EXAM II Material Flashcards
Ribonuclease/Deoxyribonuclease
Converts long RNA/DNA chain to short RNA/DNA oligomer
Phosphodiesterase
Converts RNA/DNA oligomers into nucleotide monophosphates (NMPs) or deoxynucleoside monophosphate (dNMPs)
Nucleotidase*
Converts NMPs and dNMPs to nucleosides and deoxynucleosides
Nucleotide –> Nucleoside
Nucleosidase
Removes the base from the ribose or deoxyribose
Xanthine oxidase
Converts Hypoxanthine (precursor of something that the body can get rid of) to Xanthine
And Xanthine to Uric acid
Drug target for treatment of gout
Contains 2FADs, 2Mo atoms, 8Fe atoms per molecule of enzyme
Allopurinol
Inhibits the action of Xanthine Oxidase
Prevents the build up of uric acid which can lead to gout
Urate Oxidase
Catalyzes the oxidation of uric acid into Allantoin - a soluble compound
Gout symptoms
Painful, inflammed joints; mainly effects big toe (metatarsal pharangeal joint); can form cystals bc nonsoluble
Causes of Gout
Over production of uric acid; primary hyperuricemia
Underexcretion of uric acid; secondary hyperuricemia
Sodium urate crystals precipitate in synovial fluid of joints; deposits in kidney; acute inflammatory response via phagocytic cells engulfing crystals and releasing factors that initiate this
Diet rich in beans, lentils, spinach w/ meat, seafood, OH
Types of organic solvents that lipids are soluble in
Ethanol (alcohols)
Oils
What is the greatest biologically significant property of lipids, contributed by ____?
Hydrophobicity, contributed from FA (hydrocarbon tails); ability to form the bilayers and michelles
What does it means to be ionized?
When a atom/molecule gains or loses electrons; FA at ionized at physiological pH and have a (-) charge at the carboxy end
Palmitic acid –> Palmitate (16:0)
Oleic acid –> Oleate (18:1)
Structure of Triacylglycerols (TAGs)
Glycerol backbone with 3 acetyl acid goups
Derivatives of TAGs can serve as:
Hormones, Signal Molecules, and Intracellular Messengers
How would you name this from both ends? assume n=4
- From omega end: omega-3
- From carboxy end: cis-delta7
What are the EFAs?
Omega-3 = Linoleate (18:2)
Omega-6 = Linolenate (18:3) Octadecatrienoic; Veggie oils
Omega-6 Arachidonate (20:4) Hemp oil
Which FA configuation is most common in the body?
Cis (always)
Ex: oleic acid - non ionized
Oletate = ionized
What are the major 3 functional classes of FA?
NEFAs
Omega-3s and Omega-6 Essential FA
What are the 2 NEFAs?
Palmitic acid (16:0) Hexadecanoic - ionized = palm oil
Stearic acid (18:0) Octadecanoic - ionized = several uses
What enzyme converts RNA to DNA?
Ribonucleotide reductase
oxy –> deoxy
List common:
Disaccharides
Oligosaccharides
Polysaccharides
Di = sucrose, maltose, lactose
Oligo = glycoprotein, glycolipid
Poly = Glycogen, starch, cellulose
Special features of the archaeon
Single-celled organism
- Avoids hydrolysis bc it has an ether bond b/w Phosphate head group and glyerol backbone (ROR)
- Branched and Saturated (linear) = more resistant to oxidation
- Inverted stereochemistry of central C in glycerol backbone
3 major membrane lipids
Phospholipids = PGs
Glycolipids = cerebroside
Cholesterol
Components of Phospholipid?
- Glycerol backbone
- 2 FAs (hydrophobic)
- Phosphate group = philic
- Alcohol = philic
Phosphoglycerol components:
- Glycerol backbone
- 2 Acyl groups (FA) (RCOO)
Unsaturated FA usually occupy C2, Sat = C1
- Phosphate + Alcohol
What is the intermediate in forming a number of phospholycerides?
Phosphatidate/Diacylglycerol 3-P
Glycerol backbone, 2 acyl/FA, P
Small amounts present in membrane
What are the 5 Phosphoglycerides that are derived from Phosphotidase? What type of bond is formed?
Ester bond; Carb. acid & OH DSACI
- Diphosphatidylglycerol - Inner mito membrane
- Phosphatidylserine - memory & cognition
- Phosphatidylamine - nervous tissue
- Phosphatidylcholine - cell membrane, pulmonary surfactant
- Phosphatidylinositol - signaling
Components of Sphingolipids
- Sphingosine backbone
- Long, unsaturated hydrocarbon chain bound with double bond
- Amino OH (NH3+, 2 OH = all diff Cs on backbone)
Sphingomyelin components
A Sphingosine = Phospholipid; membranous myelin sheath
- Sphingosine backbone
- Phosphotidase-derived group (Phosphotidylcholine)
- FA bound with amino group via Amide bond
- Unsaturated Hydrocarbon Chain
Glycolipid components
- Sphingosine backbone
- Unsaturated hydrocarbon chain
- Amino group
- Sugar residue linked to OH (ECM = polar)
Cerebroside Components:
Complex Glycosphingolipid in muscles and nerve cell membranes (Monoglycosylceramides)
- Sphingosine backbone
- Long, unsaturated hydrocarbon chain
- Glucose or Galactose bound to OH
- FA bound to amino group
Why is cholesterol considered a sterol?
Contains branched aliphatic side chain of 8-10 C atoms
Contains an OH goup
What type of bonds are associated with the bilayer?
Noncovalent
What are the charge distributions along a bilayer membrane?
Phobic = negative (ICM)
Philic = positive (ECM)
Membrane is electrically polarized
What are the driving forces of lipid bilayer formation?
- Hydrophobic Interactions (predominate)
- VDW (b/w lipid tails)
- Electrostatic (b/w polar heads and water)
List the 3 things that occur due to the hydrophobic interactions of membranes
- Extensive membranes are usually formed
- Self-sealing occurs bc it is energetically favorable = thermodynamic stability
- The bilayers close on themselves forming closed compartments maintaining its integrity
Lipid bilayers have low permeability for:
Ions and polar molecules
i.e. Glucose (+)
What type of interactions are peripheral proteins involved with in the lipid bilayer and how can they be removed?
H-bonds and Electrostatic
Can be removed via salt or pH changes
List 2 examples of integral membrane proteins?
- Bacteriorhodopsin (BR)
light-driven proton pump; mainly alpha-helices (most common transmembrane structure bc flexible)
- COX 1/PGHS 1 integral protein but not membrane spanning
Function of lipids on lipid bilayer and how are they attached?
Consitute/mediate protein-protein interactions and covalently associated with proteins
What 3 modifications do lipid-linked proteins perform on the lipid bilayer?
- Palmitoylation
- Farnesylation
- GPI
Palmitoylation
One of the lipid-protein modifications
Covalent attachment via thioester bond of FA to a cys residue
Farnesylation
Covalent attachment of a farnesyl unit (C15) to C-terminal tetrapeptide (CAAX) with the further addition of a thioether linkage w/ Cys residue
Anchors protein to membrane & protein-protein interaction
GPI Anchor
Anchors proteins to outer leaflet of plasma membrane
Common with cell-surface hydrolytic enzyme and adhesions, tethered to cells via GPI
What are the 2 compartments of the mito membrane?
- Intermembrane space = Oxidative Phosphorylation
- Matrix = TCA and FA oxidation