ap bio unit 2: cell structure function

what does larger surface area entail?

more efficient resource exchange

purpose of membrane-bound organelles in eukaryotes (compartmentalization)

to increase surface area (e.g. mitochondria double membrane)

nucleus

stores genetic info in eukaryotes

nucleolus

produces/assembles ribosomes

endoplasmic reticulum (ER)

structure connected to nuclear membrane

smooth ER

produces lipids

rough ER

covered with ribosomes used to make proteins

golgi apparatus

helps process and package things, especially proteins to be exported

• appears as a series of stacked membranes near cell membrane

• think ____ = fat = bouncer

lysosomes

contains digestive enzymes, destroys viruses, break down excess or worn out cell parts, carries out apoptosis (____ = clean)

vacuole

contains fluid/food, there is a huge one in plant cells

mitochondria

powerhouse of cell

cristae

folds on mitochondria inner membrane that inc. SA

cell wall

rigid, semipermeable barrier for plant cells and some bacteria (cellulose)

chloroplasts

have green pigment that absorbs sunlight in photosynthesis

chlorophyll

green pigment in chloroplast

chromoplast

have colorful pigments, found in flowers and fruit

plastid

chloroplast, chromoplasts, and leucoplasts (plant organelles containing pigment or food)

• differing pigments = differing light absorption frequencies

carotenoids

colorful (red, orange, yellow) pigments in chromoplasts

leucoplast

has no pigment, is used to store starch

apoplastic pathways

go thru cell wall (comms)

sympoplastic pathways

go thru cytoplasm (comms)

stem cells

can turn into a lot of different specialized cells

phospholipid components

hydrophilic glycerol+phosphate head, hydrophobic fatty acid tails

fluid mosaic model

the membrane is like a jelly soup of phospholipids, proteins, and cholesterol, and carbohydrates that kind of float near each other

glycolipids

carb chains that stick out of the membrane, allowing for cell to cell comms

cholesterol purpose

modulates fluidity with changing temperature (fixes excess rigidity or fluidity)

receptor protein

sticks out of membrane w/ tentacles (e.g GPCR) so it can recognize things

adhesion protein

sticks out of membrane with a hook that allows it to stick to other cells

passive transport/simple diffusion

no energy needed, goes down gradient without help until dynamic equilibrium is reached

facilitated diffusion

passive transport but with a channel protein

active transport

pumps against conc. gradient

channel protein

lets charged or big substances through membrane through facilitated diffusion

carrier protein

gated diffusion of materials (passive and active transport depending on the situation)

Na+ and K+ pump steps

1. na+ and atp bind to pump

2. atp hydrolysis (atp → adp + phosphorylated protein) changes pump conformation

3. shape change discharges na+ and k+ can bind to pump

4. phosphorylated protein from 2 is released and k+ can go into cell against k+ conc. gradient

recognition protein

immune system, recognizes diseased cell

primary active transport

requires atp and active transport creates a membrane potential

secondary active transport

uses electrochemical gradient as energy source as atp

• when two ions have opposite gradients, one is transported passively, which provides the voltage for the active transport of the other

uniporter

allows one molecules through membrane (either passive or active)

cotransporter

allow two mcules through membrane at same time (secondary active transport with a nonpolar solute and ion)

symporter

cotransporter where both are in same dir

antiporter

cotransporter where both are in opp dir

where does water move toward?

high solute conc. (low solvent conc.)

hypertonic

surroundings are more conc. w solute

plasmolysis

when plant cells shrivel in hypertonic solution

hypotonic

surroundings are less conc. w/ solute

isotonic

surroundings are same solute conc

aquaporin

protein channel for water

plasmodesmata

narrow channels between cell walls of neighboring plant cells

stomata

openings in plant cells for co2 and h2o regulation (opens when there is light)

water potential

describes the potential energy of water, moves from high potential to low potential (measured in kPa)

water potential = pressure potential + solute pot

pressure potential

the pressure a closed container exerts on its contents, 0 for open container, usually +

solute potential

measures solute content, always 0 for pure water, adding solute lowers solute pot, always (-)

solute pot = iCRT

i = ionization const.

R = gas cons.t

T = temp (K)

C = conc. (M)

phagocytosis

intake of big mcules (eating)

pinocytosis

small mcules suspended in fluid (drinking)

receptor mediated transport

regulated entry of mcules (messaging)