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Cell theory
1. all living organisms are composed of one or more cells
2. the cell is the basic unit of life
3. all cells arise from pre-existing cells
What are the 3 common characteristics of a cell?
1. the outer boundary of the cell is the plasma membrane
2. all cells store genetic information in the form of DNA
3. everything inside the plasma membrane that is not DNA or the nucleus is cytoplasm
prokaryotes
DNA is found in the cytoplasm, not the nucleus, they have no membrane-bounded
organelles (bacteria)
eukaryotes
membrane-bounded organelles, house DNA within the nucleus (fungi, plants, animals)
what is the purpose of mitosis?
growth and to increase the number of cells
what is the purpose of meiosis?
produce gametes
, mitosis
as the cell grows larger it synthesizes the components necessary for 2 cells and then
divides to form 2 identical daughter cells
cell cycle
The regular sequence of growth and division that cells undergo
the three phases of interphase
G1, S, G2
G1
the cell grows larger
S
the cell replicates its DNA
G2
the cell prepares to divide
cytokinesis
division of the cytoplasm
Gamete
sex cell
fertilization
when male and female gametes fuse
zygote
the fertilized egg (restored to the normal number of chromosomes 46)
chromatin
DNA unwound into a thin strand