lecture 5

Question 1

deifne Limit of Resolution

Answer 1

the minimum distance at which two objects can be distinguished.

Question 2

explain why electron microscopes are capable of finer resolution than light microscopes

Answer 2

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

Question 3

how is a prokaryote (bacteria) different from a eukaryotic

Answer 3

lack a nucleus, dna not in a nuclear membrane
lack intracellular organelles
have a cell wall

Question 4

describe a phospholipid molecule

Answer 4

choline, phosphate, glycerol make the polar hydrophilic head group, 2 fatty acids make the hydrophobic chain

Question 5

describe a phospholipid bilayer and a micelles

Answer 5

hydrophilic outside, hydrophobic inside. forms water impermeable barrier

Question 6

describe membrane proteins association with the lipid bilayer

Answer 6

hydrophobic proteins in the mddle in alpha helix. hydrophilic proteins on the inside and outside which can be glycolsylated

Question 7

what is a glycocalyx

Answer 7

cell coat made of oligo and polysaccharide side chains

Question 8

functions of a plasma membrane

Answer 8

transports materials along cell surface
exo and endocytosis
intracellular adhesion and recognition
signalling
selective permeability
Cell morphology and movement

Question 9

smooth er found where

Answer 9

found in liver, mammary gland (lipid biosynthesis ) and in ovary, testis, adrenal gland (steroidogenesis)

Question 10

function of the ER

Answer 10

export proteins which bud off the ER
membrane, lipid and steroid synthesis
detox reactions

Question 11

function of golgi complex

Answer 11

receives proteins from RER on cis face and exports proteins on trans face.
vesicles to apical membrane, form lysosomes, secretory vesicles
detox reactions

Question 12

lysosome function

Answer 12

engulfs and digest bactera/foreign

Question 13

what makes lysosomes, what do they contain

Answer 13

made by golgi apparatus, contain hydrolytic enzymes; nucleases, lipases

Question 14

function of a peroxisome

Answer 14

detoxify (oxidise) alcohol, phenols, formaldehyde

Question 15

describe structure of a mitochondria

Answer 15

outer membrane, matrix, inner membrane folded into cristae

Question 16

what do the structures of the mitochondria do

Answer 16

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

Question 17

describe the cytoskeleton

Answer 17

actin filaments (5-9nm) cortical distribution under plasma membrane
intermediate filaments (10nm) form tough meshwork under cytoplasm
keratin filaments in epithilial cells

Question 18

how is a blister formed

Answer 18

epidermis lifts from dermis, doesnt stick together.

also occurs if mutant keratin gene

Question 19

where are microtubules found

Answer 19

in moving structures, spindles, cilia, flagella

Question 20

describe microtubules

Answer 20

long hollow cylinders made of tubulin

9+2 arrangement of microtubules in cilia

Question 21

function of nucleus

Answer 21

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.

Question 22

what are the 3 components of the cytoskeleton

Answer 22

microtubules, microfilaments, intermediate filaments