question

___________ is the process by which information encoded in DNA is converted to information encoded in RNA.

answer

Transcription

question

In humans, the hormone testosterone enters cells and binds to specific proteins, which in turn bind to specific sites on the cells' DNA. These proteins probably act to do what?

answer

help RNA polymerase transcribe certain genes

question

It is possible for a cell to make proteins that last for months; hemoglobin in red blood cells is a good example. However, many proteins are not this long-lasting; they may be degraded in days, hours, or even minutes. What is the advantage of short-lived proteins?

answer

Short-lived proteins enable the cells to control their activities precisely and efficiently.

question

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called _____.

answer

RNA interference

question

Which of the following best describes siRNA? A) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor B) a double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA C) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns D) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits

answer

B) a double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA

question

How do master regulatory genes function in cell differentiation?

answer

1. The transcription factors they produce coordinately control related genes. 2. They are often capable of changing some fully differentiated cells of different types into their particular cell type. 3. They may produce proteins that stimulate production of more of the master regulatory gene. 4. They produce proteins that act as transcription factors to produce proteins specific to the function of the particular cell type.

question

How do cells become differentiated?

answer

Different genes are expressed so that different proteins are produced.

question

A cell is considered to be differentiated when it _____.

answer

produces proteins specific to a particular cell type

question

Imagine that you've isolated a yeast mutant that contains histones resistant to acetylation. What phenotype do you predict for this mutant?

answer

The mutant will show low levels of gene expression.

question

The primary difference between enhancers and promoter-proximal elements is that enhancers _____.

answer

are at considerable distances from the promoter; promoter-proximal elements are close to the promoter

question

The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different _____.

answer

sets of regulatory proteins

question

Gene expression is often assayed by measuring the level of mRNA produced from a gene. If one is interested in knowing the amount of a final active gene product, a potential problem of this method is that it ignores the possibility of _____.

answer

translational control

question

Not long ago, it was believed that a count of the number of protein-coding genes would provide a count of the number of proteins produced in any given eukaryotic species. This is incorrect, largely due to the discovery of widespread _____.

answer

alternative splicing

question

One way to detect alternative splicing of transcripts from a given gene is to _____.

answer

compare the sequences of different mRNAs made from the given gene

question

In one set of experiments she succeeded in increasing acetlylation of histone tails. Which of the following results would she most likely see?

answer

decreased chromatin condensation

question

miRNAs can control gene expression by what action?

answer

binding to mRNAs and degrading them or blocking their translation

question

Some time later, she finds that the introduced strand separates into single-stranded RNAs, one of which is degraded. What does this enable the remaining strand to do?

answer

bind to complementary regions of target mRNAs

question

The fact that plants can be cloned from somatic cells demonstrates that _____.

answer

differentiated cells retain all the genes of the zygote

question

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

answer

genes involved in control of the cell cycle

question

Which of the following would be most likely to lead to cancer? A) amplification of a proto-oncogene and inactivation of a tumor-suppressor gene B) hyperactivity of a proto-oncogene and activation of a tumor-suppressor gene C) hyperactivity of both a proto-oncogene and a tumor-suppressor gene D) failure of a proto-oncogene to produce a protein and amplification of a tumor-suppressor gene E) failure of both a proto-oncogene and a tumor-suppressor gene to produce proteins

answer

A) amplification of a proto-oncogene and inactivation of a tumor-suppressor gene

question

All your cells contain proto-oncogenes, which can change into cancer-causing genes. Why do cells possess such potential time bombs?

answer

Proto-oncogenes are necessary for the normal control of cell growth and division

question

Which of the following types of mutation would convert a proto-oncogene into an oncogene?

answer

a mutation that greatly increases the amount of the proto-oncogene protein

question

Proto-oncogenes _____.

answer

stimulate normal cell growth and division

question

The product of the p53 gene _____.

answer

inhibits the cell cycle

question

Tumor-suppressor genes _____.

answer

encode proteins that help prevent uncontrolled cell growth

question

BRCA1 and BRCA2 are considered to be tumor-suppressor genes because _____.

answer

their normal products participate in repair of DNA damage

question

Forms of the Ras protein found in tumors usually cause which of the following?

answer

excessive cell division

question

Muscle cells differ from nerve cells mainly because they

answer

express different genes.

question

Cell differentiation always involves

answer

the production of tissue-specific proteins, such as muscle actin.

question

Which of the following is an example of post-transcriptional control of gene expression? A)gene amplification contributing to cancer B)the removal of introns and alternative splicing of eons C)the binding of transcription factors to a promoter D)the folding of DNA to form heterochromatin E)the addition of methyl groups to cytosine bases of DNA

answer

B)the removal of introns and alternative splicing of exons

question

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

answer

the rate at which the mRNA is degraded.

Mastering Biology Chapter 18 – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards