AP BIO- unit 2

prokaryotic cells

• very small

• lack membrane bound organelles

• no nucleus

• have ribosomes 

• bacteria 

eukaryotic cells

• larger

• have a membrane bound nucleus and membrane bound organelles

• plants and animals

• more complex 

the cell/plasma membrane

• lipids, carbs, proteins

• fluid mosaic model

• separates cells from environment

• selectively permeable

  • only allows or actively transports certain materials in/out of cells

  • small, non-polar molecules (O, N, CO2)

• involved in cell communication

• phospholipid bilayer

proteins

• integral proteins

• peripheral proteins

integral proteins

• runs completely through the bilayer from one side to the other

• help maintain integrity of the membrane 

peripheral proteins

• located on one side of the membrane 

• don’t extend through the bi-alter 

• can act as receptors 

fluid mosaic model

• looks like a moving puzzle

• phospholipids (fluid)

• proteins embedded within (mosaic)

Nucleus

• double membrane w/ protein pores

  • allows certain specific materials to enter/exit the nucleus

• DNA storage and replication

• info relays to ribosomes

ribosomes

• MAKES PROTEINS

• site of protein synthesis

• free ribosomes

  • float freely in the cytoplasm of a cell

• bound ribosomes

  • only in eukaryotes

  • attached to ER

endoplasmic reticulum

• network of membrane channels attached to nuclear membrane

• rough and smooth

rough ER

• has ribosomes

• helps with PROTEIN synthesis, modification, and transport

smooth ER

• no ribosomes

• helps with the synthesis of LIPIDS, detoxifies compounds, breaks down glycogen

golgi apparatus

• series of flattened, membrane bound sacs

• synthesis, modification, and packaging of molecules

lipids

• hydrophilic regions

  • head of lipid- polar

• hydrophobic regions

  • nonpolar fatty acid tails

passive transport

• movement of material from high to low concentration 

• no energy required 

• diffusion 

• osmosis 

diffusion

• PT

• passive transport of molecules across a semipermeable membrane

• transport proteins help facilitate diffusion

  • aquaporins and ion channels 

osmosis

• PT

• diffusion of water

• osmolarity- total concentration of all solutes in the solution

• tonicity- the ability of an extracellular solution to make water move into or out of a cell by osmosis

hypotonic

• osmosis 

• has a lower concentration of solutes compared to another solution,

hypertonic

• osmosis

• a higher concentration of solutes than a comparable fluid, causing water to move out of cells via osmosis, leading to cell shrinkage

turgid

• when there is a lot of water in a cell that possess a cell wall, so the cells are rigid and stiff

water potential

• a measure of the relative tendency of water to move from one are to another

• solute+pressure

facilitated diffusion

• type of passive transport 

• requires the help of channel or transport proteins 

• aquaphorins

aquaporins

• channel proteins that help move water

active transport

• movement of material from low to high concentration

• energy is required

• often energy used is ATP

• protein pump

isotonic

• equal in solute concentration, particularly relating to the surrounding fluids or equal muscle tension

bulk transport

• the cellular process of moving large particles or large quantities of substances across a cell membrane using vesicles

• endocytosis

• exocytosis

• always active transport

endocytosis

• intake of large quantities of molecules

• phagocytosis, pinocytosis, receptor mediated endocytosis

exocytosis

• moving large molecules out of the cell

hypotonic

a solution with a lower solute concentration or a medical condition with deficient muscle tone

hypertonic

a higher solute concentration than another solution, which causes water to move from the area of lower solute concentration into the area of higher concentration via osmosis