Usin Genetics & storing it Flashcards
Phenotype?
Outward physical manisfestation of organisms genes
Genotype?
Full hereditary info of organism (even if not expressed)
Whats the difference between 2’-deoxyribose sugar & a ribose sugar?
On carbon 2 ribose has a hydroxyl group
On carbon 2 deoxyribose sugar has just a hydrogen
Which way is the twist of the DNA double helix?
Right hand (to the right)
How many H bonds join Cytosine & guanine?
3 H bonds between cytosine & guanine
How many H bonds between adenine & thymine?
2 H bonds between thymine & adenine
same for Adenine-Uracil
DNA is coiled around what protective protein?
Histones
What is DNA called when wrapped round a histone?
A nucleosome
List the stages of DNA packaging from smalledst to largest:
DNA
- > Nucleosome
- > Coils
- > Supercoils
- > Chromosome
At what point do the supercoils form chromosomes?
Just before cell division occurs
What makes up chromatin?
The DNA, proteins & RNA that packages DNA within the nucleus
What are the 2 forms of chromatin?
Heterochromatic (condensed) form
Euchromatic (extended) form
Why must the double helix strands seperate during transcription & replication?
To remove the histone & folding barriers so enzymes have access to the DNA
In what two ways is the chromatin made more accessible to enzymes? (regarding histones)
By enzymatically modifying the histones or by displacing them with chromatin remodelling complexes.
Both are reversible
How many new DNA molecules are made in replication?
2
What does semi-conservative replication mean?
It means each of the 2 new DNA molecules contains 1 strand from the original & 1 new strand.
In what direciton is the DNA replicated?
From 5 prime end to the 3 prime end.
5’ to 3’
Why is DNA replication bi-direcitonal?
Because the DNA are anti-parallel, i.e. their prime ends are in reverse to eachother.
So ones built upward & one downward
Which DNA template strand is the lagging & which the leading?
The laggine strand is the one trying to build in the opposite direction to the unzipping
The leading is the one building DNA in the same direction as the unzippin
What are okazaki fragments?
Pieces of new DNA being made on the lagging template that will join together at the end.
What are hte coding sections of DNA called?
Exons
What are the ‘junk’ sections of DNA called?
Introns
What do you call teh process of making mRNA?
TRanscription
How is mRNA different to the DNA?
mRNA only uses the exons, stiching them together without hte introns in between
