Transcript Microlife

Micro life
Understanding how the cell works
Advantages in Cell Structure
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Small size allows for EASY ACCESS for Nutrients and waste
removal (Osmosis and Diffusion)
Cells can become specialized to perform certain tasks
Multicellular animals have better survival chance; (If you are
single celled organism with cell flaw or cell damaged you die:
Prokaryote/bacteria)
In multicellular organisms cells can replaced when damaged:
However, the more complex the organism the less
“regeneration”
Specialized Cells create more complex organisms and organs
with better abilities: however, harder to repair when damaged
and some can be not be repaired: Nerve, Brain cells in humans
2 Factors which limit cell’s size
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1. Cell Volume- the space that the cells physically fills
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2. Surface Area- area of the cell’s surface which
interacts with the environment around the cell
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The ratio of cell’s S.A. to its volume is what limits the
cell size
The reason is that diffusion or osmosis will not work
well when volume of cell out grows it’s S.A.
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Cell Life Stages
G 1 Stage
Cell increases in
size
Organelles double
New Cytoplasm
forms
Cell functions
Normally
S Stage
All Genetic
Material is
replicated
G 2 Stage
Cell begins the
process of
Mitosis or cell
Division
Twin Chromosomes Nucleus
then form an
Disappears and
attachment poit
Chromosomes
called a centromere
become visible
Centrioles appear
and Spindle Fibers
Steps of Mitosis
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Interphase- nucleus disappears and chromosomes
appear
Prophase- Chromosomes move to center of cell;
Centrioles move to opposite ends
Metaphase- Spindle fibers attach to chromosomes in
middle of cell
Anaphase- Chromosomes are pulled toward opposite
ends of cell (centrioles)
Telophase- Chromosomes, centrioles, and spindle fibers
disappear; nucleus reforms and cell splits its cytoplasm
to make 2 new “daughter” cells (cytokinesis)
Cellular Respiration
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Use of
Nutrients in a
cell to provide
energy for the
cell to
function
What is Diffusion
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Diffusion is how cell’s breathe
Works through Cell Membrane- “Gatekeeper of
the cell”
Oxygen gas naturally want to go inside cell
because cell contains a lower amount of oxygen
inside:
Carbon Dioxide naturally want to leave cell
because of high levels of Carbon Dioxide inside
cell and low amount outside
What is Osmosis?
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Natural flow of water
across and through the
cell membrane
Allows for nutrients to
enter and leave cell
without using energy
Energy then can be
reserved for specialized
functions/abilities
Passive Transport
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Requires no energy
to move material
throughout the cell
Diffusion and
Osmosis are forms
of Passive
Transport
Active Transport
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Energy is required to allow
material enter the cell
membrane . Nutrients that
are not water dissolved in
water must be brought in this
way into the cell:
Example would be an
Amoeba engulfing its food
(single celled organism) or
the use of cilia to cause food
to enter cell membrane for
digestion in the vacuoles