Transcript Bulk Transport

Robert Hooke - 1665
Antonie von Leeuwenhoek -1675
Matthias Schleiden
Theodor Schwann
Rudolf Virchow
1.
Living things are made up of cells.
2.
The cell is the basic unit of life.
3.
All cells come from pre-existing cells by division.
4.
Cells contain DNA which is passed from cell to cell during cell division.
5.
All cells are basically the same in chemical composition.
6.
All energy flow (metabolism & biochemistry) of life occurs within cells.
Crossing the Membrane
•CO2
•O2
•Small molecules
Small molecules that can cross CM
freely.
Diffusion
• Concentration gradient – different between
concentration of one molecule in one area vs.
another.
• Diffusion occurs down a concentration
gradient.
Osmosis
• In cells, osmosis is the diffusion of water
across a cell membrane.
Turgor Pressure vs. Plasmolysis
Turgor Pressure vs. Plasmolysis
Facilitated diffusion
• Passive Transport
• No energy required
• Occurs “down” the concentration gradient
• Diffusion & Osmosis are examples of passive
transport
• Facilitated diffusion makes use of carrier
proteins
Active Transport
•
•
•
•
Moving against the concentration gradient
Going from low concentration to high
Energy is needed to transport molecules.
Involves carrier proteins
Bulk Transport
• Many macromolecules are too large to be
transported by carrier proteins.
• They are transported in or out of the cell by
means of vesicle formation