Brar Flashcards
Triglycerides (TAGs)
packaged w/cholesterol, phospholipids and proteins to form VLDL
MTP
assembles VLDLs into chylomicrons
Where are VLDLs processed?
golgi complex
What happens to cAMP levels and lipolysis during fasting?
cAMP levels rise due to decrease in insulin and rise in glucagon; this stimulates lipolysis
How do saturated FAs affect cholesterol?
They elevate it
How do monounsaturated FAs affect cholesterol?
lower cholesterol and LDL
Beta oxidation
breaks down even chain FA through 4 steps producing ATP and acetyl CoA
Carnitine deficiency
compromises skeletal mm and liver during fasting
Medium Chain Acyl CoA Dehydrogenase Deficiency (aka MCAD Disease)
most common inherited defect in the beta oxidation sequence;
affected enzyme catalyzes the first reaction in beta-oxidation of medium chain;
sx: fasting hypoglycemia during infancy/childhood; pt may die during first hypoglycemic attack
Refsum disease
defect in peroxisomal alpha-oxidation
What are High HDL levels associated with?
decrease risk for heart disease
What role do peroxisomes play in FA oxidation?
only site for very long chain FA oxidation
Omega oxidation
alternative pathway to beta oxidation; produces dicaboxylic acids that can be utilized in beta oxidation
Peroxisomal A-, B-
oxidation and microsomal omega oxidation are not feedback regulated; they fxn to lower levels of water insoluble compounds which resemble FAs that are toxic
Alpha oxidation
used in peroxisomes to break down dietary phytanic acid which cannot undergo beta oxidation
Beta oxidation
FA molecules are broken down in mito to generate acetyl CoA (enters krebs)
Malonyl CoA
serves as an intermediate 2 C donor to a growing chain; inhibits carnitine palmitoyltransferase I; prevents movement of FAs into mitochondria
What is the relationship between linoleic acid and arachidonic acid?
Linoleic acid is elongated and desaturated into arachidonic acid which is an immediate precursor for most prostaglandins
What is phospholipase A2 and what does it have to do with snake venom?
a compound that causes hemolysis by lysing the phospholipid cell membranes of RBCs; it is found in snake venom!
What does the carnitine shuttle do?
utilized in transporting fatty acyl CoA into mitochondrial matrix
Carnitine Palmitoyl Transferase I (CPT I)
couples carnitine to free FA
Carnitine Palmitoyl Transferase II (CPT II)
removes carnitine group; regenerates carnitine
What are the 4 reactions in beta oxidation?
- Dehydrogenation
- Hydration
- Oxidation
- Thiolysis
How many ATPs are generated by each turn of beta oxidation?
17
What extra enzymes are needed to metabolize unsaturated FAs?
Enoyl CoA Isomerase (for monounsaturated FAs) and 2,4-dienoyl CoA reductase (for PUFAs)
When are ketone bodies produced?
In the absence of glucose, during fasting
Vasopressin
aka ADH; regulates water retention; raises BP
Oxytocin
uterine contractions, delivery of milk from glands, bonding/trust
Glucagon
causes liver to convert glycogen to glucose
Secretin
regulates duodenal pH
Glutathione
reducing agent
Describe the structure of polypeptide chains
Primary: determined by sequence of AA
Secondary: formed by different regions of sequence (alpha helices, beta strands)
Tertiary: packing elements into globular unit
Quaternary: several pp chains interacting called subunits
Hydroxyl AA
form covalent bonds with carbohydrates
Proline
introduces kinks into protein chains
Why do people with phenylketonuria (PKU) have light complexions and how do you tx?
because the problem with phenylalanine hydroxylase affects the synth of melanin; tx by severely restricting phenylalanine but not eliminating it completely because it is essential!
Sarin, malthion
form covalent bond at active site of acetylcholinesterase
Production of ammonia
Glutamate + NAD+ –> a-ketoglutarate + NADH + NH3
Assimilation of ammonia
Glutamate + NH3 + ATP –> glutamine + ADP + Pi
Nitrogen balance
nitrogen consumed - nitrogen excreted
When is the nitrogen balance zero?
in healthy adults
When is the nitrogen balance positive?
childhood, pregnancy, muscle building, healing
When is the nitrogen balance negative?
protein malnutrition, deficiency of essential amino acids, stress
Glucogenic AAs
Alanine, Arginine, Asparagine, Aspartate, Cysteine, Glutamate, Glutamine, Glycine, Proline, Serine, Histidine, Methionine, Threonine, Valine
Ketogenic AAs
Leucine, Lysine
Which AAs make Acetyl-CoA?
Isoleucine, Leucine, Tryptophan
Which AAs make Acetoacetyl CoA?
Leucine, Lysine, Phenylalanine, Tryptophan, Tyrosine
Which AAs make Pyruvate?
Serine, Threonine, Glycone, Tryptophan, Cysteine, Alanine
Which AAs make Oxaloacetate?
Aspartate, Asparagine
Which AAs make a-ketoglutarate?
Proline, Arginine, Histidine, Glutamine, Glutamate
Which AAs make Succinyl-CoA?
Methionine, Valine, Threonine, Isoleucine
Which AAs make Fumarate?
Phenylalanine, Tyrosine, Aspartate
Folic acid
receives 1 C fragments from donors and transfers them to intermediates in the synth of AAs, purines and thymidine monophosphate
What inhibits heme synth?
Iron, lead, heme
Which AAs make Catecholamines?
Phenylalanine, Tyrosine
Which AAs make Serotonin?
Tryptophan
Which AAs make Histamine?
Histidine
Which AAs make Glutathione?
Glutamate, Cysteine, Glycine
Which AAs make Nitric Oxide?
L-Arginine
What makes NAD/NADP?
Niacin
Which AAs make Thyroid Hormones?
Tyrosine
Adenosine Deaminase (ADA) Deficiency
converts adenosine –> inosine; causes severe combined immunodeficiency (SCID); kids die before 2 yo
Gout
hyperuricemia w/recurrent attacks of acute arthritic joint inflammation; tx: allopurinol
