Question 1

Which of the following statements best explains why the DNA of a mosquito and an elephant is nearly indistinguishable, yet the two species are so different?

Accepted Answer

The differences in species result from the way nucleotides are arranged in their DNA.

Question 2

Lactose intolerance is caused by the inability to properly digest lactose. Which of the following is a direct biological solution for someone with lactose intolerance?

Accepted Answer

Consuming lactase pills along with food containing lactose.

Question 3

Which of the following best describes an organic compound?

Accepted Answer

A carbon-based molecule, often with hydrogen, oxygen, and nitrogen.

Question 4

Methane ($CH_4$) is a simple organic compound. How many hydrogen atoms are present in one molecule of methane?

Accepted Answer

$4$

Question 5

Which functional group is common to all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($-COOH$)

Question 6

A dehydration reaction is important in the synthesis of biological polymers. What is the result of a dehydration reaction between two monomers?

Accepted Answer

Two monomers are linked together and a molecule of water is removed.

Question 7

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

Accepted Answer

Starch

Question 8

Cellulose and starch are both polymers of glucose. Why can humans digest starch but not cellulose?

Accepted Answer

Humans have enzymes that break the bonds in starch but not the bonds in cellulose due to their different structures.

Question 9

Which of the following statements about lipids is correct?

Accepted Answer

Lipids are hydrophobic and do not mix with water.

Question 10

A triglyceride is formed by joining one glycerol molecule with three fatty acids. What type of reaction is responsible for this process?

Accepted Answer

Dehydration reaction

Question 11

Which type of fat is most likely to be solid at room temperature and contribute to atherosclerosis?

Accepted Answer

Saturated fat

Question 12

Hydrogenation of plant oils results in which of the following?

Accepted Answer

Creation of trans fats, which are unhealthy

Question 13

Which of the following is NOT made of protein?

Accepted Answer

Cellulose

Question 14

A single amino acid substitution in hemoglobin can cause sickle-cell disease. What is the most direct consequence of this substitution?

Accepted Answer

The protein folds into a different shape, altering its function.

Question 15

Which of the following is a monomer of nucleic acids?

Accepted Answer

Nucleotide

Question 16

If one DNA strand has the sequence $GAAT$, what is the sequence of the complementary strand?

Accepted Answer

$CTTA$

Question 17

Which of the following is a difference between DNA and RNA?

Accepted Answer

RNA contains ribose sugar, while DNA contains deoxyribose.

Question 18

Which major biological theme is illustrated by the fact that the sequence of nucleotides on your chromosomes contains your genetic legacy?

Accepted Answer

Information flow

Question 19

A study found a 100% correlation between lactose intolerance and having cytosine (C) rather than thymine (T) at a particular site in a chromosome. What does this finding demonstrate?

Accepted Answer

A small change in a DNA nucleotide sequence can affect protein production and organism well-being.

Question 20

In cultures where dairy products are a staple, what evolutionary process likely led to increased lactose tolerance?

Accepted Answer

Natural selection favored mutations that kept the lactase gene active beyond infancy.

Chapter 3: The Molecules of Life – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards