Multicellular organisms begin life as a
single cell
Humans become trillions of cells because of
cellular reproduction
Asexual reproduction
Doesn't require sperm or egg Required in sexual reproduction
Growth
cell duplicates its contents (including DNA and organelles)
Cell division
Parent cell contents divides into two daughter cells
DNA replication
is the copying of DNA.
DNA is periodically wound around histones to form
nucleosomes
How many chromosomes do humans have?
46
Just before cell division chromatin condenses into
chromosomes
Duplicated chromosomes are composed of
sister chromatids joined at the centromere.
Nucelosomes
Chromosomes consist of subunits that are composed of DNA and histones.
Chromatin
Beads on a string that has nucleosomes
Does each sister chromatid have different DNA or identical?
Identical
The Cell Cycle divided into three stages
G1 stage before DNA replication
- Cell doubles organelles
-Accumlates materials for DNA synthesis
- Makes decision whether to divide or not
Or it go can into
G0 arrested does not go on to divide
- This is cardiac arrest
S - DNA synthesis
- Results in each
The cell cycle
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