Chapter 12 (Exam 3 bio)
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
identical copies of each other if they are part of the same chromosome
Chromatids
In animal cells, cytokinesis occurs by a process known as
cleavage
The first sign of cleavage is the appearance of a _______, a shallow groove in the cell surface near the old metaphase plate
cleavage furrow
Many of the events of mitosis depend on the mitotic spindle, which begins to form in the _____ during prophase. This structure consists of fibers made of microtubules and associated proteins
cytoplasm
______ filaments are fibrous proteins coiled into cables that maintain cell shape and anchor the nucleus.
intermediate
Following cytokinesis in an animal cell, how many centrioles does each new daughter cell possess?
2
_____ is a complex of DNA and protein.
Chromatin
________in the cell cycle control system regulate the cell cycle through a variety of stop and go signals
checkpoints
"Cytokinesis" refers to __________.
the division of the cytoplasm
During binary fission in a bacterium __________. The term binary fission, meaning "division in half,"
the origins of replication move apart
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 chromatids does a human somatic cell contain after interphase and just prior to mitosis?
92
If a human somatic cell is just about to divide, it has __________ chromatids.
92
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 region of a chromosome holding the two double strands of replicated DNA together is called __________.
a centromere
The radial arrays of shorter microtubules that extend from the centrosomes are called
asters
During interphase, the chromosomes ______ be distinguished individually because the chromosomes are still in the form of loosely packed chromatin fibers.
cannot
A cell's endowment of DNA, its genetic information, is called its
genome.
DNA replication occurs in __________
the S phase of interphase ("S" stands for synthesis of DNA).
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
A cell entering the cell cycle with 32 chromosomes will produce two daughter cells, each with
32 chromosomes present in each of the daughter cells
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
How can a protein outside the cell cause events to happen inside the cell?
A protein outside the cell can bind to a receptor protein on the cell surface causing it to change shape and sending a signal inside the cell.
Which of the following structures is/are part of the mitotic spindle? Nonkinetochore microtubules Kinetochore microtubules The aster All of the listed responses are part of the mitotic spindle. Centrosome
All of the listed responses are part of the mitotic spindle
Which of the following is FALSE regarding sister chromatids? Sister chromatids are created when DNA is replicated. Sister chromatids are separated during mitosis. Sister chromatids form in the S-phase stage of the cell cycle. Both of the sister chromatids end up in the same daughter cell after cytokinesis has occurred. Sister chromatids are attached to one another at the centromere.
Both of the sister chromatids end up in the same daughter cell after cytokinesis has occurred. (Each of the sisters ends up in a deff cell after cell divison)
______are components of centrosomes from which microtubules called asters radiate that are involved in the division of chromosomes during cell division.
Centrioles
Within the nucleus of a non-dividing cell, the DNA is organized into discrete units called ______, Structures that carry genetic info
Chromosomes
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?
Cytokinesis
is the effect of an external physical factor on cell division.
Density-dependent inhibition
The _______phase is the part of interphase during which cell growth occurs. This phase also contains a cell cycle checkpoint that can determine if a cell continues on to the S phase.
G1
DNA replication does NOT occur during the?
G1 and G2 phase of interphase
During what phase in the cell cycle would you find the most DNA per cell?
G2
DNA replication occurs during the S phase of interphase, NOT after the
G2 phase
______ occurs prior to meiosis and mitosis.
Interphase
What effect does phosphorylating a protein have on that protein?
It changes the shape of the protein, most often activating it
____are made up of subunits of actin, and function in muscle contraction and changes in cell shape.
Microfilaments
________are made up of subunits of tubulin, and are structures along which substances are transported in the cell. - they are hollow rods constructed from globular proteins called tubulins—shape and support the cell and serve as tracks along which organelles equipped with motor proteins can move.
Microtubules
_____facilitate the movement of chromosomes in mitosis in all eukaryotes.
Microtubules
_______ microtubules from opposite poles overlap each other extensively during metaphase.
Nonkinetochore
What is the best description of the structure of a chromosome in the nucleus of a non-dividing cell? One long DNA molecule, associated with many proteins. Two long DNA molecules wound around each other, associated with many proteins. One long DNA molecule, with no proteins. Two long DNA molecules wound around each other, with no proteins.
One long DNA molecule, associated with many proteins.
In 1855 _________ stated, "Where a cell exists, there must have been a preexisting cell." First to recognize that living cells cannot arise spontaneously, but arise only from previously existing cells
Rudolf Virchow
Which of the following events does NOT occur during interphase of the cell cycle? Separation of the sister chromatids Protein production Production of new mitochondria Production of the endoplasmic reticulum Duplication of the chromosomes Growth of the cell
Separation of the sister chromatids
______separate during mitosis in diatoms and dinoflagellates.
Sister chromatids
The ___________________; regulates whether cell division proceeds. can initiate or stop cell division. regulates cell division. does NOT function properly in cancer cells.
The cell cycle control system
Which of the following statements describes a cell that undergoes mitosis but not cytokinesis? The cell dies. The cell has one nucleus. The cell has not proceeded through interphase. The cell does not contain a nucleus. The cell contains more than one nucleus. The cell has undergone transformation and become a cancer cell.
The cells contain more then one nucleus
Which of the following events occurs during metaphase of mitosis? The chromosomes align along the metaphase plate of the cell. The mitotic spindle forms. The nuclear envelope disappears. The sister chromatids are pulled apart toward opposite sides of the cell. The nuclear envelope forms again. The chromosomes condense.
The chromosomes align along the metaphase plate of the cell
Which of the following events occurs during PROMETAPHASE of mitosis? The chromosomes align along the metaphase plate of the cell. The centrosomes move away from each other. The nuclear envelope fragments. The sister chromatids are pulled toward opposite sides of the cell. The mitotic spindle forms. The nuclear envelope forms again.
The nuclear envelope fragments
How does the process of mitosis DIFFER between most eukaryotes and other eukaryotes such as diatoms and dinoflagellates? The nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates. The nuclear envelope remains intact in most eukaryotes but fragments in diatoms and dinoflagellates. Microtubules do not facilitate the movement of chromosomes in diatoms and dinoflagellates. The chromosomes are not duplicated prior to mitosis in diatoms and dinoflagellates. Sister chromatids are not separated during mitosis in diatoms and dinoflagellates.
The nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates.
Which of the following events occurs during anaphase of mitosis? he mitotic spindle forms. The sister chromatids are pulled apart toward opposite sides of the cell. The nuclear envelope forms again. The chromosomes align along the metaphase plate of the cell. Spindle fibers attach to the centromeres of the chromosomes. The nuclear envelope fragments.
The sister chromatids are pulled apart toward opposite sides of the cell.
is the process that causes normal cells to act like cancer cells.
Transformation
Which of the following events occurs during telophase of mitosis? The chromosomes condense. The sister chromatids separate. The nuclear envelope fragments. The chromosomes align on the metaphase plate. DNA replicates. Two distinct daughter nuclei form in the cell.
Two distinct daughter nuclei form in the cell.
In ______ the centrioles are at opposite ends of the cell. The paired centromeres of each chromosome are separated by spindle microtubules, liberating the sister chromatids, which begin moving toward opposite poles of the cell.
anaphase
begins when the paired centromeres of each chromosome separate, liberating the sister chromatids, which begin moving toward 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 (assuming no mutation has occurred)
The abnormal cells may remain at the original site if they have too few genetic and cellular changes to survive at another site. In that case, the tumor is called a_______ tumor.
benign
a tumor is one that does NOT spread to other parts of the body.
benign
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 animal cells, the assembly of spindle microtubules starts at the
centrosome
a subcellular region containing material that functions throughout the cell cycle to organize the cell's microtubules
centrosome
A _____ is a duplicated chromosome.
chromatid
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________.
chromatin
The cell would have one nucleus if ________occurred.
cytokinesis
During interphase, the genetic material of a typical eukaryotic cell is __________.
dispersed in the nucleus as long strands of chromatin
Observations of cancer cells in culture support the hypothesis that cancer cells __________.
do NOT exhibit density-dependent inhibition
Before the cell can divide to form genetically identical daughter cells, all of this DNA must be copied, or replicated, and then the two copies must be separated so that each daughter cell ends up with a complete
genome.
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
a structure made up of proteins that have assembled on specific sections of DNA at each centromere
kinetochore
a _______ tumor includes cells whose genetic and cellular changes enable them to spread to new tissues and impair the functions of one or more organs. Sometimes a few cells from a malignant tumor may separate from the original tumor, enter blood vessels and lymph vessels, and travel to other parts of the body. There, they may proliferate and form a new tumor.
malignant
Both daughter cells of a mitotic division have complete sets of _______ and _____ chromosomes, NOT _______, identical to those of the parent cell.
maternal and paternal; chromatids
During_____ , the mitotic spindle aligns the chromosomes at the metaphase plate, a region along the equator of the cell.
metaphase
Sometimes a few cells from a malignant tumor may separate from the original tumor, enter blood vessels and lymph vessels, and travel to other parts of the body. There, they may proliferate and form a new tumor. This spread of cancer cells to locations distant from their original site is called
metastasis
The spread of cancer cells to other locations in the body is known as
metastasis
In a dividing animal cell, the ____ microtubules are responsible for elongating the whole cell during anaphase.
nonkinetochore
In _______ , the nuclear envelope fragments and the kinetochores attach to microtubules.
prometaphase
The nuclear envelope fragments during _____ of mitosis.
prometaphase
the nuclear envelope fragments and the kinetochores attach to microtubules. During metaphase, the mitotic spindle aligns the chromosomes at the metaphase plate, a region along the equator of the cell.
prometaphase
During _____, chromatin condenses into distinct chromosomes, the nucleolus disappears, and the mitotic spindle apparatus begins to form. centrosomes move away from each other during ______ apparently propelled along the surface of the nucleus by the lengthening bundles of microtubules between them. This structure is responsible for maneuvering the chromosomes around the cell during mitosis
prophase
Each duplicated chromosome appears as two identical sister chromatids during ______ of mitosis.
prophase
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
In what phase does the chromatin fibers become more tightly coiled, condensing into discrete chromosomes observable with a light microscope. The nucleoli disappear. Each duplicated chromosome appears as two identical sister chromatids joined at their centromeres and, in some species, all along their arms by cohesins (sister chromatid cohesion). The mitotic spindle (named for its shape) begins to form. It is composed of the centrosomes and the microtubules that extend from them. The radial arrays of shorter microtubules that extend from the centrosomes are called asters ("stars"). The centrosomes move away from each other, propelled partly by the lengthening microtubules between them.
prophase
The centrosomes move away from each other during ____ of mitosis.
prophase
The centrosomes move away from each other during _____ of mitosis.
prophase
The chromosomes condense during _____ of mitosis.
prophase
The mitotic spindle forms during _______ of mitosis.
prophase
durning _____we observe the formation of the spindle, the condensation of chromatin, and the disappearance of the nucleolus.
prophase
Which of the following does NOT occur during mitosis? condensation of chromatin the movement of chromosomes to opposite poles separation of chromatids replication of chromosomes alignment of chromosomes along the cell's equator
replication of chromosomes
Binary fission involves the replication and division of a _____ chromosome, whereas mitosis involves the division of________ , replicated chromosomes.
single; multiple
The centromere is a region in which __________.
sister chromatids are attached to one another in prophase
In_______, a new nuclear envelope begins to synthesize, the mitotic spindle breaks down, the chromatin uncoils, and cytokinesis begins.
telophase
Which of the following phases of mitosis is essentially the OPPOSITE of prometaphase in terms of the nuclear envelope? telophase anaphase S phase interphase metaphase
telophase
Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?
telophase
a new nuclear envelope begins to synthesize, the mitotic spindle breaks down, the chromatin uncoils, and cytokinesis begins.
telophase
A cell biologist examined the DNA content of a cell from a fruit fly larva during the G1 phase and determined that it had 150 units of DNA. After measuring the DNA content of the same type of cell after the G2 phase, it was discovered that the cell had 300 units of DNA. How is this possible? The DNA was replicated during the S phase of interphase, which occurs between the two G phases. The DNA was not replicated. This was the result of a mutation. The DNA was replicated during the G2 phase of interphase. The DNA was replicated during the G1 phase of interphase. The DNA was replicated prior to interphase. The DNA was replicated after the G2 phase of interphase.
the DNA was replicated during s phase of interphase which occurs between the two G phases
DNA replication occurs in __________.
the S phase of interphase in both somatic and reproductive cells
One event occurring during prophase is __________. the synthesis of a new nuclear envelope the beginning of the formation of a spindle apparatus the alignment of chromosomes in a single plane division of the centromere cytokinesis
the beginning of the formation of a spindle apparatus
Which of the following events does NOT occur during prophase of mitosis? Nucleoli disappear. The chromosomes condense. Each duplicated chromosome appears as two identical sister chromatids. The centrosomes move away from each other. The mitotic spindle breaks down. The mitotic spindle forms.
the mitotic spindle breaks down
