Question 1

Which of the following statements best describes the fundamental structural difference between prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotic cells lack a membrane-bound nucleus, while eukaryotic cells possess a membrane-bound nucleus.

Question 2

A patient’s blood pH drops from 7.4 to 7.1. Which of the following best explains how a buffer system in the blood would respond?

Accepted Answer

The buffer will absorb excess $$ \mathrm{H}^+ $$ ions to minimize the change in pH.

Question 3

Which of the following is an example of a negative feedback mechanism in the human body?

Accepted Answer

Regulation of blood glucose by insulin and glucagon.

Question 4

In a phylogenetic tree, what does a node (branch point) represent?

Accepted Answer

The most recent common ancestor of the descendant lineages.

Question 5

Which of the following best describes adaptive radiation?

Accepted Answer

The rapid evolution of many diverse species from a common ancestor when new habitats become available.

Question 6

Which of the following is the correct sequence of steps in the scientific method?

Accepted Answer

Observation, hypothesis, experiment, analysis, conclusion.

Question 7

How does a scientific theory differ from a hypothesis?

Accepted Answer

A theory is a well-supported explanation based on a large body of evidence, while a hypothesis is a testable prediction.

Question 8

Which four elements make up over 90% of the human body by mass?

Accepted Answer

Oxygen, carbon, hydrogen, nitrogen

Question 9

The atomic number of an element is determined by:

Accepted Answer

The number of protons in the nucleus.

Question 10

Why can’t you change the number of protons in an atom without changing the element?

Accepted Answer

Because the number of protons defines the element’s identity.

Question 11

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule consists of two or more atoms bonded together, while a compound consists of two or more different elements bonded together.

Question 12

Which type of bond is formed when there is a large difference in electronegativity between two atoms?

Accepted Answer

Ionic bond

Question 13

What type of bond holds the hydrogen and oxygen atoms together within a single water molecule?

Accepted Answer

Polar covalent bond

Question 14

Which property of water is primarily responsible for its high surface tension?

Accepted Answer

Cohesion due to hydrogen bonding

Question 15

Why does ice float on liquid water?

Accepted Answer

Ice is less dense than liquid water due to the formation of a crystalline lattice.

Question 16

A solution has a pH of 4. What is the concentration of $$ \mathrm{H}^+ $$ ions in the solution?

Accepted Answer

$$ 1 	imes 10$$^{-4}$$ $$ mol/L

Question 17

Which of the following best explains why some substances are hydrophobic?

Accepted Answer

They are nonpolar and do not form hydrogen bonds with water.

Question 18

Which of the following is a characteristic of a well-designed scientific experiment?

Accepted Answer

It includes a control group and tests only one variable at a time.

Question 19

Which of the following best describes a hybrid orbital?

Accepted Answer

An orbital formed by the combination of two or more atomic orbitals on the same atom.

Question 20

If an atom has an atomic number of 12 and an atomic mass of 24, how many neutrons does it have?

Accepted Answer

12

General Biology Study Guide: Step-by-Step Guidance for Key Concepts

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