Module 4, Lectures 1,2 Flashcards
What are the four major classes of organic molecules?
Carbohydrates
lipids
proteins
nucleic acids
What atoms categorize functional groups?
Oxygen, nitrogen, sulfur or phosphorus
Properties of alcohols?
Low Molecular weight Oh are water soluble
Hydrogen bonding
Undergo nucleophilic substitution reactions
Can be oxidised
Form esters with carboxylic acids
What can different types of alcohols be oxidised to?
Primary = aldehydes then carboxylic acids
secondary = Ketones
Tertiary are not readily oxidised
What is the difference between ethers and esters?
Ethers may be cleaved and are generally unreactive. Esters are easily cleaved by reaction with nucleophiles.
What is the difference between amines and amides?
Amines are very basic, whereas amides are not basic or nucleophilic
Thiols?
Thiol groups react like alcohols - the sulfur nucleophile
Disulfides?
Important reaction in organic chemistry.
Oxidation leads to disulfide that links peptide chain.
Phosphorus containing functional groups?
H3PO4 forms a series of phosphate esters where the OH groups are successfully replaced.by OR groups from alcohols.
Benefits/functions of Phosphorus containing functional groups?
Help to solubilise compounds in water.
Quite resistant to hydrogen bonding
What is the concept of Biological recognition?
The “host” component can be considered the larger molecule, and it encompasses the smaller, “guest”, molecule.
What factors control the shape of a host molecule?
Polar or non-polar internal attractions or repulsions
Steric effects - interaction of large groups avoided
Geometric constraints imposed by rigid structural vblocks
Aldehydes Vs Ketones?
Aldehydes are more reactive because the C of ketones is less attractive to nucleophiles.
• Steric: less hindered for the aldehyde. Aldehydes have at least one (small) H substituent. Ketones have two bulky substituents.
• Electronic: electron donating alkyl groups reduce d+ charge on C
of C=O. Ketones have two groups, aldehydes have one.
What is a carbonyl group/compound?
a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=OA compound containing a carbonyl group is often referred to as a carbonyl compound.
What are hemiacetals?
Hemiacetals and acetals dominate chemistry of carbohydrates. Eg glucose is a hemiacetal.
Carbon is attached to two oxygen atoms, one is an OH and the other OR.
How does a hemiacetal form?
When an aldehyde reacts with an alcohol.
What are acetals, and how are they formed?
Acetals are geminal-diether derivatives of aldehydes or ketones, formed by reaction with two equivalents (or an excess amount) of an alcohol and elimination of water.
What are imines and how are they formed?
Imines are the nitrogen analogues of aldehydes and ketones, containing a C=N bond instead of a C=O. bond. They are formed through the dehydration reaction of an aldehyde or ketone with an amine
Briefly describe the chemistry of vision?
Reversible attach compounds to proteins (eg retinal and opsin).
Different opsins give different photoreceptors optimal for different colours.
Isomerisation triggers a cascade of events that sends signal from the eye to brain.
Once this occurs photoreceptor is no longer active. the spent chromosome is exchanged for a fresh one and the imine link allows chromosome to be released.
