lipids

Question 1

what are lipids

Answer 1

heterogeneous organic molecules

very insoluble
hydrophobic

Question 2

what are lipids functions

Answer 2

stores of energy 
structural elements of membranes
enzyme cofactors 
hormones 
vitamins 
signalling molecules

Question 3

what are the lipid vitamins

Answer 3

ADEK

Question 4

what are the main classes of lipids

Answer 4

fatty acids
triacylglycerol (adipose tissue)
phospholipids
glycolipid (lipid with carb attached) 
steroids

Question 5

what are fatty acids

Answer 5

hydrocarbons chains with a carboxylic acid group

saturated or unsaturated

Question 6

how do we name fatty acid

Answer 6

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

Question 7

saturated fatty acid has…

Answer 7

no kinks

Question 8

what are the 4 categories of Fatty acids

Answer 8

essential
good fats
bad fats
really bad fats

Question 9

what are essential fatty acids

Answer 9

linoleic and alpha linoleic

get from plants as cant synthesis fats longer than 6C

Question 10

what are good fats

Answer 10

good in cardiovascular terms

high in polyUNSATURATED fatty acids (vegetable oils)

Question 11

what are bad fats

Answer 11

high in SATTURATED fatty acids
BEEF
stearic acid

Question 12

what are really bad fats

MAN MADE

Answer 12

Trans fatty acids

come form hydrogenation of vegetable oils - margarine

Question 13

when can bad (saturated) fats sometimes be good

Answer 13

saturated fats play an important part in myelination

Question 14

what is omega 3

Answer 14

derived from linoleic acid
lowers plasma cholesterol
lowers TAG

Question 15

what is TAG (triacylglycerol’s)

Answer 15

a ESTER of fatty acids and glycerol

water insoluble and collect into droplets

dietary fuel and adipose tissue insulation
`

Question 16

what are phospholipids

Answer 16

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

are also amphipathic

Question 17

what does amphipathic mean

Answer 17

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

Question 18

where are most lipids digeste

Answer 18

the small intestine

Question 19

how are TAG molecules digested

Answer 19

small intestine - pancreatic enzymes

emulsification by bile salts and peristalsis

Question 20

what dose digested TAG become and by what enzyme

Answer 20

it becomes a monoacylglycerol and two fatty acids

Question 21

what do bile salts act as

Answer 21

biological detergent

and creates micelles

Question 22

what is produced when cholesterol esters are digested

Answer 22

broken down into cholesterol and a free fatty acid

Question 23

what do phospholipids become and how

Answer 23

they are hydrolysed to become a Fatty acid and a lysophospholipid

Question 24

how are lipids taken up

Answer 24

by micro villi
DIFFUSION

short and medium fatty acids diffuse across without micelles

long chain FA need a micelle created by bile salts

Question 25

what forms a micelle

Answer 25

bile salts

Question 26

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

Answer 26

get steatorrhea oily and smell like shit excess lipids

Question 27

what happens after absorption

Answer 27

the intestinal cells resynthesize the fats TAG

Question 28

what happens to TAG once its resynthesized

Answer 28

its insoluble so packaged up into chylomicrons these are then released by exocytosis into the lymph

Question 29

what happens when chylomicrons reach tissue

Answer 29

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

Question 30

where is lipoprotein lipase found

Answer 30

capillaries in adipose tissue and skeletal muscle e

Question 31

what happens once the chylomicron is depleted of TAG

Answer 31

becomes chylomicron remnants and go to the liver

Question 32

how are FA release from TAG

Answer 32

in response to adrenaline | hormone sensitive lipase is release

Question 33

how are fatty acids transports

Answer 33

free FA binds to serum albumin (plasma protein) most are esterified and carried by lipoproteins

Question 34

what are lipoproteins

Answer 34

transports fats hydrophobic cores TAGS hydrophilic surface phospholipids

Question 35

what do LDL carry

Answer 35

cholesterol rich - bad liver to tissue atherosclerosis

Question 36

what do HDL carry

Answer 36

cholesterol rich | from tissue and arteries to liver - converted to bile salts

Question 37

what dose the beta pathway do

Answer 37

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

Question 38

where dose beta oxidation occur

Answer 38

in the mitochondria matrix

Question 39

what are the 3 stages of beta oxidation

Answer 39

activation transport degradation

Question 40

how are FA release from the TAG in adipose tissue

Answer 40

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

Question 41

what happens during activation why

Answer 41

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

Question 42

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

Answer 42

using the carnitine

Question 43

what dose each beta oxidation cycle release

Answer 43

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

Question 44

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

Answer 44

2 carbons shorter

Question 45

what happens to really long FAs to be broken down

Answer 45

undergo preliminary beta- oxidation in peroxisomes | then diffuse in to mitochondria

Question 46

what takes the fatty acyl across the inner mitochondrial membrane by which enzyme

Answer 46

carnitine translocase

Question 47

what binds the fatty acyl to carnitine

Answer 47

carnitine transferase 1

Question 48

what unbinds the carnitine from the fatty-acyl

Answer 48

carnitine transferase 2

Question 49

what is carnitine

Answer 49

a non essential amino acid made from lysine

Question 50

what inhibits the carnitine fatty-acyl transferase

Answer 50

malonyl CoA

Question 51

where is malonyl CoA used other than as an inhibitor what dose this mean

Answer 51

in fatty acid synthesis FA synthesis and degradation cant occur simultaneously

Question 52

what dose the amount ketogenisis depend on

Answer 52

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

Question 53

what are ketones | what are they used by

Answer 53

water soluble transporters of Acetyl CoA cardiac, skeletal muscles the brain

Question 54

when are ketone bodies made

Answer 54

during fasting or starvation

Question 55

where are ketones made

Answer 55

in the liver (liver cant use ketones)

Question 56

how are ketones transported

Answer 56

soluble in blood | don't need albumin or lipoprotein

Question 57

where dose fatty acid synthesis occur

Answer 57

in the cytoplasm liver, mammary gland, adipose tissue

Question 58

what happens with excess ketones

Answer 58

lead to blood pH drops and go into a coma

Question 59

how does acetyl CoA synthesise Fatty acids

Answer 59

needs to be transferred from matrix to cytoplasm via the citrate shuttle then malonyl-CoA

Question 60

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

Answer 60

NADH becomes NADPH

Question 61

how is malonyl CoA forms

Answer 61

using the enzyme Acetyl CoA carboxylase on Acetyl CoA

Question 62

what are eicosanoids

Answer 62

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

Question 63

what are eicosanoids important precursors for what are these used in

Answer 63

prostaglandins (pain), thromboxane (clotting), leukotrienes used in inflammation, CNS messengers

Question 64

what dose aspirin inhibit

Answer 64

thromboxane (clotting)

Question 65

what to steroid hormones do what is the starting material for these

Answer 65

chemical messengers cholesterol