Lipid Metabolism

Question 1

Tay Sachs disease

Answer 1

Lack of HEXA which breakdown gangliosides

Cherry red spot in macula (eye)

Question 2

Structural lipids includes

Answer 2

Phospholipids and Glycolipids

Question 3

Phospholipids include, and their structure

Answer 3

Glycerol phospholipids/Phosphoglyceride

Glycerol backbone with two FA via ester linkage and choline/ethanolamine via phosphodiester linkage

I.e. Plasmalogens = cardiomyocytes plasma membrane. Protection against radicals

Question 4

Sphingolipid structure

Answer 4

Sphingosine backbone with FA via amide linkage

I.e. Sphingomyelin - neuron myelin sheath

Question 5

Glycolipids include

Answer 5

Glycosphingolipids and Gangliosides

Question 6

Glycosphingolipid

Answer 6

Sphingosine backbone with FA.

Involved in nerve impulses

Simple - cerebroside
Complex - 2+ goboside

Question 7

Ganglioside

Answer 7

Nerve tissue

ABO blood group
Oligosaccharide head attached to Salic acid residues

Stem cell markers

Question 8

Saturated fats

Answer 8

Unbranched, single bonds, solid at room temp

I.e. Palmitic acid

Question 9

Monosaturated Fats

Answer 9

1 double bond
Waxy.

I.e. Palmitoleic acid.
Oliec

Question 10

Polyunsaturated fats (PUFAs)

Answer 10

Two or more double bonds

Cis = healthy

I.e. Arachidonic acid
Linolenic

Question 11

Triaglycerides include:

Answer 11

Glucagon (mobilize) and insulin (store) –> lipoprotein lipase releases TG for storage

Question 12

Chylomicrons

Answer 12

Largest and least dense

Synthesized in ER of small intestine

Core lipid: dietary TG, cholesterol esters

B48, C,E

Question 13

ApoC

Answer 13

A lipoprotein lipase enzyme converts TG to free FA and glycerol which is stored and oxidized in the target tissues

Question 14

ApoE

Answer 14

Binds liver receptors involved in Chylomicron uptake to be degraded

Question 15

B48

Answer 15

Acquires ApoC and ApoE from HDL while moving through blood and lymph system

Question 16

VLDL

Answer 16

High in diet fat, cholesterol and converted into TG and packaged in muscle and adipose tissue for storage and usage

Core lipids - endogenous TG

B100, ApoC, ApoE

IDL is a remnant and converted to LDL

Question 17

LDL

Answer 17

Synthesized via VLDL

Core lipids- endogenous cholesterol, esters

ApoB-100

Cholesterol converted to extra hepatic tissue

Question 18

HDL

Answer 18

Synthesized in liver and nascent intestine

Core lipid - endogenous

ApoA, ApoC, ApoE = nascent HDL

Collects cholesterol via all transfer proteins towards liver to be excreted.

Question 19

Equation to determine cholesterol levels = plaque

Answer 19

LDL = VLDL - IDL

Question 20

Abetalipoproteinemia

Answer 20

Deficiency in ApoB48 and ApoB-100

Low LDL, VLDL, CHylomicrons = no absorption or transport

Symptoms: fatty stool, early death

Question 21

Familial defective ApoB-100

Answer 21

Mutant in ApoB-100

LDL receptor binding problem resulting in high cholesterol LDL levels

Autosomal dominant

Question 22

ApoA

Answer 22

Good

High HDL component

Question 23

ApoB

Answer 23

Bad

High chylomicrons, VLDLs and LDLs

MI risk assessment using ApoB/ApoA ratio

Question 24

Zellwegers syndrome

Answer 24

No peroxisomes

Facial features, liver, CNS

Question 25

Infantile Refsum Disease

Answer 25

High serum copper and iron, acidic serum and CSF Hypomyelination

Question 26

ELISA function

Answer 26

To measure Ag-Ab quantification of hormones/enzymes/NTs that are present in blood/tissues/fluids,etc. The target protein is the Ag, then lab made Ab binds Direct, Indirect, and Sandwich (most sensitive)

Question 27

Neimann Pick Disease

Answer 27

Rare autosomal recessive Acid sphingomyelinase enzyme = accumulation of sphingomyelin in brain, spleen, liver Mental retardation Type A: neurological, early infancy Type B: non-neurological, no mental retardation, preteen

Question 28

HMG-CoA Reductase

Answer 28

Rate limiting step of cholesterol biosynthesis, forming Mevalonate from HMG-CoA. Activated by insulin which dephosphorylates HMG via protein phosphatase Inhibited by glucagon/Epi which activates protein kinase which phosphorylates HMG-CoA Reductase

Question 29

Systemic primary carnitine def.

Answer 29

No carnitine transporter Low plasma carnitine High urine carnitine Muscle weakness, hypoketotic hypoglycemia

Question 30

CPT-1 def

Answer 30

Long chain FA cannot go into mito High plasma carnitine Early childhood

Question 31

CPT-II def

Answer 31

Adult form- not fatal, muscle damage Severe infantile form - sudden death risk Fatal neonate form - highly fatal

Question 32

Intermediates of the biosynthesis of cholesterol

Answer 32

1. Isopentenyl-pyrophosphate 2. Geranyl-pyrophosphate 3. Farnesyl-pyrophosphate ---> prenylated proteins such as: Rho/Ras, Dolichol, ubiquinone/Coenzyme Q, Heme a

Question 33

SREBP - sterol regulatory element binding protein

Answer 33

Promotes transcription of HMG CoA reductase forming endogenous cholesterol biosynthesis During low Intracellular cholesterol