-
a. 1882: __allowed him to observe the behavior of chromosomes during __ and __
- Flemming
- mitosis and cytokinesis
-
Phases of the Cell Cycle
State percentage of time
- mitosis (10%: shortest part)
- interphase (90%)
-
Interphase
1. A cell that is about to divide does what in preparation for cell division
2. __, during which a cell grows by producing proteins and cytoplasmic organelles like mitochondria ad endoplasmic reticulum, which are __, __, __.
- grows and copies its chromosomes
- Subphases
- G1
- S
- G2
-
a. G1 (first gap)
i. __
b. S phase
i. __
ii. __
c. G2 phase
i. __
d. M phase
i. __
- grows
- Only time chromosomes are duplicated
- Continues to grow as it copies its chromosomes
- Grows more as it completes preparations for cell division
- Divides
-
i. Cell may undergo one division in 24 hours
1. M phase=__
2. S= __
3. G1 =__
a. Most variable in length in different types of cells
i. Some don’t divide at all or rarely and spend time in __phase
4. G2= __
- less than an hour
- 10-12 hours
- 5-6 hours
- G0
- 4-6 hours
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Phases of Mitosis
- Prophase
- Metaphase
- Anaphase
- Telophase
-
i. Prophase
1. __ condense
2. __disappear
3. Each duplicated chromosome appears as __ joined at their __and along their __by __(__)
4. __ begins to form
a. __ and __; __of shorter microtubules that extend from centrosomes are __
5. Centrosomes move away from each other, propelled by __
ii. Prometaphase
1. __ fragments
2. Microtubules now invade __area
3. Chromosomes more condensed
4. Each of two chromatids have __, a specialized protein structure at the centromere
a. Some microtubules attach to these, causing what?
5. __ interact with those from the opposite pole of the spindle
- Chromatin fibers
- Nucleoli
- two identical sister chromatids
- centromeres
- arms
- cohesins
- sister chromatid cohesion
- Mitotic spindle
- Centrosomes and microtubules
- radial arrays
- asters
- lengthening of microtubules
- Nuclear envelope
- nuclear
- kinetochore
- jerking the chromosomes back and forth
- Nonkinetochore microtubules
-
i. Metaphase
1. __at opposite poles
2. Chromosomes at __, with __lying at plate
3. For each chromosome, the __of the__are attached to __ coming from opposite poles
- Centrosomes
- metaphase plate
- centromeres
- kinetochores
- sister chromatids
- kinetochore microtubules
-
i. Anaphase
1. __stage
2. Begins when __
a. Allows __ of each pair to part suddenlyà __becomes __
3. Two liberated daughter chromosomes begin moving toward opposite ends of cell as kinetochore microtubules __; microtubules attached to centromere region, they move __first
4. The cell elongates as the __ lengthen
5. End of anaphase= __
- Shortest
- cohesin proteins are cleaved
- sister chromatids
- chromatin
- full-fledged chromosome
- shorten
- centromere
- nonkinetochore microtubules
- two ends of cell have equivalent—and complete—collections of chromosomes
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i. Telophase
1. Two daughter __form in cell
2. __ arise from fragments of parent cell’s __ and other portions of the __
3. __reappear
4. Chromosomes become less condensed
5. Any remaining spindle microtubules are __
6. __, the division of one nucleus into two genetically identical nuclei, is now complete
- nuclei
- Nuclear envelopes
- nuclear envelope
- Endomembrane system
- Nucleoli
- depolymerized
- Mitosis
-
i. Cytokinesis
1. Division of the __is usually well under way by late telophase, so the two daughter cells appear shortly after the end of mitosis
2. In animal cells, cytokinesis involves the formation of a __, which pinches the cell in two
-
cytoplasm
cleavage furrow
-
a. The Mitotic Spindle
i. Many events depend on it
1. Begins to form in cytoplasm during __
ii. Consists of fibers made of __and __
1. Material from other __, which disassemble
iii. __ elongate by incorporating more subunits of the protein __and shorten by losing subunits
-
prophase
- microtubules
- associated proteins
- microtubules
- Spindle microtubules
- tubulin
-
i. Animal cells
1. Assembly of spindle microtubules starts at __, a subcellular region containing material that functions throughout the cell cycle to organize the cell’s microtubules
a. In center: __(not important)
-
i. During Interphase:
1. Single __duplicates, forming two that remain together near nucleusà move apart during __ and __ as microtubules grow out; end of __, they are at opposite ends
a. An __, a radial array of short microtubules, extends from each centrosome
2. Spindle includes __,__, and __.
- centrosome
- prophase and prometaphase
- prometaphase
- aster
- centrosome, asters, microtubules
-
i. Each of the two sister chromatids of a duplicated chromosome has a __, a structure of proteins associated with specific sections of chromosomal DNA at each centromere
1. In opposite directions
kinetochore
-
i. __: some attach to kinetochores (kinetochore microtubules)
1. When one is captured, the chromosomes begins to move toward the pole from which those microtubules extend, but is checked when other microtubule attaches
a. Tug of war
Prometaphase
-
i. Metaphase: equal pole causes them to be at __
1. Meanwhile, __not attached elongate, and by metaphase they __and interact with other __ from the opposite pole of the spindle
2. __have also grown and are in contact with plasma membrane
3. Spindle complete
- metaphase plate
- microtubules
- overlap
- nonkinetochore microtubules
- Asters
-
i. Structure meets function during __
1. __holding together __ are cleaved by enzyme called separateà __--> move towards opposite ends of cells
- anaphase
- Cohesins
- sister chromatids
- full-fledged chromosomesà
-
a. Mechanisms for kinetochore movement
i. __proteins on kinetochores walk chromosomes along microtubules, which __at their __ends after the motor proteins have passed
ii. Reeled in by motor proteins at spindle poles and that the microtubules __after they pass by these __proteins
- Motor
- depolymerize
- kinetochore
- depolymerize
- motor
-
a. Nonkinetochore microtubules elongate whole cell during __
i. Overlap each other extensively during __
-
i. During __, the region of overlap is reduced as __ attached to the __walk them away from one another, using energy from __
1. As the microtubules push apart from each other, their __ are pushed apart, elongating the cell
2. At the same time, the __lengthen somewhat by the addition of __subunits to their overlapping ends, resulting in continuing overlapping
- anaphase
- motor proteins
- microtubules
- ATP
- spindle poles
- microtubules
- tubulin
-
i. End of __: duplicate groups of chromosomes have arrived at opposite ends of the elongated parent cell
ii. __: nuclei re-form
iii. __: begins during __ or __, and the spindle disassembles by __of microtubules
- anaphase
- Telophase
- Cytokinesis
- anaphase or telophase
- depolymerization
-
Cytokinesis
a.
Occurs by __
i.
First: __ (shallow
groove in cell surface near old -_)
b.
__side: contractile ring
of __ associated with molecules of the protein __
i.
__microfilaments interact with
__molecules, causing ring to __
1.
Contraction like pulling of
drawstring
ii.
__deepens until
parent cell is pinched in two, producing two completely separated cells, each
with its own nucleus and share of cytosol, organelles, and other subcellular
structures
- cleavage
- cleavage furrow
- metaphase plate
- Cytoplasmic
- actin microfilaments
- myosin
- Actin
- myosin
- contract
- Cleavage furrow
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c. Plant cells i. No __
ii. During __, vesicles derivedfrom __move along microtubules to middle of cell, where they coalesce,producing a __
1. Cell wall materials carried invesicles collect in __as it grows
iii. __enlarges until itssurrounding membrane fuses with the __ along the perimeter of cell iv. Two daughter cells with own plasmamembrane 1. New __ arises from contentsof __ forms between cells
- cleavage furrow
- telophase
- Golgi
- cell plate
- cell plate
- Cell plate
- plasma membrane
- cell wall
- cell plate
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