Exam 3: Ch 9 Isolating Organelles & Perturbing Cell Functions Flashcards Preview

Cellular and Molecular Biology > Exam 3: Ch 9 Isolating Organelles & Perturbing Cell Functions > Flashcards

Flashcards in Exam 3: Ch 9 Isolating Organelles & Perturbing Cell Functions Deck (21):
1

receptor-mediated endocytosis

take in larger molecules than ions by forming coated pits that pinch off to form endosomes

receptors bring in specific molecules

2

lysosome

organelle with an acidic degradative environment

full of enzymes called acid hydrolases in the lumen

3

endoplasmic reticulum

largest internal membrane system

flattened membrane bound sacs and tubules

4

smooth ER

site of fatty acid and phospholipid synthesis

5

rough ER

ribosome studded ER

site of membrane protein and secreted protein synthesis

6

golgi apparatus

stack of flattened membranes called cisternae

proteins are modified and sorted before transport to final destination in plasma membrane or endosomes

7

secretory pathway

protein synthesis in ER --> golgi --> secretion

includes memb. bound proteins

8

peroxisome

spherical organelle with oxidase enzymes

use molecular oxygen to oxidize toxins

9

initial step in purifying organelles

release cell's contents by rupturing plasma membrane/cell wall

blender (sonication), osmosis, pressurized tissue homogenizer

10

_______ can separate many types of organelles

differential centrifugation

makes lots of pelleted fractions

11

equilibrium density gradient centrifugation

separate cellular components by density

12

organelle-specific _____ are useful in preparing highly purified organelles

antibodies

use of monoclonal Ab to specific organelle proteins

ex. clathrin

13

clathrin monoclonal ab

selectively bind clathrin bound vesicles in a crude prep of membranes

isolated via low speed centrifugation

14

fat and muscle cells contain a glucose transporter ______ that is localized to the memb of vesicles

GLUT4

add insulin and vesicles fuse with plasma memb. and increase # of GLUT4

purify with monoclonal Ab to GLUT4 protein

15

if no Ab specific for the organelle under study is available, use

epitope tag then monoclonal Ab

16

3 steps to identifying all the proteins in an organelle

obtain pure organelle

identify all the sequences of the proteins in the organelle

have a genome sequence to identify the proteins from which all the peptides came

17

discovery of a new drug?

chemical library used to search for chemicals that inhibit a specific process

uses microscopy

ex. monastrol inhibits spindle assembly (used as anti-tumor agent)

18

RNAi method

suppress expression of gene with miRNA (block translation) or siRNA (degradation)

function in nucleus with target mRNA (imperfect (miRNA) or perfect (siRNA))

RISC: RNA induced silencing complex

19

siRNA knockdown (customized siRNA-RNAi)

identify sequence in target mRNA and synthesize siRNA to add

if perfect binding, no target protein made

20

shRNA

short hairpin RNA cleaved by dicer to form siRNA

alternative knockdown strategy by adding DNA constructs that generate siRNA when transcribed

once shRNA is expressed, siRNA always made

21

genomic screen with siRNA in fruit flys

explore effects of using siRNA to suppress each protein-coding gene in fruit flys