Chapter 6
During which phase of mitosis does the nuclear envelope re-form?
telophase
which stage of the mitosis is this: -chromosomes arrive at opposite poles and begin to decondense -nuclear envelope material surrounds each set of chromosomes -the mitotic spindle breaks down
telophase
A human bone marrow cell in the prophase stage of mitosis contains 46 chromosomes. Therefore, there are a total of __________ sister chromatids in this cell.
92
Imagine that a human skin cell went through mitosis but did not undergo cytokinesis. How many chromosomes would be in the cell?
92
What is the difference between a benign tumor and a malignant tumor?
Benign tumors do not metastasize; malignant tumors do
Which of the following statements regarding prokaryotes is false? Which of the following statements regarding prokaryotes is false? A. Prokaryotic cells are generally smaller and simpler than eukaryotic cells. B. In prokaryotes, daughter chromosomes are separated by an active movement away from each other and the growth of a new plasma membrane between them. C. Prokaryotic chromosomes are more complex than those of eukaryotes. D. Most prokaryotes reproduce by binary fission.
C. Prokaryotic chromosomes are more complex than those of eukaryotes.
Which of the following statements regarding cell division is false? A. Cell division is the basis of both sexual and asexual reproduction. B. Cell division is necessary for development to occur. C. Cell division can reproduce an entire organism. D. Cell division is common in eukaryotes but rare in prokaryotes.
Cell division is common in eukaryotes but rare in prokaryotes.
Which of the following occurs during interphase? A. a reduction in the size of the nuclear membrane B. separation of newly formed DNA to opposite ends of the cell C. cell growth and duplication of the chromosomes D. cytokinesis
Cell growth and duplication of the chromosomes
what are the parts of interphase?
G1 S G2
where are the three checkpoints located and their regulations?
G1-all conditions for cell division favorable G2-all chromosomes have been replicated without any damage M-near the end of the metaphase are chromotids, correctly connected to spindle fibers
During binary fission, each copy of the duplicating chromosome moves to opposite ends of the cell. What does this achieve?
It ensures that each daughter cell receives one copy of the chromosome.
During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles?
Metaphase
what gene suppresses tumors?
P53 gene
Which of the following features likely accounts for the difference between plant and animal cell cytokinesis? A. Plant cells have cell walls. B. Plant cells have two sets of chromosomes; animal cells have one set of chromosomes. C. Animal cells lack chloroplasts. D. Animal cells lack the microfilaments required for forming a cleavage furrow.
Plant cells have cell walls
what may occur if cells are cancerous?
-cell cycle regulation stops operating normally -mutation is passed to daughter cells -mutated cells aren't functional -tumor may occur
what are the characteristics of binary fission?
-not as complicated as eukaryotes -very rapid -single circular DNA chromosomes -chromosome not enclosed in nucleus
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 in one of the grasshopper daughter cells?
100 units
how many chromosomes do gametes (sex cells) have?
23
how many human cells are homologous pairs?
23
A human somatic cell contains __________ chromosomes.
46
How many chromosomes do humans have in somatic cells?
46
Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?
The sequences are identical.
The stage of mitosis during which the chromosomes move toward separate poles of the cell is _____.
anaphase
which stage of mitosis is this: -Cohesin proteins binding the sister chromatids together break down -sister chromatids (now chromosomes) are pulled toward opposite poles -non-kinetochore spindle fibers lengthen, elongating the cell
anaphase
names for the animal and plant cells stage for cytokinesis
animal cells-cleavage furrow plant cells-cell plate
Definition of mutagenic agent
anything in the environment that may lead to cell mutations
Eukaryotic chromosomes differ from prokaryotic chromosomes in that they
are housed in a membrane-enclosed nucleus.
In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____.
are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes
what is the cell division function for prokaryotes?
asexual reproduction
A cell replicates its entire chromosomal DNA only __________.
before it is about to divide
A cleavage furrow forms in an animal cell during _____.
cytokinesis
The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called
cytokinesis
what stage of the cell cycle does the daughter cells separate?
cytokinesis
what are cell division functions in multicellular organisms?
development growth repair
In bacterial cells, binary fission involves __________.
distribution of a copy of the single parental chromosome to each daughter cell
A benign tumor differs from a malignant tumor in that a benign tumor
does not metastasize
cause of cancerous cells
error (mutation) in a gene (DNA sequence)
wht genomic DNA cell does this description fit: several double-stranded, linear DNA molecules called chromosomes
eukaryotic cells
You see a cell with several nuclei and you know that something is different about cell division. What is the most likely explanation?
failure of cytokinesis following mitosis
Which of the following is a feature of plant cell division that distinguishes it from animal cell division? A. production of four (rather than two) new cells per mitotic division B. formation of a cell plate C. lack of cytokinesis D. formation of a cleavage furrow
formation of a cell plate
During asexual reproduction, yeast cells can produce
genetically identical offspring
Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are
homologous chromosomes
what chromosomes does this description fit: -same length -same staining pattern -genes for the same characteristics are located in the same location -each member of the pair originates from a different parent
homologous chromosomes
Chromatids are
identical copies of each other if they are part of the same chromosome
Eukaryotic cells spend most of their cell cycle in which phase?
interphase
Sister chromatids are
joined together at a centromere
In some organisms such as certain fungi and algae, cells undergo mitosis repeatedly without subsequently undergoing cytokinesis. What would be the consequence of this?
large cells containing many nuclei
Which of the following is a correct representation of an event that occurs in mitosis? A. prometaphase—there is movement of the chromosomes to the poles. B. anaphase—the nuclear envelope disappears. C. prophase—chromosomes uncoil. D. metaphase—chromosomes line up on the equatorial plane.
metaphase
which stage of mitosis is this: -mitotic spindle is fully developed -centrosomes are at opposite poles of the cell -chromosomes are lined up at the metaphase plate - each sister chromatid is attached to a spindle fiber originating from opposite poles
metaphase
what is the final stage for the cell cycle?
Cytokinesis
Which of the following statements correctly describes the timing of DNA synthesis? A. DNA is synthesized in G2 of interphase immediately preceding mitosis. B. DNA is synthesized continuously throughout the cell cycle C. DNA is synthesized only during mitosis. D. DNA is synthesized in the S phase of interphase.
DNA is synthesized in the S phase of interphase.
what are the genes called that code for normal cell cycle?
Proto-oncogenes
The genetic material is duplicated during
S phase
DNA replication occurs in _____.
S phase of interphase
Which of the following statements regarding the cell cycle control system is false? A. The cell cycle control system triggers and controls major events in the cell cycle. B. The cell cycle control system includes three key checkpoints to complete a cell cycle. C. The cell cycle control system operates independently of the growth factors. D. The cell cycle control system receives messages from outside the cell that influence cell division.
The cell cycle control system operates independently of the growth factors.
You and your lab partner are observing a cell under a microscope, but you do not know whether it is a eukaryote or a prokaryote. Which of the following observations regarding the chromosomes would you use to immediately conclude that the cell is a eukaryote?
The chromosomes are housed in a membrane-enclosed nucleus.
You are observing a single cell under a microscope. You go home for the night, and the next day you see four cells. The four cells look similar, and when you stain them with a dye that binds to DNA they all appear to contain the same amount of DNA as the original cell. What likely happened overnight?
The single cell divided to form two new cells, and the two new cells each divided to form four total cells, all by asexual reproduction.
Which of the following occurs during mitosis? A. Organelles replicate. B. Two genetically different daughter cells result. C. Two daughter nuclei, one at each pole of the cell, are generated. D. Chromosomes replicate.
Two daughter nuclei, one at each pole of the cell, are generated
genome
a cell's complete complement of DNA
DNA replication is ___directional
bi-
what is prokaryote cell division called?
binary fission
G0 (Subzero) phase
cells not actively dividing (temporary or permanent)
A benign and a malignant tumor differ in that _____.
cells of a benign tumor remain within the tumor, whereas cells of a malignant tumor can spread to other body tissues
After fertilization, the resulting zygote begins to divide by __________.
mitosis
what are the genes called that can cause cells to become cancerous?
oncogenes
the genomic DNA in prokaryotes characteristics
one, double-stranded DNA molecule which is circular
what is the name of the starting point of DNA replication?
origin
A cell that has a cell wall is undergoing cell division, and the following events are observed: the formation of a cell plate and the division of the cell into two daughter cells. What type of cell is being observed and what process(es) is it going through?
plant cell; telophase and cytokinesis of mitosis
asexual reproduction
produces offspring genetically identical to the parent
The term binary fission is best applied to _____.
prokaryotes
which stage of mitosis is this: -chromosomes continue to condense -kinetochores appear at the centromeres -mitotic spindle microtubules attach to kinetochores -centrosomes move toward opposite poles
prometaphase
In the telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _____.
prophase
The phase of mitosis during which the mitotic spindle begins to form is
prophase
which stage of mitosis is this: - chromosomes condenses and become visible -spindle fibers emerge from the centrosomes -nuclear envelope breaks down -nucleolus disappears
prophase
mitosis in the correct chronological order
prophase prometaphase metaphase anaphase telophase
the structure around cell wall once formed
septum
Prior to mitosis and after S phase, each chromosome of a eukaryotic cell consists of a pair of identical structures called
sister chromatids