Lecture 4 Organics Flashcards
What are amides?
Strong smelling functional groups which replace hydrogen with a NH2 group
What is the functional group of an amide?
R-NH2
True or False? Amides are similar to alcohols?
True
Is ammonia solution and ammonium hydroxide the same thing or different things?
The same thing
Are amides weak or strong bases?
Weak bases and can act as buffers
How many lone pairs do amides have?
One lone pair of electrons and therefore has a trigonal bipryamidal shape
What is a primary amide?
When there is 1 carbon bonded to N
What is a SECONDARY amide?
When there is 2 carbons bonded to N
What is a TERIARY amide?
When there is 3 carbons bonded to N
Amides are similar to what?
Carboxylic acids with the hydroxyl group being replaced with the amine group
True or False? The chemistry of amides is similar to that of carboxylic acids
True
Are amides less or more acidic than carboxylic acids?
Less acidic because the nitrogen is much less able to stabilise the negative charge
Primary amides are formed by what?
Reacting a carboxylic acid with ammonia aka condensation reaction
If the attacking group is an amine what is the product?
A secondary amide. aka condensation reaction, water is lost
Is the amide bond or ester bond much more easily hydrolisable?
Amide bond due to the lower electronegativity of the nitrogen. This has important consequences for the amides in biological systems
Secondary amides and esters are the basic compounds of what?
Many commercial polymeric compounds
True or False? Amides hold many polymers together making proteins
True
What is kevlar?
A tough amide polymer that gains its strength from the hydrogen bonds that occur between amide proteins and carbonyl groups
What is switterion?
a molecule or ion having separate positively and negatively charged groups.
What is the n-terminus?
The N-terminus is the start of a protein or polypeptide referring to the free amine group (-NH2) located at the end of a polypeptide.
What are disulfide bridges?
A functional group with the structure R−S−S−R′. The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups
What are amino acids?
The building blocks of proteins
What is the structure of an amino acid?
An R group, An acid group, A hydrogen, and An amino group all surrounding a carbon
What gives amino acids their different properties?
The different R-groups. This also gives proteins their 3D shape and properties
Are amines acidic or basic?
basic
Are carboxylic acids acidic or basic?
Acidic
What is the zwitterionic form?
Sits in between the extremes of the amino acids. Its charges balance to give a neutral compound that is soluble in water
What are peptides?
Molecules containing at least one peptide bond (secondary amide between two amino acids)
What are proteins?
Polypeptides constructed of many amino acids all held together by peptide bonds
True or False? Breaking of a peptide bond is very slow in water
True
True or False? Small peptides are never the basis for medicinal chemicals.
False
How do we read the sequences of residues of amino acids?
From the N-terminus to the C terminus.
LHS to RHS
How many different amino acids are there?
20
How are proteins able to catalyse reactions?
Because proteins have complex three dimensional structures
What do enzymes do?
Catalyse reactions that allow for life to occur.
Are the peptide links in proteins floppy or stiff?
Floppy with free rotation about most bonds
Interactions in the protein chain cause what?
Folding which forms the secondary structure
Which interactions cause the secondary structure of proteins?
Non-covalent hydrogen bonding interactions give the a-helices and b-sheets in the secondary structure
What does the tertiary structure of proteins depend on?
How the primary and secondary structures are arranged.
What can the tertiary structure interactions be?
Hydrogen bonds, ionic, or covalent (disulfides) bonds
How is the quarternary structure of proteins formed?
Several tertiary protein structures clump together.
Where is energy stored in ATP?
In the phosphate bond
