Free Practice Quiz Question List

8 Cellular Regulation Online Quiz Questions

Use this free practice quiz with 20 questions to review 8 Cellular Regulation, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

True or false: Adding a phosphate group to a protein always activates it.

A
True
B
False

Choose one

1 point

Two cell types in one organism have distinct patterns of gene expression. Which explanation best fits this difference?

A
They usually contain different DNA sequences, so each cell type has a different set of genes.
B
They use different combinations of regulatory proteins to control which genes are expressed.
C
They make the same proteins, but move them to different parts of the cell.
D
They differ because only one cell type can use transcription factors.

Written response

1 point

A cell needs to add a phosphate group to a target protein. What enzyme class performs this reaction?

Fill in the blank

1 point

In a metabolic pathway, the final product inhibits an enzyme near the beginning of the pathway. This is an example of .

Choose one

1 point

An external condition prompts a cell to increase transcription of genes involved in a particular response. Which mechanism could connect that condition to the change in transcription?

A
The signal directly changes the cell's DNA sequence.
B
The signal makes every gene in the cell produce more RNA.
C
The signal activates a pathway that changes transcription-factor activity.
D
The signal prevents RNA from being translated into protein.

Choose all

1 point

Select all mechanisms that can alter protein activity or function without first making new proteins.

A
A small molecule binds to a regulatory site and changes a protein's activity.
B
A transcription factor increases transcription of the gene encoding the protein.
C
A kinase adds a phosphate group to a target protein.
D
The cell changes where the protein is located.

True or false

1 point

True or false: A cell-cycle checkpoint can delay progression when a key condition has not been met, giving time for a problem to be addressed.

A
True
B
False

Fill in the blank

1 point

A cell delays chromosome separation until each chromosome is properly attached to the .

Written response

1 point

A protein is tagged with ubiquitin for proteasomal degradation. What cellular structure degrades it?

Choose one

1 point

A cell is preparing to move from one cell-cycle stage to the next. Which statement best describes how cyclin-dependent kinases contribute to this transition?

A
Cdks become active when they bind to p21, which starts DNA replication.
B
Cdks become active when they bind to particular cyclins, and the complexes promote stage transitions.
C
Cyclins directly separate chromosomes by attaching them to the spindle.
D
Cdks are active throughout the cycle, while cyclin amounts remain constant.

Choose one

1 point

A regulatory protein activates transcription of its own gene, helping sustain its production. Which interpretation best describes this arrangement?

A
Negative feedback, because the protein blocks its own production.
B
Negative feedback, because all transcription-factor activity reduces gene expression.
C
Positive feedback, because the protein reinforces the process that produces it.
D
Neither kind of feedback, because feedback only occurs in metabolic pathways.

Choose one

1 point

A cell detects DNA damage before DNA replication. Which sequence best describes a regulatory response that can slow cell-cycle progression?

A
DNA damage activates cyclins, which speed the cell into DNA replication.
B
DNA damage activates p53, which promotes p21 production; p21 can slow progression into DNA replication.
C
DNA damage causes the spindle checkpoint to separate chromosomes immediately.
D
DNA damage activates proteasomes, which remove all cyclins and stop gene expression.

Choose all

1 point

Select all outcomes that positive feedback can help produce.

A
A response can grow stronger.
B
A pathway's final product necessarily inhibits its first enzyme.
C
A cellular state can be maintained.
D
The output always reduces activity in the process that generated it.

Open ended

1 point

A cell receives an external signal and responds quickly, but it may also need to maintain the response after the initial signal. Describe how regulation of existing proteins and regulation of gene expression can contribute to different time scales, and explain how positive feedback could help maintain the response.

Choose one

1 point

An external signal activates a pathway in a cell, and the cell then produces more RNA from genes needed for a particular response. Which mechanism most directly connects the signal to this change?

A
The signal directly converts existing RNA into protein.
B
The signal changes transcription-factor activity, increasing transcription of response genes.
C
The signal causes all proteins in the cell to be degraded.
D
The signal prevents regulatory proteins from interacting with DNA.

Choose one

1 point

Two cell types generally contain the same DNA but make different sets of proteins. Which explanation best accounts for this difference?

A
Each cell type must contain a completely different genome.
B
Different cell types express distinct genes because their DNA sequences are all different.
C
Different combinations of regulatory proteins can produce distinct patterns of gene expression.
D
Each cell type expresses every gene in its genome at the same level.

Choose one

1 point

A cell needs to alter an enzyme’s activity quickly, before it could make additional enzyme molecules. Which mechanism could produce this rapid response?

A
A small molecule binds a regulatory site and changes the activity of an existing protein.
B
The cell first transcribes and translates a new copy of the protein.
C
The cell replicates the gene encoding the protein.
D
The cell changes the DNA sequence of the protein’s gene.

Written response

1 point

In a metabolic pathway, the final product inhibits an enzyme near the pathway’s beginning. What type of feedback loop does this describe?

Written response

1 point

After DNA damage activates p53, which Cdk inhibitor can p53 promote the cell to produce, slowing progression into DNA replication?

True or false

1 point

Two cells transcribe a gene at the same rate, but one cell breaks down the gene’s RNA more quickly. True or false: assuming other factors are unchanged, the faster breakdown can reduce the amount of RNA available for translation.

A
True
B
False