Chapter 12 test
The centromere is a region in which
chromatids remain attached to one another until anaphase.
The ___________has a narrow "waist" at a specialized region, called the centromere, where the two chromatids are attached to each other
chromosome
If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will
complete the cycle and divide.
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle ?
cytokinesis
The somatic cells derived from a single-celled zygote divide by which process?
mitosis
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis. Specifically, taxol must affect ?
the fibers of the mitotic spindle.
During binary fission in a bacterium _____
the origins of replication move apart
Why do chromosomes coil during mitosis?
to allow the chromosomes to move without becoming entangled and breaking
The following occurs during Porphase of mitosis in animals except 1) the nucleus can no longer be seen. (2 the centrioles move toward opposite poles (3 Chromosome are duplicated ?
(3) chromosome are duplicated
If there are 20 chromatids in a cell, how many centromeres are there ?
10 ( 1 centromer to 2 chromatids)
If there are 20 chromatids in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis?
10 (chromotids to chromosomes is 2÷n)
If a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase?
16 (Chromosome to chromosome = (2 x n)
If there are 20 centromeres in a cell at anaphase , how many chromosome are there in each caughter cell following cytokinesis ?
20 ( 1 centromer to a chromosome)
If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis?
20 (each chromosome has a it own centromere)
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 .. chromatid to chromosomes = less ( n ÷ 2)
Starting with the fertilized egg (zygote) a series of 5 cell divisions would produce an early embryo with how many cells
32
A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each containing how many chromosomes?
46 (chromatid to chromosome = 2÷n)
If a somatic human cell is just about to divide, it has _____ chromatids
92 (46 + 46) chromosomes. look at the language it not asking about chromsomes.
What is a Chromatid ?
A replicated chromosome
____________ begins when the paired centromeres of each chromosome separate, liberating the sister chromatids, which begin moving toward opposite poles of the cell.
Anaphase
All of the following occur during mitosis except [1. formation of a spindle [2. synthesis of DNA [3 condensing of chromosomes. [4 uncoupling of chromatids at the cetromere
[2. synthesis of DNA
Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants?
a cell plate begins to form at telophase, whereas animals a cleavage furrow is initiated at that stage.
Nerve and muscle cells are in what phase ?
Go
The Centromere is the region in which ?
The chromatids are attached to one another.
How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle?
The daughter cells have the same number of chromosomes and the same amount of DNA.
A critical control point in the cell cycle where stop and go-ahead signals can regulate the cycle.
Check point
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called
Chromatin
One difference between cancer cells and a normal cell is that
Cancer cell continue to divide even when they are tightly packed togeter
What is the difference between a benign tumor and a malignant tumor?
Cells of benign tumors do not metastasize; those of malignant tumors do.
Sister chromatids are attached to one another in prophase at the ______________
Centromere
What is the name for the special region on a duplicated chromosome that hold the siter chromatids together ?
Centromere
Where do the microtubules of the spindle originate during mitosis in both plant and animal cells?
Centrosome
______________is the division of the cytoplasm that follows the mitotic division of the nucleus.
Cytokinesis
__________ is characterized by cells having three copies of chromosome 21
Down syndrome
How many maternal chromosomes are present in a somatic human cell not engaged in cell division?
Each human somatic cell has a total of 46 chromosomes. Only half are maternal chromosomes.(23) **
True or False , the mitotic spindles in prokaryotic cells are composed of microtubules.
False
Cells that are in a nondividing state are in which phase?
G0
A particular cell has half as much Dna as some of the other cells in a mitotically active tissue. The cell in question is most likely in
G1
The "restriction point" occurs where ?
G1
The shortest part of the cell cycle
M phase
At which stage of mitosis are chromosomes lined up in one plane in preparation for their separation to opposite poles of the cell?
Metaphase
This is the longest of the mitotic stages
Metaphase
What stage do 2 Centromere s arranged at opposite poles of the celll
Pro-Metaphase
Which term describes two centrosomes arranged at opposite poles of the cell?
Prometaphase
Centromeres uncouple, sister chromatids are separated and the 2 new chromosomes move opposite pole of the cell.
Prophase
When do centrioles began to move apart in amimal cells ?
Prophase
DNA is replicated at this time of the cell cycle:
S
DNA is replicated at this time of the cell cycle ?
S phase
in both somatic and reproductive cells, DNA replication occurs ?
S phase
Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with
Two nuclei.
The formation of a cell plate is beginning across the middle of a cell and nuclei are re-forming at opposite ends of the cell. What kind of cell is this?
a plant cell undergoing cytokinesis
What is a chromatid?
a replicate chromosome
telos- =
an end (telophase: the final stage of mitosis in which daughter nuclei are forming and cytokinesis has typically begun)
The phase of mitosis during which the chromosomes move toward separate poles of the cell is _____
anaphase
Which term describes centromeres uncoupling, sister chromatids separating, and the two new chromosomes moving to opposite poles of the cell?
anaphase
The function of the mitotic cell cycle is to produce daughter cells that _____
are genetically identical to the parent cell
pro- =
before (prophase: the first mitotic stage in which the chromatin is condensing)
Each of the sisters ends up in a ___________
different cell after cell division.
During which phases of mitosis are chromosomes composed of two chromatids?
from G2 of interphase through metaphase
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
meio- =
less (meiosis: a variation of cell division that yields daughter cells with half as many chromosomes as the parent cell)
During _____________, the chromosomes line up on the metaphase plate.
metaphase
If cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus, at which stage will mitosis be arrested?
metaphase
Which is the longest of the mitotic stages?
metaphase
Movement of the chromosomes during anaphase would be most affected by a drug that
prevents shortening of microtubules.
Chromosomes first become visible during which phase of mitosis?
prophase
Which term describes centrioles beginning to move apart in animal cells?
prophase
