unit 2: cell structure and function

topic 1: organelles (add photos)

prokaryote (dna) - naked + circular dna; no introns

eukaryote (dna) - protein-bound + linear dna; has introns

prokaryote (organelles) - no nucleus; not membrane-bound; 70S ribosomes

eukaryote (organelles) - has nucleus; membrane-bound; 80S ribosomes

eukaryote (reproduction) - binary fission; haploid (single chromosome)

prokaryote (reproduction) - mitosis + meiosis; diploid (paired chromosomes)

nucleus - holds DNA; chromatin; nucleolus

chromatin - site of transcription; dna to rna; in nucleus

nuclear envelope - lipid bilayer surrounded nucleus; continuous with the ER

nuclear pore - gateway into the nucleus

nucleoplasm - protoplasm within the nucleus

cytoplasm - protoplasm outside the nucleus

nucleolus - site of ribosome biogenesis/creation; in the nucleus

ribosomes - site of translation; made of protein + rna; large + small sub-unit

ribosome (location) - in cytoplasm, rough ER, mitochondria, + chloroplast

endoplasmic reticulum - rough + smooth component

rough ER - many ribosomes; synthesis of proteins (sealed + excreted)

smooth ER - few ribosomes; synthesis of carbohydrates, lipids, + steroid hormones; detoxification

golgi apparatus - distributes lipids + proteins; cis face receives; trans face releases; macromolecules sort, tagged, + packaged through the cisternae

lysosome - disposal of proteins, polysaccharides, lipids, nucleic acids, + organelles; low pH enzymes (acidic)

vesicles - membrane sacks for storage + transport; connects the endomembrane system

endomembrane system - organelles that modify, package, + transport lipids/proteins; nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, + cell membrane

endomembrane sequence - (dna) → transcription → (rna) → nuclear pore → cytoplasm→ rough ER’s ribosome (protein synthesis) → (protein) → cis-golgi → trans-golgi → vesicle storage

mitochondria - creates ATP (cellular respiration)

chloroplast - plant; creates glucose via photosynthesis

endosymbiosis theory - mitochondria + chloroplast were prokaryotes that joined eukaryotes

vacuole - for storage; mostly water + enzymes; very large

cytoskeleton - made of microfilaments (actin), intermediate filaments (fibrous proteins), + microtubules (hollow tubulin cylinders)

topic 2: the cell membrane

phospholipids - polar phosphate head; 2 non-polar fatty acid tails

micelle - single layer sphere of phospholipids

liposome - hollow bilayer sphere of phospholipids

peripheral proteins - attach to cell membrane surface; temporary

integral proteins - stick to hydrophobic region of cell membrane; permanent

transmembrane - integral protein on both side of membrane

monotopic - integral protein on both side of membrane

channel - transmembrane integral protein; facilitates movement of material across membrane

glycoproteins - protein + carbohydrate; receptor molecule + cell recognition

glycolipids - lipid + carbohydrate; receptor molecule + cell recognition

cholesterol - reduces effects of temperature on membrane fluidity

topic 3: cell transport

permeable (through cell membrane) - small uncharged molecules

slightly permeable (through cell membrane) - small polar molecules

permeable (through cell membrane) - large or charged molecules

concentration gradient - different concentrations of a substance across a space; substance wants to reach equilibrium (go from high concentration to low)

passive transport - follows concentration gradient; no energy needed

facilitated diffusion - passive transport; uses integral proteins

channel proteins - integral protein open on both sides of membrane; quicker diffusion

aquaporin - channel protein for water

carrier protein - integral protein open on only one side of membrane at a time; slower diffusion; selective

active transport - against concentration gradient; energy needed

pumps - carrier protein; moves substance against concentration gradient; uses ATP

uniporter - carries one molecule/ion

symporter - carries two molecules in the same direction

antiporter - carries two molecules in the opposite directions

primary active transport - uses ATP**

secondary active transport - uses electrochemical gradient**

phagocytosis - intake of food/pathogen; need lysosome to break down

pinocytosis - intake of small molecules; don’t need lysosome to break down

receptor-mediated endocytosis - receptor protein captures target molecule

exocytosis - expels material from cell; vesicle joins membrane

endocytosis - membrane forms vesicle around molecule to bring it into cell

topic 4: osmosis

solution - liquid mixture where a minor component (solute) dissolves into a major component (solvent)

osmosis - movement of water across a semipermeable membrane based on the concentration gradient

osmolarity - solute concentration of a solution

human osmolarity - 0.3M

tonicity - comparison of the osmolarity of two solutions separated by a semipermeable membrane

hypertonic - higher external osmolarity

isotonic - equal osmolarity

hypotonic - lower external osmolarity

animal cells (tonicity) - hypertonic: shrivels; isotonic: perfect condition; hypotonic: swells/cytolysis

plant cells (tonicity) - hypertonic: plasmolysis; isotonic: acceptable condition; hypotonic: full, turgor/rigid

turgor pressure - pressure from cell under hypotonic conditions

water potential (Ψ) - pressure potential (Ψ_p) + solute potential (Ψ_s); quantifies the tendency of water to move across gradient

solute potential (Ψ_s) - -iCRT

pressure potential (Ψ_p) - accounts for other forces affecting the movement of water (like cell walls)

i - ionization constant; how many molecules can the solvent divide into

C - concentration; M, mol/L

R - pressure constant; 0.0831; (L*bars)/(mol*K)

T - temperature; K