Bartling Exam 1 Study Guide Flashcards
What is the solid storage form of lipids found primarily in adipose tissue?
Triglycerides
What molecule is central to both carbohydrate and fat metabolism?
Acetyl-CoA
Fatty Acid Structure and Physical Properties
Longer chain -> poorer solubility, higher melting point
Less double bonds -> poorer solubility, lower melting point
Major class of polar membrane lipids derived from phosphatidic acid
Phospholipids
Fatty acids are esterified to what molecule?
Glycerol -> Triglyceride
Sphingolipids
2nd largest
Sphingosine backbone, non-saponifiable (amide linkage)
Cell surface recognition sites (RBC type)
Bacterial endotoxin
Long O-antigen side chains
Lipid A: hydrophobic anchor- inflammatory response
Lipopolysacharide
Cholesterol
- Only in animal fat
- Made in liver
- Controls membrane fluidity
- Storage and transport
- Steroid hormone precursor
Steroid Hormones
- No alkyl chain (unlike cholesterol)
- More polarity than cholesterol
- Move through blood stream attached to protein carriers
Terpenes
- Simple lipids w/out fatty acid
- 2 isoprenes
- Flavors and odors
- Vitamin precursors
How is lipid metabolism regulated?
Controlled by rate of triglyceride hydrolysis in adipose tissue.
Regulated by hormones (insulin, glucagon, epinephrine, cortisol)
What is the carnitine shuttle?
Fatty acyl-CoA too large and polar to penetrate inner membrane -> FA transferred to carnitine -> antiport mechanism brings carnitine with FA in
Products of beta-oxidation of even-numbered FA?
Fatty Acyl-CoA (with 2 less carbons)
1 mol each of:
Acetyl-CoA
FADH2
NADH
Beta-oxidation products of unsaturated FA
Already partially oxidized -> Less FADH2 and less ATP
Beta-oxidation products of odd-number FA
Same as even until last rxn -> Propionyl-CoA instead of Acetyl-CoA -> Succinyl-CoA -> TCA cycle
Beta-oxidation products of branched FA
Can’t beta oxidase, so alpha oxidation instead -> CO2 and Acetyl OR Propionyl-CoA
What is a ketone body?
- Carbonyl w/2 R groups branching off
- Formed during fasting/starvation (rich energy source)
- Spares glucose and degradation of muscle protein for gluconeogenesis
Acetyl-CoA Carboxylase
Phosphorylation (glucagon) inhibits, Dephosphorylation (insulin) activates.
Enzymatic and carrier protein function.
Forms Malonyl-CoA from Acetyl-CoA (stage 1 lipogenesis)
Malate Shuttle
Transports Acetyl-CoA out through inner mitochondrial membrane by transfer of two-carbon units (citrate out, malate in)
Main fat storage info molecule
Protein hormone
Reduces appetite, increases energy expenditure
Leptin
Fatty Acid Synthesis Steps
- Priming of cysteine group with Acetyl-CoA
- Malonyl-CoA transferred
- 3-ketoacyl synthase catalyzes rxn of acetyl group and malonyl residue
- Malonyl-CoA displaces ACLU group
- Rxn repeated 7X
Catalyzes hydrolysis of ester bonds -> glycerol and FA for fuel
Lipase
Group of drugs that act to reduce levels of fats (triglycerides/cholesterol) in blood
Statins
Bile Acids
- Formed in liver, stored in gallbladder
- Emulsifies fats into micelles
- Derived from cholesterol
Carbohydrate Chirality
D- hydroxyl group on R
L- hydroxyl group on L
Anomeric Carbon- when cyclic sugar is formed through tautomerization -> new asymmetric center
Most abundant carbohydrate in nature?
Cellulose (plant cell walls)
Starch vs Glycogen
Starch- plants, alpha 1,4
Glycogen- animals, alpha 1,6
Amino sugar found in bacterial cell walls and connective tissues as hyaluronate?
Peptidoglycan (murein)
Lipids or Carbohydrates more energy?
Lipids. FA are more “reduced” than carbs; FA are no polar and not hydrated by water
How many stereoisomers can be made from aldoses?
2^n (number of asymmetric centers)
Why has glucose been evolutionary selected as blood sugar?
- It exists in nonreactive, inert, cyclic conformations
- Least oxidizable and least reactive with protein
- Highest percent of sugar found in cyclic form
Relationship between sugars and blood types?
Blood determined by sugars located on head groups.
- NAG: A antigen
- Gal: B antigen
- NAG + Gal : AB antigen
- No NAG or Gal: O antigen
Polar lipids from phosphatidic acid (Phosphatidylcholine, Phosphatidylserine, etc.)
Ester bonds (saponifiable)
Glycerophospholipids
Primary starting material of Glycerol-3-phosphate for synthesis of phosphatidic acid
Liver- Glycerol
Adipose- Glucose
Sphingolipids with covalently bound sugars (blood typing)
Glycolipids/Glycosphingolipids
