Biological Molecules I Flashcards
Marcomolecules
- Composed of
molecular subunits
Supramolecular Complexes
- Assembly
of macromolecules
Cells and organelles
Comprised of
supramolecular complexes
Biomacromolecules
- Natural polymers (MW > 5000) are assembled from
monomers with MW < 500, usually
Amino acids form
- Protiens and are part of amide chemistry
Fatty acids form
- Phospholipids which are part of ester chemistry
Carbohydrates form
- Poly saccarides which are part of acetal chemistry
Nucleobases form
- Nucleic acids which is part of phosphoester chemistry
Biomacromolecules assembly and function
- Interact with one another to form cellular structures in specific highly regulated ways
- Responsible for cellular functions and are weak reversisble and reliant on cellular shape
Important structural factors of Biomacromolecules
- Chiral molecules which exist as
single enantiomers - Stereospecific specific configurations in the interacting molecules
- Water is the solvent of all biochemical processes, and it often acts also as a reactant in biochemical reactions
Carbohydrates
- Carbon (C), Hydrogen (H), Oxygen (O) atoms
- Monosaccharide Molecular Formula: Cm(H2O)n
- Empirical Formula (most simple sugars)
Deoxyribose
- Missing OH group compared to normal carbohydrate
Carbohydrate Structure
Monosaccarides
- Carbohydrates that cannot be hydrolysed to simple compounds
- Contains a single poly hydroxy alderhyde or ketone
Disaccharides
- Sugars that can be hydrolysed to monosaccarides
- Sicrose
Polysaccarides
- Carbohydrates that can be hydrolysed to monosaccharides
- Cellulose
Classification of monosaccharides
- Number to carbons - trios and tetrose
- Whether sugar contains ketone or alderhyde group
- Sterochemical configuration furthest away from carbonyl group
- D if OH close to carbonyl group (right side) and L if not close to carbonyl (left)
When do D and L sugars usually form
- D forms in naturally occouring sugars
- L forms in the enantiomers
Epimers
- Diastereomers that differ in the sterochemistry of a single carbon
Carbohydrate Chemistry
- Reactions catalysed by trace of strong acid hemi acetl
- Generally unstable and nucleophillic addiction to C=O
Steps of carbohydrate chemistry
- Protonation of carbonyl group
- OH group acts as a nucleophile
- Deprotonation gives a cyclic hemiacetyl
-5- and 6-membered cyclic hemiacetals are
stable
Aldohexoses
- Favour six membered rings
- Hemiacetal link inbetween alderhyde carbon and hydroxyl group on C5
Anomers of monosaccharides
- Diastereomic product anomer
- First carbon is anomeric carbon only boned to 2 O
- In distilled water at room temp - alpha anomer inter convert to form mixture
Reactions with carbohydrates
- Reduction with NaBH4 and nickel catalyst
- Oxidation - monosaccharide is a reducing sugar can act as a reducing agent free aldehyde and ketone group
Formation of aldonic acid
- Addition of bromine water to Aldose forms aldonic acid
Formation of aldaric acids
- Addition of nitric acid forming aldaric acid from aldose
Glycoside formation
- Form glycosidic bond from addition of alcohol and H+
- Form aglycone OCH3
Alkylation to give ethers and esters
Add excess alkyl halide and Ag2O forms ether
Add Ac2O pyridine to form ester
Maltose
Glucosidic linkage 1,4 alpha antomer
Cellobiose
1,4 glucosidic linkage beta glucoside linkage beta antomer
Disaccharides lactose
Beta 1,4 galactosidic linkage
Beta anomer galactosidic linkage
Axial 4-hydroxy group of galactose
Gentiobiose
- Beta 1,6 glycosidic linkage beta anomer
Sucrose
- Alpha-D-glucopyranosyl-beta-fructofuranoside
- Alpha anomer glycosidic link on glucose
Alpha and beta anomer fructose and sucrose
Polysaccharide
Carbohydrate that contains monosaccharides joined by glycosidic bonds
Oligosaccharides
- Smaller polysaccharide contains 3 - 10 monosaccharide units
Anomeric carbon and glycoacidic links
- Except units of chain all anomeric carbon atoms are involved in glycosidic links
Cellulose
Polysaccharide of D glucose monomers
Stronger than steel
Dietry fibre not digested
Low fibre constipation and gut diseases
High fibre reduce cholesterol and risk of diabetes
Polysaccharide function
- Intracellular energy store - starch plants polymers of glucose
- Rigid structure of the cell walls
- Extra and intracellular signalling attached to membranes proteins and lipids
Sweeteners
- Steviol glycosides unusual glycosidic bond hard to break
Lactulose
- Beta 1,4 glucosidic linkage
- Galactose and fructose beta anomer
- Osmotic laxative not naturally occurring
Water accumulation and unusual mode of action no target
Cardiac Glycoside
Digitalis Lanata source of cardiovascular disease
Foxgloves - toxic to cardiac glycosides
Digoxin - used for heart failure and CV conditions monitor for toxicity
Glucosamine
- Simple amino sugar supplement for joint health
Polysaccharide in cells
- Attached to proteins on surface of cells
- Important mediators of cellular communication
ABO blood groups
DNA and RNA
- Hold genetic info
- DNA carries genetic info
- RNA uses the info to make bio molecules and components of cell
Primary structure of DNA and RNA
phosphide ester bond linn two nucleotides
Restriction on rotation sugar forms puckered
- 4 atoms in single plane
- Fifth atom C2 and C3 i the same ending or opposite exo to C5
DNA and RNA secondary structure
- 2 chains of DNA in opposite directions double strand base pair allow specific H bonding
Aldopentose + Ketohexoses
- Formation of a six membered ring
