Why don’t chicken have teeth?
They have the genes require to produce the proteins to produce teeth, but they do not activate those genes
- In this case, a change in developmental cues, alters which genes are expressed in the ‘dental issue’
What is the importance of gene regulation? (3)
1) Allows multicellular organisms to have differentiated cell types
2) Allows organisms to grow until they reach a particular size
3) Allows organisms to acclimate to changes in their environment
How do cells adapt to their environment?
Lactose in the E.coli cell
4 steps
1) Lactose becomes available in the environment of the bacterium
2) Due to gene regulation, the bacterium produces more Lactose permease (proteins) and B-galactosidase
3) The bacterium readily uses the lactose until it is gone
4) Most proteins involved with lactose use are degraded
What is able to break down lactose in the cell?
B-galactosidase
little green things
What transports lactose into the cell?
Lactose permease
Transport protein
Cells need to alter the amounts of ________ to survive in changing environments
Specific proteins
In bacteria, at which level is the altering of the amount of specific proteins done at?
Transcription
Increased Transcription = _______________= ____________
Increased Transcription = Increased Translation = Increased Protein
Which phase does a gene change into mRNA?
Transcription
Which phase does mRNA change into a protein?
Translation
Which phase does the protein change into a functional protein? Eukaryotes!!
Post-translation
_________ is critical in the development of multicellular
Gene regulation
During human development what is needed at different stages?
During human development, different hemoglobins are required at different stages
The correct _____ must be turned on and off at the correct times
genes
Which type of cell has more layers of regulation? What are they?
Eukaryotes
1) Transcription
2) Processing of mRNAs
3) Translation
4) Post translation
Eukaryote:
Transcriptional regulation
Determines which genes are transcribed
- Regulation of transcription
- Chromatin remodeling to make genes accessible for transcription
Eukaryote:
Posttrancriptional regulation
Determines types and availability of mRNAs to ribosomes
- Variations in pre-mRNA processing
- Removal of masking proteins
- Variations in rate of mRNA breakdown
- RNA interference
Eukaryote:
Translational regulation
Determines the rate at which proteins are made
- Variations in rate of initiation of protein synthesis
Eukaryote:
Posttranslational regulation
Determines the availability of finished proteins
- Variations in rate of protein processing
- Removal of masking segments
- Variations in rate of protein breakdown
What is a chicken-a-saurus?
A chicken with teeth, finger, and a tail
T or F
It doesn’t matter where the proteins are made
False;
We need the right proteins made in the right amounts at the right time, in the right place
What do changes in the sequence of DNA molecules do?
They may alter the production or function of a particular protein
How can mutations be seen?
Mutations can be seen as generating a new allele for a given gene even if it does not cause a change in phenotype
Small changes in the DNA sequence can cause ___ differences in __________
Big differences in protein sequence
What can larger changes in the DNA sequence cause?
Larger changes in the DNA sequence cause the removal of entire genes or even the addition of new genes
What are the 5 types of consequences of point mutations within the coding sequence of a structural gene?
Mutation in the DNA; Effect on polypeptide
1) None; None
2) Base substitution; SILENT- causes no change
3) Base substitution; MISSENSE - changes one amino acid
4) Base substitution; NONSENSE- changes to a stop codon
5) Addition (or deletion) of a single base; FRAMESHIFT- produces a different amino acid sequence
Mutations can alter phenotypes by what? (4)
1) Generating a non-functional protein
2) Changing how a protein works
3) Altering when a gene is expressed
4) Changing where a gene is expressed
One __________ in the hemoglobin gene causes sickle-cell anaemia
One base difference
The T to A mutation in the sickle-cell disease example changes what?
Changes an amino acid in the protein from Glutamate to Valine
- From a hydrophilic to a hydrophobic amino acid
Pleiotropic
When one base change causes a number of phenotypic changes
In Whippet dogs, what can a mutation do?
A mutation in the Myostation Gene leads to increased muscle mass
What does a 2 base deletion pair cause in the Myostatin gene?
Introduces and early stop codon
Mutations
- In nature, mutations are random occurences
- They can range from simple base pair changes to loss of chromosome fragments
Mutations can be caused by ___________________
any agents that damage DNA & random mistakes of the DNA replication process
- EX. UV light- too much sun = certain chemical viruses
Which type of mutations will more likely be passed on?
Mutations that help an organism compete will be more likely to be passed on to the next generation than mutations that are not helpful
_______ favours evolution
Mutations are/ are not always bad
Strong selective pressure favours evolution
Mutations are not always bad
Malaria
A debilitating disease cause by trypanosome Plasmodium falciparum which is transferred to humans via bites from the mosquito Anopheles gambiae
The blood cells of individuals with sickle-cell disease are less able to support the Plasmodium parasite, so what is the advantage?
So they do not get as sick from Malaria
So the disease allele provides a competitive advantage to individuals in certain environments
Especially in heterozygous form