Question 1

Which of the following statements best explains the endosymbiotic theory as it relates to mitochondria and chloroplasts?

Accepted Answer

Mitochondria and chloroplasts originated as independent prokaryotic organisms that were engulfed by a host cell, forming a symbiotic relationship.

Question 2

A scientist observes a cell with the following features: a cell wall, a central vacuole, chloroplasts, and a nucleus. Which type of cell is being observed?

Accepted Answer

Plant cell

Question 3

Which cytoskeletal component is primarily responsible for the movement of chromosomes during mitosis, and what is its basic structure?

Accepted Answer

Microtubules; hollow tubes made of tubulin dimers

Question 4

Which of the following best describes the fluid mosaic model of the cell membrane?

Accepted Answer

A dynamic structure with proteins and lipids moving laterally within a bilayer of phospholipids.

Question 5

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will swell and possibly burst because water enters the cell by osmosis.

Question 6

Which of the following best explains why steroid lipids, such as cholesterol, help maintain membrane fluidity at low temperatures?

Accepted Answer

Steroid lipids prevent phospholipids from packing too closely, thus maintaining fluidity.

Question 7

Which of the following is a key difference between facilitated diffusion and active transport across a cell membrane?

Accepted Answer

Facilitated diffusion does not require energy, while active transport requires ATP.

Question 8

A hormone acts as a ligand and binds to a receptor on the plasma membrane of a target cell. What is the most likely immediate result of this binding?

Accepted Answer

A conformational change in the receptor protein, initiating a signal transduction pathway.

Question 9

Which of the following best describes the role of motor proteins in intracellular transport?

Accepted Answer

They use ATP to move vesicles along cytoskeletal tracks such as microtubules.

Question 10

During which phase of the cell cycle does DNA replication occur?

Accepted Answer

S phase of interphase

Question 11

A cell with two sets of chromosomes (2n) undergoes mitosis. What will be the chromosome number in each daughter cell after division?

Accepted Answer

$$2n$$

Question 12

Which of the following best distinguishes a benign tumor from a malignant tumor?

Accepted Answer

A benign tumor does not invade surrounding tissues, while a malignant tumor can invade and metastasize.

Question 13

Which of the following is a characteristic of viruses that distinguishes them from living cells?

Accepted Answer

Viruses cannot carry out metabolism or reproduce independently.

Question 14

Which of the following best describes the difference between the lytic and lysogenic cycles of a bacteriophage?

Accepted Answer

The lytic cycle results in immediate destruction of the host cell, while the lysogenic cycle integrates viral DNA into the host genome.

Question 15

Which of the following is true about the movement of phospholipids in the cell membrane?

Accepted Answer

Phospholipids can move laterally within the same layer but rarely flip-flop between layers.

Question 16

A patient is given an intravenous solution that is hypertonic relative to their red blood cells. What is the most likely effect on the cells?

Accepted Answer

The cells will shrink as water leaves them by osmosis.

Question 17

Which of the following best explains why only certain cells respond to a specific hormone?

Accepted Answer

Only cells with the appropriate receptor for the hormone can respond to it.

Question 18

Which of the following is a function of the Golgi body in eukaryotic cells?

Accepted Answer

Modifying, sorting, and packaging proteins for secretion or delivery to other organelles.

Question 19

Which process is responsible for the uptake of large particles, such as bacteria, by a cell?

Accepted Answer

Phagocytosis

Question 20

Which of the following best describes the structure and function of ribosomes?

Accepted Answer

Complexes of RNA and protein that synthesize polypeptides by translating mRNA.

Introductory Biology Study Guide: Cells, Membranes, Cell Cycle, and Viruses

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