Question

Cyanobacteria in a low nitrogen environment have photosynthesizing, vegetative cells and oxygen-sensitive heterocysts linked together. Which of the following adaptations to the heterocyst allow(s) it to be in this high oxygen environment?

		a. Thick cell walls
		b. Oxygen scavenging proteins
		c. Gas vesicles
		d. A and B
		e. B and C

When the pathogenic E. coli reaches the gut, the toxin operon is quickly transcribed and multiple proteins translated at once. What helps produce the large number of proteins to be made in this bacterium?

		a. Operon structure
		b. Multiple copies of the operon
		c. Increased concentration of helicase
		d. Polyribosomes

The Shine-Delgarno sequence (-10 -35) region upstream of the operon is interrupted by a transposon. How might this influence the operon?

		a. Increases rate of transcription
		b. Decreases rate of transcription
		c. Transcription begins but then aborts
		d. It doesn’t influence the operon at all

You are trying to determine the mechanism of horizontal gene transfer between something in Flask A and bacteria in Flask B. If the mechanism is transformation, which of the following treatments would stop the transfer?

		A. DNase digestion
		B. Proteinase digestion
		C. Filtration
		D. RNase digestion

Which statement describes an example of comparative genomics to reveal the capabilities of a bacterium?

		a. Escherichia coli was grown on media with different nutrients to analyze the bacterium’s metabolism
		b. The ST and LT toxin genes were located in only enterotoxigenic Escherichia coli
		c. Transposon mutagenesis was used in Escherichia coli to knock out genes
		d. Escherichia coli was grown in the lab for 25 years to determine rate of evolutionary change

n the MEGA antibiotic plate experiment, mutations in the bacterial population that allow for survival in increasing doses of antibiotics are maintained due to:

		a. Evolution
		b. Mobile elements
		c. Replication errors
		d. Selective environment

In the LTEE research and the MEGA antibiotic plate experiment, mutations that arise in the bacterial populations are due to:

		a. Evolution
		b. Environmental factors
		c. Replication errors
		d. Mobile elements

All are multiple choice questions. A brief explanation isn't required however but please support answer if you can for me! Please.

Answer 1

Question 1.) Answer is D.) A and B cynobacteria have heterocysts - produces three additional cell wall, it produces proteins that scavenges the any remaining oxygens.

Question 2.) Answer is A.) Operon structure, the shiga toxin has two subunit genes A and B were stx b acts a promoter and fails to terminate the translation resulting in production of large number of proteins.

Question 3.) Answer is D.) It does not influence the operon at all as transposons are the jumping gene which alters the dna sequence that give rise to mutation thus either activate or inactive the gene expression.

Question 4.) Answer is A.) DNase digestion because the HGT by transformation is transfer of genetic material in dna if the naked dna is degraded by DNase digestion the transfer would be stopped.

Question 5.) Answer is B.) The ST and LT toxin genes were located only in enterotoxigenic e.coli as there toxins are known to cause mortality associated with diarrhoea etc, were the comparative analysis helps in knowing difference between Harmless E.coli vs ETEC.

Question 6.) Answer is A.) Evolution as the bacteria are exposed to doses they adapt to them and survive until their maximum potential beyond that they die. It happens due to evolution among bacteria as they are exposed to different enviroments and etc they adapt and survive to the higher dose of antibiotics

Question 7.) Answer is A.) Evolution, they adapt and change their defence pattern to their exposure. That results in mutation of genes causing the bacteria to become resistant to antibiotics even at higher doses.

Thankyou..