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Cellular Transport
Chapter 8
The detailed structure of an animal cell’s plasma membrane
The fluidity of membranes
Some functions of membrane proteins
Cells move substances through the cell membrane by
a process called transport
• Two Types of Transport:
–Passive Transport
–Active Transport
What is Diffusion or Passive Transport?
• Requires no energy from cell.
• Molecules move from high concentration to low concentration.
• Molecules move with the concentration gradient.
The diffusion of solutes across membranes
What’s happening?
How would diffusion happen in a cell?
How would diffusion happen in a cell?
How would diffusion happen in a cell?
How would diffusion happen in a cell?
How would diffusion happen in a cell?
How would diffusion happen in a cell?
How would diffusion happen in a cell?
How would diffusion happen in a cell?
Osmosis is a type of diffusion
Cell Membrane
Osmosis is a type of diffusion
Cell Membrane
Osmosis is a type of diffusion
Cell Membrane
Osmosis is a type of diffusion
Cell Membrane
Osmosis is a type of diffusion
Cell Membrane
Osmosis is a type of diffusion
Cell Membrane
Osmosis is a type of diffusion
Cell Membrane
Osmosis is a type of diffusion
Cell Membrane
Osmosis
HELP WANTED!Facilitated Diffusion
tranport proteins help substances (glucose) pass through the cell membrane. Still passive transport - no energy required.
I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
HELP WANTED! I’m a Channel, I can help!
Two models for facilitated diffusion
Water balance of cells without walls:
100% Distilled Water
80% H2O
70% Water30% Dissolved
Substances
80% H2O
80% Water20% Dissolved
Substances
80% H2O
Which way did the water move?
100% Distilled Water
80% H2O
Why did the cell get so big?
Which way did the water move?
80% Water20% Dissolved
Substances
80% H2O
Why did the cell stay the same
size?
Which way did the water move?
70% Water30% Dissolved
Substances
80% H2O
Why did the cell get so small?
The water balance of living cells
The contractile vacuole of Paramecium: an evolutionary adaptation for osmoregulation
REVIEW1. What part of the cell regulates what
goes in and out?2. What are the two components of
the cell membrane?3. What are the two types of
transport?4. What are the characteristics of
passive transport?
MORE REVIEW
1. Explain diffusion. Why does it occur?
2. Explain osmosis. Why does it occur?
3. Explain facilitated diffusion.
4. What is the role of the transport protein in facilitated diffusion?
Even MORE Review!
1. What happens to an animal cell when there are more dissolved substances on the outside of the cell?
2. The inside?3. When there are equal
amounts?
How is Active Transport different?
1. Active transport requires energy.
2. Molecules move from low concentration to high concentration
3. Molecules move against concentration gradient.
Review: passive and active transport compared
The sodium-potassium pumpActive Transport
An electrogenic pump
Cotransport
Endocytosis• Cells bring large in particles using
cell membrane
– There are 2 types:• Phagocytosis
• Pinocytosis
Phagocytosis
• This is the ingestion of large particles.• Your white bloods cells also do this.
Amoeba
Pinocytosis
• Tiny pockets form along cell membrane, and pinch off into vacuoles inside the cell. Sometimes called “Cell Drinking”
Exocytosis
• This is how the cell gets rid of waste.
The three types of endocytosis in animal cells
REVIEW1. How is Active transport different
from passive?2. What part of the cell is used to bring
in particles?3. How does a cell (including white
blood cells) take in LARGE particles?
4. How does a cell take in small or liquid particles?
