B2: cells & organelles

cell membrane

selectively permeable barrier that regulates the movement of substances in & out the cell

phospholipid bilayer

cellular membrane component that contains hydrophilic (water attracting) heads & hydrophobic (repelling tails)

membrane proteins

facilitate transport, used as receptors, & provide structural support

integral proteins

embedded in the membrane

peripheral membrane proteins

on the membrane surface

carbohydrates

attached to the membrane surface

cholesterol

helps stabilize membrane fluidity

integral proteins

amphipathic proteins that aid in cell signaling & transport of substances in & out of the cell

transmembrane proteins

span the entire membrane

peripheral membrane proteins

generally hydrophilic proteins that can function as receptors, aid in cell recognition, work as enzymes, or help with w cell adhesion

receptors (integral or peripheral)

transmit a signal into the cell

agonists

molecules that bind to receptors & activate a biological response

antagonists

molecules that bind to receptors & prevent other molecules from binding, inhibiting a biological response

adhesion

proteins attach cells to other things (like other cells) & anchor the cytoskeleton

cellular recognition

glycoproteins are used for cells to recognize each other

fluid mosaic model

describes how the cell membrane compromise can move freely

temp (fluidity)

higher temps inc fluidity

cholesterol (fluidity)

holds membrane together at high temps; keeps membrane fluid at low temps

degrees of unsaturation (fluidity)

saturated fatty acid pack more tightly than unsaturated fatty acid

simple diffusion

travel of small, uncharged molecules (O2, CO2, H2O) or lipid-soluble molecules (steroids) across the cell membrane along the concentration gradient

facilitated transport

large or charged molecules travel across the cell membrane through channel proteins along the concentration gradient

active transport

molecules travel across the cell membrane against the concentration gradient

primary active transport

membrane transport proteins pump molecules against the concentration gradient via ATP hydrolysis

secondary active transport

uses the energy from 1 molecule moving down its electrochemical gradient to drive the transport of another molecule against gradient

endocytosis

cell membrane internalizes extracellular substances

phagocytosis

cellular eating

pinocytosis

cellular drinking

receptor mediated endocytosis

endocytosis that is initiated by dissolved molecules binding to peripheral membrane receptor proteins

clathrin mediated endocytosis

clathrin (protein) facilitates endocytosis

exocytosis

internal substances released to the extracellular space

organelles

membrane bound cellular structures w specialized jobs

cytosol

aq intracellular fluid

cytoplasm

gelatinous intracellular material that contains both cytosol & organelles

nucleus

protects & stores DNA

nucleoplasm

cytoplasm of the nucleus

nuclear envelope

encapsulates the nucleus; contains both an inner & outer phospholipid bilayer

nuclear pores

channels in the nuclear envelope

nucleolus

produces components of ribosomes (rRNA)

ribosomes

produce proteins via translation

eukaryotic ribosomal subunits

60S & 40S assemble in the nucleoplasm & are exported to the cytosol to combine & form the full ribosomal (80S)

prokaryotic ribosomal subunits

50S & 30S assemble & combine in the cytosol (70S)

free flowing ribosomes

produce proteins that function in the cell

rough ER ribosomes

produce proteins for extracellular or cellular membrane use

endomembrane system

the nucleus, rough & smooth ER’s, Golgi apparatus, lysosomes, vacuoles, & cell membrane work tg to modify, package, & transport proteins & lipids

rough ER

organelle attached to the outer membrane of the nuclear envelope

smooth ER

extends off the rough ER

Golgi apparatus

stores, modifies, & exports proteins to be secreted from the cell

peroxisomes

perform hydrolysis, break down stored fatty acids, & help with detoxification

lysosomes

membrane bound organelles that break down cellular waste via hydrolytic enzymes & help facilitate apoptosis (animal cells)

apoptosis

programmed cell death

vacuoles

membrane bound vesicles used for storage (water, nutrients, waste) or transport

chloroplasts

in plants & some protists & perform photosynthesis

plastid

double membraned organelles found only in plant cells & algae

centrosomes

organelles found in animal cells