Notes
Gene Expression & Regulation
Content of the notes (1)
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DNA is genetic material, but...
It's really boring!
For the DNA to actually convey a trait, it must be transcribed and translated.
It's the resulting protein that actually results in the genetic trait.
An analogy...
DNA
The Recipe Book
RNA
Cheap, disposable copy of one recipe
Protein
What you make when you follow the recipe
Transcription
Translation
The 'Universal' Genetic Code
Translation
Ask yourself...
When an egg is first fertilized by a sperm, all the mRNA in that cell came from the mother. The sperm only carries DNA, not mRNA. What does this mean about the genetic influence of a father during the first few hours after fertilization?
Changes in DNA lead to changes in mRNA. Changes in mRNA lead to changes in protein.Changes in protein change everything!
An analogy...
DNA
Bake at 350F
Bake at 355F
Very little change
DNA
Bake at 350F
Bake at 550F
Very burnt cookies!
Change the DNA, Change the RNA, Change the Protein!
Mutations
Base-Pair Substitution
Deletion
Insertion
Translation
Ask yourself...
How could two different mutations result in alleles that produce the same phenotype?
Every gene for every protein is every cell of a multicellular organism.
To be expressed, a gene must be transcribed
Not just one!
RNA Polymerase makes the mRNA
The Promoter
Transcription Factors
TF
Copying the gene is just the first step!
Master Genes
Transcription factors will often be master genes. Because transcription factor is a protein, it must be encoded by a gene. Makes the cell the kind it needs to be by turning off and on certain genes.
Homeotic Genes
When a gene is in charge of a whole structure, we call it a homeotic gene. It is responsible for whole structures, not just genes.
Knockout!
Scientists can remove a gene to find out the importance or function of said gene.
Barr Bodies
The inactivated X chromosome in female mammals. Females are mosaic (only certain genes are shown) and can be seen in the color of cats.
Ask yourself...
If a steroid drug acts by turning on a transcription factor, why might it have a lot of side effect?
Transcription & translation video
Mutations Video
Gene Regulation video