Question 1

Which of the following statements best describes the principle of cell theory?

Accepted Answer

All living organisms are composed of cells, and all cells arise from pre-existing cells.

Question 2

A researcher uses transient transfection to introduce a gene into cultured cells. Which of the following best describes the outcome of this technique?

Accepted Answer

The introduced gene is expressed temporarily and does not integrate into the host genome.

Question 3

Which organelle is responsible for the synthesis of proteins that are destined for secretion from the cell?

Accepted Answer

Rough endoplasmic reticulum

Question 4

A scientist is comparing animal and plant cells. Which feature is unique to plant cells?

Accepted Answer

Presence of a cell wall composed of cellulose

Question 5

Which of the following best explains how two cells with identical genomes can differentiate into distinct cell types?

Accepted Answer

Differential gene expression regulated by chromatin modifications and DNA methylation

Question 6

In the context of chromatin remodeling, which modification is most likely to increase gene expression?

Accepted Answer

Histone acetylation

Question 7

A researcher wants to determine whether a specific protein binds to a particular DNA sequence in living cells. Which technique should they use?

Accepted Answer

Chromatin immunoprecipitation (ChIP)

Question 8

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

Accepted Answer

Hydrogen bonds

Question 9

A protein's tertiary structure is stabilized by several types of interactions. Which of the following is NOT typically involved in stabilizing tertiary structure?

Accepted Answer

Peptide bonds

Question 10

Which amino acid class is most likely to be found in the transmembrane region of a membrane protein?

Accepted Answer

Nonpolar (hydrophobic) amino acids

Question 11

A mutation in the CFTR gene leads to cystic fibrosis. Which aspect of membrane protein function is most directly affected by this mutation?

Accepted Answer

Ion transport across the plasma membrane

Question 12

Which technique would best allow a researcher to measure the mobility of membrane proteins in living cells?

Accepted Answer

Fluorescence Recovery After Photobleaching (FRAP)

Question 13

A scientist mutates the SNARE domain of syntaxin and observes a loss of clustering with other syntaxins. What is the most likely explanation for this result?

Accepted Answer

The SNARE domain is required for protein-protein interactions necessary for clustering.

Question 14

Which equation best represents the relationship between the rate of diffusion ($$D) $$and the distance ($$x) a $$molecule travels in a cell?

Accepted Answer

$$x = \sqrt{2Dt}$$

Question 15

A researcher uses immunocytochemistry to detect a protein in cultured cells. Which of the following best describes the principle behind this technique?

Accepted Answer

Antibodies are used to specifically bind and visualize the protein of interest.

Question 16

Which of the following scenarios best illustrates molecular complementarity in protein function?

Accepted Answer

An enzyme binds its substrate with high specificity due to complementary shapes and charge distributions.

Question 17

A scientist is designing an experiment to test whether a transcription factor activates a target gene. Which of the following would be the best control?

Accepted Answer

Cells transfected with an empty vector lacking the transcription factor gene

Question 18

Which of the following best describes the function of the Golgi apparatus in eukaryotic cells?

Accepted Answer

Modification, sorting, and packaging of proteins for secretion or delivery to other organelles

Question 19

A cell biologist uses fluorescence activated cell sorting (FACS) to isolate a population of cells expressing a specific surface protein. Which principle does FACS rely on?

Accepted Answer

Cells are labeled with fluorescent antibodies and sorted based on fluorescence intensity.

Question 20

Which of the following best describes the effect of DNA methylation on gene expression?

Accepted Answer

DNA methylation typically represses gene expression by preventing transcription factor binding.

Cell Biology Exam 1 Study Guide: Cells, Proteins, Membranes, and Experimental Techniques

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