DNA, RNA and Protein Synthesis Flashcards
differences in DNA in eukaryotes and in prokaryotes
- DNA of euk is associated with histones, DNA of pro is not
- euk is linear, pro is circular
- longer of euk, pro is shorter
what is a homologous chromosome
contains chromosomes from both mother and father
a homologous chromosome contains the same genes
what is a chromatid
the chromosomes of two homologous pairs are then called chromatids
what is a gene
A section of DNA that encodes the Amino Acid sequence of a polypeptide
genome and proteome definition
the full set of DNA found in a organism
full range of proteins that can be synthesised from the genome
splicing in both prokaryotes and eukaryotes
splicing is the process of removing non coding from coding in the mRNA
eukaryotes have pre - mRNA because it needs splicing from introns that are non coding
prokaryotes have mRNA made directly, there is no introns, only exons
it then becomes functional mRNA
steps of transcription
1) DNA helicase attaches and bvreaks hydrgoen bonds, unwinding DNA
2) complementary RNA nucleotides form hydrogen bonds with exposed nucleotides of DNA
RNA polymerase forms phosphodiester bonds between RNA nucleotides
3) mRNA leaves through nuclear pores into cytoplasm, ready for translation
3 important features of the genetic code
- its degenerate ( more than one code for amino acid
-degenerate
- non - overlapping
steps of translation
top of tRNA has a binding site for amino acid at the bottom is the triplet of bases
1)small subunit of ribose binds to mRNA at start codon
2) tRNA anti codon complimentary to codon of mRNA attaches by hydrogen bonds. 2nd tRNA moves in with the complementary codon
3) peptide bond forms between the two amino acids - catalysed by PEPTIDYL TRANSFERAE - requires ATP
4) ribosome moves to next codon with tRNA - forms peptide bond
stops until stop codon of mRNA
draw simple structure of a nucleotide
