AP BIO— Unit 2

Ch. 6, Ch. 7, Ch. 36

cell theory

• all living matter is composed of one or more cells

• the cell is the structural and functional unit of life

• all cells come from other cells

prokaryotic

no nucleus

eukaryotic

nucleus

why are cells small?

• favorable SA:V ratio (like in lab)

• metabolic requirements

what’s not in a animal cell?

• chloroplast

• central vacuole

• cell wall

whats not in a plant cell?

• lysosomes

• centrioles

what is the cytoplasm?

in between the cell membrane and nucleus, the “fluid part” of the cell

what is the nuclear membrane?

its a double membrane that surrounds the nucleus

what is the inner part of the nuclear membrane made of?

a protein matrix— gives the nucleus its shape

what are nuclear pores?

holes through both nuclear membranes, allows things to go in and out of the nucleus

what is the nucleolus?

its the place where DNA is stored in the nucleus, the park that is the dark color

what is chromatin?

chrom = colored

tin = threads

the thing that helps to form chromosomes in cells

what does the nucleus do?

store genetic info, control center of cell

what are ribosomes?

made of protein and rRNA

no membrane

does protein synthesis

where are ribosomes?

chilling in cytoplasm (making protein for cytosol) OR membrane-bound (they make protein and smth else ships it away)

whats the endomembrane system?

membranes connected through touching each other OR through the transfer of segments through vesicles

cells are an endomembrane system?

whats the endoplasmic reticulum?

makes up half of the cells

often continuous with the nucleus membrane

there is smooth ER and rough ER

smooth ER

no ribosomes

creates lipids (lipid synthesis)

stores carbs

detoxification of poisons

rough ER

has ribosomes

makes (secretory) proteins

what does the gogli apparatus look like?

stack of pita bread (made of cisternae)

cis face of golgi…

receives

trans side of golgi…

ships

what does the golgi do?

processes (modifies ER products)

ships (packages and sends ER products)

what are lysosomes?

single membrane

made from golgi

breaks down cellular material with enzymes (important in cell death)

vacuole structure

single membrane

bigger than golgi

what are the types of protists vacuoles?

contractile, food, plant central

contractile vacuoles function

pump out water

food vacuole function

store ingested food until lysosomes digest it

plant central vacuole

very large single vacuole (90% of the plant cell) and stores water/other ions and pigments

mitochondria structure

2 membranes— inner has more surface area than outer

mitochondria function

cell respiration: the release fo energy from food

ATP generation

powerhouse of the cell

chloroplast structure

2 outer membranes

complex internal membrane

fluid-like stroma found in inner membrane

contains the green pigment in chlorophyll

chloroplast function

photosynthesis

endosymbiont theory

eukaryotes are prokaryotes and they become dependent on each other —> evolved into a single organism

byproduct of the eating was mitochondria and chloroplast

peroxisomes

single membrane

break down peroxides

sometimes break down alcohols or fatty acids

who has a cell wall?

plants, prokaryotes, fungi, some protists

what makes up the cytoskeleton?

microtubules, microfilaments, intermediate filaments

what are microtubules?

thickest of the three

made of hollow rods tubulin

can grow or shrink

what are microtubules main job?

movement

it also helps to move chromosomes in cell division (makes up spindle)

what assists tubulin in movement?

dynien

how do microtubules move things?

Cilia and Flagella

what is cilia?

small things that cover like the entire cell and aid in movement

what is flagella?

long thing that helps the cell move, usually only a few

what are microfilaments?

thinnest of the three

made of intertwined actin

can grow or shrink

what are microfilaments main job?

tension

in what ways do microfilaments utilize tension?

support cell shape

cleavage furrow

muscle contractions (aided by myosin)

what is the cleavage furrow?

the in between state of cell division

what are intermediate filaments?

intermediate in size

supercoiled

very sturdy

what is the extracellular matrix (ECM)?

meshwork of things outside animal cells

outside cell membrane

what does the ECM do?

varies from cell to cell but it:

holds cells together

contributes to cell behavior and communication

helps coordination of tissues

what is the cell junction in plant cells?

plasmodesmata

what is the plasmodesmata?

a channel between plant cell walls

joins internal environments

allows the movement of water and other small solutes

what are the cell junctions in animal cells?

gap junctions, desmosomes, tight junctions

what are gap junctions

a channel between animal cell walls

joins internal environments

allows the movement of water and other small solutes

what are desmosomes?

coordinate movement by connecting intermediate filaments of two cells

what are tight junctions?

fuse adjacent cell membranes (like a pinch)

seal the space between cells

prevents leakage

what does amphipathic mean?

has hydrophobic and hydrophilic part

what model does the cell membrane take?

fluid mosaic model

what is the fluid mosaic model?

means that cell membrane is fluid and has a mosaic of proteins

what are the types of movement on the cell membrane?

lateral (very common)

flip-flopping (uncommon)

what does cholesterol do in the cell membrane?

acts as a buffer, usually helps to saturate the membrane but at cold temps it keeps them spread apart

when the cell membrane is unsaturated it is…

fluid

when the cell membrane is saturated it is…

viscous

cholesterol is a…

steroid

the cell membrane is…

selectively permeable

what types of things can make it through the cell membrane?

small non-polar things, for example:

hydrocarbons or CO2/O2

isotonic

same amount of concentration

hypotonic

lower concentration

hypertonic

higher concentration

moving with the concentration gradient is the equivalent of moving…

from high —> low concentration

what is osmosis?

the passive diffusion of water across the membrane

lysed

too much water enters, bursts

shriveled

too much water exits, shrivels

flaccid cell

weak cell

plasmolyzed cell

very very weak cell

what is osmoregulation? is it found in all cells?

pumps built into some cells that help regulate water concentration

what are transport proteins?

allow for polar molecules to pass through the membrane

what are the types of transport proteins?

Channel and Carrier

what is the transport protein specific to water?

aquaporis or smth like that

are channel proteins active or passive?

passive

are carrier proteins active or passive?

both; active when going against the gradient, passive when flowing with the gradient

what is cotransport?

when you couple the downhill diffusion of one substance with the uphill diffusion of another

what are the types of bulk transport?

endocytosis and exocytosis

what is exocytosis?

the exiting of a substance from a cell

what is exocytosis?

the engulfing of a substance to the cell

what are the types of endocytosis?

Phagocytosis, Pinocytosis, receptor-mediated

what is phagocytosis?

the engulfing of large food particles

what is pinocytosis?

the engulfing of large amounts of fluid

what is receptor-mediated exocytosis?

the engulfing of a substance only when that substance attaches to a receptor

what were the byproducts of plant evolution?

taller plants and bigger leaves bc it = more sunlight

need for better anchorage

more evaporation—> better transport system

what is the xylem?

the tube of the tree

transports water and minerals from roots to shoots

what is the phloem?

transports the products of photosynthesis (sugars, amino acids, minerals) from where they are made (source) —> where they are needed (sink)

what are the two major pathways of transport in plant cells?

apoplast and symplast

what is apoplast?

transport outside the cell/external to the main parts of the cell

what is symplast?

transport within the cell/through the entire mass of the cytosol and plasmodesmata

how do plants transport solutes short distances?

very similar to animal cells:

both active and passive transport

uses pumps (lotta proton pumps)

uses transport proteins (specifically A LOT of aquaporins)

how do plants transport water short distances?

osmosis but the direction of flow is determined by water potential (takes pressure into consideration)

what is water potential?

the ability for water to do work/its potential energy

unit is megapascals (MPa)

solute potential + pressure potential

what is a typical plant cells MPa?

0.50

what is solute potential?

molarity (pure water = 0)

when solute concentration increases, solute potential decreases

number always negative