Enantiomers
Stereoisomers that are MIRROR IMAGES of one another
-Asymmetric carbon farthest from aldehyde determines D/L designation
d
...
Diastereomers
Stereoisomers that are NOT mirror images of one another
Anomers
Stereoisomers that DIFFER in configuration at the ANOMERIC carbon (carbon part of carbonyl group)
Epimers
Stereoismers that differ in configuration at ONE CARBON other than the ANOMERIC carbon
Aldehyde and ketone carbons are...
ELECTROPHILIC
Alcohol oxygen atom is..
NUCLEOPHILIC
When aldehydes are attacked by alcohols...
HemiACEtals form
When ketones are attacked by alcohols...
HemiKETALS are formed
Sugar phosphates are important intermediates in...
Metabolism, functioning as activated compounds in syntheses.
Reduction of the sugar carbonyl yields....
An alditol
Glycoside formation
The ELIMINATION of water between the HYDROXYL group of the anomeric carbon of a CYCLIC saccharide and HYDROXYLG group of another compounds yields ____.
Ribose
Standard FIVE CARBON sugar
Glucose
Standard SIX carbon sugar
GALACTOSE
Epimer of glucose at C4
MANNOSE
EPIMER of glucose at C2
Fructose
KETOSE form of glucose
Conformational isomers
Moleules with the SAME STEREOCHEMICAL configuration, but differ in the 3-D CONFORMATION (BOND ROTATION)
Monosaccharides can form polysaccharides via..
GLYCOSIDIC bonds
Sucrose, physiological role
- Fruits, seeds, roots, honey
-Final product of PHOTOSYNTHESIS, used as PRIMARY ENERGY
Lactose, physiological role
-Milk, some plant sources
-Major ANIMAL ENERGY source
Trehalose
-Yeast, other fungi, insect blood
-Major CIRCULATORY sugar in insects; used for ENERGY
Maltose
-Plants (starch) and animals (glycogen)
-Dimer derived from starch and glycogen polymers
Cellobiose
-Plants (cellulose)
-Dimer of the cellulose polymer
Gentiobiose
-Some plants (gentians)
-Constituent of PLANT GLYCOSIDES and some POLYSACCHARIDES
FOUR major features of disaccharides?
-Sugar monomers involved and their stereochemistry
-Carbons involved in linkage
-Order of sugars
-Configuration of the anomeric carbon
What is the delta G for glycosidic bond formation?
About +15 kJ/mol
-Activation is needed
In lactose biosynthesis...
The activated sugar is UDP-galactose
-Used as a high energy derivative of GALACTOSE that condenses with glucose to form LACTOSE
3 groups of polysaccharides
1. ENERGY STORAGE poly (starch and glycogen)
2. STRCTURAL poly (Cellulose)
3. LUBRICANTS (glycoaminoglycans)
Amylose secondary structure
The orientation of successive glucose residues favors the formation of a helix with a large INTERIOR core and stabilized by HYDROGEN bonds.
Glycogen and starch form...
GRANULES in cells
Granules contain...
Enzymes that synthesize and degrade these polymers (glycogen and starch)
Amylopectin
branched starch
Glycogen and amylopectin have...
ONE REDUCING end BUT MANY NONreducing ends
Reducing sugars
any sugar that is capable of acting as a reducing agent because it has a free aldehyde group or a free ketone group.
Nonreducing sugars
do not have an OH group attached to the anomeric carbon so they cannot reduce other compounds.
Examples of nonreducing and reducing sugars
All monosaccharides such as glucose are reducing sugars. A disaccharide can be a reducing sugar or a non-reducing sugar. Maltose and lactose are reducing sugars, while sucrose is a non-reducing sugar.
Enzymatic processing occurs in...
many NONREDUCING ends
Cellulose
Carbohydrate component of plant cell walls.
-Major structural polysaccharide in lants
Fibrous parts of plants include...
Other polymers:
-XYLANS
-GLUCOMANNANS
Fungi, bacteria, and protozoa secrete what?
CELLULASE
-Allows them to use WOOD as source of GLUCOSE
Most animals cannot use cellulose as a fuel source because..
-Fibrous and water-insoluble
-LACK ENZYME to hydrolyze (B1-->4) linkages
Ruminants and termites live...
SYMBIOTIALLY with microorganisms that produces CELLULASE
Glycosaminoglycans
-Polymers of REPEATING disaccharide units
-Serve structural and nonstructural purposes in vertebrates
-Connective, epithelial, and neural tissues
-Form matrices to hold together proteins in skin/connectie tissues
-Act as viscosity increasing and lubricant
TWO example of glycoasamnioglycans
1. HEPARIN
-Binds to ANTIPROTHROMBIN III and inhibits BLOOD CLOTTING
2. HYALUROONIC acid
-Abundant in synoival fluid of joints and vitreous humor of the eye; biological lubricant
Peptidoglycan
Bacterial (gram positive) cell walls have cross-linked multilayered polysaccharide-peptide complexes
Describe the long chain of peptidoglycan
Long chains of strictly alternating copolymers of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) are crosslinked through short peptides
Peptidolycan syntesis is site of...
ACTION of the earlist ANTIBIOTICS (such as penicillin)
-gram positive bacterial cell wall
Type A has...
GalNAc glycosyltransferase activity
Type B has...
Gal glycosyltranserase activity
Type AB has..
BOTH, while Type O has NEITHER
Universal blood donor
Type O
Universal blood receipeitn`
Type AB
Check slide 57 of lecture 11
yas
What is a target for antiiviral drugs?
Influenza neuraminidase
Influenza Neuraminidase
Breaks down protective mucus coating of the respiratory tract
Assists viral budding and release
Keeps viruses from sticking together
Participates in host cell fusion
Tamiflu
Oseltamivir
-Analog of sialic acid substrate
-Inhibits neuraminidase and BLOCKS release of newly formed virus particles from infected cells
Releae of virus at the conclusion of a cycle of infection requires....
Neuraminidase action to cleave SIALIC ACID (aka N-acetylneuraminic acid) from the remainder of N-linked oligosaccharide chains
Major functions of lipids
-Energy storage
-Membrane strucure, signaling
Lipids have..
LIMITED SOLUBILITY in aqueous media
-AMPHIPATHIC- contain both hydrophobic and hydrophilic regions
Lipids that DO NOT contain fatty acids
-Cholesterol
-Terpenes
Lipids that contain fatty acids
STORAGE AND MEMBRANE LIPIDS
waxes
fats and oils (triacylglycerols)
glycerophospholipids
prostaglandins
saturated fatty acid
a long-chain hydrocarbon with SINGLE covalent bonds in the carbon chain; the number of hydrogen atoms attached to the carbon skeleton is maximized
-BUTTERRR
UNSATURATED fatty acid
A fatty acid that has one or more DOUBLE bonds between the carbons in the hydrocarbon tail. Such bonding REDUCES the number of hydrogen atoms attached to the carbon skeleton.
-OILLLL
-One or more CIS C-C DOUBLE BONDS
OMEGA 3 fatty acids are...
ESSENTIAL nutrients
-Humans need them but CANNOT synthesize them
-including ALA, DHA, and EPA
What are fatty acid esters of glycerol?
TRIACYLGLYCEROL
Melting points of satrated and unsaturated
Unsaturated: LOWER MELTING points
FLUIDITY OF FATTY ACIDS..
Decreases as the chain LENGTH INCREASES and the number of CIS double bonds DECREASES
Fatty acids carry MORE ENERGY per carbon because they are...
MORE REDUCED
Fatty acids carry less WATER, per gram because...
THEY ARE NONPOLAR
GLUCOSE AND GLYCOGEN are for..
SHORT-TERM energy
-Needs quick delivery
FATS are for..
LONG TERM (months) ENERGY NEEDS
-Good STORAGE, SLOW delivery
Glycerophospholipids
Major class of NATURALLY OCCURRING phospholipids
-Phosphate containing head groups
Phospholipases
Hydroylze glycerophospholipids
Plasmalogen
A glycerophospholipid in which the C1 substituent linkage forms a vinyl ether that is more easily oxidized than its ester counterpart is called a ______.
Glycoglycerolipids
-second class of membrane lipids
-Carbohydrate linked to their HEAD GROUP
Sphingolipids
Third class of membrane constituents
-Fatty acid is LINKED to the AMINO ALCOHOL SPHINGOSINE via an AMIDE BOND
Glycosphingolipids
FOURTH class of membrane lipids
-GLYCANS attached to head groups� sphingolipids w/ head groups composed of sugars bonded by glycosidic linkages
-not phospholipids b/c they have no phosphodiester linkage
- found on the outer surface of the plasma membrane
Cholesterol
-Bulky, rigid structure disrupts regular FATTY ACID CHAIN packing in membranes
-WEAKLY AMPHIPATHIC because of OH
-Precursor to all steroids
Fatty acid esters of cholesterol are...
Extremely APOLAR
Steroids bind...
PROTEINS for transport into tissues
Vitamin D2 and D3
REGULATE Ca2+ METABOLISM
Lack of vitamin D leads to...
RICKETS
Vitamin A
Helps producing retinol for photoreceptors in LOW LIGHT conditions
-Synthesized by plants
Vitamin K
Particiaptes in BLOOD CLOTTING
- produce prothrombin, a protein and clotting factor that is important in blood clotting and bone metabolism
Vitamin E
Prevents OXIDATIVE DAMAGE
Natural waxes are formed when...
a lone chain fatty acid is ESTERIFIED to a long chain ALCOHOL
Waxes are completely water..
INSOLUBLE; because of the very small POLAR region
Soaps are formed by...
TREATMENT of fatty acids with STRONG BASES such as NaOH or KOH to form a SODIUM or POTASSIUM salt
Soaps form....
MICELLES around OILS
-EMULSIFYING the oil
UNLIKE soaps, synthetic detergents such as...
SDS are NOT precipitated by CALCIUM OR MAGNESIUM ions
Slide 41 review
yas
How does cholesterol impact fluidity?
increasing fluidity at LOW temperatures and decreasing fluidity at HIGH temperatures
-Acts as BUFFER
Bacteriorhodopsin
Pigmented protein found in abundance in the plasma membrane of the salt-loving archaeon Halobacterium halobium; pumps protons out of the cell in response to light.
Bacteriorhodopsin-Based Phototrophy
some archaea use a type of phototrophy that involves bacteriorhodopsin, a membrane protein which functions as a light-driven proton pump
a proton motive force is generated
an electron transport chain is not involved
E.g. Halobacterium
Protein Lipidation
POST-TRANSLATIONAL modifiations that anchor proteins to the membrane
Palmitoylation
The addition of palmitic acid (a 16-carbon fatty acid) to cysteine residues of a polypeptide chain.
Myristoylation
The addition of myristic acid (a 14-carbon fatty acid) to the N-terminal glycine residue of a polypeptide chain.
Geranylgeranylation
addition of gernalogeranyl
Famesyl
Addition of famesyl
Insertion of proteins into the membrane bilayer....
is a COTRANSLATIONAL process and requires the RIBOSOME and the TRANSLOCON, that acts as a MULTISUBUNIT complex that acts as a protein conducting channel
The translocon complex facilitates...
the insertion of HYDROPHOBIC regions of protein sequence into the bilayer
Flippase
requires ATP to transport lipids from one leaflet to another
-(P-type ATPase) moves PE and PS from outer to cytosolic leaflet
Floppase
(ABC transporter) moves phospholipids from cytosolic to outer leaflet
Scramblase
moves lipids in either direction, toward equilibrium
Chargaff's Rules
Mole percent of DNA base composition A=T and G=C
Net reaction of glycolysis
glucose + 2ADP + 2Pi + 2NAD+ ->
2 pyruvate + 2 ATP + 2 NADH + 2H+ + 2 H2O
net reaction of pentose phosphate pathway
3x Ribose 5 Phosphate --> 2x F6P and Glyceraldehyde 3 Phosphate (GAP)
Net reaction of gluconeogenesis
2 pyruvate + 4 ATP + 2 GTP + 2 NADH + 2H+ + 6 H2O -->
GLUCOSE + 4ADP + 2GDP+ 2NAD+ + 6PI
Net reaction of glycogen synthesis
Glycogen + G6P + ATP+ H2O -->
Glycogen + ADP+ 2Pi
Net reaction of glycogen breakdown
Glycogen +Pi -->
G6P + Glycogen