Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

bm210 biochemistry > B4 lipids > Flashcards

B4 lipids Flashcards

1
Q

what is the structure of a phospholipid

A

2 fatty acids joined to a glycerol mol with a phosphate and an alcohol tail

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

phosphatidylinositol (P1)

A

precursor of signalling mols

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

phosphatidylserine (P2)

A

a key eat me signal in apoptosis

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

phosphatidylcholine (PC)

A

structural component of membranes

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

phosphatidylethanolamine (PE)

A

donor of functional groups to some membrane anchored proteins; structural roles, regulates curvature

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

sphingomyelin

A

parent sphingolipid
a precursor of some signalling mols, involved in lipid rafts

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

cholesterol

A

can be as much as % of membrane lipid
key in regulating fluidity and permeability
involved in lipid rafts

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

each glycerophospholipid is a class with variations in what side chains

A

fatty acyl

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

fatty acids can be saturated or saturated
what does this mean

A

saturated (no double bonds)
unsaturated (double bonds)

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

how many Cs long is a fatty acid

A

12-22

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

lipids are amphipathic
what does this mean

A

have both hydrophobic and philic regions
in this case a hydrophobic tail and a polar head group

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

what does it mean for a membrane to be described as fluid

A

they accommodate protein conformational changes without loss of integrity

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

certain signals catalyse the breakdwon of Ptdlns (4,5)P2 into what

A

inositol triphosphate and diacylglycerol
both are key intracellular messengers

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

GPL biosynthesis is via what pathway and where

A

phosphatidate and within the ER

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

what is de novo glycerophospholip synthesis

A

combination of activated alcohol (headgroup) with diacylglycerol

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

what cellular lipid is a major component of lung surfactant

A

PC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what does PC normally maintain

A

surface tension of fluid to keep alveoli open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what does low PC result in

A

collapse of alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is respiratory distress syndrome and who does it affect

A

often premature babies
laboured breathing blue fingers/toes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how is respiratory distress syndrome treated

A

ventilation (O2) and artificial surfactant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is ceramide

A

precursor for sphingomyelin (the major sphingolipid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is ceramide synthesised from

A

synthesised from serine and palmitoyl-CoA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how are sphingolipids further modified

A

addition of sugars

24
Q

what are gangliosides

A

important in cell surface mols
highly prevalent in nervous tissue

25
Q

what is a disease involving gangliosides

A

tay sachs disease

26
Q

what does tay sachs disease involve

A

an inherited disorder
affects motor function, then vision, fatal by 3 years
can be diagnosed during pregnancy
no treatment available

27
Q

what causes tay sachs disease

A

inability to degrade gangliosides
(normally happens in lysosomes)
lysosomes (esp in neurons) fill with gangliosides

28
Q

what is sphingosine phosphorylated by and what does it produce

A

by sphingosine kinase
generating sphingosone 1-phosphate
a key signalling mol

29
Q

what is cholesterol

A

an essential component of membranes
helps maintain membrane bilayer integrity and regulates permeability

30
Q

what is cholesterol a precursor of

A

steriods, vitamins, and bile salts

31
Q

what is excess cholesterol associated with

A

cardiovascular disease

32
Q

what does cholesterol biosynthesis use

A

acetyl CoA

33
Q

3 steps of cholesterol biosynthesis

A
  1. synthesis of isopentyl pyrophosphate (via mevalonate) the building block of cholesterol
  2. condensation of 6 mols of isopentyl pyrophosphate to form squalene
  3. cyclisation of squalene and further processing to cholesterol
34
Q

how much does the rate of cholesterol synthesis vary and what is it dependent on

A

700 fold
depending on how much is in the diet

35
Q

the rate of synthesis is responsive to how much cellular cholesterol is present
what is this mechanism

A

feedback regulation

36
Q

what is the major site of cholesterol synthesis
and site of significant synthesis

A

liver
intestines

37
Q

what regulates cholesterol synthesis

A

HMG-CoA reductase
(integral membrane protein in the ER)

38
Q

how does HMG-CoA reductase regulate cholesterol synthesis

A

catalyses the committed step of cholesterol synthesis
its amount
its activity

39
Q

what are the 4 ways in which HMG-CoA reductase is controlled

A

-rate of synthesis of HMG-CoA reductase mRNA
-rate of translation of HMG-CoA reductase mRNA to protein
-rate of degradation of HMG-CoA reductase protein
-phosphorylation state of HMG-CoA reductase protein

40
Q

what transcription factor is used in the transcriptional regulation of HMG-CoA reductase

A

SREBP
sterol regulatory element binding protein

41
Q

what is SRE (sterol regulatory element) in transcriptional regulation of HMG-CoA reductase

A

region of HMG-Coa reductase gene to which DNA binding domain of SREBP binds

42
Q

what is the rate of translation of HMG-CoA reductase mRNA to protein inhibited by

A

nonsterol metabolites derived from mevalonate

43
Q

what senses increasing levels of sterols

A

HMG-CoA reductase membrane domain

44
Q

after increasing levels of sterols have been detected the membrane domain indirectly acts with what and what is the result

A

ubiquitinating enzymes
HMG CoA reductase becomes polyubiquitinated

45
Q

after HMGCoA red becomes polyubiquitinated what happens

A

is extracted from membrane and degraded by the proteasome

46
Q

what does phosphorylation do to the catalytic activity of HMGCoA red

A

decreases

47
Q

what is phosphorylation carried out by in regulation of HMG CoA reductase

A

AMP activated protein kinase

48
Q

what does phosphorylation of HMG-CoA red do to cholesterol synthesis

A

stops it

49
Q

how is cholesterol transported throughout the body and their structure

A

in body fluids in lipoprotein particles
hydrophobic lipid core, surrounded by polar lipids and proteins

50
Q

what is the good cholesterol

A

HDL (high density lipoprotein

51
Q

what is the bad cholesterol

A

LDL (low density lipoprotein)

52
Q

what are bile salts, where are they synthesised and stored

A

-detergents (solubilise dietary lipids)
-synthesised in liver
-stored in gall bladder and released into small intestine

53
Q

what are the 5 classes of steroid hormones

A

-progestagens
-glucocorticoids
-mineralcorticoids
-androgens
-oestogens

54
Q

what are statins

A

HMG-CoA reductase inhibitors
act as lipid lowering drugs to reduce cholesterol

55
Q

when are statins prescribed

A

if patient has at least one risk factor for coronary heart disease

56
Q

what are the 3 statins regularly prescribed

A

atorvastatin
fluvastatin
lovastatin

bm210 biochemistry (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions