Molecular Biology Flashcards
How many codons in normal eukaryote cells?
64 in total.
61 code for amino acids.
3 code for stop codons.
What does DNAa do?
Recognises the Ori region and gives a conformational change in the DNA to start unwinding.
What does DNAb do?
DNAb is helicase. It’s a six unit ring structure that unzips the DNA, knocking off anything in the way.
What does DNAc do?
DNAc breaks open the hexomer of helicase and mounts it on the DNA strand, before repairing the hexomer.
In Transcription what is promoter and what is it recognised by?
The promoter is the -35 & -10 regions and they are recognised by the Sigma factor.
In DNA Replication what is the promoter and what is it recognised by?
The Ori region is the promotor and it is recognised by DNAa.
What terminates Replication?
Topoisomerase or telomerase.
What terminates Transcription?
The formation of a hair-pin loop or Rho protein.
A Millimetre is how large?
10^-3 metres
A nanometre is how large?
10^-6 metres
A micrometer is how large?
10^-9 metres
What is AB1157?
The wild type strand of E.coli.
In a Molecular Biology lab what three things must you check before you start an exercise?
That you have been provided the correct equipment foe the experiment.
Find out where and at what temperature the experimental organisms are kept.
Know the correct genetic markers for the experimental organisms.
What are the three stop codons?
UAA, UAG & UGA
What codon is the “start” of most genes?
The codon is AUG which codes for Metformin (Met)
What direction do RNA and DNA polymerase build in?
They build in the 5’—>3’ direction, which means they move from the 3’ end to the 5’ end of the molecule.
What are we refering to when we talk about the “Fidelity” of a DNA polymerase.
Fidelity is the polymerases ability to accurately replicate a template.
Name three spontaneous mutations.
Tautomerism: The amino acid swaps to a imino acid which is a constitutional isomer.
Deamination: The NH2 amino group can be hydrolysed and lost, you then have a uracil.
Depurination: The bond holding the base to the sugar gets cleaved.
What does Dam Methylase do?
Adds a methyl group to thymine groups to mark older strands to help MutS when it does DNA mismatch repair.
What is a “Generalised Transducer”
It is a lytic phage that breaks down the nuclear envelop and packages some bacterial DNA by chance, this becomes a generalised transducing particle.
What is a “Transductant”
A cell that has become genetically recombinant through horizontal gene transfer involving transducing particles.
What is a “Generalised Transducer”
It is a lytic phage that breaks down the nuclear envelop and packages some bacterial DNA by chance, this becomes a generalised transducing particle.
What is a “Transductant”
A cell that has become genetically recombinant through horizontal gene transfer involving transducing particles.
What is the difference between Polycistronic mRNA and Monocistronic mRNA?
Polycistronic mRNA has multiple ORF’s on a single strand and is more commonly found in prokaryotes.
Monocistronic mRNA has only one ORF per strand and is more commonly found in eukaryotes.
