Learning curve chapter 11
Which example is not a use of apoptosis in the regular functioning of an organism?
All of the above are routine applications of apoptosis
When does a cell make the commitment for another cell cycle?
At the transition between G1 and S
How were the internal signals that control the transitions between stages of the cell cycle discovered?
By fusing different cells together
A bacterial cell has a mutation in the ter gene. The most likely result would be that
DNA replication would continue past where it was supposed to stop
A bacterial cell has a mutation in the ter gene. The most likely result would be that
DNA replication would continue past where it was supposed to stop.
The molecules that make up a chromosome are _______ and _______.
DNA; proteins
What stage in the cell cycle comes immediately before S?
G1
A eukaryotic organism has a mutation that causes it to produce more p21 protein. Which is the most likely result of the mutation?
If the organism receives radiation, cell division will be slowed more than it would in an organism with normal levels of p21
At what point would you expect a cyclin-Cdk complex to regulate the repair of incomplete DNA replication?
In S phase
What is the essential difference between necrosis and apoptosis?
In apoptosis, the cell death is part of the normal developmental process; in necrosis, by contrast, the cell death is the result of something gone wrong.
At what point is the cell cycle likely to be the most difficult to reverse or to stop?
Late in G1 phase, after the restriction point (R)
Which statement about mitosis-associated microtubules is false?
Once formed, they persist throughout mitosis
Predict the effect of a mutation that makes histone proteins negatively charged.
The histones will attract the DNA less, disrupting the chromatin structure.
Imagine that there is a mutation in the Cdk gene such that its gene product is nonfunctional. What effect will this mutation have on a mature red blood cell?
There will be no effect, because mature red blood cells do not enter the cell cycle
What action do Cdk's perform on target proteins?
They add a phosphate group to the protein.
Which statement about plant cytokinesis is true?
Vesicles fuse to form a cell plate.
Evidence from yeast suggests that the maturation-promoting factor of sea urchins is
a Cdk
Mutations in the hypothetical gene S67 can lead to cancer when these mutations reduce the expression of the gene. Thus, S67 is likely
a tumor suppressor.
The product of a gene inhibits cyclin production. Thus, it is most likely
a tumor suppressor.
Organisms of a species of fern have both a multicellular haploid and a multicellular diploid phase. This is an example of
alternation of generations
An excess of one type of chromosome in a cell is an example of
aneuploidy
Which condition is a form of cell death?
apoptosis
tumors
are larges masses of cells
You examine a population of dividing cells with an electron microscope, and you see a large, floppy, circular string near the center of the cell that seems to be tangled with another floppy circular string. Deducing that the strings are the replicating DNA of the cell, you determine that the cell is a prokaryote and is undergoing _______.
binary fission
Which of the following is an example of cells that normally do not divide being stimulated to divide?
both a and b
Which molecules play a role in apoptosis?
caspases
A mutation in _______ can lead to aneuploidy.
cohesin
After the centromeres separate during mitosis, the chromatids, now called _______, move toward opposite poles of the spindle.
daughter chromosomes
As a result of fertilization, the number of chromosomes in the zygote _______ in comparison to the number of chromosomes in each of the gametes.
doubles
During mitotic anaphase, chromosomes migrate
from the equatorial plate toward the poles
You want to design a new drug that will help with wound healing. A class of molecules you will most likely investigate is _______.
growth factors
Nucleosomes contain _______ and _______.
histones; DNA
An environmental change can lead to the production of more than the expected amount of cyclin. This would tend to _______ the activity of the Cdk, which would lead to _______ phosphorylation of the target protein, which in turn would lead to _______ cells being stopped at the checkpoint.
increase; increased; fewer
A typical complete eukaryotic cell cycle consists of
interphase, mitosis, and cytokinesis
Chromatin is most like beads on a string during _______. At this stage, it is the _______ densely packaged.
interphase; least
Which statement about asexual reproduction is true?
it involves the production of clones
Which statement about independent assortment is false?
it requires chiasmata
A tissue in a plant contains three types of cells that divide at different rates. You would expect the cell type that divides most rapidly to spend _______ time in the _______ phase than the other cells
less; G1
A patient who was treated for skin cancer was considered in remission but now has tumors in other organs. This is due to _______ of the original cancer.
metastasis
The mitotic spindle is composed of
microtubules
Which phenomenon will most likely lead to aneuploidy?
nondisjunction
Bacteria typically have _______, whereas eukaryotes have _______.
one chromosome that is circular; many chromosomes that are linear
A triploid plant has
one extra set of chromosomes.
When you cut yourself, the wound will most likely release
platelet-derived growth factor.
Which type of microtubule forms the spindle
polar
Paclitaxel
prevents the functioning of microtubules in a cell
Microtubules are formed between the poles and the chromosomes to make up the spindle. This is most likely to occur during
prometaphase
Genetic recombination occurs during
prophase of meiosis I.
When dividing cells are examined under a light microscope, chromosomes first become visible during
prophase.
The replication of the DNA in chromosomes during S phase leads to the formation of _______ in G2.
sister chromatids
A cell in G2 has 0.8 pg of DNA. How much DNA did that cell have in G1
0.4 pg
Bald eagles reproduce through _______ cycle, the fertilized bird egg is _______, and the _______ stage of the life cycle is represented within the eggshell.
A (diplontic); 2n; zygote
Which change could potentially disrupt the process of cytokinesis in a dividing cell?
A mutation in the gene that encodes actin
What is the order of events for cell division in prokaryotes and eukaryotes?
A reproductive signal, replication, segregation of DNA, and cytokinesis
