topic 4 Flashcards
Non-overlapping
Each base is part of only one triplet.
Degeneracy
More than one codon codes for a single amino acid;
Codon
- Triplet / three bases on mRNA;
- Accept nucleotide for base
- That code for an amino acid;
Transcription
- Hydrogen bonds (between DNA bases) break;
- (Only) one DNA strand acts as a template;
- (Free) RNA nucleotides align by complementary base pairing;
- (In RNA) Uracil base pairs with adenine (on DNA) OR (In RNA) Uracil is used in place of thymine;
- RNA polymerase joins (adjacent RNA) nucleotides;
- (By) phosphodiester bonds (between adjacent nucleotides);
- Pre-mRNA is spliced (to form mRNA) OR Introns are removed (to form mRNA);
Translation
- (mRNA attaches) to ribosomes OR (mRNA attaches) to rough endoplasmic reticulum;
- (tRNA) anticodons (bind to) complementary (mRNA) codons;
- tRNA brings a specific amino acid;
- Amino acids join by peptide bonds;
- (Amino acids join together) with the use of ATP;
- tRNA released (after amino acid joined to polypeptide);
- The ribosome moves along the mRNA to form the polypeptide;
Ribosome structure
RNA And protein
Gene mutation
- Change in the base/nucleotide (sequence of chromosomes/DNA);
- Results in the formation of new allele;
Gene mutation with no effect
- Genetic code is degenerate (so amino acid sequence may not change);
OR
Mutation is in an intron (so amino acid sequence may not change); - Does change amino acid but no effect on tertiary structure;
- (New allele) is recessive so does not influence phenotype
Gene mutation with positive effect
- Results in change in polypeptide that positively changes the properties (of the protein)
OR
Results in change in polypeptide that positively changes a named protein; - May result in increased reproductive success
OR
May result in increased survival (chances);
Genome definition
(All) the DNA in a cell/organism;
Proteome definition
(The proteome is the full) range of / number of different proteins that a cell is able to produce (at a given time);
OR
(The proteome is the full) range of / number of different proteins the genome / DNA is able to code for
mRNA compared to tRNA
- mRNA does not have hydrogen bonds / base pairing, tRNA does;
OR
mRNA is linear / straight chain, tRNA is cloverleaf; - mRNA does not have an amino acid binding site, tRNA does;
Accept mRNA cannot carry an amino acid, tRNA can - mRNA has more nucleotides;
- (Different) mRNAs have different lengths, all tRNAs are similar / same length;
- mRNA has codons, tRNA has an anticodon;
Pre-mRNA compared to mRNA
- Introns (in pre-mRNA);
- Removal of sections of (pre-mRNA) / splicing
Exon definition
Base/nucleotide/triplet sequence coding for polypeptide/sequence of amino acids/primary structure
Homologous chromosomes
(Two chromosomes that) carry the same genes;