6.1 Cellular Control Flashcards
Which structure of a protein does genetic mutation effect?
Primary structure
What are the two types of DNA mutation?
Point Mutation and InDel Mutation
What is point mutation?
When one base pair is swapped for another
Why does point mutation sometimes have no effect?
DNA code is degenerate so multiple codons code for the same amino acid
What are the 3 types of point mutation?
Silent
Missense
Nonsense
What is a silent point mutation?
A mutation that codes for the same amino acid so has no effect
What is a missense point mutation?
A mutation that leads to a different amino acid, changing the primary structure. This will in turn affect the tertiary structure.
What is a nonsense point mutation?
A mutation that causes the codon to become a stop codon. This will truncate the protein
What is InDel mutation?
An insertion or deletion of a base pair. This will cause all the bases to shift along and read as different codons. This is described as a frameshift.
What is the result of InDel mutation?
A frameshift causing a change in the primary (and therefore tertiary) structure of the protein.
What do bacteria (e.g E.coli) usually use as a respiratory substrate?
Glucose
What respiratory substrate do bacteria use when there is no glucose
Lactose
What are required to metabolise lactose in bacteria
Lactase (B-galactosidase) Lactose Permease (B-galactosidase permease)
What induces the synthesis of lactase and lactose permease
The presence of lactose
What is the name of the stretch of DNA that codes for lactase and lactose permease?
The lac operon
What are the two structural genes on the lac operon?
Lac Z (for lactase) Lac Y (for lactose permease)
What is the function of the regulator gene on the lac operon?
To code for the repressor molecule (Lac I). The molecule can either bind to lactose or to the operator gene.
What is the function of the promotor gene on the lac operon?
A binding spot for RNA polymerase to begin transcription
Describe what happens at the lac operon when lactose is present.
- the repressor molecule binds to lactose
- this changes the shape of the molecule causing it to unbind from the operator region
- RNA polymerase is able to bind to the promoter region
- the enzymes can be synthesised
Describe what happens at the lac operon when lactose is absent.
- the repressor molecule binds to the operator region
- RNA polymerase is unable to bind to the promotor gene
- the enzymes can’t be synthesised
What are the 3 types of gene regulation in eukaryotic cells?
Transcription Factors
Post Transcriptional Regulation
Post Translational Regulation
Describe transcription factors.
A short protein (or non coding RNA) that slides along the DNA and activates/deactivates the gene by allowing/not allowing RNA polymerase to bind to the promoter region
What are introns?
Non coding regions of DNA that are not expressed
What are exons?
Coding regions of DNA that are expressed
