BIOL Chapter 12
Interphase Chromosomal appearance
(4) unreplicared in G1. (4) replicated but uncondensed after S phase. consisting of two sister chromatids.
For a cell to replicate it must:
-copy its chromeosomes -seperate the copies -divide the cytoplasm to generate daugther cells that have the same chromosomal complement as the parent cell
According to this research, a pancreatic cancer patient with which of the following would likely fair the best?
A patient with a large number of cheater cells.
During _____ centromeres come apart, and sister chromatids become full-fledged chromosomes, which migrate to opposite poles of the cell.
Anaphase
In _____ the cohesin proteins are cleaved, and the kinetochores move toward the poles of the cell, separating the sister chromatids.
Anaphase
The material that makes up eukaryotic chromosomes: consists of DNA molecule compleced with histone proteins
Chromatin
A structure containing genetic information as genes
Chromosome
S/ Synthesis Phase
DNA replication, which occurs during interphase
Interphase
G1, S, and G2
The _ Checkpoint delays until _ replication is complete and any damaged _ present is repaired.
G2;chromosome;DNA
Before mitosis can take place, this phase must be done in order to prepare and mature the cell
Gap 2 phase
Prometaphase
Microtubules attach to kinetochores
M phase consist of _ or _, when chromosomes _, and cytokenises, when the parent cell divides into two daughter cells
Mitosis; Mieiosis;seperate
Chromatid
One double stranded DNA copy of a replicated chromosome with its associated proteins
how would the graph appear 12.2 if the y aaxis represented the percentage of cells labeled, not just the ones undergoing mitosis
The graph would contain a straight horizontal line, indicating that the percentage of radiolabeled cells in the culture does not vary over time. The value of the line would be about 30 percent, reflecting the proportion of cells in the asynchronous culture that would have been radiolabeled during the pulse. (S phase is about a third of the cell cycle.)
Sister Chromatids
The two attached, double-stranded DNA copies of a replicated chromosome. When chromosomes are replicated, they consist of two sister chromatids. The genetic material in sister chromatids is identical. When sister chromatids separate during mitosis, they become independent chromosomes.
The activity of Cdk is further regulated by _ of _ in its activating site and _from its inhibitory site
addition;phosphate;removal
Chromatin
complex of DNA and histone proteins
metaphase
middle phase
centromere
where chromatid copies remain held together. when attached to the centromere they are called sister chromatids.
Explain relationship between chromsomes & DNA, Chromatin, and sistter chromatids
(1) DNA is the genetic material in chromosomes. (2) Chromosomes are made of chromatin, which is a complex of DNA and histone proteins. (3) Sister chromatids are identical copies of the same chromosome that are joined together.
G2 Phase
-After Synthesis -Before Mitosis
What is IGF-II?
A chemical that stimulates growth in pancreatic tumors.
in plant cells involves the formation of a cell plate.
Cytokinesis
The _ Checkpoint regulates progress based on _ availability, cell size, DNA damage, and _ signals.
G1;nutrient;social
Cells perform functional roles during this phase, and decide if they will replicate and morph into S phase
Gap one phase
During prophase, the microtubules of the mitotic spindle ____
Legnthen
During anaphase, the nonkinetochore microtubules ___ and move past each other, and the kinetochore microtubules ___.
Lengthen; Shorten
If this research holds true, which of the following would happen in treatment?
Non-producing cells would cause the destruction of a tumor.
The G1 checkpoint depends in part on the _ protein, which prevents progression to S phase and G1 _, which trigger progression to S phase. Defects in Rb and G1 cyclin are common in cancer.
Rb; G1 cyclin-Cdk complexes
During what phase of the cell cycle does the DNA become replicated? See Section 12.1
S
unreplicated chromosome
one long DNA wrapped around proteins
centrioles
one of two small cylindrical structure contained within the centrosome
two chromatids is how many chromosomes
one. its two copies of the same one dna strand/chromeosome attached by a centromere and bunched up
Events of ___ include the condensation of chromatin and the dispersal of nucleoli.
prophase
gene
region of DNA in a chromosome that codes for a particular protein or RNA
During __ both nuclear envelopes and nucleoli re-form
telophase
if the shown cell has 60 picograms of DNA & 22 chromosomes in the G1 phase how much DNA and chromosomes are in 1. the prophase, anaphase, and each daugther cell.
(1) The prophase cell has replicated its DNA, so it will have twice as much DNA (120 picograms). Each chromosome will have two chromatids, but the number of chromosomes will remain at 22. (2) The anaphase cell still has 120 pg of DNA, but when the chromatids separate, each is defined as a daughter chromosome, so the cell has 44 chromosomes. (3) After cytokinesis, each daughter cell will have as much DNA (60 pg) and as many chromosomes (22) as the parent cell in G1 phase. If you stated that the daughter cells have more or less DNA or chromosomes than the parent cell, recall that mitotic cell division does not change the number of chromosomes or the amount of DNA.
G1 Phase
-After Mitosis -Before Synthesis
interphase stuff
-cell spends most of their time in it -prepare to divide or growing -chromosomes long strings
Consider an animal cell in which motor proteins in the kinetochores normally pull the chromosomes along the kinetochore microtubules during mitosis. Suppose, however, that during metaphase, this cell was treated with an inhibitor that blocks the function of the motor proteins in the kinetochore, but allows the kinetochore to remain attached to the spindle. The inhibitor has no effect on any other mitotic process, including the function of the nonkinetochore microtubules.
1. Will this cell elongate during mitosis? yes 2. Will the sister chromatids separate from each other? yes 3. Will the chromosomes move to the poles of the cell? no
What is the difference between a chromatid and a chromosome? See Section 12.1
A chromatid is one half of a replicated chromosome, whereas a chromosome consists of DNA wrapped around proteins in a highly organized manner. Replicated DNA contains two sister chromatids that remain attached until anaphase.
Which answer correctly associates a phase of mitosis with what happens to chromosomes during that phase? See Section 12.2 (
Anaphase: Sister chromatids separate. During anaphase ("against-phase"), replicated chromosomes split into two identical sets of unreplicated chromosomes that are pulled to opposite poles of the cell.
The division of the cytoplasm following mitosis is called _____. See Section 12.2
Cytokinesis
in animal cells involves the formation of a cleavage furrow.
Cytokinesis
During telophase, the nonkinetochore microtubules____
Dissasemble
Chromosomes become visible during
During prophase, the chromatin fibers become discrete chromosomes.
Which statement is correct concerning the relationship between chromosomes and either genes, chromatin, or sister chromatids? See Section 12.2
Each replicated chromosome consists of two sister chromatids. Replication of a chromosome's single DNA double helix produces two identical dsDNA copies called sister chromatids.
Cancer is characterized by loss of control at the _ checkpoint, resulting in cells that divide in an uncontrolled fashion; and _, or the ability of tumor cells to spread throughout the body
G1;metastasis
Metaphase
Kinetochores are motionless in relation to poles of the cell
Anaphase
Kinetochores move toward poles of the cell Cohesins break down
The first _ checkpoint delays _ until all chromosomes are correctly attached to the _
M-phase;anaphase;spindle apparatus
The second _ checkpoint delays the onset of _ and _ until all chromosomes properly partitioned
M-phase;cytokinesis;G1
____ marked by the alignment of chromsomes along the metaphase plate, is brought about by kinetochores aligning and then remaining motionless relative to the poles of the cell.
Metaphase
Which group of cells would be least likely to contain cells in S phase? See Section 12.1
No longer dividing cells of the mammalian brain. Post-mitotic cells will exit the cell cycle and will not contain cells in S phase.
You are an oncologist doing research that confirmed what was known about producer/cheater relationships in pancreatic tumors. What did you find out?
Producers get nothing from cheaters.
Spindle fibers attach to kinetochores during
Prometaphase
____is marked by fragmentation of the nuclear envelope, expansion of the spindle into the nuclear region, and attachment of some spindle fibers to the chromosomes via the kinetochores.
Prometaphase
In ______, the microtubules of the spindle apparatus begin to assemble from individual tubulin subunits. As the identical chromatids of each pair of sister chromatids condense during this stage, they are held together by cohesin proteins.
Prophase
Centromere
Specialized region of a chromosome when sister chromatids are most closely joined to each other.
Telophase
Spindle microtubules dissassemble
As ______ proceeds, the kinetochore microtubules of the spindle disassemble. As the chromosomes reach the poles of the cell, the nuclear envelopes of the two new daughter nuclei form.
Telophase
For the experiment shown in Figure 12.6, which answer best describes what the prediction would be if chromosome movement were based on microtubule shortening at the spindle pole? See Section 12.2
The darkened section will move toward the spindle pole but the distance between chromosomes and the darkened section will remain constant. Daughter chromosomes will move toward the pole at the same rate as the darkened sections.
Which of the following is a hallmark of cancer cells?
They multiply quickly
Prophase
Tubulins assemble into spindle microtubules. Cohesins join sister chromatids of duplicated chromosomes.
chromosomes
a single lond DNA double helix rapped around proteins, or histones.
During sister chromatids separate and daughter chromosomes migrate to opposite poles.
anaphase
chromosome movement
before each is replicated, as it starts they compact to move easier. then one copy of each chromosome are distributed to each (2) daughter cell
condensed replicated chromosomes
chromatids condense complete around histones into ugly x shape, 10,000 times shorter than original legnth.
microtubules
components of the cytoskeleton alpha and beta, assymetric, plus side grows minus dissasembles. originate from MTOCs, which define the 2 poles of the spindle apparatus & produce large numbers of microtubules, plus end grows out to cytoplasm.
Phophase. Chromosomes _. The spindle apparatus begins to _, and polar microtubules overlap eachother.
condense;form
first type of movement in anaphase
daughter chromosomes move to opposite poles via attachment to kinetochore proteins to the shrinking kinetochore microtubules.
Prometaphase. The nuclear envelope _. Microtubules _ to the kinetochores of chomosomes, which begin _ to the middle of the spindle.
disintergrate;attach;moving
polar microtubules
during prophase some of the microtubules extend from each spindle pole and overlap one another
replicated chromosome
each (formally unreplicated) strand has two double stranded copies of the same DNA helix, called chromatids
kintochores
each sister chromatid has one, assembled at the centromere. since the centromere is also where chromatids area ttached, two kinetochores are on opposites sides of each replicated chromosome. microtubules attached to these structures are called kinetochore microtubules
DNA
encode the cells hereditary information, or genetic material
astral microtubules
hold spindle poles in place, extend from MTOCs and interact with proteins on plasma membrane.
each set of the two sets of separated chromosomes is
identical to that of the parent cell before chromosome replication
metaphase plate
imaginary plane between the spindle poles where chromosomes align in metaphase
Eukaryotic cells divide by cycling between __ and M phase
interphase
Nucleoli are present during
interphase
in early prometaphase
kinesin and dyienin motors attach to kietochores and walk the chromosomes up and down microtubules, when they reach the plus end the kinetochore proteins secure their attachment ,then pushed or pulled back until they reach the middle of the spindle
During ___chromosomes align along the metaphase plate
metaphase
in telophase
nuclear envelope re-forms around each set of chromosomes chromosomes decondense two independent nucleoi form
Spindle apparatus
produces mechanical forces that move replicated chromosomes during early mitosis and pull chromatids apart in late mitosis consists of microtubules
Interphase consist of the S phase where chromsomes _, and the G1 and G2 phases when cells _ and _ for division
replicate;grow;prepare
cytokinesis begin at the
spindle aparatus
centrosome
structure seving as microtubule orgnaizing center for cells cytoskeleton and for the spindle apparatus during cell division.
Cytokinesis often but not always accompanies
telophase
Anaphase
tension begins to split the cohesions that hold the sister chromatids together at the centomeres. each replicated chromosome pulled apart, creating 2 independent daughter chromosomes. (doubles number of chromosomes in cell).
M phase chromosomal apperance
the replicated chromosomes consisting of two chromatids (previosly an ugly x shape are a more condensed ugly x shape.) . The sisters separate and become daughters (4) unreplicated long single strings result in each daughter.
why the chromosomes are "still" in metaphase
the spingle apparatus finshes forming, the polar microtubules that extend from each spindle pole overlap the middle of the cell, creating pole to pole conection, each chromosome linked by kinetochore microtubules reaching out from opposite poles are exerting the same amount of tension, or pull. (tug of war balancing in the middle bcs of slow growth of plus ends at kinetochores and dissasembly at minus end at the MTOCs)
During prophase a homologous pair of chromosomes consists of _____.
two chromosomes and four chromatids
second type of anaphase movement
two poles of spindle pushed and pulled further apart. push is motor proteins overlapping polat microtubules, forcing poles away from eachother. pull comes from diffrent motors on the plasma membrane walking along astral microtubules & dragging the poles to opposite sides of the cell