🏷️ LIMITED TIME OFFER: GET 20% OFF GRADE+ YEARLY SUBSCRIPTION →
Log in
HomeClass Notes1,200,000US530,000

BSCI 10001 Lecture Notes - Lecture 23: Catabolite Activator Protein, Catabolite Repression, Lac Repressor

45 views2 pages
emmagennaro
28 Apr 2019
School
Kent State University
Department
Biological Sciences
Course
BSCI 10001
Professor
Adam Arthur Leff

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

The amount or activity of any protein found inside a bacterial cell could be governed in any of 3 ways: We are going to focus on transcriptional control. You may remember we said earlier that when e. coli is put in growth medium containing both glucose and the disaccharide lactose, it will use up all the glucose before starting to metabolize the lactose. And we learned that jacob and monod found that, after all the glucose had been used up, the presence of lactose causes the expression of two genes, lacz ( -galactosidase) and lac y (galactosidase permease). The tandem pair of lacz and lac y genes, coordinately expressed, was called the lac operon . They also discovered a third gene that regulated the expression of lacz and lac y. And we learned that they then discovered that two other genetic elements are present immediately in front of the lacz gene, the promoter and the operator .

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers

Related Documents

BSCI 10001 Lecture Notes - Lecture 24: Pribnow Box, Tata Box, Lac Operon
emmagennaro
BSCI 10001 Lecture Notes - Lecture 21: Pribnow Box, Lac Operon, Sigma Factor
emmagennaro
BSCI 10001 Chapter Notes - Chapter 18: Trp Operon, Lac Operon, Operon
emmagennaro

Related Questions

1) In the wildtype (the DNA sequence most commonly found in nature) lac operon, transcription is severely down-regulated. A mutation in lacI that causes an early stop codon in the sequence (called a lacI - strain) results in an operon that has high levels of transcription of the polycistronic m-RNA. What type of regulatory protein is the LacI protein (hint: we covered this type of protein in lecture)?

The Lac regulatory protein is called a repressor. (is this correct)

2) If a bacterium with a wildtype lac operon is grown in the presence of lactose, high levels of transcription result for a while, however, eventually transcription is again down-regulated. If, on the other hand, the sugar IPTG is present (instead of lactose), transcription levels are high and remain high. What function do IPTG and lactose share? How are they differently affected by the operon product? (need help with this question)

Lactose and IPTG affected by the operon are both inducers of the Lac-Operon. (is this correct)

3) What is “epigenetics”? What forms of gene regulation are usually involved in epigenetic control of a trait? Why do we have such a limited understanding of epigenetic processes? (need help with this question)

Epigenetics is the study of phenotype changes that do not change the DNA sequence. Genes can be turned on and off based on environment situations of past generations, (parents or even grandparents) were exposed. Examples of some environmental factors could be diet, stress, smoking, drinking alcohol, and diseases. Histone modification and methylation are usually involved in epigenetic control of a trait. (is this correct)

please answer all the questions answering only one question is not helpful!
Question 1

0 / 1 pts

Which of the following E. coli strains with the lac genotypes will synthesize beta-galactosidase in the presence of lactose?

Note: Superscript wouldn't work in the answers, so for example, lacIs means lacIs(superrepressor of lacI)

lacI– lacP– lacO– lacZ– lacY–

lacIs lacP+ lacO+ lacZ+ lacY– / lacI+ lacP+ lacO+ lacZ– lacY+

lacIs lacP– lacO+ lacZ– lacY+ / lacI+ lacP+ lacO+ lacZ+ lacY+

lacI– lacP– lacO+ lacZ+ lacY+

lacI+ lacP+ lacO+ lacZ+ lacY+

Question 2

0 / 1 pts

Some mutations in the trp 5' UTR region increase termination by the attenuator. An example of a mutation that may have this effect is a

Choose the best answer!

mutation that changes the bases in region 3 of the 5' UTR, such that they no longer pair with region 2 or 4.

deletion of the two tryptophan codons in the 5' UTR leader peptide.

deletion in region 2 in the 5' UTR that prevents it from pairing with region 3.

The second and third answers are correct.

The first, second, and third answers are correct.

IncorrectQuestion 3

0 / 1 pts

Several examples of antisense RNA regulating translation in bacterial cells have been discovered. If you wanted to design a construct to artificially control translation of a bacterial gene with antisense RNA, what type of sequences should the antisense RNA contain?

A sequence complementary to the operator of an operon.

A sequence complementary to a 5' UTR.

A sequence complementary to the Shine-Dalgarno site of the mRNA.

The first and second choices are correct.

The second and third choices are correct.

Question 4

0 / 1 pts

Which of the following correctly describes the function of microRNAs?

Choose the best answer.

MicroRNAs are encoded by genes in the genome of an organism.

MicroRNAs form mRNA which encodes a protein repressor for another gene.

MicroRNAs encode a mRNA that base pairs with itself, forming double stranded RNA.

MicroRNAs are cut into small pieces, then bound by the complex of proteins called RISC to repress the translation of other mRNAs in the cell.

The first and second answers are correct.

The first, third, and fourth answers are correct.

The third and fourth answers are correct.