AP 18/19 review quiz

If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then

• The amino acid inactivates the repressor
• The enzymes produced are called inducible operons
• The repressor is active in the absence of the amino acid
• The amino acid acts as a corepressor

Muscle cells differ from nerve cells mainly because they

• express different genes
• contain different genes
• use different genetic codes
• have unique ribosomes

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NGSS.HS-LS1-4

NGSS.HS-LS3-2

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

• Irreversible binding of the repressor to the promoter
• Buildup of a substrate for the pathway controlled by the operon
• Continuous transcription of the operon’s genes
• Reduced transcription of the operon’s genes

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NGSS.HS-LS3-2

The functioning of enhancers is an example of

• Transcriptional control of gene expression
• A post transcriptional mechanism for editing mRNA
• The stimulation of translation by initiation factors
• Post-translational control that activates certain proteins

Absence of bicoid mRNA from a Drosphila egg leads to the absence of anterior larval body parts and mirror image duplication of posterior parts. This is evidence that the product of the bicoid gene

• is transcribed in the early embyro
• normally leads to formation of tail structures
• normally leads to formation of head structures
• leads to programmed cell death

Which of the following statements about the DNA in one of your brain cells is true

• It is the same as the DNA in one of your heart cells
• most of the DNA codes for protein
• the majority of genes are likely to be transcribed
• many genes are grouped into operon-like clusters

Cell differentiation always involves

• the production of tissue-specific proteins
• the movement of cells
• the selective loss of certain genes from the genome
• the cells sensitivity to environmental cues

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NGSS.HS-LS1-4

Which of the following is an example of post-transcriptional control of gene expression?

• the addition of methyl groups to cytosine bases of DNA
• the binding of transcription factors to a promoter
• the removal of introns and splicing together of exons
• gene amplification contributing to cancer

Within a cell, the amount of protein made using a given mRNA molecule depends partly on

• the degree of DNA methylation
• the rate at which mRNA is degraded
• the presence of certain transcription factors
• the types of ribosomes present in the cytoplasm

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

• proto-oncogenes first arose from viral infections
• proto-oncogenes normally help regulate cell division
• proto-oncogenes are mutant versions of normal genes
• cells produce proto-oncogenes as they age