Q: A transmission electron micrograph of Klebsiella pneumoniae is shown at a magnification of $45{,}000\times$. If the measured diameter of the bacterium in the image is $2\ \mathrm{cm}$, what is the actual diameter of the bacterium in micrometers ($\mu\mathrm{m}$)?

$\frac{2\ \mathrm{cm}}{45{,}000} \times 10{,}000\ \mu\mathrm{m}/\mathrm{cm} = 4.44\ \mu\mathrm{m}$

Question 1

Which of the following best explains why transmission electron microscopes (TEMs) are necessary for studying the internal structure of cells, rather than light microscopes?

Accepted Answer

TEMs have a much higher resolving power, allowing visualization of structures as small as $0.1\ \mathrm{nm}$.

Question 2

A scientist observes a cell with the following features: a plasma membrane, cytosol, ribosomes, and a nucleoid region, but no membrane-bound organelles. Which type of cell is being observed?

Accepted Answer

Prokaryotic cell

Question 3

Which of the following statements about the phospholipid bilayer is correct?

Accepted Answer

The bilayer forms spontaneously due to the amphipathic nature of phospholipids.

Question 4

Gram-positive and gram-negative bacteria differ in their cell wall structure. Which feature is unique to gram-negative bacteria?

Accepted Answer

An outer membrane outside the peptidoglycan layer

Question 5

According to the endosymbiont theory, which of the following is evidence that mitochondria originated from prokaryotic cells?

Accepted Answer

Mitochondria have double membranes and their own ribosomes.

Question 6

Which organelle is primarily responsible for modifying, sorting, and packaging proteins for secretion or delivery to other organelles?

Accepted Answer

Golgi apparatus

Question 7

A cell is observed to have large numbers of rough endoplasmic reticulum (ER). What is the most likely function of this cell?

Accepted Answer

Production of secreted proteins

Question 8

Which of the following is NOT part of the endomembrane system?

Accepted Answer

Mitochondrion

Question 9

A transmission electron micrograph of Klebsiella pneumoniae is shown at a magnification of $45{,}000	imes$. If the measured diameter of the bacterium in the image is $2\ \mathrm{cm}$, what is the actual diameter of the bacterium in micrometers ($\mu\mathrm{m}$)?

Accepted Answer

$\frac{2\ \mathrm{cm}}{45{,}000} 	imes 10{,}000\ \mu\mathrm{m}/\mathrm{cm} = 4.44\ \mu\mathrm{m}$

Question 10

Which of the following best describes the function of histones in eukaryotic cells?

Accepted Answer

Histones help package DNA into nucleosomes, regulating gene expression.

Question 11

Which organelle is responsible for the conversion of light energy into chemical energy in plant cells?

Accepted Answer

Chloroplast

Question 12

Which of the following statements about ribosomes is TRUE?

Accepted Answer

Ribosomes are nonmembranous organelles responsible for protein synthesis.

Question 13

A cell is observed to have a large central vacuole, chloroplasts, and a cell wall. Which type of cell is this most likely to be?

Accepted Answer

Plant cell

Question 14

Which cytoskeletal element is primarily responsible for maintaining cell shape and resisting tension?

Accepted Answer

Intermediate filaments

Question 15

Which of the following best explains the advantage of compartmentalization in eukaryotic cells?

Accepted Answer

It enables incompatible biochemical processes to occur simultaneously in different organelles.

Question 16

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

Accepted Answer

Breakdown of waste materials and cellular debris

Question 17

Which of the following best describes the difference between smooth and rough endoplasmic reticulum (ER)?

Accepted Answer

Rough ER has ribosomes attached and synthesizes proteins; smooth ER lacks ribosomes and synthesizes lipids.

Question 18

Which of the following structures is found in both prokaryotic and eukaryotic cells?

Accepted Answer

Ribosomes

Question 19

A scientist is comparing the size of a bacterium and a human cell. If the bacterium is $2\ \mu\mathrm{m}$ in diameter and the human cell is $20\ \mu\mathrm{m}$ in diameter, what is the ratio of the volume of the human cell to the bacterium, assuming both are spherical? (Use $V = \frac{4}{3}\pi r^3$)

Accepted Answer

$1000:1$

Cell Structure, Microscopy, and Prokaryotic vs. Eukaryotic Cells

Study Guide - Practice Questions

Study Guide - Flashcards