Organic - Amino Acids, Proteins & DNA Flashcards
(27 cards)
What is the boiling point of amino acids and why?
Melting point in excess of 200C due to ionic bonds.
Are amino acids soluble in water?
Yes, amino acids are soluble in water and other polar solvents
How do amino acid molecules undergo an internal acid-base reaction?
They contain an acidic carboxyl group and a basic amino group on the same molecule.
What is a zwitterion?
An ion with two charges (dipolar)
How do you name an amino acid?
1) Find the longest chain that contains the carboxylic acid group.
2) Number the carbons in the chain, starting with the carbon in the carboxylic acid group as number 1.
3) Write down the positions of any NH2 groups and show with the word ‘amino.’
Where on an amino acid is affected by changes in pH?
COOH and NH2
What are the charges on an amino acid zwitterion?
Positive on NH3+ and negative on COO-
What are the charges on an amino acid at a low pH?
Only positive on NH3+ and a normal COOH
What are the charges on an amino acid at a high pH?
Only negative on COO- and a normal NH2
What are some roles of enzymes in the body?
- Enzymes
- Muscle fibres
- Antibodies
- Bone
- Haemoglobin and chlorophyll
What is a dipeptide?
Two amino acids bonded together
In what process do two amino acids join?
In a condensation reaction
In what process do two amino acids seperate?
In a hydrolysis reaction
What is the primary structure of a protein?
The sequence of amino acids in a chain that makes up a polypeptide chain, joined by peptide bonds.
What is the secondary structure of a protein?
The peptide links can form hydrogen bonds with eachother, meaning that it produced a unique shape that can most likely be an alpha helix or beta pleated sheet.
What is the tertiary structure of a protein?
Extra bonds can form between different parts of the polypeptide chain, which gives the protein a 3D shape.
Where does hydrogen bonding occur in a protein?
Exist between polar groups (OH and NH2), they stabalise both the secondary and tertiary structure of the protein.
Where do disulfide bonds occur in a protein?
The amino acid cysteine contains a thiol group (-SH), these can lose their H atoms to form S-S disulfide bonds which help to stabalise the tertiary structure
What process can be used to identify unknown amino acids?
Thin Layer Chromatography (TLC)
What are the two ways amino acids can be visible on a TLC plate?
1) Ninhydrin
2) UV light
What are some functions and characteristics of enzymes?
- They catalyse every metabolic reaction in living organisms
- Enzymes are proteins, but some have non-protein compounds
- Every enzyme has an active site that a substrate fits into
- The active site is 3D and is part of the tertiary structure
What is an inhibitor?
Inhibitors compete with the substrate to bond to the active site, causing a slower rate of reaction.
What is cisplatin?
Cisplatin is a complex of platinum (II) with chloride ion ligands and two ammonia ligands in a square planar shape.
What is cisplatin used for?
An anticancer drug
