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The Cell Cycle Quiz #7

Terms in this set (56)

A defining feature of living things:
Cell Division
In what kind of organism does division of one cell reproduce the entire organism?
In unicellular organisms
What do multicellular eukaryotes depend on cell division for?
-Development from a fertilized cell
-Growth
-Tissue repair
What type of cell division are prokaryotes reproduced by?
Binary Fission
Besides prokaryotes, what other two organelles divide by binary fission?
-Mitochondria
-Chloroplasts
What 3 steps are involved in binary fission?
-The DNA (Chromosome) is replicated
-The cell elongates, pulling the 2 copies of the DNA apart
-Plasma membrane pinches inward, dividing the cell into 2
How often does the bacteria E.Coli divide?
Every 20 minutes
Where is the genomic DNA attached to in the cell of an E.Coli?
Plasma Membrane
Does E.Coli or Eukaryotic cells have more DNA?
Eukaryotic cells
What is DNA associated with?
Large number of protiens
What is the complex of DNA and proteins called?
Chromatin
What are the major proteins in chromatin called?
Histones
What happens in chromosome condensation?
Chromosomes will coil and become thicker and more compact
When replication is finished,each duplicated chromosome consists of how many identical DNA double helices?
2
What are the two identical DNA double helices called?
Sister chromatid
What are the protiens called that attach to the chromatids?
cohesins
Centromere:
Where the chromatids are most closely attached
What happens to the two sister chromatids during cell division?
They are pulled apart
Once the chromatids are separated, what are they called?
Chromosomes
Cell Cycle:
-chromosomes are copied (DNA replication)
-the 2 copies are divided (mitosis)
-the cell is divided into 2 (cytokinesis)
What are the 2 phases cell cycle is divided into?
-mitotic phase
-interphase
The key even in interphase is DNA replication, where does it occur?
-S (synthesis) phase
What is the part of interphase before S called?
G1 (GAP 1)
What is the part between S and mitosis called?
G2 (Gap 2)
Interphase typically takes up what % of the cell cycle?
90%
What are the 4 phases of mitosis?
-prophase (pro-before)
-Metaphase (meta-after)
-anaphase (ana- up)
-telophase (telo- end)
-prometaphase
What happens during prophase?
DNA in the nucleus condenses
What forms and disappears in prophase?
forms- spindle fibers
disappears- 2 nucleoli, site of synthesis of ribosomal RNA)
What happens during pro metaphase?
microtubules of the spindle begin to attach to sister chromatids
what happens during metaphase?
The chromosomes align on the equatorial plane of the cell
How does the alignment occur?
when the spindle microtubules extending from the two poles of the cell push and pull on the chromosomes ?
at what stage are the chromosomes most condensed?
metaphase
What happens during anaphase?
the two chromatids making up each chromosome are pulled apart
What is the shortest phase of mitosis?
Anaphase
When does anaphase occur?
When the cohesion proteins are broken down
If its an animal cell, during what stage does the cell elongate?
Anaphase
What happens during telophase?
Nuclear envelopes start to form around the separated chromosomes
What happens to the chromosomes during telophase?
They start to become ,less condense
What re-appears during telophase?
Nucleoli
What is the last phase of mitosis?
Telophase
When does the mitotic spindle form?
In the cytosol during prophase
What does the mitotic spindle consist of?
Fibers made of microtubules and associated proteins
When does the assembly of mitotic spindles start?
at the centrosome
Centrosome:
-it includes a pair of centrioles
-centrioles are not present in plant cells
when does the two centrosomes move apart from each other ?
During prophase and pro metaphase
What do the spindle microtubules towards?
The equatorial plane
Aster:
The radial array of short microtubules extending from each chromosome
What do each of the 2 sister chromatids have?
Kinetochore
Kinetochore:
A structure of protiens associated with specific sections of chromosomes DNA at the centromere
Metaphase plate
At metaphase, the centromeres of all the duplicated chromosomes are on the equatorial plane
What is cell division called?
Cytokineses
Does cytokinesis occur the same in plants and animals?
No
How does cytokinesis happen in animal cells?
A ring of microfilaments from around the equator of the cell and as the ring contracts, a cleavage furrow appears
what happens as the cleavage furrow depends?
It eventually divides the cell into 2 daughter cells
do the daughter cells seperate during cytokinesis in a plant cell?
No
what does the cell plate connect in the plant cell?
It connects with the existing plasma membrane and cell wall
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