Biological molecules Flashcards
Facts
All life on earth share a common chemistry, this provides indirect evidence for evolution.
Despite their great varied, the cells of all living organisms contain only a few groups of carbon based compounds that interact in a similar ways
Our most common component in cells is water
Carbohydrates
Proteins form many cell structures
They are also important as are they enzymes, chemical messengers and components of the blood
Nucleic Acids
Carry the genetic code for the production of proteins
The genetic code is common to viruses and to all living organisms, providing evidence for evolution
Biomolecules
A group of chemicals found in ALL living organisms.
All molecules are made up of atoms
Covalent bonds
Atoms share a pair of electrons in their outer shell producing a more stable molecule
Ionic bonding
The transfer of electrons result in ions with opposite charges attract each other creating an electrostatic attraction.
Hydrogen bonding
Formed when electrons in covalent bonds are unevenly distributed leading to the formation of permanent dipoles
+ dipoles is attracted to lone pair of electrons on an oxygen or nitrogen atoms making a weak electrostatic bond
Collectively these can be very strong
Monomers and Polymers
Monomers are small subunits that can be linked together to form long chains called polymers
This happens by polymerisation and makes macromolecules.
Joining monomers to make polymers involve condensation reactions
Breaking down polymers to produce monomers involve a hydrolosis
Condensation Reaction
Joins two molecules together with the formation of a chemical bond and involves the elimination of a water molecule.
Bonds the smaller components together into larger molecules
Hydrolosis reaction
Breaks a chemical bond between two molecules and involves the use of water
Breaks larger molecules (polymers) into smaller components (monomers)
Smaller molecules can easily diffuse into cells or transported by protein channels
Metabolism
Collective name of the chemical processes that takes place in living organisms
Solute, solvent and solution
A solute is a substance dissolved in a solvent:
Solute + Solvent = Solution
Solvent= a liquid that has dissolved a substance
Solute= the substance that has dissolved
Solution= the final product after dissolving has happened
Carbohydrates
Made up of carbon, water and oxygen
They are sugars (saccharides)
1. Monosaccharides
2. Disaccharides
3. Polysaccharides
Monosaccharides
The monomers from which larger carbohydrates form
E.g. glucose, glactose and fructose
Monosaccharides are sweet tasting and soluble
Formula: CH20(3-7)
Isomers
Molecules with identical chemical formulas but distinct arrangements
Alpha glucose Beta- Glucose
H H H OH
OH OH HO H
Disaccharides
Pairs of monomers join to form a disaccharides
Glucose+glucose=maltose+water
Glucose+fructose=sucrose+water
Glucose+galactose=lactose+water
How do disaccharides form
Condensation reaction between two monosaccharides forming a glycosidic bond (water removed)
How do Disaccharides split
Hydrolysis reaction breaks the glycosidic bond (addition of water), splitting the disaccharides into two monosaccharides.
Polysaccharides
Polymers are formed by condensation reactions between many monomer glucose units
Examples;
Glycogen and starch are formed by condensation of alpha-glucose
Cellulose formed by condensation of Beta-glucose
Test for reducing sugars
Test: Benedict’s reagent
Process: Heat liquid sample( water bath for 5 minutes) with Benedict’s
Positive result: blue-red
Due to the reduction of copper(II) sulfate in Benedict’s to form insoluble red precipitate copper(I) oxide
Semi- quantatuve test for reducing sugars
Estimates fhe approximate amount of reducing sugar in a sample
Blue= none
Green= very low
Yellow= low
Orange= medium
Brick red= high
Examples of monomers
Amino acid, nucleotide, monosaccharide
Examples of polymers
Protein, cellulose, starch and glycogen
What is the process of adding monomers to a growing chain called and what type of reaction is involved?
Polymerisation and Condensation
What is the process of removing monomers from a chain and what type of reaction is involved?
Depolymerisation and Hydrolosis
What type of bond do condensation reactions form between two monomers?
Covalent bonds
What components are involved in a hydrolysis reaction that releases an amino acid?
Polypeptide and Water
Products of condensation reactions
- condensation of amino acids produce proteins
- condensation of two monosaccharides produces disaccharides (many disaccharides form polysaccharides
- condensation of fatty acids and monoglycerides produces lipids
Products of hydroloysis
- Hydrolysis of proteins produces amino acids
- Hydrolysis of carbohydrate produces disaccharides and monosaccharides
(Disaccharides= two monosaccharides joined together) - Hydrolysis of lipids produces fatty acids and monoglycerides
Hydrolysis of proteins
Produces amino acids
Hydrolysis of carbohydrate
Produces disaccharides and monosaccharides
Hydrolysis of lipids
Produces fatty acids and monoglycerides
