Chap 1.4- Cell Membrane and Diffusion Prin.

Question 1

Fluid Mosaic Model of a cell membrane

Answer 1

Proposes that the membrane is a phospholipid bi-layer in which the proteins are either partially or entirely embedded like tiles in a mosaic picture.

Question 2

Cell Membrane

Answer 2

A Cell Membrane is what separates the inside of the cell from the “outside” environment. formed of 2 main components: lipids and proteins.

Question 3

Lipids (Amphipathic Phospholipids)

Answer 3

bi-layer of the membrane formed by:

• Hydrophilic heads (Water loving) these face the outside.
• Hydrophobic tails (Water hating) these face the inside hiding behind the heads. ex: Fatty acids, Cholesterol.

Question 4

Protein components inside the cell membrane

Answer 4

• Peripheral- (outside of the cell membrane) these can attach or remove themselves from the membrane.
• Integral- Inside the Cell membrane. Some have a channel that allows molecules through into the cell, or out of the cell.

Question 5

Selective Permeability 3 methods

Answer 5

allows only certain molecules to pass through the membrane.

• Diffusion (Passive Transport)
• Active Trasport
• Special methods

Question 6

Diffusion - Passive Transport

Answer 6

Small molecules move from an area of higher contraption on one side of the membrane to an area of lower concentration on the other side.
Does not Require ATP

Question 7

Concentration Gradient

Answer 7

difference in the concentration of a substance from one place to another.

Question 8

Active Transport

Answer 8

occurs when molecules or ions are pumped from an area of lower concentration to one of greater concentration (against the concentration gradient). Because the molecules do not naturally want to move in this direction, additional energy (ATP) is required.

Question 9

Special Methods

Answer 9

Endocytosis

Exocytosis

Question 10

Endocytosis

Answer 10

occurs when a biomacromolecule outside of the cell is enclosed in an invagination of the cell membrane, forming a vesicle inside the cell (endo- refers to “bringing in”). Endocytosis includes three specialized transportation methods: 1) phagocytosis, 2) pinocytosis, and 3) receptor-mediated endocytosis).

Question 11

Phagosytosis

Answer 11

Is endocytosis of extremely large objects, such as other cells. Once the cell is enclosed in a vesicle from the membrane, it fuses with lysosomes inside the cell and is digested.
(Phago) means- “To eat”

Question 12

Pinocytosis

Answer 12

is endocytosis of tiny droplets of fluids. This process is like phagocytosis except the cell membrane “pinches” inward without needing to extend pseudopods to ingest material.
(pino)- To drink

Question 13

Receptor Mediated Endocytosis

Answer 13

Whatever is not needed gets caught by “coated pits” and then they close up. then the “Coated pits (Clatherin)” detach and go back to the cell membrane.

Question 14

Exocytosis

Answer 14

Cells expel material into the extracellular space. Occurs when a biomacromolecule is enclosed inside the membrane of a vesicle (usually formed by breaking off the Golgi complex), which then fuses with the cell membrane (the vesicle), ejecting the biomacromolecule from the cell (exo- refers to “going out”).

Question 15

Osmosis

Answer 15

Diffusion of water

Question 16

Hypotonic Solution

Answer 16

more solutes (salt) inside the cell than the outside. Water will be able to move inside the cell to try to balance out but it can cause it to burst out because solutes are slower to get out.

Question 17

Isotonic

Answer 17

equal Solutes and water inside and outside, it will keep the cell balanced from the water

Question 18

Hypertonic Solution

Answer 18

More solutes (salts) found outside of the cell than inside. The water will move to the outside solutes because its easier for it to get our and the cell will shrink.

Question 19

Facilitated diffusion

Answer 19

• When the molecules (bigger ones) go through the channels found through the integral proteins. (Channel proteins)
• Carrier proteins: integral carrier protein specific for a certain molecule temporarily binds to the molecule and then releases it to the other side.

Question 20

Cellular Respiration

Answer 20

When cells use oxygen to make Carbon dioxide, water and ATP