Key Concepts Quiz
This activity contains 22 questions.
operon regulatory genes are _____.
expressed only when the repressor is inactivated
expressed only when the repressor is activated
turned on when RNA polymerase binds to the DNA
A mistake during DNA replication prevents the
repressor from binding to the operon operator. When these cells are placed in a solution containing chicken broth, what happens?
The transcription of the repressor protein is inhibited.
The transcription of the
operon would be inhibited.
The repressor would bind to the operator.
Tryptophan would bind to the repressor.
What controls the way in which a zygote differentiates?
Operons mature and control gene expression.
The DNA of genes that will not be expressed are degraded.
Genes that will be expressed are made.
Selective genes are turned on and off, depending on the fate of the cell.
When are DNA molecules the least tightly coiled?
S phase of interphase
phase of interphase
Anhidrotic ectodermal dysplasia is an X-linked disorder that results in the absence of sweat glands. How would this condition be manifested in a heterozygous female?
She would not have sweat glands.
She would have a normal amount of sweat glands.
She would have a random pattern of tissue with and without sweat glands.
The question cannot be answered without knowing which allele is dominant.
In eukaryotic cells, several proteins are involved in the process of transcription. This process involves enhancers that are _____.
DNA sequences located adjacent to the gene that they regulate
a type of transcription factor
bound by activators causing DNA to bend
Alternative RNA splicing has revealed inaccuracies in the one gene–one polypeptide hypothesis. Why?
It shows that it takes more than one gene to code for most polypeptides.
It really should be the one intron–one polypeptide hypothesis.
Transcription of the same gene can lead to the production of different mRNAs.
It really should be the one exon–one polypeptide hypothesis.
MicroRNA (miRNA) controls _____.
Microtubules in the cytoplasm of the cell are composed of two protein subunits, α-tubulin and β-tubulin. Addition of colchicine to the cells results in the disassembly of the microtubules and consequently an increase in the concentration of tubulin subunits. Based on your knowledge of translational regulation, what changes in protein production would occur?
an increase in the rate of translation for tubulin
a decrease in the rate of production of tubulin
an increase in the stability of the tubulin mRNA
alternative splicing of tubulin mRNA
A similar protein is found in both a bacterial cell and a single-celled eukaryote. However, the prokaryote seems to produce a much higher amount of the protein. A detailed investigation of the control mechanisms of this protein in both organisms would include which of the following experiments?
the mechanisms of transcriptional control
identification of alternatively spliced mRNA
the involvement of nuclear transport mechanisms
mechanisms of the addition of a 5′ cap
In embryonic mice, a homeotic gene controls development of the neck, which includes the larynx and thymus. If this gene were deleted, a full-term mouse would show _____.
normal development of the larynx and thymus, because other genes would take over
lack of development of the larynx and thymus
development of the larynx and thymus in the lower body
inability of the embryo to form an adult mouse
A researcher performs a DNA microarray but forgets to add the enzyme reverse transcriptase. This is important because the enzyme makes _____ from a(n) _____ template.
In eukaryotic cells, signal transduction pathways involve _____.
signal molecules that bind with transcription factors embedded in the plasma membrane
signal molecules that are released from the nucleus of the target cell
relay proteins that initiate transcription in the nucleus
a series of relay molecules, of which the last activates a transcription factor
Steward's experiment with carrot cells revealed that _____.
a cell from root tissue will grow new root tissue
an entire plant can grow from an undifferentiated cell
an entire plant can grow from a differentiated cell
once cells differentiate, they can only express a specific combination of genes
Using nuclear transplantation, it is possible to generate _____ for therapeutic uses.
embryonic stem cells
Since the first animal was produced using a fully differentiated cell, a number of observations have been made. Which of the following statements is true in regard to reproductive cloning?
Cloned animals are behaviorally identical to their parent animals.
Cloned animals develop chronic conditions that are usually only associated with old age.
Cloned animals are physically identical when compared to their parents.
Cloned animals never stop growing because, similar to cancer cells, the cloned cells never stop dividing.
Stem cells could be immensely important in the treatment of which of the following conditions?
loss of a limb
spinal cord injuries
Proto-oncogenes have the potential to become oncogenes. Which of the following is most likely to lead to cancer?
a viral infection
a mutation in a gamete
a tissue injury
a mutation that causes the proto-oncogene to become overactive
The Rb protein prevents mitosis by inhibiting cells from entering S phase. Human papillomavirus (HPV) is thought to inhibit the action of the Rb protein in cervical epithelial cells. What would be the effect of cervical cells being infected with HPV?
The number of cells in the G
phase of the cell cycle would increase.
The mitotic rate would increase.
The mutation rate would decrease.
The growth of cervical cells would decrease.
Colonoscopy is the examination of the large colon. It allows for visual diagnosis of ulcers and polyps, which may lead to colon cancer. A polyp _____.
causes mutations that lead to colon cancer
is a malignant tumor
is a cluster of abnormal cells
can form after one exposure to a carcinogen
A mutation in the
gene can _____.
inhibit cell division
stimulate cell division
gene to turn off
control cell division
Which of the following cell types would most likely have a high rate of error in DNA replication and consequently a rapid mutation rate?
neurons in G
enucleated red blood cells
epithelial skin cells
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