted Answer

A change in primary structure affecting protein function.

Question 6

Which of the following best describes the structure of a nucleotide found in DNA?

Accepted Answer

A five-carbon sugar, a phosphate group, and a nitrogenous base.

Question 7

If one strand of DNA has the sequence $$5'	ext{-}GAATGC-3'$$, what is the sequence of the complementary strand?

Accepted Answer

$$3'	ext{-}CTTACG-5'$$

Question 8

Which of the following is a polysaccharide used by plants to store energy?

Accepted Answer

Starch

Question 9

Why can humans digest starch but not cellulose, even though both are polymers of glucose?

Accepted Answer

The bonds between glucose monomers in cellulose cannot be broken by human enzymes.

Question 10

Which of the following best explains why lipids are hydrophobic?

Accepted Answer

They consist mostly of nonpolar hydrocarbon chains.

Question 11

A triglyceride is formed by joining which of the following components?

Accepted Answer

One glycerol and three fatty acids via dehydration reactions.

Question 12

Which of the following is a correct pairing of DNA bases?

Accepted Answer

Adenine with Thymine

Question 13

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

Accepted Answer

RNA contains ribose and uracil, while DNA contains deoxyribose and thymine.

Question 14

Which of the following is a real-world example of a dehydration reaction?

Accepted Answer

Formation of a peptide bond during protein synthesis.

Question 15

Which of the following is NOT a characteristic of all carbohydrates?

Accepted Answer

They are all hydrophobic.

Question 16

Which of the following best explains the genetic basis for lactose intolerance?

Accepted Answer

A single nucleotide change outside the lactase gene can affect enzyme production.

Question 17

Which of the following is a function of cholesterol in animal cells?

Accepted Answer

It is a key component of cell membranes.

Question 18

Which of the following best illustrates the theme of 'structure and function' in biology?

Accepted Answer

The way glucose is used as both energy and a building block in plants.

Question 19

Which of the following is a likely consequence of protein denaturation?

Accepted Answer

Loss of biological function due to altered shape.

Question 20

Which of the following is a real-world example of evolution affecting human biology?

Accepted Answer

Lactose tolerance in populations with a history of dairy farming.

Chapter 3: The Molecules of Life – Study Notes

Study Guide - Practice Questions