AP bio unit 2

cells, organelles, membranes, Dr. Carlson

Cell membrane

Selective barrier that control the transportation of molecules in and out of the cell

Structure of cellular membrane

Hydrophilic “head” phosphate group, hydrophobic “tail” fatty acids, aqueous environment on inside and outside

Integral protein

proteins embedded in the cell membrane

Peripheral proteins

Proteins attached to the membrane but not embedded

Transmembrane protein

integral proteins that go all the way through the membrane on both sides

function of carrier proteins

to transport hydrophilic molecules through the membrane

Carrier proteins

proteins that transport molecules in the membrane

Function of cholesterol in membrane

reduce membrane fluidity at moderate temps, but at low temps it avoids solidification and freezing

Functions of membrane proteins

Transportation of polar molecules, catalyze reactions of enzymes, attach to cytoskeleton and extra-cellular matrix for stability, cell-cell recognition, intercellular joining or attachment of two cells, and signaling/communication between cells

Selectively permeable

some substances are allowed to pass through, but others need support by something else or aren’t allowed in

Why are cells so small?

its efficient and easier to get nutrients in and out faster and if it was bigger the volume would increase making the demand for proteins increase

Nucleus

Double layer membrane-enclosed organelle that contains chromosomes, ribosomes, and the nucleolus and controls and regulates activity in the cell

Smooth ER

transport system made up of tubular membranes that detoxifies cells and synthesizes lipids

Rough ER

Made up of sacs that synthesize and modify proteins in membrane-bound ribosomes to send them out for transportation

Cytoskeleton

structural part that acts as a highway system around the cell

Lysosomes

membrane-bound sacs that break down trash and dead organelles (garbage disposal)

Vacuole

Membrane bound structure that stores nutrients and waste

Golgi body

flattened sacs that act as a mailman packaging proteins and lipids for transport and fold and modify newly synthesize cellular products

Chloroplast

Green, plant-only organelle that photosynthesizes

Mitochondria

double-layer membrane powerhouse of the cell that produces and synthesizes ATP and energy for the cell

Ribosomes

Made up of two RNA and proteins that synthesize the proteins according to mRNA

Cell wall

Plant-only organelle that holds up the structure of the cell and makes sure things can’t get in and out that shouldn’t

Surface area to volume ratio in cells

Affects the ability to obtain necessary nutrients, get rid of waste, acquire or get rid of thermal energy, and exchange chemicals and energy with the environment

Surface area of the plasma membrane

Must be large enough to adequately exchange materials, if size increases the surface area-to-volume ratio decreases which affects properties

Phospholipids

has both hydrophilic and hydrophobic regions, where polar hydrophilic phosphate regions orient to aqueous external or internal, and non polar hydrophobic fatty acid region face the interior of the membrane

Plasma membrane

consists of structure framework of phospholipid molecules that are embedded with proteins, steroids, glycoproteins, and glycolipids

Equilibrium

Equal concentration of molecules on each side

Diffusion

Passive movement of molecules from a level of higher concentration to lower concentration

Facilitated difusion

Diffusion with the help of something else (ex: membrane proteins)

Passive transport

transportation not involving ATP

active transport

transportation involving the use of ATP

Sodium-potassium pump

Protein pump in the cellular membrane that uses a phosphate group for ATP to pump in and out molecules of sodium and potassium used in the nervous system

Proton pump

form of active transport used in photosynthesis and cellular respiration that lets in hydrogen

Phagocytosis

process for encasing food particles in the membrane to be let in a cell to be digested by the lysosomes

Pinocytosis

surrounds solutes to bring in a cell

receptor-mediated endocytosis

Endocytosis supported by a receptor

exocytosis

process of pushing out a large particle using the membrane

Endocytosis

the process of bringing a large particle into the cell through the membrane

Osmosis

Process of molecules in a solvent passing through a semipermeable membrane to get from an area of low to high concentration

water potential

where water moves from high to low potential (concentration)

Hypotonic in animal cells

more solutes in cell than the environment, makes cell burst

hypotonic in plant cells

turgid (normal) condition where the cell is happiest

Isotonic in animal cells

where solutes in the cell are equal to the environment, normal and stable condition

Isotonic in plant cells

Flaccid state where there is no pressure on anything outside the cell

Hypertonic in animal cells

shriveled state where all water is diffused out of the cell

hypertonic in plant cells

state where membrane is pulled away from cell walls and shrinks or tears

contractile vacuole

stores water in cells with no cell wall in hypotonic environments to maintain homeostasis

Endosymbiosis

Where two organisms live together with one inside the other

compartmentalization of eukaryotes

additional internal plasma membranes that create specialized compartments to compartmentalize cellular functions and increase efficiency of reactions 

compartmentalization in prokaryotic cells

one plasma membrane with no specific compartments but still maintains a homeostatic environment 

hydrolytic enzymes

work well in acidic environments to break down and digest food particles

evolution of eukaryotic cells

folded, evolved, and adopted characteristics of prokaryotes by infolding of plasma membranes and organelles evolved from on free living prokaryotes

Endosymbiont theory

the idea that the mitochondria and chloroplasts likely evolved from once free living prokaryotes via endosymbiosis