AP Biology Practice Quiz: Gene Expression and Cell Specialization
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: July 2026
Test your understanding with short quizzes. This quiz has 15 questions to check your progress.
Question 1 of 15
All Questions (15)
A) To bind to promoter regions and initiate transcription.
B) To directly translate mRNA into proteins.
C) To act as negative regulatory molecules that always block transcription.
D) To replicate the DNA before cell division.
Correct Answer: A
According to the provided content, transcription factors bind to promoter or enhancer DNA sequences to initiate transcription, which affects gene expression.
A) The presence of different genes in each cell.
B) The regulation of gene expression leading to different cell products.
C) Mutations that occur after the cells are formed.
D) The different number of chromosomes in each cell type.
Correct Answer: B
The content explains that the regulation of gene expression leads to phenotypic differences in cells and that differential gene expression influences cell products and functions.
A) By binding to DNA and blocking transcription.
B) By enhancing the binding of RNA polymerase.
C) By speeding up the translation of mRNA.
D) By acting as a template for transcription.
Correct Answer: A
The text explicitly states that negative regulatory molecules can inhibit gene expression by binding to DNA and blocking transcription.
A) All cells in an organism become identical.
B) The organism's DNA sequence is altered.
C) Cells develop specialized products and functions.
D) The rate of mutation increases significantly.
Correct Answer: C
The provided content states that gene regulation leads to differential gene expression, which in turn influences cell products and functions, leading to cell specialization.
A) Carbohydrates
B) Lipids
C) Certain small RNA molecules
D) ATP synthase
Correct Answer: C
The content specifies that certain small RNA molecules play roles in regulating gene expression.
A) The phenotype will be unaffected because RNA polymerase can still bind.
B) The phenotype may be altered because the expression of the gene is affected.
C) All genes in the organism will be overexpressed.
D) The organism will produce an excess of negative regulatory molecules.
Correct Answer: B
The content explains that the binding of transcription factors affects gene expression, and gene expression affects the organism's phenotype. If binding is prevented, expression will change, likely altering the phenotype.
A) A negative regulatory molecule binds to the promoter.
B) Small RNA molecules are completely removed from the nucleus.
C) Transcription factors and RNA polymerase bind to a promoter or enhancer.
D) The cell's DNA is fully condensed into a chromosome.
Correct Answer: C
The text states that transcription factors and RNA polymerase bind to promoter or enhancer DNA sequences to initiate transcription.
A) Gene regulation ensures that all genes are expressed at all times to maximize function.
B) By controlling which genes are expressed, gene regulation allows for the development of specialized cells, leading to complex organismal phenotypes.
C) Gene regulation primarily functions to prevent mutations in DNA, thus preserving the organism's phenotype.
D) The phenotype of an organism is determined by its genes alone, with regulation playing a minor role.
Correct Answer: B
This answer connects multiple points from the content: gene regulation (2, 5) leads to differential expression (5), which results in different cell products/functions (5) and ultimately contributes to the organism's overall phenotype (1, 2).
A) A negative regulatory molecule is firmly bound to the promoter.
B) RNA polymerase is bound to the promoter region.
C) A small RNA molecule has degraded the DNA sequence.
D) The promoter region has been deleted from the gene.
Correct Answer: B
The content states that RNA polymerase binds to promoter sequences to initiate transcription. Active transcription implies this binding has occurred.
A) A transcription factor binding to an enhancer sequence.
B) RNA polymerase initiating the synthesis of an mRNA strand.
C) A regulatory molecule binding to DNA and blocking transcription.
D) A gene being expressed to produce a specific cell product.
Correct Answer: C
The content specifies that negative regulatory molecules can inhibit gene expression by binding to DNA and blocking transcription. This is a direct example of inhibition.
A) By the binding of ribosomes to the DNA.
B) By the binding of transcription factors to promoter regions.
C) By the rate of protein degradation in the cytoplasm.
D) By the number of mitochondria in the cell.
Correct Answer: B
The first point of the provided content directly links the binding of transcription factors to promoter regions with the control of gene expression and its effect on the organism's phenotype.
A) Only transcription factors can regulate gene expression.
B) All gene regulation acts by blocking RNA polymerase.
C) Phenotypic differences are unrelated to gene expression.
D) Molecules other than proteins, such as small RNAs, can regulate gene expression.
Correct Answer: D
The content explicitly states that 'Certain small RNA molecules play roles in regulating gene expression.' This finding directly supports that statement.
A) Expressing different genes allows cells to create unique products and perform specific functions.
B) Expressing different genes causes cells to have different DNA sequences.
C) All specialized cells express the exact same set of genes but at different rates.
D) Differential gene expression only occurs in non-specialized stem cells.
Correct Answer: A
According to the text, differential gene expression 'influences cell products and functions,' which is the basis of cell specialization.
A) A promoter is a protein that binds to DNA, while a transcription factor is a DNA sequence.
B) A promoter is a DNA sequence where transcription begins, while a transcription factor is a molecule that binds to it.
C) Both are proteins, but promoters block transcription while transcription factors activate it.
D) Both are DNA sequences, but promoters are transcribed while transcription factors are not.
Correct Answer: B
The content states that transcription factors bind to promoter DNA sequences to initiate transcription. This implies the promoter is a location on the DNA and the transcription factor is the molecule that binds there.
A) The presence of Gene X and its promoter.
B) The presence of RNA polymerase and ribosomes.
C) The presence of transcription factors that bind to the Gene X promoter and the absence of negative regulators for that gene.
D) The presence of small RNAs that universally block all transcription and the presence of negative regulators for Gene X.
Correct Answer: C
This question requires synthesizing multiple concepts. Since both cells have the same DNA (Gene X and its promoter), option A is incorrect. Both have RNA polymerase (B). For Gene X to be expressed specifically in muscle cells, the activating transcription factors must be present and the inhibiting negative regulators must be absent, which is a key part of differential gene expression.