lipids Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what are lipids

A

heterogeneous organic molecules

very insoluble
hydrophobic

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

what are lipids functions

A
stores of energy 
structural elements of membranes
enzyme cofactors 
hormones 
vitamins 
signalling molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the lipid vitamins

A

ADEK

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

what are the main classes of lipids

A
fatty acids
triacylglycerol (adipose tissue)
phospholipids
glycolipid (lipid with carb attached) 
steroids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are fatty acids

A

hydrocarbons chains with a carboxylic acid group

saturated or unsaturated

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

how do we name fatty acid

A

18: 0 - 18 carbons no double bond
18: 1 - 18 carbons - 1 double bond

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

saturated fatty acid has…

A

no kinks

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

what are the 4 categories of Fatty acids

A

essential
good fats
bad fats
really bad fats

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

what are essential fatty acids

A

linoleic and alpha linoleic

get from plants as cant synthesis fats longer than 6C

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

what are good fats

A

good in cardiovascular terms

high in polyUNSATURATED fatty acids (vegetable oils)

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

what are bad fats

A

high in SATTURATED fatty acids
BEEF
stearic acid

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

what are really bad fats

MAN MADE

A

Trans fatty acids

come form hydrogenation of vegetable oils - margarine

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

when can bad (saturated) fats sometimes be good

A

saturated fats play an important part in myelination

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

what is omega 3

A

derived from linoleic acid
lowers plasma cholesterol
lowers TAG

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

what is TAG (triacylglycerol’s)

A

a ESTER of fatty acids and glycerol

water insoluble and collect into droplets

dietary fuel and adipose tissue insulation
`

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

what are phospholipids

A

made of glycerol, two fatty acids and a phosphate group - has an ester link

are also amphipathic

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

what does amphipathic mean

A

has a phosphate head which is hydrophilic and hydrophobic tales (2 FAs)

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

where are most lipids digeste

A

the small intestine

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

how are TAG molecules digested

A

small intestine - pancreatic enzymes

emulsification by bile salts and peristalsis

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

what dose digested TAG become and by what enzyme

A

it becomes a monoacylglycerol and two fatty acids

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

what do bile salts act as

A

biological detergent

and creates micelles

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

what is produced when cholesterol esters are digested

A

broken down into cholesterol and a free fatty acid

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

what do phospholipids become and how

A

they are hydrolysed to become a Fatty acid and a lysophospholipid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how are lipids taken up

A

by micro villi
DIFFUSION

short and medium fatty acids diffuse across without micelles

long chain FA need a micelle created by bile salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what forms a micelle

A

bile salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what happens if pancreatic lipase is inhibited or you can uptake fats

A

get steatorrhea
oily and smell like shit
excess lipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what happens after absorption

A

the intestinal cells resynthesize the fats TAG

28
Q

what happens to TAG once its resynthesized

A

its insoluble so packaged up into chylomicrons

these are then released by exocytosis into the lymph

29
Q

what happens when chylomicrons reach tissue

A

TAG hydrolysed into FA and glycerol (used in glycolysis) by lipoprotein lipase

the FA are then used for energy or made back into TAG for storage

the chylomicron remnants then head to the liver

30
Q

where is lipoprotein lipase found

A

capillaries in adipose tissue and skeletal muscle e

31
Q

what happens once the chylomicron is depleted of TAG

A

becomes chylomicron remnants and go to the liver

32
Q

how are FA release from TAG

A

in response to adrenaline

hormone sensitive lipase is release

33
Q

how are fatty acids transports

A

free FA binds to serum albumin (plasma protein)

most are esterified and carried by lipoproteins

34
Q

what are lipoproteins

A

transports fats
hydrophobic cores TAGS

hydrophilic surface
phospholipids

35
Q

what do LDL carry

A

cholesterol rich - bad
liver to tissue
atherosclerosis

36
Q

what do HDL carry

A

cholesterol rich

from tissue and arteries to liver - converted to bile salts

37
Q

what dose the beta pathway do

A

degrades fatty acids 2 carbons at a time to form Acetyl CoA, NADH and FADH2

38
Q

where dose beta oxidation occur

A

in the mitochondria matrix

39
Q

what are the 3 stages of beta oxidation

A

activation
transport
degradation

40
Q

how are FA release from the TAG in adipose tissue

A

hormone
to make ATP into cAMP
makes activated protein kinase which release free FA

41
Q

what happens during activation

why

A

FA becomes fatty acyl CoA in cytoplasm

the addition of the CoA makes this energetically feasible

which is too big to diffuse in to the mitochondria

42
Q

how dose the fatty acid acyl CoA get from the cytoplasm to the mitochondria matrix

A

using the carnitine

43
Q

what dose each beta oxidation cycle release

A

1 acetyl CoA
1 NADH
1 FADH
and a shorter carbon species

44
Q

how much shorter is the fatty acid after each beta oxidation cycle

A

2 carbons shorter

45
Q

what happens to really long FAs to be broken down

A

undergo preliminary beta- oxidation in peroxisomes

then diffuse in to mitochondria

46
Q

what takes the fatty acyl across the inner mitochondrial membrane

by which enzyme

A

carnitine

translocase

47
Q

what binds the fatty acyl to carnitine

A

carnitine transferase 1

48
Q

what unbinds the carnitine from the fatty-acyl

A

carnitine transferase 2

49
Q

what is carnitine

A

a non essential amino acid made from lysine

50
Q

what inhibits the carnitine fatty-acyl transferase

A

malonyl CoA

51
Q

where is malonyl CoA used other than as an inhibitor

what dose this mean

A

in fatty acid synthesis

FA synthesis and degradation cant occur simultaneously

52
Q

what dose the amount ketogenisis depend on

A

limited supply/used up oxaloacetate and a build up of acetyl CoA

53
Q

what are ketones

what are they used by

A

water soluble transporters of Acetyl CoA

cardiac, skeletal muscles
the brain

54
Q

when are ketone bodies made

A

during fasting or starvation

55
Q

where are ketones made

A

in the liver (liver cant use ketones)

56
Q

how are ketones transported

A

soluble in blood

don’t need albumin or lipoprotein

57
Q

where dose fatty acid synthesis occur

A

in the cytoplasm

liver, mammary gland, adipose tissue

58
Q

what happens with excess ketones

A

lead to blood pH drops and go into a coma

59
Q

how does acetyl CoA synthesise Fatty acids

A

needs to be transferred from matrix to cytoplasm

via the citrate shuttle

then malonyl-CoA

60
Q

what is made during the citrate shuttle while getting acetyl CoA in to the cytoplasm

A

NADH becomes NADPH

61
Q

how is malonyl CoA forms

A

using the enzyme Acetyl CoA carboxylase

on Acetyl CoA

62
Q

what are eicosanoids

A

signalling molecules made by the oxidation polyunsaturated fatty acids (omega 3)

63
Q

what are eicosanoids important precursors for

what are these used in

A

prostaglandins (pain), thromboxane (clotting), leukotrienes

used in inflammation, CNS messengers

64
Q

what dose aspirin inhibit

A

thromboxane (clotting)

65
Q

what to steroid hormones do

what is the starting material for these

A

chemical messengers

cholesterol