lecture 5 Flashcards
deifne Limit of Resolution
the minimum distance at which two objects can be distinguished.
explain why electron microscopes are capable of finer resolution than light microscopes
Limit of Resolution is proportionate to wavelength
Resolution improves as w/l decreases
for light microscope is 0.2 µm
for electron microscope is 0.002 nm
how is a prokaryote (bacteria) different from a eukaryotic
lack a nucleus, dna not in a nuclear membrane
lack intracellular organelles
have a cell wall
describe a phospholipid molecule
choline, phosphate, glycerol make the polar hydrophilic head group, 2 fatty acids make the hydrophobic chain
describe a phospholipid bilayer and a micelles
hydrophilic outside, hydrophobic inside. forms water impermeable barrier
describe membrane proteins association with the lipid bilayer
hydrophobic proteins in the mddle in alpha helix. hydrophilic proteins on the inside and outside which can be glycolsylated
what is a glycocalyx
cell coat made of oligo and polysaccharide side chains
functions of a plasma membrane
transports materials along cell surface exo and endocytosis intracellular adhesion and recognition signalling selective permeability Cell morphology and movement
smooth er found where
found in liver, mammary gland (lipid biosynthesis ) and in ovary, testis, adrenal gland (steroidogenesis)
function of the ER
export proteins which bud off the ER
membrane, lipid and steroid synthesis
detox reactions
function of golgi complex
receives proteins from RER on cis face and exports proteins on trans face.
vesicles to apical membrane, form lysosomes, secretory vesicles
detox reactions
lysosome function
engulfs and digest bactera/foreign
what makes lysosomes, what do they contain
made by golgi apparatus, contain hydrolytic enzymes; nucleases, lipases
function of a peroxisome
detoxify (oxidise) alcohol, phenols, formaldehyde
describe structure of a mitochondria
outer membrane, matrix, inner membrane folded into cristae
what do the structures of the mitochondria do
matrix: 100s enzymes, has mito DNA, can divide to form daughter cells
inner mem: ox reactions for respiratory chain, makes atp by atp synthase
outer mem: permeable to large mol
describe the cytoskeleton
actin filaments (5-9nm) cortical distribution under plasma membrane intermediate filaments (10nm) form tough meshwork under cytoplasm keratin filaments in epithilial cells
how is a blister formed
epidermis lifts from dermis, doesnt stick together.
also occurs if mutant keratin gene
where are microtubules found
in moving structures, spindles, cilia, flagella
describe microtubules
long hollow cylinders made of tubulin
9+2 arrangement of microtubules in cilia
function of nucleus
rna synthesis, dna synthesis and repair rna processing and ribosomes assembly - It stores the cell’s DNA - It coordinates the cell’s activities; metabolism, growth, protein synthesis, mitosis.
what are the 3 components of the cytoskeleton
microtubules, microfilaments, intermediate filaments
