3.13 Amino Acids,DNA And Proteins Flashcards
What groups make up an amino acid?
- Amine
- Carboxylic acid
- R group
What are the features of chirality in amino acids?
- All chiral except glycine
- Form two non super impossible mirror images as enantiomers
Are Amino acids an acid or a base?
Both as they are amphoteric
How do amino acids react with acids/bases?
- Acids= Amine group reacts
- Bases= Acid group reacts
What happens if the R group is also an amine/acid group in an acid base reaction?
Both of the reacting groups will react
What is a zwitterion?
A species with two ions
What are the properties of an amino acid?
- FOund as white solids
- Conduct electricity when aqueous/molten
What reactions do amino acids undergo?
- Acid + Base
- Acid + Alcohol—> Ester + H2O
- Nucleophilic substitution with a halogenoalkane
- Nucleophilic addition-elimination with an acyl chloride
- Condensation reaction to make proteins
How can peptides/polypeptides be hydrolysed?
- Can be heated with conc HCl or conc NaOH
- Hydrolyses the substance and breaks the peptide bond
How are proteins formed?
Condensation reactions between amino acids
What bonds bond proteins?
Peptide bonds
What is the primary structure of a protein?
- The sequence of amino acids in proteins/polypeptide
What is the secondary structure of proteins?
- Alpha Helix- corkscrew/spiralling of chain held in place by hydrogen bonds
- Beta pleated sheets- chains fold into parallel strands and H bond occurs further down the chain
What is the tertiary structure of proteins?
- The folding og the secondary structure into more complex shapes
What interactions occur within the tertiary structure of a protein?
- Hydrogen bonding
- van der waals
- disulfide bridges
- Ionic bonds
- Permanent dipole
What is the quaternary structure of a protein?
- Overall folding into a complex 3D shape so more than one polypeptide interacts with
What is stereospecificity?
The active site of an enzyme is selective of a shape of a substrate meaning it can catalyse only one of the enantiomers
What needs to be in place for an enzyme to work?
- Interactions between active site and enzyme need to be strong enough for substrate to be held in place long enough for it to be catalysed and weak enough for it to be released
How do drugstore work as enzyme inhibitiors?
- Enter active site and bind strongly to block it
- Bind to another part of enzyme which changes shape of active site
What are the three parts of DNA?
- A sugar
-A phosphate - A NItrogenous base
How many hydrogen bonds do G and C form?
3
How many hydrogen bonds do A and T form?
2
How does cisplatin stop a cancer tumour growing?
- Stops DNA replication
-Pt binds to N in guanine in DNA
What are some side effects of cisplatin as an anti-cancer drug and why?
- Stops healthy cell replication
- Can cause weakened immunity,hair loss etc.
Why do amino acids have different solubilities in chromatography?
- Different solubilities in mobile phase
- Different attraction to stationery phase
