D1.2 Protein synthesisIB Biology SL: Flashcards

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What is transcription?

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What is transcription?: Synthesis of RNA using a DNA template.
Role of RNA polymerase?: Separates DNA strands and links RNA nucleotides complementary to the template strand.
Which RNA base pairs with adenine on the DNA template?: Uracil.
Why does transcription not damage the gene?: DNA is only a template; the RNA separates and no DNA bases are changed.
Why is transcription important in controlling gene expression?: It is the first stage, and a key point where genes are switched on or off.
What is translation?: Synthesis of a polypeptide using the base sequence of mRNA.
Where does mRNA bind on the ribosome?: The small subunit.
How many tRNAs can bind to the large subunit at once?: Two.
Codon vs anticodon?: Codon: three bases on mRNA. Anticodon: complementary three bases on tRNA.
Why is the code triplet?: 4² = 16 is too few for 20 amino acids; 4³ = 64 is enough.
What is degeneracy?: More than one codon codes for the same amino acid.
What is universality?: The same codons code for the same amino acids in almost all organisms.
What bond links amino acids during translation?: A peptide bond.
How many peptide bonds in a 10-amino-acid polypeptide?: Nine.
Sickle cell mutation?: GAG → GUG in mRNA, so valine replaces glutamic acid at position 6 of β-globin.