Download Topic One: Cell Membrane - Red Hook Central Schools

Cells
And
Cellular Transport
Where does the name “cell” come
from?
• “Cells” were named by Englishman Robert
Hooke in 1665.
• He observed that cork wood looked like
monk’s cells in a monastery.
The Cell Theory
1. The cell is the basic unit of structure and function.
2. All organisms are made of one or more cells.
3. All cells come from pre-existing cells.
Exceptions to the Cell Theory
1. Viruses!! They have DNA and/or RNA inside a
protein shell. They are capable of reproduction
inside another living cell, but not on their own.
2. Mitochondria and chloroplasts have their own DNA
and can reproduce inside a cell.
3. Obviously….the first cell.
This is the human Herpes Virus!
Levels of Organization…Continued
Organs
Organ Systems
Organism
Types of Cells
Prokaryotic Cells Eukaryotic Cells
• The first and most
primitive cells
• Lack a nucleus and other
membrane bound
organelles (mitochondria,
etc)
• Bacteria are the ONLY
prokaryotes
• Most organisms have
eukaryotic cells (ex: all
plant and animal cells!)
• All genetic material is
contained in a nucleus
• Have many membrane
bound organelles
1.
13.
12.
2.
11.
3.
4.
10.
5.
9.
6.
7.
8.
14.
1.
2.
Lysosome
13.
3.
4.
12.
5.
11.
6.
10.
7.
8.
9.
Cell Organelle Functions
Cell Membrane: provides a barrier between the cell
and the environment.
Vacuole: stores water, minerals and sometimes
food.
Lysosome: a sac of digestive juices (acts like a
stomach).
Mitochondria: where cellular respiration takes
place, our energy comes from here!
Golgi Bodies: “packages” cell material, wraps a
membrane around protiens and materials made in
the cells.
Cell Organelle Functions
Centrioles: (ONLY in animal cells) help the cell
undergo cellular division, or mitosis.
Cytoplasm: jelly like material that fills in the extra
space in a cell, also where most of our chemical
rxns occur.
Ribosomes: site of protein production.
Endoplasmic Reticulum (ER): Transports materials
around the cell.
Nuclear Membrane: separates the nucleus from the
rest of the cell.
Cell Organelle Functions
Nucleolus: dense part of a nucleus, where RNA is
made.
Nucleus: stores DNA, controls most cellular
activities.
Cell Wall: rigid structure around the outside of
plant cells to give them structure and support.
Chloroplast: site of photosynthesis, makes sugar
molecules using sunlight, water and carbon
dioxide.
The Cell Membrane
A barrier that separates a cell from its surroundings.
Also called:
The Lipid Bi-Layer, Fluid Mosaic Model,
And
The Plasma Membrane
Cell membranes are “semi-permeable”
because they allow some molecules to pass
through, while others cannot.
Components of the Cell Membrane
MOVIE
Just the lipids!
Membrane Facts!
The lipid bilayer consists of two (bi) layers
of phospholipids.
The ____________
hydrophilic heads point to the
outside and the ____________
hydrophobic tails point to
the inside of the membrane.
Various _________
proteins molecules are
embedded in the membrane as well
Cell Membrane Cross Section
This is one of many
kinds on proteins
embedded in the
membrane.
This is the Lipid
Bilayer. Why
does this name
fit?
Membrane Proteins
Marker Proteins: They are like a “name tag”
for the cell.
Membrane Proteins
Continued…
Channel Proteins: These proteins
reach through the membrane to both sides.
It allows specific molecules to pass from
one side of the membrane to the other.
Transport Proteins: Proteins that
physically move molecules across the
membrane. There are a variety of types!
YouTube - Cell membrane animation
Cellular Transport
Cellular Transport
• Passive Transport does
NOT require cellular
energy (ATP)
• Moves molecules from
high to low concentration
• Active Transport DOES
require ATP
Diffusion
The movement of molecules from an area of HIGH
concentration to an area of LOW concentration.
The direction of diffusion is called the concentration
gradient.
This is a form of passive transport.
_________
LARGE molecules CANNOT diffuse, regardless of
concentration gradient!
What types of molecules can NOT diffuse??
Even though all
molecules seem small to
us, they do vary in size a
lot!
Large molecules can
NOT cross the cell
membrane!
Large molecules must
rely on active transport.
Cellular Transport
• Passive Transport does • Active Transport
NOT require cellular
DOES require ATP
energy (ATP)
• Moves molecules from
high to low
concentration
Examples:
• Diffusion
Osmosis
Osmosis is a special
name for the diffusion
WATER across a
of ________
semi-permeable
membrane.
Because this requires
NO ATP, it is called
Passive transport
_____________.
Water always moves from
low to high SOLUTE
concentration.
This is osmosis!
•If a cell is placed in a
solution with a LOWER
concentration of solute, it
will _________
swell (water
enter
will _________
the cell)
•If a cell is placed in a
solution with a HIGHER
concentration of solute, it
will _________
shrivel (water
will _________
the cell)
leave
Cellular Transport
• Passive Transport does • Active Transport
NOT require cellular
DOES require ATP
engery (ATP)
• Moves molecules from
high to low
concentration
Examples:
• Diffusion
• Osmosis
Phagocytosis
This is “cell eating”. A cell engulfs (or wraps itself around)
a food particle thus creating a food vacuole.
This is a type of ACTIVE TRANSPORT!
Clip
Cellular Transport
• Passive Transport does • Active Transport
NOT require cellular
DOES require ATP
engery (ATP)
Examples:
• Moves molecules from • Phagocytosis
high to low
concentration
Examples:
• Diffusion
• Osmosis
Pinocytosis
This is “cell drinking”. The cell membrane pinches inward
(like a pin poking a hole) and creates a vacuole of dissolved
particles.
This is a type of ACTIVE TRANSPORT!
Clip
Cellular Transport
• Passive Transport does
NOT require cellular
engery (ATP)
• Moves molecules from
high to low
concentration
Examples:
• Diffusion
• Osmosis
• Active Transport
DOES require ATP
Examples:
• Phagocytosis
• Pinocytosis
Membrane Proteins Using Cellular Energy: The
proteins we learned about in the membrane
sometimes require energy!
Cellular Transport
• Passive Transport does
NOT require cellular
energy (ATP)
Examples:
• Diffusion
• Facilitated Diffusion
• Osmosis
• Active Transport
DOES require ATP
Examples:
• Phagocytosis
• Pinocytosis
• Use of membrane
proteins (ex: transport
proteins)
Moving Molecules Against the
Concentration Gradient
•The sodium ions are more highly concentrated on the inside of
the cell.
•With the help of ATP, the sodium ions are still pumped back
into the cell (against the concentration gradient).
Cellular Transport
• Passive Transport does
NOT require cellular
energy ATP)
Examples:
• Diffusion
• Facilitated Diffusion
• Osmosis
• Active Transport DOES
require ATP
Examples:
• Phagocytosis
• Pinocytosis
• Use of membrane proteins
(carrier proteins, etc)
• Moving molecules from
low to high concentration