Cell Movement and Transport How cells move and how they maintain homeostasis

Flagella Flagella are tail-like attachments of cells Found on bacterial cells, some protistan cells, sperm cells Allows certain cells to move through a liquid substance http://svj8dfc.edu.glogster.com/cytoskeleto n-cilia-flagella/ Flagella

Tiny hair-like projections of the cell membrane that allow cells to move or “sweep” debris away EX. Some protistan cells; the cells that line the respiratory tracts of animals http://rookc.pbworks.com/w/page/461975 20/Paramecium Cilia

Transport across the Membrane How does the cell maintain homeostasis?

Cell Membrane Controls what enters and leaves the cell. It is the #1 structure needed to maintain cell homeostasis. The primary component of the cell membrane are phospholipids; second in number are membrane proteins.

In a solution, there are two components: solute(s) and a solvent Solutes are the substances being dissolved in the solution (i.e. salt, sugar, etc.) Solvent is the substance the solutes are placed in to be dissolved. WATER!!! Solute vs. Solvent

Passive Transport DIFFUSION IS THE KEY WORD Requires no ATP (energy) Simple Diffusion: Molecules of a substance (NOT WATER) move from the area they are of higher concentration to an area of lower concentration DIRECTLY THROUGH the phospholipid bilayer. EX.GASES & LIPID SOLUBLE SUBSTANCES Passive Transport

Diffusion

FACILITATED DIFFUSION DOES NOT REQUIRE ENERGY!!! Small polar molecules (OTHER THAN WATER) cannot pass directly through the phospholipid bilayer They still move from an area of high concentration to an area of lower concentration, but need HELP from a transport PROTEIN Ex. GLUCOSE, AMINO ACIDS (WATER SOLUBLE SUBSTANCES) FACILITATED DIFFUSION

Facilitated Diffusion Facilitated diffusion requires a protein, but still DOES NOT require energy The molecules move from a high concentration to a low concentration Facilitated Diffusion

Osmosis DOES NOT REQUIRE ENERGY!!! The movement (diffusion) of WATER from an area of higher concentration to an area of lower concentration. ONLY WATER, NOTHING ELSE. Water, although polar, can pass DIRECTLY THROUGH the phospholipid bilayer. Osmosis

Isotonic: The concentration of the solute molecule in question is equal inside and outside the cell. Hypertonic: The concentration of the solute molecule is in higher concentration in the solution outside the cell. Hypotonic: The concentration of the solute molecule is in lower concentration on the solution outside the cell. Osmotic Solutions

When cells are placed into a hypertonic solution, water moves out of the cell, as it is in higher concentration inside the cell. The cell shrivels up. Hypertonic solutions REALLY SUCK!!! They suck water out of the cells placed in them. This is what happens when someone is dehydrated, and can be fatal if not corrected. Hypertonic Solutions

When cells are placed into a hypotonic solution, water moves into the cell, as its concentration is greater in the solution. The cell swells. Hypotonic solutions cause cells to swell up like a hippo! This happens to a certain extent every time you drink something. This, too, can prove fatal if you drink too much water. Yes, it’s possible and has lead to death. Hypotonic Solutions

http://internalandexternalenvironments2012. wikispaces http://internalandexternalenvironments2012.wikispaces.com/Hypertonic,+hypotonic+and+isotonic+effects+on+plants+and+animal+cells. Hyper, Hypo, and Isotonic Solutions

Active Transport Look for words that end in –cytosis or the word pump. REQUIRES ATP (ENERGY!!!) -cytosis: LARGE molecules are moving into or out of the cell through the creation of vesicles. Pump: Ions are being pumped AGAINST the concentration gradient through a membrane protein. (Na+/K+ Pump) The ion is moving from a lower concentration to a higher concentration. Active Transport

Pump mechanisms move ions from a low concentration to a higher concentration This requires energy (ATP) Pump Mechanism

Endocytosis: Large molecules are being transported via a vesicle INTO the cell. Ex. Phagocytosis: Cell eating. What some of your white blood cells do to bacterial cells. (Oh…Disgusting!!!) Exocytosis: Large molecules are leaving (EXITING) the cell through a vesicle. Ex. When a protein that has been made by the cell has to leave the cell from the Golgi Body to go to another area to carry out its function. -Cytosis Examples

Pictures of Exocytosis and Endocytosis http://legacy.owensboro.kctcs.edu/gcaplan/anat/notes/API% 20Notes%20E%20Membranes%20and%20Movement%20Acro ss%20Membranes.htm Endocytosis http://www.tutorvista.com/content/biology/biology- iii/biomembranes/biological-processes.php Pictures of Exocytosis and Endocytosis