Exam #3 Chapter 9
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B?
cleavage furrow formation and cytokinesis
Following cytokinesis in an animal cell, how many centrioles does each new daughter cell possess?
two
During what phase in the cell cycle would you find the most DNA per cell?
G2
Assume that you are dealing with a species in which the number of chromosomes in each somatic cell is 14. How many sister chromatids are present in the early telophase of mitosis?
0
A cell biologist carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle contained 200 units of DNA. What would be the amount of DNA at G1 of the cell cycle in one of the grasshopper daughter cells?
100 units
How many maternal chromosomes are present in a somatic human cell not engaged in cell division?
23
If a cell contains 60 chromatids at the start of mitosis, how many chromosomes will be found in each daughter cell at the completion of the cell cycle?
30
If a somatic human cell is just about to divide, it has _____ chromatids.
92
Down syndrome is characterized by cells having three copies of chromosome 21. As a cell in an individual with Down syndrome prepares to enter mitosis, how many chromatids would be present?
94
What is the difference between a benign tumor and a malignant tumor?
Cells of benign tumors do not metastasize; those of malignant tumors do.
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called _____.
Chromatin
When a cell in S phase is fused with a cell in G1, _____.
DNA synthesis begins immediately in the original G1 nucleus
A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in
G1
A cell entering the cell cycle with 32 chromosomes will produce two daughter cells, each with _____.
None
The person credited with first recognizing (in the 1860s) that living cells cannot arise spontaneously, but arise only from previously existing cells, is _____. ()
Rudolf Virchow
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely
a plant cell in the process of cytokinesis
The function of the mitotic cell cycle is to produce daughter cells that _____.
are genetically identical to the parent cell (assuming no mutation has occurred
A biochemist measured the amount of DNA in cells growing in the laboratory and found that the quantity of DNA in the cells doubled _____.
between the G1 and G2 phases
In the cells of some organisms, mitosis occurs without cytokinesis. This will result in
cells with more than one nucleus.
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?
cytokinesis
During interphase, the genetic material of a typical eukaryotic cell is _____.
dispersed in the nucleus as long strands of chromatin
Which of the following is involved in the binary fission of bacteria?
distribution of a copy of the single parental chromosome to each daughter cell
"Cytokinesis" refers to _____.
division of the cytoplasm
Observations of cancer cells in culture support the hypothesis that cancer cells _____.
do not exhibit density-dependent inhibition
Tissue culture experiments with PDGF demonstrate that without this substance _____.
fibroblasts fail to divide
Chromatids are _____.
identical copies of each other if they are part of the same chromosome
You would know a dividing cell was a plant cell rather than an animal cell if you saw that _____.
it had formed a cell plate
At which stage of mitosis are chromosomes lined up in one plane in preparation for their separation to opposite poles of the cell?
metaphase
Which of the following represents a mismatch or incorrect description?
metaphase: the nuclear envelope disappears
Which of the following processes does NOT occur in dividing bacteria?
mitosis
You would be unlikely to see which of the following human cells dividing?
nerve cell
In a human skin cell that is going through the cell cycle, when do the centrosomes separate?
prophase
In telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _____.
prophase
Which of the following does not occur during mitosis?
replication of DNA
Which of the following does NOT occur during mitosis?
replication of chromosomes
Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?
telophase
DNA replication occurs in _____.
the S phase of interphase in both somatic and reproductive cells
One event occurring during prophase is _____.
the beginning of the formation of a spindle apparatus
During binary fission in a bacterium _____.
the origins of replication move apart