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4.8 Cell Division
Terms in this set (63)
What are the two ways that cells divide?
Mitosis and meiosis.
What type of cells divide by mitosis?
What type of cells divide by meiosis?
What is the definition of cell division?
One cell divides to produce two cells.
What functions does cell division provide?
Production, replacement, and maintenance of cells.
What pair of perpendicularly oriented cylindrical structures is contained in a centrosome?
What is the function of the centrosome in the process of cell division?
Organization of microtubuules that facilitate movement of chromosomes during cell division.
How many separate DNA molecules are there in a typical human cell?
46 separate DNA molecules.
What two 'shapes' does genetic material organize into?
Loosely coiled chromatin or tightly coiled chromosomes.
When is the loosely coiled chromatin normally seen?
During interphase; when DNA is able to direct the production of cellular proteins through transcription.
When is the chromosome usually seen?
Only when the cell is dividing, for compact and organized packaging and movement.
How is the chromatin distiguished from a chromosome?
A chromatin is a loose bundle of DNA strands; a chromosome is a tightly coiled package, with a clearly defined shape.
What is the term for all of the steps in the division of a somatic cell in both structure and function between its formation and the time it divides into two identical cells.
The cell cycle.
What is the term for two identical cells that have just divided.
What are the two major phases in the cell cycle?
Interphase and the mitotic (M) phase.
What are the 3 sub phases of interphase?
G1 Phase, S Phase, G2 phase.
What are the 2 subphases of the Mitotic phase?
Mitosis and cytokinesis?
What the definition of interphase?
A time of normal metabolic activities when the cell is not diving; chromatin is not visible by light microscopy.
What is the definition of the mitotic phase?
Cell division produces two identical daughter cells from one mother cell.
Define the G1 phase.
It is it the first gap phase: a growth phase during which protein synthesis and metabolic activity occur; new organelles are produced; centriole replication begins at end of this phase.
Define the S phase
Nuclear DNA is replicated
Define the G2 phase
Second gap phase: brief growth period for production of cell division enzymes; organelle replication continues; centriole replication finishes.
Division of the nucleus; continuous series of nuclear events that distribute two sets of chromosomes into two daughter nuclei; mitosis is divided into four phases-prophase, metaphase, anaphase, and telophase.
Usually begins before telophase ends; cleavage furrow formed from a contractile ring of microfilaments; cytoplasm divides, completing formation of two daughter cells.
In which phase do most cells spend most of their lives?
Why is the G1 phase important for cell division?
It is the time when structures needed for DNA replication are formed, including the duplication of the centrioles to produce two centriole pairs.
What is the S in S-phase short for?
How many chromosomes are replicated in the S phase?
All 46 chromosomes.
What are the duplicated chromosomes called?
What attaches the two sister chromatids together at the center?
Define the centromere.
The nonstaining constriction of a chromosome that is the point of attachment of the spindle fiber.
What are other important components (besides the chromosomes) that are synthesized during the S-phase?
Deoxyribonucleotides and the enzyme DNA polymerase.
During the S phase, what is the term for the original DNA strand that is replicated?
The parent DNA strand.
When the parental DNA strands are split, what is the term for each strand being copied?
What enzyme holds onto the templates as a new strand is being formed?
What are the 4 steps in the process of DNA duplication in the S-phase?
 Unwinding of DNA molecule;  Breaking the parent strands apart;  Assembly of new DNA strands;  Restoration of DNA double helix.
After the parental strands become templates, is the original DNA molecular strand restored?
No, it becomes two strands containing the same information.
After the parental strands become templates, are the new DNA molecules restored to the shape of a double helix?
Yes, DNA always creates a double helix, even after duplication.
During DNA duplication, how much of the original information is copied to the new strand of DNA?
All of the information (nucleotides) are copied exactly as they are read, given their complementary pairings.
In DNA duplication, what pairs with adenine? (ii)
In DNA duplication, what pairs with thymine? (ii)
In DNA duplication, what pairs with cytosine? (ii)
In DNA duplication, what pairs with guanine? (ii)
What is the briefest form of interphase?
What is completed during the g2 phase?
Centriole replication is.
In addition to centriole replication, what is completed during the G2 phase?
Organelle production continues, and enzymes needed for cell division are synthesized.
What is the long term for the G1 phase?
The first gap phase.
What is the long term for the G2 phase?
The second gap phase.
What are the four phases of mitosis?
Prophase, Metaphase, Anaphase, Telophase
In what phase do chromatin become supercoiled into chromosomes; the nucleolus breaksn down and disappears; spindle fibers begin to grow from the centriols; the centriole paris are pushed apart; finally, the dissolution of the nuclear envelope occurs.
In which phase do the chromosomes align along the equatorial place of the cell and fibers attach to the centromere from the centrioles?
In which stage do the spindle fibers cause the sister chromatids to be moved apart toward the cell's poles with the centromere leading the way, arms trailing behind?
In which phase do the chromosomes arrive at each cell poll; chromosomes uncoil and return to the chromatin; a new nucleus forms a nucleolus, mitotic spindle breaks up and disappears; and a new nuclear envelope forms?
What phase is telophase said to be the opposite of?
What is a learning strategy for remembering prophase?
P = puffy; the ball of chromatin forms a puffy ball within the nucleus.
What is a learning strategy for remembering metaphase?
M = middle; During this phase, the chromosomes align along the middle oof the cell.
What is a learning strategy for remembering anaphase?
A = apart; During this phase, the sister chromatids are pulled apart.
What is a learning strategy for remembering telophase?
T = two; two new cells become noticeable as a cleavage furrow deepens to divide the cytoplasm.
What is the final major even in the mitotic phase?
What is the term used to describe the process of cell division during cytokinesis (2 words)?
When can cytokinesis begin splitting the cell?
Late anaphase-late telophase
Describe the process of DNA replication that occurs during the S phase of interphase.
The DNA strand is completely copied by DNA polymerase enzymes, splitting it into two templates and forming complementary base pairs. This makes two exact copies of the parent DNA strand.
What are the events that occur during the mitotic phase?
Mitosis & Cytokinesis