6.1 CELLULAR CONTROL Flashcards
Define mutation
- A random change in DNA base sequence which may create a non functioning protein or give advantage to the organism
State four mutagenic agents
- UV
- Gamma
- X-ray
- Carcinogens
State the two types of mutation
1) Substitution mutation
2) Insertion or deletion/indel mutation
State the three forms of substitution mutations
1) silent
2) nonsense
3) missense
Define silent mutation
- When the altered base triplet still codes for the same amino acid as before
- Protein structure not altered
Define nonsense mutation
- When the altered base triplet codes for a different amino acid than before
- Protein structure altered
Define missense mutation
- When the altered base triplet codes for a stop codon
- Protein structure altered and shortened
State and explain what type of insertion or deletion/indel mutations cause a frameshift
- A single base insertion/deletion
- Because genetic code is non overlapping and read in groups of three bases
Describe expanding triple nucleotide repeats
- number of repeat triple nucleotides increases during meiosis from generation to generation
- (-CAG CAG CAG-)
State the cause of huntingtons disease
- Expanding triple nucleotide repeats
State the regulatory mechanism at transcriptional level gene expression
- Lac operons for prokaryotes and eukaryotes
- Transcription factors ONLY for eukaryotes
State the regulatory mechanism at post-transcriptional level gene expression
- The editing of primary mRNA and removal of introns to produce mature mRNA
State the regulatory mechanism at post-translational level gene expression
- Protein activation by cyclic AMP
Define operon
- a group of genes that function as a single transcription unit
Draw a lac operon section of DNA