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)
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1
Q

receptor-mediated endocytosis

A

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

receptors bring in specific molecules

2
Q

lysosome

A

organelle with an acidic degradative environment

full of enzymes called acid hydrolases in the lumen

3
Q

endoplasmic reticulum

A

largest internal membrane system

flattened membrane bound sacs and tubules

4
Q

smooth ER

A

site of fatty acid and phospholipid synthesis

5
Q

rough ER

A

ribosome studded ER

site of membrane protein and secreted protein synthesis

6
Q

golgi apparatus

A

stack of flattened membranes called cisternae

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

7
Q

secretory pathway

A

protein synthesis in ER –> golgi –> secretion

includes memb. bound proteins

8
Q

peroxisome

A

spherical organelle with oxidase enzymes

use molecular oxygen to oxidize toxins

9
Q

initial step in purifying organelles

A

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

blender (sonication), osmosis, pressurized tissue homogenizer

10
Q

_______ can separate many types of organelles

A

differential centrifugation

makes lots of pelleted fractions

11
Q

equilibrium density gradient centrifugation

A

separate cellular components by density

12
Q

organelle-specific _____ are useful in preparing highly purified organelles

A

antibodies

use of monoclonal Ab to specific organelle proteins

ex. clathrin

13
Q

clathrin monoclonal ab

A

selectively bind clathrin bound vesicles in a crude prep of membranes

isolated via low speed centrifugation

14
Q

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

A

GLUT4

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

purify with monoclonal Ab to GLUT4 protein

15
Q

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

A

epitope tag then monoclonal Ab

16
Q

3 steps to identifying all the proteins in an organelle

A

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
Q

discovery of a new drug?

A

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
Q

RNAi method

A

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
Q

siRNA knockdown (customized siRNA-RNAi)

A

identify sequence in target mRNA and synthesize siRNA to add

if perfect binding, no target protein made

20
Q

shRNA

A

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
Q

genomic screen with siRNA in fruit flys

A

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