DNA to Protein Flashcards
which carbon always has an OH group?
3’
Which carbon always has the phosphate group?
5’
which carbon makes the difference between RNA and DNA?
2’
What is a nucleoside made up of?
sugar + base
What is a nucleotide made up of?
nucleoside + phosphate(s)
What is the difference between RNA and DNA building blocks and give examples of some
RNA building block don’t have d e.g ATP GTP, DNA building block are like dATP, dGTP
What is polymerisation?
phosphodiester bond is formed between a free 3’ OH group and a 5’ triphosphate
Only which end are new nucleic acids added on?
3’ carbon end
What is the catalyst for DNA replication?
DNA polymerase
What is required to start DNA rep?
RNA primer
Leading strand has what carbon free?
3’
Describe lagging strand
5’ carbon free so replicated in fragments with Okazaki fragments being produced
What unwinds DNA?
helicase
What are 3 main forms of RNA and describe what they do.
rRNA, tRNA, mRNA. rRNA combines with protein to form ribosome. tRNA carries amino acid chain to be incorporated into protein. mRNA carries genetic info for protein synthesis
the specific amino acid is attached to which end of tRNA?
3’
How many RNA polymerases do eukaryotes and prokaryotes have?
eukaryotes have 3 prokaryotes have 1
Describe the steps of transcription
RNA Polymerase binds, DNA chain unwinds. RNA initiation (selection first nucleotide) and elongation. Termination
TATA box is present where?
on RNA 25 nucleotides before transcription starts
What does TBP do?
recognises TATA box and kinks DNA
What 2 factors extend transcript on own
TFIIF and POL II
What direction is RNA synthesised?
5’ to 3’
Describe termination
RNA makes stem loop structure. Enzymes cleaves RNA
Describe 2 ways of regulating transcription
requires specific transcription factors and binds to DNA in presence of a promoter
What happens to steroid receptors once activated in cytoplasm?
move to nucleus and bind to DNA
What two things happen to process ends of mRNA?
Addition of cap on 5’ end and addition of poly(a) tail on other end
Give 3 traits of genetic code
unambiguous, degenerate, universal
What do Aminoacyl-tRNA synthetases do?
Bind amino acids to corresponding tRNA molecule
how any rRNA molecules are in the ribosome?
4
What two things does initiation require?
initiation factors and GTP for energy
what does the elongation factor do?
brings next aminoacyl-tRNA to A site
when is the EF released?
when GTP is hydrolysed
what does peptidyl transferase do?
catalyses peptide bond formation between amino acid at P and A sites
when does termination occur?
when stop codon enters A site. Release factor then binds
what does a nonsense mutation result in?
a new termination codon
what is a frameshift mutation?
addition or deletion in one or two base pairs
Free ribosomes make proteins destined for?
nucleus, mitochondria
Ribosomes bound to nucleus make proteins for?
Golgi, ER
