8.1- Genes and the genetic code 0.0 / 5 ? BiologyDNA, genes and protein synthesisASAQA Created by: Megan2413Created on: 10-04-17 18:43 What is a gene? A section of DNA that contains the coded information for making polypeptides and functional RNA 1 of 21 What is included in functional RNA? mRNA and tRNA 2 of 21 Where can the location of the gene be described as? The locus 3 of 21 What is the genetic code? The order of bases on a DNA molecule 4 of 21 How many amino acids regularly occur in proteins? 20 5 of 21 How many bases code for an amino acid? 3 6 of 21 How many possible combinations of three bases are there is there are 4 DNA bases? 64 7 of 21 What is a group of three DNA bases called? Triplet 8 of 21 What are the five features of the genetic code? - Degenerate - Start code - Stop triplet- Non-overlapping - Universal 9 of 21 What is meant by a degenerate code? Most amino acids are coded for by more than one triplet (generally 2-6 triplets) 10 of 21 What is the start code for every gene? Methionine 11 of 21 What is methionine? A triplet at the start of every gene to show the start- it is later removed if it doesn't form part of the polypeptide 12 of 21 What are stop triplets? They mark the end of a gene and don't code for any amino acid. 13 of 21 How many stop triplets are there? 3 14 of 21 What is meant by non-overlapping code? Each base sequence is only read once 15 of 21 How is the genetic code universal? Each triplet codes for the same amino acid in all organisms (with a few exceptions) 16 of 21 What is indirect evidence for evolution? The fact that the genetic code is universal 17 of 21 What is an exon? A coding section of a gene 18 of 21 What is an intron? A non-coding section of a gene 19 of 21 What do introns usually contain? Multiple repeats of bases 20 of 21 What types of cells don't contain introns? Prokaryotic cells 21 of 21
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