Polymers, Amino Acids & DNA Flashcards
Condensation Polymer definition
In a condensation reaction, two molecules join to form a larger one, with a small molecule such as H2O or HCl being released
Two main types of condensation polymers
- Polyesters - formed from carboxylic acids and alcohols.
- Polyamides - formed from carboxylic acids and amines.
Terylene
Uses:
Carpets, clothing.
Heat treated polyesters used for drinks bottles
Nylon 6,6
Uses:
Nylon is used as fibres in clothing
Properties: Elastic, strong abrasion resistant
Kevlar
Kevlar is used in the manufacture of body armour and crash helmets.
Properties: Strong, light and heat resistant
Drawing 2 dipeptides
2= opposite way round
Disposal of Polymers
Addition polymers are not biodegradable.
Addition polymers have non polar C-C bonds they cannot be hydrolysed.
At present these types of polymers are either incinerated or buried.
Condensation polymers are biodegradable as the delta positive C of the polar C-O bond can be attacked by nucleophiles
Hydrolysis of Polyesters
Hydrolysis of Polyamides.
Amino Acids
Zwitterions
NEUTRAL pH and in the solid state
This means amino acids have high melting points due to the strong electrostatic attractions between each zwitterion.
In ACIDIC Conditions
In ALKALINE Conditions
Forming Peptides
- If two amino acids join together they form a dipeptide
- If three amino acids join together they form a tripeptide
- If more than three amino acids join they form a polypeptide
The peptide bond can also be called an AMIDE LINK
NH2 group on the left, the COOH group on the right.
When two amino acids join together water is lost, this is a condensation reaction.
Primary (1ᵒ) Structure
sequence of amino acids
Secondary (2ᵒ) Structure
form hydrogen bonds
Hydrogen bonds form because:
- electron deficient H, attracts the lone pair on the O
- O2 highly electronegative
- large difference in elec neg between C=O/N-H
Tertiary (3ᵒ) Structure
held in place by:
- Hydrogen bonds
- Some ionic interactions (i.e. the COO- on one amino acid, and the NH3+ on another)
- Disulfide bonds
a disulphide bond is much stronger than a H-bond so has a greater affect on the tertiary structure on a protein.
Enzymes
proteins which catalyse biological processes, catalyse just one type of reaction
- The substrate binds loosely to the active site by intermolecular forces.
- This reduces the Ea to break bonds within the molecule and catalyse the reaction.
- active site = stereospecific (one optical isomer fits)
Chiral centre = more than one enantiomer, only 1 enantiomer fits into active site, not 100% efficient
How can an inhibitor prevent enzyme catalysing reactions
- inhibitor fits into a stereospecific active site of enzyme
- blocks substrate from binding to the site
Using tech to prevent enzymes replicating
- computer modelling maps stereospecific active site
- molecule designed to fit into site and block substrate
What is DNA made up of
- A phosphate
- A sugar
- A base
Datasheet
State the meaning of complementary
ADENINE ALWAYS BONDS TO THYMINE WITH 2 HYDROGEN BONDS
GUANINE ALWAYS BONDS TO CYTOSINE WITH 3 HYDROGEN BONDS
Draw a ring around cystine molecule
Cell Division
(1) This is the strand of DNA which is going to replicate itself
(2) The hydrogen bonds between base pairs break, and the two strands start to unravel
(3) New nucleotides come and attach to the separate strands. A always pairs with T, C always pairs with G.
(4) The new nucleotides polymerise together by forming a phosphate-sugar bond. This creates a second ‘complementary’ strand of DNA, giving two full DNA molecules:
Anti-cancer Drugs
- Cis-platin will also bind to the DNA in healthy cells.
- This can cause unwanted side effects.
- The cis-platin drug can be targeted straight to the cancer cells to reduce the effect on healthy tissue.
- It can also be used in minimal amounts
