BBOL- DNA replication Flashcards
1
Q
What does semi-conservative mean?
A
- Comprised of one old strand an one new strand
2
Q
What is the replication fork?
A
- Where replication starts
- DNA double helix unwind by helices to allow template mediated replication
- Requires ATP
3
Q
What does DNA being semi-discontinuous mean?
A
- Only one form of DNA polymerase to build the strand
- One strand is continuously synthesised (leading strand)
- Other strand synthesised ‘Okazaki fragments’ (lagging, fragments joined by DNA ligase)
4
Q
What can excise incorrectly paired bases?
A
3’-5’ exonuclease
5
Q
What is priming?
A
DNA primase synthesises a short RNA primer that DNA polymerase, DNA polymerase erases primer and DNA ligase joins fragments together
6
Q
What proteins are associated with chromosomes and DNA, respectively?
A
chromatin and histone
7
Q
Describe the nucleosome
A
- Made up of 8 histone proteins and DNA wrapped around histone core
- Nucleosome core particle released by the hydrolysis of linker DNA with nuclease
- Nucleosomes packed into compact chromatin fibre
8
Q
Describe giemsa staining for chromosomes
A
- Gives rise to unique banding pattern - karyotype
9
Q
What are other forms of DNA?
A
- Mitochondria have their own small genome- maternal inherited
- Double stranded circular DNA
- Limited autonomy- proteins eroded by nuclear genome
