Transcript Ch.7 – Cellular Structure and Function 7.1 – Cell Discovery & Theory

Ch.7 – Cellular Structure and Function
7.1 – Cell Discovery & Theory
Cellular Discovery
Timeline
Ch.7 – Cellular Structure and Function
7.1 – Cell Discovery & Theory
Why are cells so small??
Surface Area to Volume Ratio
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Ch.7 – Cellular Structure and Function
7.1 – Cell Discovery & Theory
Cell Types
Prokaryotes
Bacteria
Eukaryotes
Plant
Animal
Ch.7 – Cellular Structure and Function
7.1 – Cell Discovery & Theory
Prokaryotes
• Are much more diverse in
both habitat and
metabolism
• Are usually single-celled.
Differentiation into
different cell types almost
never occurs.
• Have no separate nucleus.
• The cell is surrounded by a
membrane, and cell wall
but there are no internal
membranes. (Few
organelles)
Ch.7 – Cellular Structure and Function
7.1 – Cell Discovery & Theory
Eukaryotes
Cells with a nucleus and membrane-bound organelles
Plant
Cells
Animal
Cells
Cell Wall
Chloroplasts
Large Vacuole
More geometric shape
Centrioles
Lysosomes
More spherical shape
Ch.7 – Cellular Structure and Function
7.2 – The Plasma Membrane
The Cell Membrane
Organelle/Membrane interactive
animation
Cell Membranes are
Selectively Permeable
and
are primarily made up of
phospholipids
Ch.7 – Cellular Structure and Function
7.2 – The Plasma Membrane
The Cell Membrane
Other Parts
Cholesterol
Makes the
lipid bi-layer
less fluid
Glycolipids &
Glycoproteins
Carbohydrates attached
to proteins or lipids and
used for cell recognition
(Antigens)
Proteins
Used to transport
molecules across the cell
membrane
(among other uses)
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
Cellular Transport
So, just how does stuff enter and exit cells?
H2O, CO2 and small ions freely cross the cell membrane
following the natural laws of diffusion
Molecules move from
areas of high
concentration to areas of
low concentration
This is called…
moving with or down the
concentration gradient
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
Water is special….
The diffusion of water, across a membrane, down
the concentration gradient is called
OSMOSIS
A simple rule of osmosis
is that
SOLUTES SUCK
Solutes, concentrated
inside or outside of the
cell, will draw the water
in that direction
7.4 – Cellular Transport
Ch.7 – Cellular Structure and Function
Hypertonic
Isotonic
Hypotonic
20%
10%
5%
10%
10%
10%
Ch.7 – Cellular Structure and Function
Hypertonic
7.4 – Cellular Transport
What will
happen to these
cells?
Hypotonic
Isotonic
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
The artificial cell is
permeable to water and
monosaccharides only
1. Draw this diagram
2. Draw a solid arrow to
indicate which direction
the solutes will move.
3. Is the solution Hyper-,
Hypo-, or Isotonic
Hypotonic
4. Draw a dashed arrow to show the movement of water
5. Will the artificial cell become more flaccid, turgid, or
stay the same? Turgid
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
Transport proteins allow
Facilitated Diffusion to occur
•They create a tunnel that
allows specific substances
to cross the bilayer down
the concentration gradient
•They are specific to one
substance
•They are used for large
molecules or to increase
the diffusion rate of
important substances
(water & glucose)
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
Passive Transport
Active Transport
Diffusion
Osmosis
Facilitated Diffusion
•Requires ENERGY
•Substances move
AGAINST the
concentration gradient
•Requires NO ENERGY
•Substances move
WITH the concentration
gradient
Protein Pumps
Endocytosis
Exocytosis
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
Protein Pumps
OUT
IN
Example: Sodium/Potassium Pump
Na/K pump animation
Carrier Proteins
that
use ATP
(energy) to
move
molecules into
or out of the
cell
against the
concentration
gradient
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
Endocytosis
Cells take in molecules by forming vesicles at the cell membrane
2 Types
Phagocytosis
The cell engulfs
solid material
Pinocytosis
The cell “gulps”
liquid material
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
Exocytosis
Cells excrete molecules by fusing vesicles to the cell membrane
Endo- / Exocytosis Animation
Ch.7 – Cellular Structure and Function
7.4 – Cellular Transport
Identify the following: 1. Protein Pump
2. Diffusion
3. Facilitated diffusion