Class Notes (836,866)
Canada (509,937)
Biochemistry (232)

Notes Chapter 29 Supplement (Lectures 13) - Biochem 2B03.docx

4 Pages
Unlock Document

Margaret Fahnestock

Biochem 2B03 Jasmyn Lee  The modern idea of the gene was developed from studies of bacterial metabolism Central Dogma of Molecular Biology  Jacob and Monod – originators of the modern idea of gene transcription o 1961 – postulate the existence of mRNA  base composition would reflect that of DNA  heterogenous in mass (reflecting myriad proteins found in cells)  able to associate with ribosomes – site of protein synthesis  High turnover rate – permitting regulated gene function Evidence for Regulation and the Existence of mRNA  Investigation of inducible systems in bacteria E. coli  Enzyme Induction: Bacteria make certain enzymes in variable rates responding to changes in environment  Synthesis of an enzyme that acts on compound A is induced by compound A o Compound A is called an inducer Constitutive and Inducible Systems  Constitutive Proteins o Synthesized at a constant rate (not regulated)  Eg/ “housekeeping proteins”: ribosomal proteins (10,000 copies/cell)  Inducible Proteins o Synthesized at variable rates dependent on cells circumstances (regulated)  Eg/ regulatory proteins (often rate <10 copies per cell) o β-galactosidase o Galactoside permease o Thiogalactoside transacetylase  β-galactosidase (β-gal) o A sugar found in milk o Bacteria use forms of glucose (eg/ starch) as their primary carbon source o If there’s no glucose, they can use alternative carbon sources o E. coli can use lactose because it has the enzyme β-galactosidase 1 Biochem 2B03 Jasmyn Lee o β-gal is an inducible enzyme o No lactose  very little β-galactosidase o Add lactose  abundant β-galactosidzse  Jacob and Monod used genetics to study this process: o Isolation of mutant cells that can’t use lactose as carbon source o
More Less

Related notes for BIOCHEM 2B03

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.