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All cells have a plasma membrane.
◦ Controls what gets in and out.
◦ Made of phospholipid molecules
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All cells have cytoplasm
◦ Gel-like substance
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All cells have genetic material
◦ Either DNA or RNA
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All cells have ribosomes
◦ For making proteins
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Prokaryotic cells
◦ Smallest cells
◦ No nucleus or membrane-bound organelles
◦ Examples: Bacteria
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Eukaryotic cells
◦ Complex cells
◦ Have a nucleus and membrane-bound organelles
◦ Examples: Plant cells and Animal Cells
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Most cells reproduce by dividing in two.
Before they can do this, they must copy all
their genetic information, so that each new
daughter cell has a full set of genetic material
The genetic material in eukaryotic cells is in
the form of chromosomes.
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Humans have 46 chromosomes in the nucleus
of every cell
◦ Two are the sex chromosomes (X and Y)
 XX = female
 XY = male
◦ The other 44 are called autosomes
◦ They occur in matching pairs
 Called homologous chromosome pairs
 One chromosome in each pair comes from mom and
the other comes from dad
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Cells grow and reproduce just like every other
living thing.
The cell cycle represents the life cycle of a
typical eukaryotic cell.
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G1 phase: Cell grows
S phase: (synthesis) Cell copies its DNA
G2 phase: Cell continues to grow and get
ready to divide
Mitosis: The cell divides the content of the
nucleus
Cytokinesis: The cell divides its cytoplasm
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The G1, S, and G2 phase make up a stage
called interphase. The cell spends most of its
time in interphase.
The cell grows and copies DNA during
interphase.
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Mitosis is when the cell divides the contents
of the nucleus
Mitosis occurs in stages:
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Prophase
Metaphase
Anaphase
Telophase
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Cytokinesis occurs when the rest of the cell
divides.
◦ For animal cells---the cell membrane pinches in
and the cell splits in two.
◦ For plant cells---an new cell plate forms to create a
cell wall between the dividing cells.
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Prokaryotes
(bacteria cells)
reproduce by a
process known as
Binary Fission.
◦ DNA is circular (no
chromosomes)
◦ DNA copies itself
◦ Cell
divides…simple
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The reproductive cells divide by a different
method….Meiosis.
The cell divides twice.
The result is four gamete cells (sperm and
egg cells) with half the number of
chromosomes.
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Fertilization—union of
sperm and egg cell.
Sexual reproduction,
involving the production
of sperm and egg cells
by meiosis followed by
fertilization, ensures
genetic variation in all
offspring