Chapter 16 - The Genetic Code Flashcards
Aneuploidy
An abnormal number of chromosomes
Polyploidy
More than 2 homologues of one or more chromosome (ex. triploidy)
Euploidy
Normal number of homologues
What is the euploidy for humans?
2 sets of 23 for 46 chromosomes
What does DNA Methylation do?
Gene Expression - DNA more available
How many stop codons are there?
Three!
What does RNA become?
mRNA and regulatory RNA
Reverse Transcriptase
Synthesize DNA strand from RNA template - some bacteria can do this!
What direction are codons written?
5’ to 3’
Which strand of DNA is used to make RNA?
The template strands (3’ to 5’)
Missense Mutations
Replacement mutation - new codon codes for different amino acid.
Chromosome Inversion
Chromosome parts break and rotate before rejoining to rest of chromosome
Chromosome Translocation
Broken section of one chromosome attaches to another
What are the main reasons for Chromosome Mutations?
Cohesions and/or codensions malfunction. Problem in Crossing over
What is the most common number of codons that specifies a single amino acid?
Two
Translation
The coding from mRNA to proteins
One-gene, one enzyme hypothesis
Bases on N. crassa knock-out mutants that lacked the ability to synthesise certain compounds. Mutations in single genes eliminated the production of the corresponding enzyme.
How many amino acids are represented in the genetic code by just one codon?
Two
What charge does DNA have?
Negative
What charge do histones have?
Positive
Epigenetics
Changing gene expression without altering the DNA base sequence
What does DNA methylation do?
Silences gene expression
What does histone acetylation do?
Increases gene expression by making the histones less positive and less attractive to DNA.
