DNA and RNA Flashcards
What are the 4 bases in DNA
Adenine, Thymine, Guanine and Cytosine
What are the 4 bases for RNA
Adenine, Guanine, Uracil and Cytosine
Which bases are Purines
Adenine and Guanine
Which bases are Pyrimidines
Uracil, Thymine and Cytosine
What are Purines
Double Ring nucleotide bases
What are pyrimidines
Single ring nucleotide bases
What is the difference in chemical structure between DNA and RNA
RNA has a Hydroxyl (OH) group on 2C whereas DNA only has a Hydrogen (H)
What is the difference in chemical structure between DNA and RNA
RNA has a Hydroxyl (OH) group on 2C whereas DNA only has a Hydrogen (H)
Which carbon do the nucleotides attach
Carbon 1
Which carbon do the nucleotides attach
Carbon 1
Which Carbon does the phosphate group attach
Carbon 5
What is the structure of Deoxyadenosine Triphosphate (dATP)
Adenine
Deoxyribose Sugar
3x Phosphate
What is the Structure of Adenosine Triphosphate (ATP)
Adenine
Ribose Sugar
3x Phosphate
In DNA, how do the bases bind
AT (2 hydrogen bonds)
CG (3 hydrogen bonds)
What is the structure of DNA (4)
Double-Stranded
Anti-parallel
Complementary
Sugar Phosphate backbone
How does Cytosine and Guanine form hydrogen bonds
C/G
H-O
N-H
O-H
How does Thymine and Adenine form Hydrogen bonds
T/A
O-H
H-N
DNA Replication is …
Semi-conservative
How is DNA Replication started (4)
DnaA protein binds and begins the separation of strands
DnaB protein (helicase) further opens strands
Single-stranded binding protein (SSB) prevents the strands from re-joining
Replication can now begin
During Replication, which direction is DNA synthesised
5’ to 3’
How is DNA synthesised on the Leading Strand
RNA Primer added
DNA polymerase works 5’ to 3’ (towards the replication fork)
How is DNA Synthesised in the lagging strand
Multiple RNA primers attached
Okazaki fragments created in a discontinuous synthesis
How is DNA polymerase proof read
DNA polymerase 3’ to 5’ exonuclease activity cleaves incorrect nucleotide
How does Sanger DNA Sequencing work (6)
Primer binds next to the region of interest
Adds Nucleotide analogue ddNTP to prevent the further synthesis
This results in the formation of extension products (EP)
The EP is separated by Capillary Electrophoresis (CE)
A laser exited the dye-labelled DNA fragments as they pass through a tiny window at the end of the capillary
A software then detects and interprets the dye
How does Illumina sequencing work (5)
Large DNA molecules are fragmented
Ligated to short adaptors and attached to a surface chamber
All four dNTPs are added, with specific dye and terminator
one cycle = one nucleotide added = one specific colour
process repeated, adding one nucleotide at a time and imaging between
How does PCR work (5)
Amplification of specific regions from a complex background Denaturation of DNA at 75 DegC Annealing of DNA at 55DegC Extension of DNA with DNA polymerase Steps repeated 25-40 times
What does describing transcription and translation as coupled mean
They occur in the same compartment at the same time
What are the steps in Transcription (4)
DNA is copied to form mRNA
‘Cap’ (7-methyl guanosine) added to the 5’ end of the mRNA
RNA is spliced (introns removed) to form mature mRNA
Poly A tail added to the 3’ end
What are the steps in Translation (3)
Mature mRNA enters Ribosome
Codon on the mRNA complementary to that of conjugate anticodon on tRNA
Amino acids on the tRNA bind to form polypeptide chain
What is the Wobble Mechanism
The 3rd base on the codon can pair with multiple bases
Can cause unusual base pairings, such as G-U
