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Flashcards in Cellular Structure pt 2 Deck (35):
1

Lysosomes: recycling system of the cell

membrane enclosed organelles that consist of 50-60 hydrolytic enzymes most active at acidic pH:

capable of breaking down proteins, carbohydrates, lipids, and nucleic acids.

monomers escape through membrane and can be reused by cell

removes both material OUTSIDE the cell and obsolete components of the cell itself

morphologically diverse

2

Lysosomal Sorting Pathway: step 1

phosphorylation of lysosomal enzymes via mannose-6-phosphate

3

Lysosomal Sorting Pathway: step 2

binding of lysosomal enzyme to M6P receptor, followed by budding via clathrin coated pits

clathrin--adaptin--M6P receptor through membrane--M6P-L.Enzyme

4

Primary Lysosomes

enzymes inactive
storage site of lysosomal hydrolases
homogenous enzymes

5

Secondary Lysosomes

site of catalytic process
carries digestive enzymes
actively enzymatic

6

Pathways for intracellular degradation

1. Receptor mediated endocytosis
2. Autophagy
3. Phagocytosis

7

Development of Lysosomes

Primary Lysosome buds from Golgi and fuses with an early endosome. Clathrin recycled.

Early endosome matures into Late endosome, secondary lysosome buds from late endosome

8

Lysosomes are formed from

fusion of transport vesicle with endosome

9

internal pH of late endosome =

5.5

10

Familial hypercholesterolemia

mechanism of cholesterol uptake is disrupted
elevation of LDL, the predominant cholesterol transport protein in plasma

11

Primary defect of hypercholesterolemia

defect in LDL receptor

12

Peroxisomes, also called

microbodies

13

Peroxisomes are a diverse group of organelles. They contain enzymes that ______ and which in turn can be broken down by ______

produce hydrogen peroxide
H2O2 is then broken down by catalase

14

function of the microbody (peroxisome)

hydrogen peroxide production
beta oxidation of long chain fatty acids
bile and cholesterol synthesis
detoxify alcohol

15

what do we "often" find in the core of the peroxisome

"urate oxidase" crystalline core

16

Peroxisome disorder

Zellweger spectrum disorder
peroxisome biogenesis disorder
12 genes required for peroxisome synthesis: defect in any one of these genes will result in disorders on the Zellweger Spectrum

17

Zellweger syndrome

absent or reduced number of peroxisomes in the cells

syndrome present in patients at birth, has no cure, causes dead within the first year of life

18

spaces in the mito

intermembrane space
cristae space
matrix

19

space mitochondria take up in the cell

around 20%

20

mitochondria are associated with what cellular skeletal system

microtubular cytoskeleton

21

Where are the mitochdonria the least dynamic and why

high energy cells: they are more "fixed", and have to pack into tight spaces between myofibrils around flagellum of sperm cells

22

two associations of the mito in the cell talked about in class

mito associated with microtubular cytoskeleton
mito associated with ER (ER can cleave the mito)

23

3.75 billion years

first living cells

24

2 billion years

aerobic respiration becomes widespread

25

1 million years

first multicellular plants and animals

26

Evolutionary sequence leading to present day mito carrying eukaryote

an anaerobic prokaryote split into an anaerobic eukaryote and an aerobic prokaryote

eukaryote consumed the prokaryote
symbiosis

27

components of mtDNA

ATP Synthase subunits, NADH dehydrogenase subunits, cytochrome oxidases, cytochrome b,

28

Differences between the mitochondrial code and the "universal code"

UGA doesnt make STOP is makes Trp
AUA doesnt make Ile it makes Met
AGA/AGG doesn't make Arg it makes STOP

29

200 diseases related to mitochondrial DNA defects. What do a large number of these diseases effect?

tRNA genes: often mutations prevent tRNA aminoacylation

30

UGA codes for ____ and ____ in universal vs mtDNA

STOP = universal
Trp = Mt

31

AUA codes for _____ and _____ in universal vs mtDNA

Ile = universal
Met = mt

32

AGA/AGG codes for _____ and _____ in universal vs mtDNA

Arg = universal
STOP = mt

33

Mitochondrial DNA diseases can come from two places

either nucleus encoded or defects in mtDNA

34

Mother's Curse

theory: susceptibility to mito disease come from mom. this allows male harming defects to accumulate in mitochondrial genomes: they may benefit women but harm the dudes

35

Mitochondrial DNA and Aging

accumulation of ROS-generated by the respiratory chain can cause mito damage

less efficient DNA replication and repair mechanisms

ROS increases with AGE: