![Page 1: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/1.jpg)
Homeostasis and Transport
Movement of cellular materials in and out of the cell.
![Page 2: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/2.jpg)
Cell membranes help cells maintain homeostasis by controlling what substances may enter or leave cells.
![Page 3: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/3.jpg)
Cell membranes are selectively-permeable in that they allow only certain substances to pass.
![Page 4: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/4.jpg)
I - Passive Transport
• No energy input from the cell..
No ATP energy molecules used.
![Page 5: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/5.jpg)
Simplest type of Passive Transport: (simple) Diffusion
It is the (random) movement of molecules from an area of higher concentration to an area of lower concentration.
![Page 6: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/6.jpg)
In other words…
• Materials move from where there’s more to where there’s less.
![Page 7: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/7.jpg)
This difference in concentration of molecules (over a given area)is called the concentration gradient
Diffusion movement occurs with, (or down) the concentration gradient.
![Page 8: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/8.jpg)
Diffusion is driven by the kinetic energy of the molecules.
![Page 9: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/9.jpg)
Kinetic Energy – Energy of Movement
from an area oflow tohigh
concentration
![Page 10: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/10.jpg)
• Eventually the process of diffusion reaches equilibrium.
• At equilibrium the concentration of molecules are the same throughout the space. (The concentration gradient disappears)
![Page 11: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/11.jpg)
Are the molecules still moving at this point (equilibrium)?
• Yes. Molecules of a substance are always in motion to some degree except at absolute zero.
The net movement is zero.
![Page 12: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/12.jpg)
![Page 13: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/13.jpg)
Osmosis The process by which H2O molecules
diffuse across a cell membrane (selectively permeable membrane) from an area of HIGH concentration to LOW concentration.
![Page 14: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/14.jpg)
The net direction of water movement depends on the relative amount of solutes (dissolved substances) on the two sides of the cell membrane.
![Page 15: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/15.jpg)
THE THREE BASIC TYPES OF SOLUTIONS:
• Hypotonic
• Hypertonic
• Isotonic
![Page 16: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/16.jpg)
Hypotonic
• solute concentration outside the cell is lower than inside the cell cytosol.
• water diffuses into the cell
![Page 17: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/17.jpg)
Hypertonic
• solute concentration outside the cell is higher than inside the cell cytosol.
• water diffuses out of the cell
![Page 18: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/18.jpg)
Isotonic
• solute concentration outside and inside the cell are equal thus, NO net movement of water into or out of the cell
![Page 19: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/19.jpg)
How do cells deal with osmosis?
• Isotonic – usually no difficulties
interesting chromosomepattern makes thiscell have a happy
face
![Page 20: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/20.jpg)
Hypotonic environment• Unicellular freshwater organisms rid themselves
of excess water by an organelle called a contractile vacuole. (Other cells cannot get rid of the water and they may burst)
![Page 21: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/21.jpg)
What happens to ananimal cell under
different conditions?
![Page 22: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/22.jpg)
![Page 23: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/23.jpg)
What happens to aplant cell under
different conditions?
![Page 24: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/24.jpg)
![Page 25: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/25.jpg)
Facilitated Diffusion It is a type of passive transport in
which molecules pass through pores in the cell membrane. Carrier proteins help move molecules across the membrane.
![Page 26: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/26.jpg)
II - ACTIVE TRANSPORT
Cell expend energy to move materials.
Active transport always needs ATP energy molecules
![Page 27: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/27.jpg)
Active Transport is usually against the concentration gradient.
Materials move from low to high concentration.
![Page 28: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/28.jpg)
EXAMPLES OF ACTIVE TRANSPORT
• Cell Membrane Pumps (such as the Sodium-Potassium pump) It involves Carrier proteins
Sodium-Potassium Pump is important for nerve cells.
![Page 29: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/29.jpg)
• Endocytosis - cells take in fluids, large molecules, large particles and other cells.
Vesicles are formed to ingest materials.
![Page 30: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/30.jpg)
Two major types of endocytosis: • pinocytosis – movement of solutes or fluids
(Cell-drinking)
![Page 31: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/31.jpg)
• phagocytosis – movement of large particles or whole cells. (cell-eating)
Amoeba uses pseudopodia to engulf food.
![Page 32: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/32.jpg)
Exocytosis (the reverse of endocytosis)
• Vesicles fuse with the cell membrane, releasing their contents to the outside environment.
![Page 33: Homeostasis and Transport Movement of cellular materials in and out of the cell](https://reader030.vdocument.in/reader030/viewer/2022032721/56649cd85503460f949a129f/html5/thumbnails/33.jpg)
• Unicellular organisms may get rid of wastes through exocytosis.