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WorksheetsCancer, Control Elements and Activators (CRP, cAMP) for exam 4
Total questions: 23
Worksheet time: 12mins
According to the passage, what happens to the cAMP concentration in the cell when the amount of glucose increases?
cAMP concentration rises
cAMP concentration falls
cAMP concentration remains unchanged
cAMP concentration fluctuates
Fill in the blank: The lac operon is under dual control: negative control by the _______ and positive control by CRP.
lac repressor
lac promoter
lac operator
lac activator
Which molecule acts as an activator by binding to DNA and stimulating transcription of a gene in the lac operon system?
Allolactose
cAMP receptor protein (CRP)
RNA polymerase
Glucose
When both glucose and lactose are present in its environment, E. coli preferentially uses _______.
glucose
lactose
fructose
galactose
The attachment of CRP to the promoter directly stimulates gene expression in the lac operon.
True
False
What is the role of chemical modifications to histones in eukaryotic organisms?
They regulate gene transcription
They synthesize proteins
They degrade DNA
They transport RNA
Fill in the blank: The N-terminus of each histone protein in a nucleosome protrudes outward from the nucleosome, making it accessible to various modifying enzymes that catalyze the addition or removal of specific chemical groups, such as acetyl (—COCH3), methyl, and ________ groups.
phosphate
sulfate
hydroxyl
carboxyl
Which chemical modification to histones appears to promote transcription by opening up chromatin structure?
Methylation
Phosphorylation
Acetylation
Glycosylation
The addition of methyl groups to histones can lead to the condensation of chromatin and reduced transcription.
True
False
Fill in the blank: A cluster of proteins called a ________ assembles on the promoter sequence at the 'upstream' end of the gene.
transcription initiation complex
ribosome
spliceosome
repressor complex
What is the function of control elements in eukaryotic genes?
They serve as binding sites for transcription factors
They synthesize mRNA
They degrade histones
They transport proteins
Which of the following is true about some cancer cells?
They need growth factors to divide
They do not need growth factors to divide
They cannot divide
They always respond to control mechanisms
Fill in the blank: Some cancer cells ________ their own growth factors.
make
destroy
ignore
absorb
Which statement is correct about cancer cells?
They only divide in the presence of growth factors
They convey a growth factor’s signal without the presence of the growth factor
They never divide
They always have normal cell cycle control proteins
Fill in the blank: Some cancer cells have mutations in ________.
cell cycle control proteins
photosynthetic pigments
digestive enzymes
structural carbohydrates
Thus, the lac operon is both ________ and positively controlled. (Fill in the blank)
negatively
chemically
structurally
randomly
The state of the repressor (with or without bound allolactose) determines whether transcription ________.
occurs at all
is always inhibited
is never regulated
is independent of the repressor
What does the state of CAP (with or without bound cAMP) control in the lac operon?
Whether transcription occurs at all
The rate of transcription
The binding of allolactose
The production of cAMP
Which of the following best describes the role of enhancers in eukaryotic gene regulation?
They increase the rate of transcription when bound by activator proteins
They degrade mRNA after transcription
They block ribosome assembly
They synthesize DNA
Fill in the blank: In the lac operon, the presence of lactose leads to the inactivation of the ________.
promoter
repressor
operator
activator
Which chemical modification to histones is most commonly associated with reduced gene expression?
Phosphorylation
Methylation
Glycosylation
Acetylation
Which term is synonymous with "enhancers?"
Proximal control elements
Activators
Inducers
Distal control elements
True or False: Proximal control elements have activators bound to them.
