Thread Of Life Flashcards
DNA description
Double-stranded helix
Made from: sugar (deoxyribose) phosphate group and bases
Phosphate and sugar groups bonded by
Condensation reaction
Base to sugar bonding
Condensation reaction
DNA stands held by
H bonding
Nucleotide contains
One sugar
One phosphate
One base
Nucleotide –> DNA
Condensation polymer
What data was used to support final DNA idea
X-Ray crystallography
Protein synthesis
DNA is unzipped, code is transcribed into mRNA (complimentary version of code.
mRNA passes from nucleus to cytoplasm where ribosomes translate the code. Codon (3 bases) code for one amino acid
A.a bought to ribosome by tRNA
RNA : DNA
RNA
Ribose
U
And single stranded
DNA
deoxyribose
T
Double stranded
DNA fingerprinting how it’s done
Sample is obtained and cut using restriction enzymes
Separated using electrophoresis
Each fragment marked with probe
Exposed on X-Ray film, producing pattern of black bars
Ownership issues with DNA fingerprinting
Who should have access to personal genetic information?
Who owns and controls genetic information?
Who owns genes and other pieces of DNA?
DNA testing issues with DNA fingerprinting
Should parents have the right to have their children tested?
Should tests be performed for genetic diseases?
Should an individual always be given his/her genetic info?
Rate of reaction =
Change in conc of reactant or product / reactant
Rise in temperatures affect on k
Increases it
Concentrations time graph and orders
\ = 0
Constant half life (L) = first
Half life not constant (L) = second
Rate - concentration graph
– = 0
/ = 1
Curve upwards (conc^2 = /) = second order
What’s an intermediate?
Chemical formed and destroyed during the course of the reaction
Rate determine step and order of reactants
Reactants in rate equation are in rate determine step
Stereoisomers :
Same molecular formula and atoms bonded in same order but arranged differently in space. 2 examples : E/Z and optical
Chiral centre
4 different atoms or groups of atoms attached to it
Optical isomers/enantionemers
What’s a racemic mixture
50:50 mixture of d- and l- optical isomers
How do optical isomers behave differently
Behave differently in the presence of other chiral molecules
Optically active molecules rotate the plane of plane-polarized light in different directions.
Laevorotatory (l-) rotates anti clockwise
Dectrorotatory (d-) rotates light clockwise
Why are amino acids bifunctional
Contains both amino and carboxyl functional group. When both on same C = alpha amino acid
zwitterion-
Amino acids
Positive group and negative group at same time
Naming dipeptides
Start at NH2 end
Primary structure of a.a
Sequence of a.a
Secondary structure of a.a
Polypeptide forms aloha helix or beta pleated sheet
Hydrogen bonding
Tertiary structure of a.a
Overall shape of a.a
Due to
I’d-I’d
Hydrogen bonding between polar side chains
Ionic bonds between ionizable side chains
Covalent bonds (eg sulfur bridges )
Hydrolysis of peptides/proteins
Amide hydrolysis
Reflux
Mod conc acid/alkali
How do you identify a.a from t.l.c
Ninhydrin as a locating agent
Ph affect on a.a
Disrupts ionic interactions
Rate equation for low concentration of substrate
Rate=k[s][e] plenty of active sites for substrate to bind to
Rate of reaction at high conc of substrate
Rate = K[e] as all active sites are saturated
Why are enzymes good in industry
Specific
Effective at low temp
Work well in aqueous environment
Often convert reactant to product in one step -increases atom economy
