3.4.2 DNA and Protein Snythesis Flashcards
(10 cards)
What is a genome
Complete set of genes in a cell
What is a proteome
Full range of proteins that a cell can produce
What are the 2 stages of protein synthesis
Transcription- production of messenger RNA (mRNA) from DNA in the nucleus
Translation - production of polypeptides from the sequence of codons carried by mRNA at ribosomes
Differences and similarities in tRNA and mRNA
Similarities- both single polynucleotide strands
Differences - tRNA is a clover shape (mRNA is linear)
tRNA has H bonds between bases (mRNA dosent )
tRNA is shorter and a fixed length (mRNA is longer and variable lengths)
tRNA has an anticodon and has amino acid binding sites
Describe transcription
H bonds break between bases are broken by DNA helicase
1 DNA strand acts as a template
Free RNA nucleotides align next to their complementary bases on the template strand (in RNA u is used instead of t)
RNA polymerase joins adjacent RNA nucleotides
Forms phosophodiester bonds via condensation reactions
Pre-mRNA is spliced to remove introns forming mRNA
How does transcription differ in eukaryotic to prokaryotic cells
No pre-mRNA in prokaryotic as gene don’t contain introns to be spliced
Describe translation
mRNA attaches to a ribosome and it moves to the start codon
tRNA brings a specific amino acid
tRNA anticodon binds to complementary mRNA codon
Ribosome moves along to the next codon so another tRNA binds so 2 amino acids can be joined by a condensation reaction, forming a peptide bind (using energy from the hydrolysis of ATP)
tRNA released after amino acid joined the polypeptide
Ribosomes move along mRNA until reaching a stop codon
Role of ATP in translation
Hydrolyses(releases energy ) so that amino acids join tRNA and peptides bonds form between the amino acids
Role of tRNA in translation
Attaches to specific amino acid
It’s anticodon complementary binds to base pairs of the mRNA codon forming H bonds
2 tRNAs being amino acids together so peptide bonds can form
Role of ribosomes in translation
mRNA bind to the ribosome
Allows tRNA with anticodon to bind
Catalyses formation of the peptide bond between amino acids
Moves along mRNA
