BIOB11H3 Lecture Notes - Lecture 10: Wild Type, Lysine, Leucine Zipper

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rubyox160

3 Sep 2016

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Lecture 10: gene regulation i (promoters and control circuits) Graph = amount of mrna ramps up in response to the presence of lactose but if you eliminate lactose, mrna decreases. Figure 12. 2 operon structure: regulatory gene encodes a repressor protein, repressor protein prevents rna polymerase from transcribing the structural genes. Induction - mrna is made (in reference to the lac operon) Promoters usually lie upstream camp is high, glucose is low and vice versa: camp binds to crp, this complex goes to the promoter region of the lac operon and attracts rna polymerase. Reporter gene gene coming from another organism that reports promoter activity. Figure 12. 34 shows you what activity the gene is involved in and where (by colour: similar example shown using transgenic plants (vascular tissue flasher fsh) Figure 12. 45: getting rid of tata box eliminates something you need for high level expression, 114% = delete repressor, so you get more expression than the wild type.

Related Questions

QUESTION 1

In the bacterial lac repressor, which of these occurs: (select all that apply)

		(a)In the presence of glucose and the absence of lactose, the repressor is actively produced.
		(b)The lac operon can be hyper-induced in the presence of low glucose by the 'cAMP binding protein' (CAMP).
		(c)In the presence of lactose and the absence of glucose the lac operon is repressed.
		(d)Allolactose is a byproduct of Î²-galactosidase, indicating high lactose when it builds up.

1.5 points

QUESTION 2

In eukaryotes the enhancer elements can be quite a distance upstream or downstream from the promoter, and transcriptional regulation is helped by protein:protein interactions.

True

False

1.5 points

QUESTION 3

The prokaryotic promoter contains a TATA box that is at -10bp upstream from the transcriptional start site.

True

False

1.5 points

QUESTION 4

During the addition of the poly A tail which of these occurs:(select all that apply)

		(a)The transcript is synthesized beyond the poly A site (AAUAAA).
		(b)The mRNA contains a 5â cap.
		(c)The transcript is cleaved 35nt downstream from the poly A site.
		(d)An enzyme complex containing an exonuclease and polyadenylate polymerase cleaves nearby the AAUAA site.
		(e)100-300 Aâs are added to the 5â end.

orangelocust889

For this question, focus on four parts:

I, the gene that produces the repressor protein;

P, the promoter region where RNA polymerase binds to initiate transcription;

O, the Operator site, where the repressor binds. When the repressor binds, it prevents transcription; and

ZYA, the three structural genes, all of which are required for the successful utilization of lactose as a food source.

In the left column of the table below, we indicate the genetic composition at the lac operon of particular strains of E. coli cells. A "+" (plus sign) following the letter indicates the wild-type allele (or normally functioning version of the gene). For I, P, and ZYA, a "-" (negative sign) following the letter indicates the mutant allele (or non-functional version of the gene). For the O allele, a "C" indicates the mutant or constitutive allele. It is not functional in that the repressor cannot bind, but it is functional in that transcription can still occur.

Given the conditions stated in each column, please indicate for each genotype whether lac mRNA is produced and at what level by typing in one of the following words in each cell in the table:

"Abundant"

"Minimal"

"None"

The completely wild-type genotype has already been filled in.

	Cellular conditions:
Genotype	Glucose present (low cAMP) and no lactose	Glucose present (low cAMP) and lactose present	No glucose (high cAMP) and lactose present
*I⁺ P⁺ O⁺ ZYA⁺*	None	Minimal	Abundant
*I^- P⁺ O⁺ ZYA⁺*
*I⁺ P^- O⁺ ZYA⁺*
*I⁺ P⁺ O^c ZYA⁺*
*I⁺ P⁺ O⁺ ZYA^-*

champagneyak301

BIOB11H3 Lecture Notes - Lecture 10: Wild Type, Lysine, Leucine Zipper

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