Mastering Biology chapter 11 – Flashcards

Unlock all answers in this set

Unlock answers
question
The term "gene expression" refers to the
answer
process by which genetic information flows from genes to proteins.
question
A gene operon consists of
answer
transcribed genes, an operator, and a promoter.
question
In a prokaryote, a group of genes with related functions, along with their associated control sequences, defines
answer
an operon.
question
The lac operon in Escherichia coli
answer
prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment.
question
Proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to bind to a promoter are called
answer
activators.
question
The expression of the tryptophan operon is controlled by
answer
a repressor that is active when it binds to tryptophan.
question
The lac operon of E. coli is ________ when the repressor is bound to lactose.
answer
active
question
Which of the following is likely to occur in E. coli cells that are grown in skim milk?
answer
The trp repressor is activated, and the cells will produce lactose-utilizing enzymes.
question
There is a mutation in the operator of the trp operon in a cell such that the trp repressor is unable to bind to the operator. If tryptophan is added to the cell, what will happen?
answer
Tryptophan will bind to the repressor, and trp enzymes will be produced.
question
The basis of cellular differentiation is
answer
selective gene expression.
question
The genes for the enzymes of glycolysis
answer
are active in all metabolizing cells, but the genes for specialized proteins are expressed only in particular cell types.
question
The relationship between DNA and chromosomes is most like
answer
thread wrapped around a spool.
question
In female mammals, the inactive X chromosome in each cell
answer
becomes a Barr body.
question
Both prokaryotic and eukaryotic cells use ________ to turn certain genes on or off.
answer
proteins
question
Enhancers are
answer
DNA sequences to which activator proteins bind.
question
RNA splicing involves the
answer
removal of introns from the molecule.
question
The coding regions of a gene are called
answer
exons.
question
Which of the following permits a single gene to code for more than one polypeptide?
answer
alternative RNA splicing
question
Small pieces of RNA that can regulate translation of mRNA are called
answer
microRNA
question
RNA interference (RNAi) can be used by
answer
cells to prevent infections from double-stranded RNA viruses.
question
All of the following mechanisms are used to regulate protein production except
answer
DNA replication.
question
Which of the following mechanisms of controlling gene expression occurs outside of the nucleus?
answer
translation
question
A homeotic gene
answer
serves as a master control gene that functions during embryonic development by controlling the developmental fate of groups of cells.
question
Which of the following statements about microarrays is false?
answer
Microarrays use tiny portions of double-stranded RNA fragments from a large number of genes.
question
In multicellular organisms, the coordination of cellular activities relies on
answer
cell-to-cell signaling and signal transduction pathways.
question
To initiate a signal transduction pathway, a signal binds to a receptor protein usually located in the
answer
plasma membrane.
question
Transcription factors attach to
answer
DNA
question
A signal outside a cell triggers changes in the transcription and translation inside the cell through
answer
signal transduction pathways.
question
Yeast are able to communicate with each other
answer
through chemical signaling.
question
Signal transduction pathways
answer
are mechanisms of communication that probably evolved in ancient prokaryotes.
question
In plants, most differentiated cells retain
answer
a complete set of their genes and retain the ability to express those genes under certain circumstances.
question
Why can some plants be cloned from a single cell?
answer
Plant cells can dedifferentiate and give rise to all of the specialized cells required to produce an entire plant.
question
Which of the following processes occurs when a salamander regenerates a lost limb?
answer
Certain cells in the limb dedifferentiate, divide, and then redifferentiate to form a new limb.
question
The cloning of Dolly the sheep
answer
demonstrated that the nuclei from differentiated mammalian cells can retain their full genetic potential.
question
The use of cloning to produce special embryonic stem cells is called
answer
therapeutic cloning.
question
Which of the following mammals has not yet been cloned and brought through the complete gestation cycle?
answer
human
question
Which of the following possible uses of reproductive cloning is still considered by most to be an unresolved ethical issue?
answer
the reproductive cloning of humans
question
Adult stem cells have limited therapeutic potential
answer
because their developmental potential is limited to certain tissues.
question
A gene that can cause cancer when present in a single copy in a cell is called a/an
answer
oncogene.
question
Which of the following is not a factor that contributes to normal cells becoming cancerous?
answer
the production of more effective tumor-suppressor gene products
question
Cancer of the colon is caused by
answer
several somatic cell gene mutations.
question
The development of colon cancer occurs slowly, and colon cancer is more frequently seen in the elderly than the young. This is most likely because
answer
usually six or more somatic mutations must occur to give rise to the cancer, which takes time.
question
Mutations in the proto-oncogene ras and the tumor suppressor gene p53
answer
disrupt normal regulation of the cell cycle.
question
Mutations in the p53 gene can lead to cancer by
answer
causing the production of a faulty protein that is no longer able to inhibit cell division.
question
The carcinogen known to cause the most cases and types of cancer is
answer
tobacco.
question
Which of the following statements regarding cancer risk factors is false?
answer
Mutagens are usually not carcinogens.
question
A cell has a mutation in both alleles of its p53 gene that causes the p53 protein to be three times as effective as normal. What do you predict would happen to this cell?
answer
The cell would divide normally or possibly not at all.
question
In thinking about their role in cell division, oncogenes are like the ________ of a car, while tumor suppressor genes are like the ________ of a car.
answer
gas pedal; brakes
question
Melanoma (skin cancer) can develop after several mutations occur in skin cells. If a woman is diagnosed with melanoma and becomes pregnant, what are the chances that her offspring will inherit melanoma?
answer
It is unlikely that the offspring will be born with melanoma.
question
A cell is expressing the mutant form of ras, but one of the downstream relay proteins is not present because of another mutation. How will cell division be affected in this scenario?
answer
The cell will not divide at all unless other proteins that stimulate cell division are present.
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New