IAS19 Flashcards

1
Q

unit membrane concept & plasma membrane staining

A

all cellular membranes have same underlying struc. & diff. functions
trilaminar shape, stained by osmium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

plasma membrane lipid components structure & movement

A

PP amphipathic, polar hydrophilic head facing outward, 2 nonpolar phobic tails facing inward
move laterally, rotate or flipflop
cholesterol interspersed among PP, determines fluid nature of membrane (more cholesterol, more interaction w/ FA chain, more rigid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

plasma membrane other components

A

proteins
integral: part of membrane structure, cannot be removed w/o damaging the membrane
periphery: binds to either side of membrane, can easily be separated
carb: complex glycoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

fluid mosaic model

A

fluidity: PP has high mobility
deg. of fluidity inc. w/ temp (dist. of PP & energy), shorter FA tail, more double bonds, less cholesterol
mosaic: proteins dispersed thruout membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

plasma membrane functions

A

C (BIR) SSCC compartmentalization: define boundaries, allows specialized activities to proceed w/o ext. interference & cellular activies to be regulated independently
scaffold for biochem activities
selective permeable barrier: allows some materials to pass but not others, allows nutrients to enter cell & wastes to exit
act as receptors to detect chem signals (trigger cellular activity cascade)
provide contact, adhesion & communication (cytoplasmic process exchange cellular components)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

cell membrane permeability

A

barrier to most water-soluble substances, selective perme. to lipid solvent, high resistance to charged & large molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

mitochondria & its membrane

A

provide energy & involved in apoptosis
double membrane: highly folded inner, smooth outer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

ER generally

A

double membrane bound
membrane runs cont. w/ outer membrane of nuclear envelope, lumen cont. w/ nuclear lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

ER types

A

rough: flattened sheets of membranes & tubules, ribosomes present for protein synthesis, span through whole cytoplasm, well-developed in protein synth. & secretory cells
proteins synthesized pass on to cisternae
smooth: no ribosomes, more tubular
for lipid synth.; detox in liver; Ca storage & release in muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

golgi apparatus

A

for modification, packing & distribution of proteins & lipids for secretion / internal use
stacked membranous, flattened cisternae w/ vesicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

golgi faces & lumen

A

cis face receives transport vesicles budded from ER containing new proteins
lumen: protein & lipid modification, progression through transport vesicles budding off from each cisterna & fusing w/ the next
trans: mature proteins & lipids released as vesicles, contains condensing granules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

lysosome

A

single membrane bound
contain enzymes to degrade phagocytosed materials
destruction of organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

peroxisome

A

smaller ver. of lysosome
contain enzymes to break down long FA & amino acids forming H2O2 byproduct, contains catalase to neut. H2O2
common in liver for detox

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

nucleus stain & nuclear envelope

A

stain in H&E: blue / purple (acidic, -vely charge) (cannot see membrane w/ H&E)
envelope: double membrane, pores form by fusion of both membranes
pores allow diffusion of small molecules, active import of proteins & rna from & into nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

nucleoplasm

A

consist of DNA, nucleoproteins, etc.
contains chromatin (DNA & histones)
basophilic, heterogeneously stained

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

types of chromatin

A

heterochromatin: dark stained, dense packed chromatin less active at gene transcription, at nuclear periphery
euchromatin: the reverse

17
Q

nucleolus

A

synthesis of rRNA, contains genes for encoding rRNA (chr 13 14 15 21 22)
process & assemble ribosomal subunits imported from CP -> transported out of nucleus

18
Q

nucleolus regions

A

fc: fibrillar center, palely stained, inactivated genes for transcription
dfc: dense fibrillar component, darkly stained, nascent pre-rRNA transcription, rRNA early modification
gc: granular component, occupies most of nucleolus, ribosomal subunit assembly at diff. stages

19
Q

cytoskeleton functions

A

microfilament, intermediate filament, microtubule (extend from centrosome to periphery)
1. maintains cell shape & used in locomotion
2. in cell division
3. guides intracellular traffic of organelles
4. provides mech strength

20
Q

microfilament & function

A

actin as building block, globular monomer g-actin polymerize to form long helical filamentous polymer f-actin
polar, + end grows faster than - end
used in muscle contraction, locomotion, cytokinesis & structural functions

21
Q

microfilament organization & contribution to movement

A

dynamically organised into bundles & networks, stabilized by interaction w/ diff. cross-linking proteins
some lie in cell cortex below plasma membrane, arranged in loose 3d mesh
in leading edge, microfilaments arranged in ||type bundles, spike-like protrusions formed by active polymerization of actin at tip of protrusion, allows movement & migration

22
Q

microfilament in cytokinesis

A

interacts w/ myosin, contracts cells through contractile ring (bundle)

23
Q

actin assembly in intestinal villi

A

actin filaments connected by actin-bundling protein fimbrin (CLP)
filaments extend down to apical cytoplasm to form network below microvilli bottom: terminal web, connected to microfilament core
stabilized by CLP filamin

24
Q

intermediate filament structure

A

bundled fibrous proteins
2 helical monomers twist to form dimer
2 dimers interact anti|| to form tetramer
tetramers assembled end to end to form protofilament

25
intermediate filament function
3SA stronger than actin filament, exhibits strain hardening during stress -> structural / tension bearing role maintain cell shape & scaffold to support cell framework anchor organelles
26
types of intermediate filament
keratin (epithelial cell), vimentin (connective tissue, smooth muscle), neurofilament (neuron), nuclear lamin (in nuclear lamina in inner nuclear membrane)
27
keratin filament & defect
forms strong network within cells, connected w/ junctional complexes -> creating sheet of cells allowing to withstand phy force in cells in mutation (no keratin production) -> cells fragile & prone to rupture in little mech. stress, skin blistering in epidermis & during dermis
28
microtubules structure
tubulin dimers (alpha, beta tubulin) -> polymerization in linear rows to form protofilament -> 13 protofilaments side-by-side to form hollow center dynamic: elongation at + end by polymerization, shortening at - end by depolymerization
29
microtubules origination
microtubule organising center (MTOC) microtubule assembly initiated & acts as anchor for one end MTOC called centrosome in animal cell (2 centrioles near nucleus) MTOC in cilia & flagella called basal bodies, extend microtubules & push out plasma membrane to form cilia / flagella
30
microtubule in mitosis
forms mitotic spindle to guide segregation of chromosome through shortening & extension
31
microtubule in IC organelle transport
axonal transport: motor proteins carry chem. components in vesicles down the axon w/ help of microtubules -> released at axonal end to synaptic cleft kinesin moves toward + end dyenin moves toward - end
32
agents that prevent microtubule function
colchicine, bind to microtubules to prevent polymerization taxol, bind to microtubules to prevent depolymerization -> affect dynamic process of mitotic spindle required for chromosomal separation -> disrupt mitosis & cell division both act as anti-mitotic drug to prevent cell proliferation