Download Cells PP - jl041.k12.sd.us

The Cell
I. Cell Theory
1. If its alive, its made of cells.
2. Cells are basic unit of life.
3. Under current conditions, cells come from
preexisting cells.
II.Limits on Cell Size
1. Surface Area is used by Cells to Obtain
Nutrients (e.g. doors)
2.Volume Measures Biomass, or How Much
Cells Need for Nutrients
II. Limits on Cell Size
3. As Cell Size Increases, Surface Area is
squared while Volume is cubed.
4. So volume increases more quickly than
surface area.
5. SA:V Ratio Limits Cell Size
III. Organelles and Cell Features
A.Cell Membrane : Selectively permeable
membrane that limits what enters and
exits a cell. Made of phospholipids bilayer
with some channels (proteins).
Label Phosphate,
Lipid Tail,
Circle Hydrophobic area in Red,
Circle Hydrophilic area in Blue.
III. Organelles and Cell Features
B. Cell Wall Rigid structure that provides
support. Found outside cells of plants,
algae and some bacteria.
III. Organelles and Cell Features
C.Nucleus – A membrane
envelop that surrounds
DNA in Eukaryotic cells.
Nucleus (because it
holds the DNA) largely
controls the cell.
III. Organelles and Cell Features
D. Cytoplasm – Liquid between cell
membrane and nucleus (if the cell were a
water balloon, this would be the water).
III. Organelles and Cell Features
E. Mitochonridion – Where sugar is
converted into useful energy (ATP).
III. Organelles and Cell Features
F. Chloroplast – In plant cells, converts
solar energy into stored chemical energy
(sugars).
III. Organelles and Cell Features
G. Ribosomes – Put amino acids together
to form proteins. Assemble proteins.
III. Organelles and Cell Features
H. Endoplasmic Reticulum –
Rough – Where many proteins are
produced. “Rough” spots are ribosomes.
Smooth – many lipids produced; moves
products through cells.
III. Organelles and Cell Features
J. Vacuoles – Stores water and solutes.
Gives plants tugor support.
III. Organelles and Cell Features
K. Cytoskeleton – Framework/Skeleton of
the cell.
Analogy Assignment:
•
•
•
•
•
•
•
Nucleus – (Brain of Cell)
Mitochondria (Power house)
Chloroplasts (Solar panel)
Ribosomes (protein factories)
Endoplasmic Reticulum (manufacturing
and shipping)
Vacuoles (Storage Locker)
Cytoskeleton (Scaffolding)
IV. Movement through Membrane
A. Cell Membrane: Lipid Bilayer with
Channels.
Hydrophobic – ‘water fearing’
Hydrophilic - ‘water loving’
B. Cell Membrane is Semipermeable –
Large and/or Charged particles can’t
pass through membrane.
IV. Movement through Membrane
IV. Movement through Membrane
1. Diffusion – Molecules move from high
concentration to low concentration due to
random motion of molecules.
IV. Movement through Membrane
2. Osmosis – Special case of diffusion in
which water molecules diffuse through a
semipermeable membrane.
Osmosis
Osmosis Terms
•
•
•
Hypotonic: Relatively high amounts of water
(Hippos live in water)
Hypertonic: Relatively lower amounts of water
and higher amounts of solutes, such as sugar or
salt. (Hyper means ‘lots’ so think of a sugar high
causing hyperactivity)
Water moves from Hypo to Hyper, or High
Concentration (of water) to Low
Concentration (of water).
Hyper, Hypo, or Iso (solution in the
bag)?
2M sucrose
solution
1 liter of
distilled water
10M sucrose
solution
2M sucrose
solution
HYPOTONIC
CONDITIONS
HYPERTONIC
CONDITIONS
ISOTONIC
CONDITIONS
Fig. 5.14, p. 88
open channel
proteins
gated channel
proteins
transport protein
lipid
bilayer
Fig. 5.10, p. 86
IV. Movement through Membrane
C. Membrane Proteins: Help move through
items that are large and/or charged.
1. Facilitated Diffusion: Requires a
specific protein but the cell doesn’t
need to expend energy. Will still go
from high to low concentration.
Passive Transport
IV. Movement through Membrane
2. Active Transport: Proteins pump items
through membrane, requiring
expenditure of ATP.
open channel
proteins
gated channel
proteins
transport protein
lipid
bilayer
Fig. 5.10, p. 86
IV. Movement through Membrane
D. Endocytosis and Exocytosis.
1. Endocytosis: Bulk movement of
materials into a cell.
ENDOCYTOSIS
• Vesicle forms from a patch of inward-sinking
• plasma membrane, enters cytoplasm
2. Exocytosis: Bulk movement of
materials out of a cell.
EXOCYTOSIS
Vesicle in cytoplasm moves to plasma membrane,
fuses with it; contents released to the outside
Fig. 5.17, p. 90
IV. Movement through Membrane