Transcript Chapter 3, Section 1

Section 3-3, 3-4, 3-5
“Movement
across the cell
membrane”
Write everything that is
underlined
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
3.3 KEY CONCEPT: The cell membrane is a
barrier that separates a cell from the
external environment.
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
Cell membranes are composed of two
phospholipid layers.
•
•
It forms a boundary between inside and
outside of the cell
…and controls passage of materials
cell membrane
inside cell
outside cell
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
•
•
•
The cell membrane is made of a phospholipid
bilayer.
There are other molecules embedded in the
membrane.
The fluid mosaic model describes the
membrane.
cell membrane
carbohydrate
chain
cholesterol
protein
protein channel
protein
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
How many layers is the cell membrane made
up of?
a.
b.
c.
d.
1
2
3
4
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
•
The cell membrane is selectively
permeable (only certain things get
through) like a screen door
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
3.4 KEY CONCEPT: Materials
move across membranes
because of concentration
differences.
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
Passive transport does not
require energy
• There are two
types of passive
transport:
1.diffusion
2.osmosis
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
1.Diffusion: Molecules
move down a
concentration gradient
• “From an area of high
concentration to low
concentration”
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
•Osmosis is the diffusion of water
• There are three types of solutions:
isotonic, hypertonic, hypotonic
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
What is passive transport?
a.
b.
c.
d.
Does not require energy to move materials
Requires energy to move materials
Depends on your definition of movement
Only sometimes does it use energy
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
What is/are the different types of passive
transport?
a.
b.
c.
d.
Diffusion
Isotonic
Osmosis
A and C
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
Diffusion is the movement of materials from an area of
___________ concentration to ______ concentration
a.
b.
c.
d.
Low to High
High to High
Low to Low
High to Low
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
Osmosis it the diffusion of ___________
a.
b.
c.
d.
Materials
Sugar
Water
Amino acids
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
Some molecules can only diffuse
through transport proteins.
•Facilitated diffusion:
diffusion through transport
proteins
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
3.5 KEY CONCEPT: Cells use energy
to transport materials that cannot
diffuse across a membrane.
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
Active transport requires energy to
move a substance against its
concentration gradient (from LOW to
HIGH)
• Passive transport requires no energy
from the cell
• Active transport is
powered by chemical
energy (ATP)
• Cells use active transport
to maintain homeostasis
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
A cell can import and
export large materials or
large amounts of material
in vesicles during the
processes of endocytosis
and exocytosis.
• Endocytosis is the
process of taking
material into the cell
– also called
Phagocytosis
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
•Exocytosis is the process of
expelling (pushing out)
material from the cell
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
What is the difference between active transport
and passive transport?
a. Active requires energy and passive does not
b. Passive requires energy and active does not
c. Passive moves big materials into the cell and active
does not
d. B and C
3.3 Cell Membrane / 3.4 Diffusion / 3.5 Transport
What does the following picture
show?
a.
b.
c.
d.
Endocytosis
Exocytosis
Diffusion
Osmosis