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Cell Reproduction
Chapter 8
Chromosomes
Vs.
Chromatin
Chromosomes
Chromatin
Think of it like
Cookies!
Chromatin
Chromosomes
MAKES
Our cells are constantly needing to replace themselves.
For example, when we get a paper cut or any kind of cut, those cells need to be replaced.
Also, cells in your stomach lining constantly need to be replaced, and even bone marrow cells.
Cell Division:
What is it?
The Cell Cycle is a sequence of separate periods of __________ & __________
The period where the cell grows in size, metabolizes, and spends a majority of its life is _______________
Also, during this period, the chromosomes are ___________ to prepare for cell division.
Growth Division
INTERPHASE
duplicated
The period where the cell undergoes nuclear division and creates 2 daughter cells is called ____________
Each daughter cell contains a ____________ set of the parent cell’s chromosomes.
MITOSIS
Complete
Which phase of the cell cycle takes the longest?
75% of a cell’s life is
spent in Interphase
Copies itschromosomes
G2
S
G1
“Checkpoints” = stop & go-ahead signals to regulate the cycle
Regulatory molecules, usually enzymes (protein kinases)To become active
kinases need a cyclin to trigger them
Often called “Cdks” (cyclin-dependent kinases)
The first phase = ____________
This is the ________ phase (OF MITOSIS) During this phase, chromatin coils to form visible _____________ Each chromosome is made up of ___ sister chromatids and are held together by a __________*Remember: The chromosomes are duplicated in ____________ to prepare for cell division
PROPHASE
longest
chromosomes2
centromere
Interphase
One Chromatid
Duplicated Chromatidsister chromatids
The TWO together are
In addition, the ________ envelope starts to disappear and the __________ disintegrates.
In animal cells, ___________ migrate to opposite ends of the cell and ________ ________ begin to form.
In plant cells _______ _______ form without centrioles.
nuclearnucleolus
centriolesspindle
fibers
Spindle fibers
The Second Phase = _____________
• The chromosomes begin to line up along the _________ of the cell
• The spindle fibers _______ to the centromeres.
• Each chromatid has its own spindle fiber attached
METAPHASE
Equator
attach
The Third Phase = ____________
This marks the ___________ of sister chromatids.
The centromeres ______ and the ______ ___________ are pulled apart to opposite poles of the cell by shortening spindle fibers
ANAPHASE
separation
splitsister chromatids
The Fourth Phase = ______________
Here two distinct _________ cells start to form.
In addition, the _____________ unwind, the spinder fibers ______ down, the _________ reappears, a new nuclear __________ forms, and a new double __________ begins to form between the two nuclei.
TELOPHASE
daughter
chromosomesbreak nucleolus
envelopemembrane
Cytokinesis
the division of ____________
Toward the end of telophase in animal cells, the plasma membrane _______ in along the equator
In plant cells, a ____ _________ forms around each cell and new cell ______ form on each side of the cell plate until separation is complete.
cytoplasm
pinches
cell membranewall
Can you identify any of the stages?
Now the cells are separated, they will continue in the cell cycle and enter __________interphase