What is the cell theory?

states that all organisms are made of cells and that all cells come from other cells

What are the 2 main compartments of the cell?

cytoplasmic compartment and nuclear compartment

Describe the structure, components, functions and characteristics of the plasma membrane

a. is a barrier,boundary, of a cell

b. is selctive and semipermeable

    i.  hydrophobic core is selective against particles that arelarge/charged

       and do not allow them to cross in/out of cell without the help

       of a carrier/channel

c. is a bilayer of phospholipids-2 hydrophilic surfaces(heads) and 2 hydrophobic cores(hydrocarbon tails)

d. composed of :

phospholipids-have a phosphoric hydrophilic head and 2 hydrocarbon tails. cholesterol- lipid that helps form rafts in the membrane and control amt of space between phospholipids and thus how much the phospholipids components can drift

proteins-

glycocalyx- sugar coating of the surface of the cell; used as signaling molecules

What are the functions of the proteins in the plasma membrane?

1. channels allow charged/large particles to pass through the membrane

2.carriers change shape to transport particles across the membrane

3.signaling molecules- for communication with other cells

4.receptors- for binding and signaling molecules

5.cellular junctions- connect neighboring cells

6. enzymes- catalyze reactions on the internal/external surface of the cell

7.recognition- for the immune system to recognize the cell as "self"

What is the fluid-mosaic theory?

fluid=able to move

mosaic= made of many things

the membrane is made of many things and those parts are able to change their position along the membrane

"to fully occupy"

if all the recpetors present are currently full, they are saturated

ligand receptor-when the ligand binds to the receptor, the gate opens

G-protein receptors- attached to receptor protein.When a signal binds to the receptor the G protein is released and shifts in the membrane to activate another component in the membrane(such as an enzyme or channel)

enzyme receptors- some enzymes in the plasma membrane have receptors and are tuned on/off by a signal molecule. The is one way for the body to control when substrate is made by the enzyme

integrin receptors- attached to the cytoskeleton of the cell. When a signal molecule binds it triggers a change in the cytoskeleton

tight junction-"button" type proteins between cells that "seal the gap" so that particles cannot pass between cells

desmosomes-"anchoring" protiens that hold neighboring cells tightly together. Important for cells that are under pressure(heart)

gap junctions-"tunnel" like protiens that allow molecules to pass directly from the inside of one cell to the inside of the neighboring cell

simple diffusion- no energy or channel is needed. Particle can diffuse across the membrane of its own accord without help.(very small particles with no charge)

facilitative diffusion-a channel or carrier is needed for the partivle to cross the membrane, but energy does not need to be applied

active diffusion- both a carrier and energy are needed to transport the particle across the membrane

hypotonic- concentration of solute in the solution is LESS than the concentration of solution inside a cell. This will cause water to flow into the cell to dilute the solute

hypertonic-concentration of solute in the solution is GREATER than the concentration of solute inside the cell. This will cause water to move out of the cell to dilute the solute

isotonic-the concentration of solute is equal in solution and in the cell. Water still moves. Just has no NET movement- for every one that goes into the cell, one will come out and vice versa

both use energy and a carrier to transport a substance across a membrane against its concentration gradient. 

primary-a substance loads into a carrier. Energy from binding a phosphate from ATP to the carrier is used to change the carrier's position and then the substance is released to the other side of the membrane.  The bond from the phosphate can be broken to once again provide energy to the carrier to face it to the original position(can bring another molecule with it).

secondary- a carrier uses energy from the bonding phosphate  from ATP to transport a molecule actoss the membrane against its conc. grad. to make it so that the molecule is available bind to another carrier loaded with a second substance and cause that carrier to change position and transport them across the membrane. So the 2nd substanceis transported at the esspense of the energy used to move the first across the membrane.

vesicular transport- moving a substance into/out of/within the cell with the use of a vesicle.

cells use it for moving substances from one place to the next within the cell (such as from rough ER to Golgi), or for taking substances into the cytoplasm or out into the ECF.

2 main types are endocytosis (taking in) and exocytosis (releasing out).

endocytosis- the plasma membrane envelops the substance outside the cell and pinches off from the membrane and now you have a vesicle in the cytoplasm with substance in it. PINOCYTOSIS= endocytosis of fluids, PHAGOCYTOSIS= endocytosis of a solid

exocytosis- vesicle within the cell docks with the plasma membrane and releases the substance to the ECF.

a.rough ER-used for protein synthesis. It's continuous with the membrane of the nucleusat its pores

b.smooth ER- used for lipid synthesis and detoxification of some substances

c.golgi apparatus- receives vesicles containing the protein made by the rough ER. Will modify these proteins by adding sugars to them if needed, then put them back into vesicles to be transported to another area of the cell, or to the plasme membrane for exocytosis

d.lysosomes- contain acids or substances like peroxides to break down cellular debris or substances that were endocytosed and need to be destroyed

this is when a cell takes in substances via channels or carriers in its membranes, then releases them from the other end of the cell. Can be facilitative, simple, or active processes.

ex:cells in the mucosa of the gut-nutrient molecules are taken in the apical surface facing the lumen, then released from the other side of the cell toward the blood supply

a.microtubles- tubulin protein that can form chains. Used for intracellular movements (they are used to move chromosomes during mitosis)

b.microfilaments- include actin and are used to constrict or contract a cell, such as the pinching motion when a cell divides

c.intermediate filaments- these provide structural support of a cell internally, like support beams of a building