T1 modules 1+2 Flashcards
name basic classes of molecules that make up cells
NUCLEIC ACIDS: hereditary material
PROTEINS: cel structure, metabolic activity
POLYSACCHARIDES: structural components, stored energy
PHOSPHOLIPIDS: primary component of cell membrane
functions of cell membrane
1) PROTECT cell from toxins
2) GATEKEEP: allow entry of select compounds
3) DISPOSE of metabolic waste
lipid bilayer composition
PHOSPHOLIPIDS (main component of membrane)
- AMPHIPATHIC: hydrophobic head, hydrophilic exterior
- made of (head to tail) hydrophilic polar group, phosphate group, glycerol and hydrophobic fatty acid carbon chains
- tails can be saturated (SB) or unsaturated with a kink (doubleB)
STEROIDS (50% of molecules in membrane)
- hydrocarbon ring (4)
lipid micells
spheres of phospholipids that form spontaneously
important for absorption of fat soluble vitamins and lipids
factors effecting membrane fluidity
1) # of C in fatty acid chain
longer chains pack tightly, decreasing fluidity
2) Kinks in chain (unsaturated)
push chains apart, increasing fluidity
3) temperature
high T increases fluidity, low T decreases fluidity via kinetic energy
4) Cholesterol
help maintain fluidity @ low T by packing close to phospholipids
helps maintain structure @ high T
REGIONS OF FLUIDITY - LIPID RAFT
- decreased fluidity
- longer unsaturated tails
- *increased cholesterol concentration (decreased fluidity)
- can hold macromolecules
- collects pr- or receptors on cell
how does fluidity impact membrane transport?
quantity and time it takes for things to pass through
more permeable membranes have more unsaturated fatty acids and less cholesterol
less permeable membranes have less unsaturated fatty acids and more cholesterol
Describe the different types of diffusion
PASSIVE (simple)
- small molecules along concentration gradients
- no energy used
- moves lipid solubles, gasses, some water, uncharged molecules
PASSIVE TRANSPORT (facilitated) *most common
- facilitated along concentration gradients
- no energy used
- moves ions, hydrophobic molecules, most water (OSMOSIS)
ACTIVE TRANSPORT
- against concentration gradient
- uses energy
2 types
PRIMARY ACTIVE TRANSPORT (eg. Na K pump)
- ATP hydrolysis directly effects transport pr-
SECONDARY ACTIVE TRANSPORT
- neighbouring pr- takes advantage of established gradient
Osmosis
water moves from HIGH to LOW concentrations to balance out solute concentrations
different concentration environments:
ISOTONIC: same int and ext concentrations
HYPOTONIC: ext has LOW solute concentration -> water IN
HYPERTONIC: ext has HIGH solute concentration -> water OUT
when did life + photosynthesis begin?
~4 billion years ago during the precambrian (proterozoic era)
first photosynthetic cells caused a boom in life
general differences between procaryotes and eukaryotes
PRO
- unicellular
- no nucleus
- older
- aerobic
EU
- multicellular
- nucleus + membrane bound organelles
- anaerobic
what makes energy in pro and eukaryotic cells?
CHLOROPLASTS in plants
MITOCHONDRIA in plants and animals
describe structure and function of a chloroplast
light -> chemical energy (stored in cho molecule bonds)
- double membrane
THYLAKOIDS - lost of flat&stacked membranes
- organized into piles (GRANA), where photosynthesis happens
describe structure and function of a mitochondria
sugars -> ATP
50-100 million in a cell
- double membrane
- inner membrane connected to CRISTAE (location of ATP synth)
theory of where cells came from
ENDOSYMBIOTIC THEORY OF ORGANELLE EVOLUTION
- cells today derived from ancestral prokaryotes with heritable genetic info
- compartmentalized info into nucleus
mutually beneficial relationship: anaerobic eukaryotes (who produce less ATP) engulfed aerobic prokaryotes (who produce more)
endosymbiotic
mutually advantageous
