Question 1

Which of the following best distinguishes the domain Eukarya from the other two domains of life on a phylogenetic tree?

Accepted Answer

Eukarya have membrane-bound organelles, including a nucleus, while Bacteria and Archaea do not.

Question 2

Which of the following is NOT a defining feature of living organisms?

Accepted Answer

Inability to metabolize energy

Question 3

Which statement correctly compares scientific laws, theories, and hypotheses?

Accepted Answer

A theory is a well-substantiated explanation, while a law describes a consistent natural phenomenon; a hypothesis is a testable prediction.

Question 4

Which of the following is an essential element of a scientific experiment designed to test a hypothesis?

Accepted Answer

A control group that does not receive the experimental treatment

Question 5

If an element has an atomic number of 8 and a mass number of 18, how many neutrons does it have?

Accepted Answer

$$18 - 8 = 10$$ neutrons

Question 6

Which of the following best describes the difference between covalent and ionic bonds?

Accepted Answer

Covalent bonds involve the sharing of electrons, while ionic bonds involve the transfer of electrons.

Question 7

Which of the following interactions is most likely to occur between two polar molecules?

Accepted Answer

Hydrogen bonding

Question 8

Which part of an amino acid determines its unique chemical properties?

Accepted Answer

The R group (side chain)

Question 9

What type of bond forms between the monomers of a protein during protein synthesis?

Accepted Answer

Peptide bond

Question 10

Which of the following best describes the difference between a condensation reaction and a hydrolysis reaction?

Accepted Answer

Condensation joins monomers by removing water; hydrolysis breaks polymers by adding water.

Question 11

Which of the following forces is primarily responsible for the secondary structure of proteins?

Accepted Answer

Hydrogen bonds between backbone atoms

Question 12

What is the monomer that comes together to make nucleic acids?

Accepted Answer

Nucleotide

Question 13

Which of the following was NOT critical information for Watson and Crick in determining the structure of DNA?

Accepted Answer

The presence of uracil in DNA

Question 14

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

Accepted Answer

RNA contains ribose sugar, while DNA contains deoxyribose sugar.

Question 15

Which naming strategy correctly identifies a six-carbon sugar with an aldehyde group?

Accepted Answer

Aldohexose

Question 16

Which of the following best describes the difference between a monosaccharide, disaccharide, and polysaccharide?

Accepted Answer

Monosaccharides are single sugars, disaccharides are two sugars linked, and polysaccharides are many sugars linked.

Question 17

Why are carbohydrates considered 'energy molecules' in biological systems?

Accepted Answer

They have many C-H bonds that can be oxidized to release energy.

Question 18

Which polysaccharide is used for energy storage in animals?

Accepted Answer

Glycogen

Question 19

Which of the following best explains why RNA is considered more likely to be the first 'living' molecule than DNA?

Accepted Answer

RNA can both store genetic information and catalyze chemical reactions.

Question 20

Which type of bond links nucleotides together in a nucleic acid strand?

Accepted Answer

Phosphodiester bond

Unit 1: Introduction and Biological Molecules – Study Notes

Study Guide - Practice Questions