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chapter 14 and 15
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64
Biology
Undergraduate 1
11/03/2010

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Term
DNA is not completely stable; the spontaneous loss of amino groups from adenine, for example, results in hypoxanthine, an unnatural base, opposite thymine. What combination of molecules could the cell use to repair this base mis-match?
Definition
nuclease, DNA polymerase, DNA ligase
Term
Mutagens can cause mutations by
Definition
a. Chemically altering DNA nucleotides
b. Disrupting DNA replication
c. Altering the genetic code of the organism
d. All of the above
answer: e. "a" and "b" only
Term
Thymine dimers are:
Definition
a form of damaged DNA caused by UV-irradiation
Term
Oncogenes can be caused by:
Definition
a. Missense mutations
b. Gene amplification
c. Chromosomal translocation
d. Retroviral insertion
answer: e. All of the above
Term
Which of the following is no longer necessary to get human cells that have turned malignant to reproduce in cell culture?
Definition
a. Nutrients
b. Anchorage to a substratum
c. Elbow room (i.e., not too dense a layer)
answer: d. "b" and "c" only
Term
The Ames test is used to:
Definition
a. determine the mutagenicity of various chemicals
Term
Point mutations that do not alter the amino acid sequence of the resulting gene product are called ___ mutations.
Definition
silent
Term
A mutation in which of the following regions is least likely to affect gene function?
Definition
Intergenic region
Term
Which of the following is necessary to get human cells to reproduce in cell culture?
Definition
a. Nutrients
b. Growth factors
c. Anchorage to a substratum
d. Early developmental state (not too differentiated)
e. Elbow room (i.e., not too dense a layer)
answer: f. All of the above
Term
When cells in cell culture form a complete single layer, they stop dividing. This is called
Definition
density-dependent inhibition
Term
A sequence in the mRNA is CUA instead of CGA. CUA codes for Leucine, whereas CGA codes for Arginine. This is the result of a mutation in the DNA that is
Definition
A missense mutation
Term
Scientists have discovered a gene (BRCA1), mutations in which confer an 85% lifetime risk of breast cancer. Without the protein product of the normal BRCA1 gene, normal breast cells may turn cancerous, that is
Definition
cancer cells do not exhibit density-dependent inhibition
Term
Neutral mutations are:
Definition
Mutations that result in AA substitutions that allow continued function of the protein product
Term
DNA is not completely stable; the spontaneous loss of amino groups from adenine, for example, results in hypoxanthine, an unnatural base, opposite thymine. What combination of molecules could the cell use to repair this base mis-match?
Definition
nuclease, DNA polymerase, DNA ligase
Term
Cancer cells have
Definition
escaped from cell cycle controls
Term
Bacterial reproduction requires
Definition
a. an overall doubling of the cell constituents
b. replication of the bacterial DNA
c. separation of two DNA loops into the daughter cells
answer: d. all of the others
Term
Which checkpoint determines whether the cell has synthesized its entire DNA?
Definition
G2 checkpoint
Term
Non-dividing cells are said to be in
Definition
G0 phase
Term
During the cell cycle, increases in the enzymatic activity of protein kinases are due to:
Definition
activation of inactive kinase by binding to cyclin
Term
The mechanics of cytokinesis in animal cells involves
Definition
. a contracting ring of microfilaments
Term
Human sperm and ova contain ___ ___ chromosomes. ("Doublet" refers to the appearance of a pair of sister chromatids.)
Definition
23 singlet
Term
Where does meiosis occur in human beings?
Definition
in testes and ovaries
Term
A karyotype is performed on one of Molly's white blood cells. It shows a pair of #1 chromosomes, a pair of #2's, a pair of #3's, and so forth, but has only one chromosome #23. She would be characterized as a:
Definition
monosomy
Term
It would take about ___ rounds of cell division for one cell to multiply to ___ cells, that is, the number in the human body.
Definition
47 ... 100 trillion
Term
Cytotechnologists take photomicrographs of chromosomes, which have bands on the chromosomes. These bands
Definition
are produced by staining the chromosomes
Term
Presumably, karyotypes of Joe Biden and Sarah Palin would differ in the following way:
Definition
Sarah's would contain two X chromosomes, but Joe's would contain an X and a Y.
Term
Scientists have decoded the dog genome - a boxer named Tasha. Tasha's high degree of inbreeding simplified the task of decoding her 2.4 billion-letter genetic code by reducing the differences between her 39 chromosome pairs. The fact that she is a female, however, left the team without a picture of the canine Y chromosome. Apparently dogs have a haploid number of:
Definition
39
Term
A new, "baby" cell goes through the cell cycle in the following order:
Definition
G1 - S - G2 - M
Term
Checkpoints during the cell cycle are important because they
Definition
ensure the integrity of the cell's DNA.
Term
During what phase of mitosis do chromatids segregate?
Definition
Anaphase
Term
Cytokinesis in plants is characterized by:
Definition
Golgi-derived vesicles coalesce at the middle of the cell, forming a cell plate whose contents form a new cell wall
Term
Sexual reproduction requires:
Definition
a. meiosis
b. gamete formation
c. fertilization
answer: d. all of the others
Term
Sexually produced offspring do not look exactly like their parents. That is because of
Definition
a. Independent assortment of chromosomes
b. Crossing over during formation of chiasmata
c. Random fertilization
answer: d. All of the others
e. None of the others
Term
More common than completely polyploid animals are mosaic polyploids, animals that are diploid except for patches of polyploid cells. How might a mosaic tetraploid arise?
Definition
By a nondisjunction during mitotic anaphase
Term
It would take about ___ rounds of cell division for one cell to multiply to ___ cells, that is, the number in the human body.
Choose one answer.
Definition
47 ... 100 trillion
Term
Cytotechnologists take photomicrographs of chromosomes, which have bands on the chromosomes. These bands
Definition
are produced by staining the chromosomes
Term
In San Francisco in 1977, Jennifer Chang (13) was hospitalized from eating poisonous mushrooms, resulting in serious liver damage. During her hospital stay, doctors grafted part of a donor liver onto her damaged one to help her liver cells regenerate. This therapy relies on the ability of resting liver cells to return to the mitotic cell cycle at the point they had left it, that is,
Choose one answer.
Definition
in G1
Term
During the cell cycle, increases in the enzymatic activity of protein kinases are due to:
Definition
activation of inactive kinase by binding to cyclin
Term
A contracting ring of microfilaments is responsible for cytokinesis in
Definition
animal cells
Term
The mechanics of cytokinesis in animal cells involves:
Definition
a contracting ring of microfilaments
Term
An early event in mitosis is the migration of two ___ around the periphery of the nucleus to establish the poles of the subsequent mitotic process.
Choose one answer.
Definition
centrosomes
Term
Sexually produced offspring do not look exactly like their parents. That is because of
Definition
a. Independent assortment of chromosomes
b. Crossing over during formation of chiasmata
c. Random fertilization
answer: d. All of the others
Term
Tetrad is defined as:
Definition
the four closely associated chromatids during synapsis
Term
How many genetically diverse gametes could be formed by meiosis in an organism whose somatic (body) cells are discovered to have eight chromosomes? (Ignore recombination.)
Definition
2 to the 4th = 16
Term
A karyotype is performed on one of Molly's white blood cells. It shows a pair of #1 chromosomes, a pair of #2's, a pair of #3's, and so forth, but has only one chromosome #23. She would be characterized as a:
Definition
monosomy
Term
Aneuploidies are more common in
Definition
Spontaneously aborted fetuses than in live births.
Term
When bacteria divide
Definition
. the distribution of DNA molecules must be regulated to insure that each daughter cell gets one
Term
A species called widget is investigated. When a karyotype analysis is done, researchers see 30 "doublet" chromosomes ( =====) with a connection point near the center of the doublet. Widget sperm and ova would contain ___ chromosomes.
Definition
15
Term
Of the periods below, which is the longest?
Definition
answer: a. G1
b. S
c. G2
d. Mitosis
Term
Of the periods below, which is the shortest?
Definition
a. G1
b. S
c. G2
answer: d. Mitosis
Term
Which statement is true?
Definition
M phase contains mitosis and cytokinesis
Term
During anaphase the chromatids move toward the poles by a process that involves:
Definition
. the chromatids walking poleward along the kinetochore microtubules
Term
The spindle is formed by the aggregation of many
Definition
tubulin subunits
Term
The spindle fibers are disassembled into tubulin during
Definition
anaphase and telophase
Term
Which comes first in meiosis?
Definition
Separation of homologous chromosomes
Term
Down syndrome is an example of:
Definition
a trisomy
Term
Iowa is full of corn. A karyotype of Iowa corn shows that it has ten different kinds of chromosomes, but that corn is tetraploid. Thus, a cell from the roots of a corn plant would have ___ chromosomes.
Definition
40
Term
The mechanics of cytokinesis in animal cells involves:
Definition
contracting ring of microfilaments
Term
Tetrad is defined as
Definition
the four closely associated chromatids during synapsis
Term
Aneuploidies are more common in
Definition
Spontaneously aborted fetuses than in live births
Term
point mutations that do not alte the amino acid sequence oftheresulting gene product are called____ nutations.
Definition
silent
Term
oncogenes can be caused by:
Definition
a. gene amplification
b. chromosomal translocation
c. retroviral insertion
answer: d. all of the other four answers
e. missense mutations
Term
In ten generations, a single cell can reproduce to become
Definition
1000 cells
Term
CdK is shorthand for
Definition
cyclin dependent kinase
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