Chapter 17 and 19: Review Questions
Dr. Jordan
1. Beadle and Tatum showed that each kind of mutant bread mold they studied lacked a
specific enzyme. Their experiments demonstrated that _____.
genes carry information for making proteins
mutations are changes in genetic information
genes are made of DNA
enzymes are required to repair damaged DNA information
cells need specific enzymes in order to function
2. The flow of information in a cell proceeds _____.
from RNA to DNA to protein
from protein to RNA to DNA
from DNA to protein to RNA
from RNA to protein to DNA
from DNA to RNA to protein
3. The information carried by a DNA molecule is in _____.
its amino acid sequence
the sugars and phosphates forming its backbone
the order of the nucleotides in the molecule
the total number of nucleotides it contains
the RNA units that make up the molecule
4. How does RNA polymerase know where to start transcribing a gene into mRNA?
It starts at one end of the chromosome.
Transfer RNA acts to translate the message to RNA polymerase.
It starts at a certain nucleotide sequence called a promoter.
The ribosome directs it to the correct portion of the DNA molecule.
It looks for the AUG start codon.
5. After an RNA molecule is transcribed from a eukaryotic gene, portions called ____
are removed and the remaining ____ are spliced together to produce an mRNA molecule
with a continuous coding sequence.
operators ... promoters
exons ... introns
silencers ... enhancers
introns ... exons
promoters ... operators
6. Which of the following processes occurs in the cytoplasm of a eukaryotic cell?
DNA replication
translation
transcription
DNA replication and translation
translation and transcription
7. Cells are able to distinguish proteins destined for secretion or compartmentation from
those to be used in the cytoplasm because _____.
there are two types of ribosomes: one group that synthesizes cytoplasmic ribosomes
only, and another type that synthesizes compartmentalized proteins only
some proteins, as they begin to be synthesized, contain a signal region that causes the
ribosome with its growing peptide to attach to the ER and move into the lumen
(space) of the ER
proteins destined for compartmentation are all synthesized in the nucleus, whereas
cytoplasmic proteins are all synthesized in the cytoplasm each compartment in the
cell (the nucleus, lysosome, and so forth) has its own set of ribosomes that
synthesize proteins unique to that compartment
ribosomes contain two types of subunits
8. Which one of the following is true of tRNAs?
Each tRNA binds a particular amino acid.
tRNAs are extremely small molecules.
tRNAs carry special sequences known as codons.
There are four types of tRNA.
All of the above.
9. A mutagen causes _____.
problems with mitosis
a change in the base sequence of DNA
blockage of the ribosome-binding sites
decreased permeability of the nuclear envelope
a reduction in the number of tRNA molecules available for protein synthesis
10. A gene is usually _____.
the same thing as a chromosome
the information for making a polypeptide
made of RNA
made by a ribosome
made of protein
11. Histones are _____.
master genes that affect development
groups of genes that respond to environmental changes
proteins around which DNA is coiled
portions of genes that are transcribed
portions of genes that are eliminated by DNA splicing
12. The difference between tandemly repetitive and interspersed repetitive DNA is that
_____.
interspersed DNA is also referred to as "satellite DNA"
interspersed repetitive DNA is found throughout the genome
most tandemly repetitive DNA is composed of transposons
most interspersed repetitive DNA is at the telomeres
the repeated unit of tandemly repetitive DNA is longer
13. Retrotransposons differ from other transposons in that _____.
retrotransposons have lost the ability to move about a genome
retrotransposons are likely to be the remains of a viral infection
retrotransposons have retained the ability to move about a genome, an ability that has
been lost by other transposons
retrotransposons move via an RNA transcript, whereas other transposons do not
Only retrotransposons can affect gene expression
14. Your muscle and bone cells are different because _____.
they contain different sets of genes
they are differentiated
they contain different operons
different genes are switched on and off in each type of cell
they contain different histones
15. DNA methylation is a mechanism used by eukaryotes to _____.
inactivate genes
increase the rate of transcription
terminate transcription
facilitate the binding of DNA to intermediate filaments
cause apopotosis
16. 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
_____.
help RNA polymerase transcribe certain genes
alter the pattern of DNA splicing
inhibit transcription
unwind the DNA so that its genes can be transcribed
cause mutations in the DNA
17. 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 or even hours. What is the advantage of short-lived proteins?
Most proteins are used only once.
Most cells have a short life span.
Cells lack the raw materials to make most of the proteins they need.
Long-lasting proteins are likely to make the cell cancerous.
Short-lived proteins enable the cells to control their activities precisely and efficiently.
18. In normal cells, the genes that malfunction in cancer usually _____.
control RNA transcription
are responsible for sex determination
code for enzymes involved in cellular respiration
are not present
regulate cell division
19. All your cells contain proto-oncogenes, which can change into cancer-causing genes.
Why do cells possess such potential time bombs?
Proto-oncogenes protect cells from infection by cancer-causing viruses.
Proto-oncogenes are genetic junk that has not yet been eliminated by natural selection.
Proto-oncogenes are unavoidable environmental carcinogens.
Cells produce proto-oncogenes as a by-product of mitosis.
Proto-oncogenes are necessary for normal control of cell division.
20. Which of the following would be most likely to lead to cancer?
amplification of a proto-oncogene and inactivation of a tumor-suppressor gene
hyperactivity of a proto-oncogene and activation of a tumor-suppressor gene
failure of a proto-oncogene to produce a protein and amplification of a tumor-suppressor
gene
failure of both a proto-oncogene and a tumor-suppressor gene to produce proteins
hyperactivity of both a proto-oncogene and a tumor-suppressor gene