Cell Size, Phases and Division
Open your journal to the
foldable!!!
Surface area to volume ratio
.
Surface area to volume ratio
6:1
4:1
2:1
-Which SA/V ratio would be more efficient
to a cell?
A large SA/V ratio…..6:1
Cell Size, cont.
Increase size of cell Decrease rate of
Diffusion
Oxygen
Nutrients
Wastes
Water
Why do cells divide?
•Growth of organism.
•Repair if injured
•Replace dead cells.
Foldable Instructions
• Fold one piece of
white paper hot dog
style.
• Cut down the middle
seam (hot dog) &
tape the short ends
together.
• Accordion fold the
paper to make 8
equal tabs.
The Cell Cycle
Draw the
diagram of
the cell cycle
on square 1
of foldable
Interphase
• The majority a cell’s life cycle is spent in
a period of growth known as
Interphase.
• Three stages
–G1- Growth
–S- DNA synthesis/replication
–G2- preparation for mitosis
• No Chromosomes are visible.
• DNA exists as chromatin
DNA and Cell Division
chromatin – DNA-when not in
chromosomes (during mitosis)
*
Interphase
Draw the
diagram of
interphase
on square 2
of foldable
White fish blastula
Interphase
Onion root tip
Chromosomes
DNA makes up the inside the
nucleus
Chromosome
centromere
Sister chromatid
Draw the
diagram of
the
chromosome
on square 3
of foldable
Cell Division
• Mitosis
–two daughter cells are formed,
each contains a complete set
of identical chromosomes
(DNA).
https://www.youtube.com/watch
?v=1TAzsL8qQeU
Prophase
• Nuclear
membrane
breaks down
• Chromosomes
condense
(appear)
• Centrioles
appear
• Spindle fibers
appear
Draw the
diagram of
prophase on
square 4 of
foldable
Metaphase
• Spindle fibers
attach to
chromosomes
• Chromosomes
“met” @ the
middle.
Anaphase
• Sister Chromatids
are pulled apart
towards the poles.
Draw the
diagram of
anaphase on
square 6 of
foldable
• Sister Chromatids
at opposite poles
• Nucleus starts to
reform
• Chromosomes
uncoil back into
cromatin (DNA
soup)
Telophase
Cytokinesis occurs
-Results in 2 new
daughtercells
Anaphase
Metaphase
Cell plate
Cleavage furrow
Telophase
Prophase
Anaphase
Prophase
Metaphase
Interphase
Cytokinesis
Telophase
Mitosis
• In Mitosis, everything is identical.
• Takes place in somatic cells
(body cells, ex: lung, skin, heart,
stomach, etc.)
Big Bang Theory
Results of Mitosis
•
•
•
•
Replace old or damaged cells.
Occurs fastest in skin cells.
Some cells like brain cells do not divide.
During early development, mitosis
produces the cells needed to make tissues
and organs.