Task 1
- State the essential amino acids for humans.
- Tryptophan, Phenylalaline, Tyrosine
- Explain the process of evolution that may have occurred to allow humans to survive without the de novo biochemical pathways to make these essential amino acids.
- A mutation may have occurred early on before leading to genetic drift
- Explain why ALL amino acids are non-essential for plants.
- Plants cannot get adequate supplies of pre-formed amino acids so they have to make all of the amino acids needed for protein synthesis de novo.
- State what makes the molecule chorismate important.
- The three aromatic amino acids are all made from chorismate
Task 2
- Explain how the types of inhibition that glyphosate COULD use to inhibit the EPSP enzyme.
- Competitive inhibition: type of enzyme inhibition where binding of the inhibitor to the active site of the enzymes prevents binding of the substrate and vice versa
- Noncompetitive inhibition: type of enzyme inhibition where inhibitor reduces activity of the enzyme and binds equally well to the enzyme whether or not it has already bound the substrate
- Product inhibition: type of enzyme inhibition where the product of enzyme reaction binds to the enzyme and inhibits its activity
Task 3
- State and describe the actual mechanism glyphosate uses to prevent the chromisate metabolism.
- Competitive inhibition: type of enzyme inhibition where binding of the inhibitor to the active site of the enzymes prevents binding of the substrate and vice versa
- Describe the model of enzyme activity discussed in this article.
- Induced fit substrate binding: when enzyme binds to substrate and changes occur in the active site, enhancing catalysis, as enzyme converts substrate to product
- Analyze the picture that shows the alanine --> glycine mutation. Explain the nucleotide changes that could have resulted in the alanine to glycine change. [there are many]
- Deletion of nucleotide(s), frameshift after nucleotides were removed, or single base substitution
- Explain the effect the G100-->A100 change has on the affinity of glyphosate for the PEP [substrate] active site.
- The change may prevent PEP binding because the enzyme loses a molecule, changing the shape of the protein
Task 4:
- Describe the IDEA of what Monsanto was attempting to do.
- Monsanto was trying to genetically modify the plants via recombinant DNA to allow the plants to resist the Roundup herbicide
- Explain, with proper sequence and language, the evolutionary process of this bacteria from this location.
- "The C4 strain of Agrobacterium sp. proved to be just the thing. This is a species of bacteria that was found growing in the waste-fed column at a factory that made glyphosate. The EPSP synthase enzyme from this bacterium (C4 EPSP synthase) was almost completely insensitive to glyphosate."
- The C4 strain of Agrobacterium sp. was originally susceptible to the glyphosate, but mutations occurred, which resulted in the production of a new kind of EPSP synthase enzyme that resisted the effects of glyphosate.
- Explain the USE of the following components of the plasmid used by Monsanto:
- ori-322 and ori-V - ori-322 is an origin of replication from plasmid pBr322 by E. coli; ori-v is an origin from plasmid RK2, a plasmid that reproduce in a wide variety of gram negative bateria
- AAC(3)-III, along with P-35S and NOS 3' - AAC(3)-III gene allows the selection of gentamycin resistance in plants; P-35S is a promoter that indicates to ribosims where to begin replication; NOS 3’ is the stop codon
- CP4-EPSPS along with P-e35S and NOS 3' and CTP2 - CP4-EPSPS gene was modified and a plant promoter (P-e35S) was added along with a polyadenylation site, NOS 3’. CTP2 is a N-terminal leader sequence that targets the protein to the chloroplast as EPSP synthase is in chloroplasts where synthesis of chorismate takes place.
- Distinguish the following descriptions of transformation in plants to the process used to transform bacterial colonies. [pGlo experiment]
- pGlo uses two main steps:
- transformation solution containing CaCl2.
- 'heat shock' that induces gene expression that stimulate bacteria to 'take up' DNA from their environment.
- Transformation of plant cells used:
- "The interesting feature of this transformation is that it is mediated by the bacteria. All you need to do is expose the plant cells to the bacteria under the right conditions and your gene of interest will end up in a plant chromosome."
- pGlo: plasmid heated to allow it to diffuse into bacteria
- plant cells: no heat required, simple exposure will lead to bacteria to be in the plant chromosome
- State the substance in the last image, that 'selects' the proper Agrobacteria with the genetically engineered plasmid to survive.
- Glyphosate
- State the plant hormones that are used to promote root and shoot development from the transformed leaf disk.
- Auxin, Gibberellin, Abscisic acid
