006 Cytoplasmic Organelles

Question 1

role of endoplasmic reticulum

Answer 1

synthesizing, packaging and processing of various cell substances

Question 2

cells that make proteins have lots of

Answer 2

Rough ER

Question 3

free ribosomes synthesize

Answer 3

proteins for intracellular use

ribosomes in general are the site of mRNA translation into sequences of AA

Question 4

the mechanism by which secretory proteins are directed to the endoplasmic reticulum is explained by

Answer 4

the signal hypothesis

Question 5

smooth ER lacks two things that the Rough ER has

Answer 5

ribosomes and tubular cisternae

Question 6

entry face on golgi

Answer 6

cis face (adjacent to ER)

Question 7

exit face on golgi

Answer 7

trans face (faces plasma membrane or nucleus)

Question 8

three parts of golgi

Answer 8

cis face
trans face
trans golgi network

Question 9

function of golgi

Answer 9

sorting secretory products (marking lysosomal enzymes with M6P)
packaging and storing secretory products into secretory granules or vesicles

Question 10

order of stuff in golgi

Answer 10

cis golgi
trans golgi
trans golgi network

Question 11

golgi disassembles during…… and reassembles during….

Answer 11

mitosis/meiosis

interphase

Question 12

anterograde traffic

Answer 12

lysosomal sorting pathway

Question 13

retrograde traffic

Answer 13

back to ER from golgi

Question 14

exocytosis or secretory pathway

Answer 14

starts in the ER through the golgi and ends on the cell surface

Question 15

endocytic pathway

Answer 15

internalization and degradation of extracellular material from the plasma membrane through endosomes to lysosomes

Question 16

clathrin coated vesicles

Answer 16

transporting products from the golgi apparatus to lysosomes or products from the exterior of the cell to lysosomes (like cholesterol)

Question 17

COP coated vesicles (coat protein)

Answer 17

transporting products between stacks of the golgi apparatus (COPI coated vesicles) and from the endoplasmic reticulum to the golgi apparatus (COPII coated vesicles)

Question 18

this surrounds the neck of the invaginated coated pit causing the neck of the vesicle to pinch off from the plasma membrane

Answer 18

dynamin

Question 19

mediates clathrin binding to the vesicle membrane

Answer 19

adaptins

Question 20

phosphorylation of lysosomal enzymes done by

Answer 20

mannose 6 phosphate

Question 21

lysosomal enzymes bind to this receptor and are separated from other glycoproteins

Answer 21

m6p receptor

Question 22

after being transported to the clathrin coated transporting vesicles, lysosomal enzymes dissociate from the M6P receptor and are surrounded by a membrane to form a

Answer 22

primary lysosome

Question 23

membranes containing the free M6P receptor are returned to the

Answer 23

golgi apparatus for recycling

Question 24

how to lysosomes maintain an acidic intralysosomal environment

Answer 24

contain an ATP dependent H+ pump

Question 25

primary lysosomes

Answer 25

storage site of lysosomal hydrolases
no digestive events
homogenous
INACTIVE enzymes

Question 26

secondary lysosome

Answer 26

engaged in catalytic process 
digestive enzymes
heterogenous
active enzymes
(has fused with something and is actively degrading molecules)

Question 27

residual bodies

Answer 27

cytoplasmic vacuole containing the leftover products of digestion after fusion with the contents of a lysosome
(usually excreted via exoytosis or become lipofuscin-granules that remain in the cytosol indefinitely)

Question 28

3 pathways for intracellular digestion

Answer 28

1. phagocytosis
2. autophagy
3. receptor mediated endocytosis

Question 29

important change in endosome maturation is

Answer 29

lowering of internal pH to 5.5

Question 30

familial hypercholesterolemia

Answer 30

cholesterol uptake disrupted
elevation of LDL —> atherosclerotic plaques
defect in gene encoding LDL receptor
LDL receptors bind, but unable to internalize

Question 31

xanthoma

Answer 31

skin condition where certain cholesterol rich fats build up under the skin

Question 32

lysosomal storage diseases

Answer 32

mutation in one of the lysosomal enzymes means that it does not work properly and proteins can accumulate in lysosomes as they cannot be digested. the low permeability of the membrane prevents proteins from leaving the organelle

Question 33

peroxisomes (microbodies)

Answer 33

cytoplasmic organelles that contain enzymes that form hydrogen peroxide which is immediately broken down by catalase

Question 34

functions of peroxisomes

Answer 34

synthesis and degradation of hydrogen peroxide
B oxidation of long chain fatty acids
bile acid and cholesterol synthesis
detoxify alcohol

Question 35

Zellweger spectrum disorders

Answer 35

caused by defects in assembly of peroxisome (all 12 genes need to be encoded correctly)
actual zellweger-absence or reduced number of peroxisome
congenital and death within first year

Question 36

five parts of mitochondria

Answer 36

1. outer mitochondrial membrane
2. inter membrane space
3. inner mitochondrial membrane
4. cristae space (formed by foldings of inner membrane)
   these folds are studded with small round bodies known as F1 particles or oxysomes
5. the matrix (space within inner membrane)

Question 37

mitochondrial DNA

Answer 37

mitochondrial diseases are sometimes caused by mutations in the mtDNA that affect mt function
other causes of mt disease are mutations in the genes of the nuclear DNA whose gene products are imported into as mt proteins as well as acquired mt conditions

Question 38

cytoplasmic inclusions

Answer 38

transitory cytoplasm components
not membrane bound organelles
mainly accumulated metabolites or deposits (colored substances or pigments like melanin)

Question 39

cytoplasic inclusions: lipofuscin granules

Answer 39

undigested lipids

accumulate from free radical damage