DNA and protein synthesis Flashcards
1
Q
what is a genome
A
the complete set of genes (including alleles) in an organism
2
Q
what is a proteome
A
the full range of proteins produced by the genome in that organism
3
Q
what is transcription
A
the sequence of DNA bases on the template strand determining the sequence of codons on the complementary mRNA
4
Q
detail the process of transcription (4)
A
- an enzyme unwinds the DNA, simultaneously separating the two strands exposing the template strand
- free activated RNA nucleotides complementary base pair through hydrogen bonding (U-A, A-T, G-C, C-G)
- RNA polymerase forms phosphodiester bonds between RNA nucleotides
- forming a single stranded (polynucleotide) mRNA
5
Q
DNA to mRNA is
A
transcription
6
Q
Describe translation
A
The sequence of triplets (codons) on the mRNA determines the order of amino acids in a polypeptide chain
7
Q
Detail the process of translation
A
- ribosome attaches to start codon at the beginning of the mRNA
- a tRNA with a complimentary anticodon pairs with the codon on the mRNA through complimentary base pairing
- a tRNA is attached to a specific amino acid
- ribosome moves over by one codon allowing the next tRNA to bind
- a peptide bond is formed between the two amino acids
- ribosome moves over by one codon again and the process continues as the next amino acid is added to the elongating chain
- the process stops when the ribosome meets a stop codon
- the polypeptide chain starts to fold into its tertiary structure
8
Q
Features of transcription in prokaryotes
A
- dna of genes have no proteins + no introns so mRNA produced can be directly translated into a polypeptide chain
9
Q
Features of transcription in eukaryotes
A
- transcription in the nucleus produces precursor mRNA (introns + exons)
- enzymes remove introns through splicing to form mature mRNA
- mature mRNA leaves the nucleus via the nuclear pore and can be translated at a ribosome
