3.13 DNA

Created by

Heather ward

Cards (33)

Sketch and label an amino acid.
Like this
are all amino acids chiral?
yes apart from glycine
Draw the ion formed by amino acids in acid solution.
Like this
Draw the ion formed by amino acids in basic solution.
like this
Recall 2 properties of zwitterions.
White solids with high mpts
Soluble in water
Recall the secondary structure of proteins.
H bonds form between peptide links
Why do we call amino acid amphoteric
Because they can act as both acids and bases
what is the general formula for amino acids?
RCH(NH2)COOH
how do we name amino acids
find the longest carbon chain and turn it into oic acid
C1 is whichever is bonded to the double bond O
whichever C the NH2 is bonded to is the prefix
what is the equation for amino acids and acid?
NH2CH2COOH + HCl = N+H3CH2COOH + Cl-
what is the reaction for amino acids with bases
NH2CH2COOH + NaOH = NH3CH2COO- + Na+ + H2O
what are zwitterions?
particles with both a positive and negative charge which are formed by the donation of a hydrogen ion from the carboxylic to amine group
why are amino acids soluble in water
they form hydrogen bonds between the O on the molecule with the H in the water
why are amino acids MPT and BPT so high?
they are ironically bonded which is stronger than covalent
what pH do zwitterions form at?
it varies and depends on the R group
in acidic conditions (low pH) what happens if the R group contains an NH2
that R group also gains a H+
in alkali solutions (high pH) what happens if the R group contains an NH2
it will also lose a H+
what is an isoelectric point
the specific pH for a molecule which zwitterions will form
how are proteins formed
condensation reactions which forms a peptide bond and releases a molecule of water
how are proteins split into amino acids?
hydrolysis reactions with 6moldm3 HCl, 110 degrees and reflux over 24 hours
what is the primary structure of proteins
individual sequence of amino acids
What are enzymes
Biological catalysts which speed up metabolic reactions
why are amino acids complimentary
because they are chiral they are only complimentary to one enantiomer
what is stereospecifity
how amino acids and only complimentary to one enantiomer due to the chiral centre
how do antibiotics work
they bind to the active site of the enzyme which is responsible for building the cell wall. if the cell wall cant be made then it will burst and die
What is cisplatin
An anti cancer drug with a square planar complex consisting of a platinum metal ion liganded to 2 ammonia and 2 chloride ions
how does cis platin work
it binds to dna in cancer cells and stops it from reproducing which kills the cell as it cant repair itself
the chloride ions in the complex are easy to displace and can detach from the complex which allows the platinum to bind to the nitrogen atom on guanine bases of dna
as cis platin binds to dna it creates a distortion in the dna strand meaning it can no longer be unwinded and copied.
what is cis platin used in?
chemotherapy as in the long term it works to eliminate cancer
what are the weaknesses of cis platin
it also affects healthy cells and stops them from reproducing. this affects blood which can suppress the immune system and increase the risk of kidney damage. it can also prevent hair cell regeneration
how can the cis platin side effects be reduced
lower dosage and ore targeted delivery to reduce the attack on healthy cells
How do H bonds form
One of the atoms in two separate bonds are very electronegative which causes the bonds to be polar
if one of the electronegative atoms (must be NOF) has a lone pair of electrons then it will form hydrogen bonds with the delta positive H in the other bond
Name the sugar in dna
2 deoxyribose
An adverse effect of cisplatin is that it also prevents normal healthy cells from replicating.
Suggest one way in which cisplatin can be administered so that this side effect is minimised.
Administer in small amounts