Bio H - Cell Transport

Phospholipid heads

• Polar and hydrophilic

• Made from GLYCEROL and PHOSPHATE functional groups

Phospholipid tails

• NONPOLAR and hydrophobic

• 1 saturated and 1 monounsaturated fatty acids

Amphipathic molecule

molecule with both hydrophilic and hydrophobic ends

Phospholipid bilayer

• tails face in

• heads face out

Selectively permeable

filters molecules from passing through (needs to be small enough)

Fluid mosaic

many different molecules free-float in the membrane

Cholesterol (in mem)

strengthens the flexible membrane

Carbs (in mem)

helps with cellular identification (marking cells)

Glycoproteins

membrane proteins with CARBS attached

Glycolipids

phospholipid with a CARB attached by a GLYCOSIDIC bond

Receptor proteins

protein that detects a signal molecule and performs an action in respond

Channel proteins

channel for specific proteins to pass through freely

Aquaporins

channel proteins allowing WATER to pass freely

Ion-gated protein

chanels that open/close in response to a stimuli

Carrier proteins

Proteins that grab molecules/ions to carry them to the other side of the membrane

Surface area of membrane

SA determines the RATE of which materials can pass IN/OUT cell; HIGH SA GOOD

Volume of cell

determines RATE of which material move WITHIN the cell; HIGH VOLUME BAD

Concentration gradient

difference in around of molecules across a space (unbalanced 2 sides)

Down concentration gradient

molecules move from HIGH to LOW concentration

Equilibrium

equal concentration throughout solution

Passive transport

• movement of molecules NOT REQUIRING energy

• moves molecules DOWN gradient

Diffusion

movement of molecules from HIGH to LOW concentration

Causes for molecular movement

• Heat energy (higher heat, higher rate of diffusion)

• Collision

Faciliated diffusion

molecules move passively thru membrane with a protein

Osmosis

diffusion of WATER across a semipermeable membrane

Isotonic

same (happy spot)

Hypotonic

swell (HIPPO)

hypertonic

shrink (small hyper dog)

Tonicity

measure of osmotic pressure gradient (water pressure moving in/out)

flaccid

isotonic for plants

crenated

hypertonic for animal cells

plasmolysis

plant hypertonic: membrane pulls away from cell wall, plant wilts

Cytolysis

animal hypotonic cell bursts because of osmotic pressure

Turgot pressure

plant hypotonic; cell membranepushed against cell wall; HOMESTASIS

Active transport

movement of molecules REQUIRING ENERGY

ATP (adenosine Triphosphate)

powers nearly all cellular work

Phosphorylation

transfers a phosphate group from ATP to another molecule because of hydrolysis

Creates ADP (adenosine diphosphate)

Sodium potassium pump

use ATP phosphorylation to pump Na+ and K+ ions across membrane; build electrical current for nerves

Exocytosis

large molecules are RELEASED from cell via vesicle

Endocytosis

large molecules moved INTO cell forming a vesicle

Phagocytosis

“cell eating”; type of endocytosis

Pinocytosis

“cell drinking”; type of endocytosis