question

Proto-oncogenes function by preventing cells from dividing uncontrollably.

answer

False

question

A woman inherits a mutant BRCA1 allele from her mother. She has an increased risk of developing breast cancer because

answer

a mutation in her normal BRCA1 allele may lead to cancer, whereas a normal individual would have to acquire two mutations (one in each allele) to develop cancer.

question

In the absence of lactose,

answer

the repressor binds to the operator, and the genes of the lac operon are not transcribed.

question

Prokaryotes regulate gene expression with a promoter.

answer

True

question

Which of the DNA sequences shown in the figure is/are bound by a regulatory protein?

answer

3

question

A protein that promotes apoptosis would be considered a(n)

answer

tumor suppressor.

question

Stem cells that contain telomerase can be found in adults.

answer

true

question

Lactose ______ the repressor, causing it to ______.

answer

inactivates; fail to bind to the operator

question

In eukaryotes, one gene may specify the construction of several proteins.

answer

True

question

A(n) ___ is to reproductive cloning as a(n) ___ is to therapeutic cloning.

answer

clone; specialized cell

question

Signal transduction pathways can stimulate transcription activators.

answer

true

question

Transcription of the genes of the lac operon is ______ unless _______ is _______.

answer

off; lactose; present

question

A positive genetic test for telomerase indicates that

answer

a cell is probably cancerous.

question

If tumor cells have a faulty, non-functional proteinase, they will be unable to undergo which of the following processes?

answer

metastasis

question

Embryonic cells and cancer cells are similar because

answer

telomerase is active.

question

Prokaryotes cannot regulate gene expression at which of the following levels?

answer

alternative mRNA processing and chromatin compaction

question

Cells from the root of a carrot may be used to generate an entire carrot plant. This illustrates that

answer

every cell of the root contains all of the plant's genes.

question

Many growth factors are classified as which of the following?

answer

oncogenes

question

The unpacking of heterochromatin into euchromatin does not immediately result in DNA transcription because

answer

histones still block the binding of RNA polymerase to the promoter.

question

Heterochromatin differs from euchromatin in that heterochromatin

answer

is transcriptionally inactive.

question

In prokaryotes, an operon includes

answer

a cluster of genes and the DNA sequences that control their transcription.

question

Which of the following is not a characteristic of cancer cells?

answer

exhibit contact inhibition

question

What would be the most likely result on the regulation of the lac operon from a non-functional repressor protein?

answer

transcription of the lactose metabolizing genes, even when lactose is absent

question

Cancer will occur if one copy of a mutant tumor suppressor gene is inherited.

answer

false

question

Specialized cells differ from one another because

answer

they only express certain genes.

question

Histone displacement is necessary for transcription to occur in euchromatin.

answer

true

question

In the absence of growth factors, the retinoblastoma (RB) protein binds a transcription activator called E2F, preventing the cell from entering S stage. A mutation in E2F occurs that causes RB to no longer bind it. This mutant E2F would be considered a(n) ________.

answer

oncogene

question

In order to clone adult animals, scientists typically begin with

answer

an enucleated egg.

question

A point mutation in the operator of the lac operon would most likely cause

answer

no binding of the repressor protein to the operator even when lactose is absent.

question

Which of the following reasons explains a possible advantage of using adult stem cells in therapeutic cloning rather than embryonic stem cells?

answer

Adult stem cells may be obtained from the patient and would be less likely to be rejected by the patient's body.

question

Angiogenesis contributes to carcinogenesis because

answer

it causes blood vessels to grow into the tumor.

question

Proteins are active immediately after translation occurs.

answer

false

question

Inheritance of mutant forms of some genes may lead to a predisposition to develop cancer. Which of the genes listed below has not been linked to hereditary forms of cancer?

answer

DScam

question

Which of the following series of events is in the correct order?

answer

no chemical binds to receptor, signal transduction pathway stimulates target gene, target gene stimulates transcription activator no signal transduction pathway stimulates receptor, transcription activator is activated by target gene no signal transduction pathway activates receptor, chemical binds to receptor, target gene stimulates transcription activator Signal transduction pathways are initiated by the binding of a chemical signal by a receptor, which initiates the pathway. The pathway usually ends with the stimulation of a transcription activator, which brings about the needed response in the cell by causing the transcription of needed genes.

question

If the maternal X chromosome is inactive and seen as Barr body in one cell, then it is the maternal X chromosome that is inactive and seen as a Barr body in every cell of that woman's body.

answer

false

question

Signal transduction pathways can stimulate transcription activators.

answer

true

question

The protein derived from a particular gene is different when it is found in a neuron than in a muscle cell. This is most likely due to

answer

alternative mRNA processing.

question

An oncogene is more likely to lead to cancer than a mutant tumor suppressor because

answer

a gain of function mutation in an oncogene need only occur in one allele before it disrupts control of the cell cycle.

question

Therapeutic cloning

answer

can produce specialized cells to treat human disease.

question

Which of the DNA sequences shown in the figure are transcribed and translated to produce proteins?

answer

1 and 4

question

A proto-oncogene differs from a tumor suppressor gene because a proto-oncogene

answer

stimulates mitosis in a normal cell, whereas a tumor suppressor gene inhibits mitosis.

question

Transcription activators are different from transcription factors in that

answer

not transcription activators are required for RNA polymerase binding, while transcription factors slow RNA polymerase binding. not transcription activators accelerate transcription, while transcription factors assist RNA polymerase binding. Transcription factors are proteins that are required for RNA polymerase to bind to a promoter. RNA polymerase can bind a promoter and transcribe a gene when transcription activators are not present, but their presence accelerates the process when they bind DNA and promote transcription.

question

A translocation may lead to cancer if it

answer

disrupts control of expression of genes that regulate the cell cycle.

question

Which of the following events in gene expression control does not occur in the nucleus?

answer

mRNA translation

question

Female mammals form Barr bodies because

answer

no compacting the chromatin in one of their X chromosomes allows them to produce more gene product than a male from the other X chromosome. Barr bodies are formed because otherwise, a female would produce twice as much gene product as a male from genes on the X chromosome, and too much of some gene products can be harmful.

question

Why is it necessary to "starve" the donor cells prior to reproductive cloning?

answer

to force the cells into G0 stage so that the nuclei removed from them will respond to cytoplasmic growth signals

question

A mutation that causes a gain of function in a tumor suppressor gene would not likely cause cancer because a tumor suppressor protein

answer

no activates a signal transduction pathway. no normally promotes the cell cycle. A tumor suppressor normally inhibits the cell cycle, and a gain of function mutation would not affect this activity. Cell division would still be repressed, and so cancer (uncontrolled cell division) would be very unlikely to result.

question

Why do adult stem cells currently have fewer uses in therapeutic cloning than embryonic stem cells?

answer

Embryonic stem cells may become any type of cell, whereas adult stem cells may only become a limited number of cell types.

question

Cancer cells have abnormal chromosomes because they express telomerase when they should not.

answer

false

question

In the regulation of the lac operon, when lactose is present,

answer

lactose binds to the repressor, making it unable to bind to the operator and allowing transcription to proceed.

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