Question 1

Which of the following best explains why two cells with identical genomes can have very different structures and functions in a multicellular organism?

Accepted Answer

They express different sets of genes due to differential gene regulation.

Question 2

A researcher wants to determine whether a specific protein is present in the nucleus of a cell. Which technique would be most appropriate for this purpose?

Accepted Answer

Immunohistochemistry

Question 3

Which of the following statements about DNA methylation is correct?

Accepted Answer

DNA methylation typically represses gene expression by promoting chromatin condensation.

Question 4

A scientist is studying a membrane protein and wants to determine which amino acids are responsible for its ability to remain embedded in the lipid bilayer. Which property of amino acids should the scientist focus on?

Accepted Answer

Hydrophobicity of the side chains

Question 5

Which of the following best describes the main difference between eukaryotic and prokaryotic cells?

Accepted Answer

Eukaryotic cells contain membrane-bound organelles, whereas prokaryotic cells do not.

Question 6

A mutation in the CFTR gene leads to cystic fibrosis. Which of the following best explains how this mutation affects membrane function?

Accepted Answer

It disrupts the function of a chloride ion channel, affecting ion transport across the membrane.

Question 7

Which of the following experimental approaches would best allow you to determine whether a specific protein domain is necessary for clustering of a membrane protein?

Accepted Answer

Mutate the domain and assess clustering using FRAP.

Question 8

Which of the following best describes the role of histone acetylation in gene regulation?

Accepted Answer

Histone acetylation relaxes chromatin structure, increasing gene expression.

Question 9

A researcher uses chromatin immunoprecipitation (ChIP) to study protein-DNA interactions. Which of the following best describes the principle of this technique?

Accepted Answer

It uses antibodies to isolate DNA fragments bound by specific proteins.

Question 10

Which of the following equations correctly represents the relationship between the free energy change ($$\Delta G$$), enthalpy change ($$\Delta H$$), entropy change ($$\Delta S$$), and temperature ($$T) in $$protein folding?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 11

A scientist is analyzing a figure from a journal article showing the results of a FRAP experiment on a membrane protein. The recovery curve is much slower for the wild-type protein than for a mutant lacking a specific domain. What is the most likely interpretation?

Accepted Answer

The specific domain promotes clustering or interactions that restrict mobility.

Question 12

Which of the following best describes molecular complementarity in protein-protein interactions?

Accepted Answer

It describes the precise fit between the shapes and chemical properties of interacting molecules.

Question 13

Which of the following scenarios best illustrates the use of a control in an experiment studying gene expression using reverse transcriptase PCR?

Accepted Answer

Including a sample with no reverse transcriptase to check for DNA contamination.

Question 14

A researcher is designing an experiment to test whether a transcription factor binds to a specific DNA sequence in vivo. Which technique should they use?

Accepted Answer

Chromatin immunoprecipitation (ChIP)

Question 15

Which of the following is a key difference between animal and plant cells?

Accepted Answer

Animal cells lack a cell wall, while plant cells possess a rigid cell wall.

Question 16

A scientist is using fluorescence activated cell sorting (FACS) to isolate a population of cells expressing a specific surface protein. Which property does FACS primarily use to separate cells?

Accepted Answer

Fluorescent labeling of surface proteins

Question 17

Which of the following best explains why transient transfection is useful in studying gene function?

Accepted Answer

It enables temporary expression of a gene to analyze its effects without stable genomic changes.

Question 18

A protein is found to have a quaternary structure. Which of the following best describes this level of protein structure?

Accepted Answer

The arrangement of multiple polypeptide subunits into a functional complex.

Question 19

A researcher is analyzing the effect of a mutation that changes a hydrophobic amino acid in the transmembrane domain of a protein to a charged amino acid. What is the most likely consequence for the protein?

Accepted Answer

The protein may fail to insert or remain stably in the membrane.

Cell Biology Exam 1 Study Notes: Cell Structure, Gene Regulation, Protein Structure, and Membranes

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