View the step-by-step solution to:

Simo Li TA's name: Jacob Edwards Thu 2:00 - 2:50 PM Yates 208 BZ350-R07 1) An undergraduate student in a biology laboratory at CSU discovered a new...

Would you mind helping me to finish my homework for molecular biology.

Simo Li TA’s name: Jacob Edwards Thu 2:00 - 2:50 PM Yates 208 BZ350-R07 1) An undergraduate student in a biology laboratory at CSU discovered a new bacterium (C. rams), which has the ability to grow on a new type of sugar called ramose. By performing some biochemical studies she found out that C. rams makes two enzymes that convert ramose to glucose. The first enzyme (Enyzme 1) converts ramose to yummose and the second enzyme (Enzyme 2) converts yummose to glucose. Both enzymes are synthesized from a single mRNA (as in lac operon) and these enzymes are expressed at very low levels in the absence of ramose but are highly induced in the presence of ramose. She has also figured out that this operon (ram operon) is regulated by repression, a mechanism similar to lac operon. This student isolated several mutants (mut1 through mut6) in which the expression of ramose metabolizing enzymes is altered. The following shows the levels of enzymes 1 and 2 in wild type and six mutants. Assume that all mutations are loss of function i.e. they inactivate the component they mutate. Use the information presented in the table to address questions “A” through “D”. A) Which mutation(s) are likely to be in the promoter for enzyme 1 and 2? B) Which mutation(s) are likely to be in the repressor or operator? C) Which mutation(s) are likely to be in the coding region of enzyme 1? D) Which mutation(s) are likely to be in the coding region of enzyme 2? 2) You are asked to isolate E.coli mutants that constitutively express lac operon. How do you go about isolating such mutants?
Background image of page 1
3) Mutant that are lacY− retain the capacity to synthesize β-galactosidase. However, even though the lacI gene is still intact, β-galactosidase can no longer be induced by adding lactose to the medium. How can you explain this result? 4) List two mutations that can result in constitutive expression of lac operon? In a given constitutive expression mutant, how do you find out which of these two mutations have taken place? 5) How would you isolate E. coli mutants, which do not express lac operon (no mRNA is produced). Knowing the regulation of lac operon by lactose and glucose list six possible mutations that can result in this phenotype. 6) For each of the E. coli strains containing the lac operon alleles listed, indicate whether the strain is inducible, constitutive, or unable to express β-galactosidase and permease. Provide an explanation for your prediction. 7) You have isolated two different mutants (reg1 and reg2) causing constitutive expression of the emu operon (emu1 emu2). One mutant contains a defect in a DNA- binding site, and the other has a loss-of- function defect in the gene encoding a protein that binds to the site. A. Is the DNA-binding protein a positive or negative regulator of gene expression? B. To determine which mutant has a defect in the site and which one has a mutation in the binding protein, you decide to do generate partial diploids using F′ plasmids. Assuming you can assay levels of the Emu1 and Emu2 proteins, what results do you predict for the two strains (i and ii) (see descriptions below) if reg2 encodes the regulatory protein and reg1 is the regulatory site?
Background image of page 2
Show entire document
Sign up to view the entire interaction

Top Answer

Hi,here is the... View the full answer

MUTATION SOLUTION.docx

A) Which mutation(s) are likely to be in the promoter for enzyme 1 and 2?
The mutation likely to be on the promoter of enzyme 1 and 2 is mutation number 2 (Mut 2) this
is because when a mutation...

Sign up to view the full answer

Why Join Course Hero?

Course Hero has all the homework and study help you need to succeed! We’ve got course-specific notes, study guides, and practice tests along with expert tutors.

-

Educational Resources
  • -

    Study Documents

    Find the best study resources around, tagged to your specific courses. Share your own to gain free Course Hero access.

    Browse Documents
  • -

    Question & Answers

    Get one-on-one homework help from our expert tutors—available online 24/7. Ask your own questions or browse existing Q&A threads. Satisfaction guaranteed!

    Ask a Question
Ask a homework question - tutors are online