Microbial metabolism exam #3

A new graduate student wanting to increase the doubling time of the microbe in order to be liked by the group designed a new experiment to increase the doubling time from thirty minutes to fifteen minutes. In the growth media, the student supplemented the growth media with a mixture of amino acids, a mixture of fatty acids, a mixture on nucleosides, and a mixture sugars. What was observed by the graduate student?

Cells growing on a mixture of amino acids are richer in total protein. Cells growing on a mixture of fatty acids are richer in lipid content. Cells growing on a mixture on nucleosides are richer in nucleic acids. Cells growing on a mixture sugars are richer in carbohydrates. The graduate student did not observe any of the above.

Why does the RNA polymerase not begin transcription of the lac operon until glucose is absence?

Cyclic AMP is not made until all the glucose is used up.

The availability of what molecule directly plays a role in promoter recognition, transcriptional repression, transcriptional activation, and transcriptional enhancement

DNA

Using the following equation (giant formula shit w/ ATP and stuff) , at what number will a cell be dead?

0.5

What percentage of the cell's energy is involved in translation?

60%-75%

What would the response of a microbe be if all precursor metabolites were abundant in its environment?

A. It would produce more precursor metabolites. B. It would produce more ATP. C. It would produce more NADH. D. It would produce more NADPH. E. All but A is correct.

If a cell is undergoing coordination during metabolism, which of the following can be affect?

Biosynthesis Fueling Macromolecular Composition All of the above None of the above

What factors would change in glycolysis if the AMP concentration was lower than the ATP concentration?

Phosphofructokinase & Pyruvate Kinase would be inhibited.

Choose the correct answer regarding why prokaryotes control amounts of enzymes produced rather than enzymatic activity.

Prokaryotic genomes organize genes of related functions into operons.

An undergraduate student starts working in a new metabolism lab. The student is charged with making and purifying a specific metabolic enzyme. However, the student is not able to express the protein. The student is told to see how much of the material used to make the metabolic enzyme is present in the culture. The student was not able to find any such material. Which of the following could be a reason why they could not find the material?

Prokaryotic mRNAs live for a short time period

what is each component of the image

Q2: promoter Q3: operator Q4: gene or protein or enzyme Q5: gene or protein or enzyme Q6: gene or protein or enzyme

Which of the following is NOT a reason why prokaryotes more often control the amounts of enzymes produced?

They move from place to place turning off their metabolic enzymes while they move.

What precursor metabolite acts as a positive allosteric effector for Phosphoenolpyruvate carboxylase and a negative allosteric effector for Pyruvate Dehydrogenase?

acetyl-CoA

Controlling the enzyme activity by --- is a --- and --- mechanism to adjust flow through the many metabolic pathways.

allosteric regulation swifter more precise

Select all that apply: which of the following control the reaction rate of enzymatic activity?

changing the amount of the enzyme decrease the activation energy of a cellular process changing the activity of the enzyme changing the intracellular concentration of one or both substrates increase the activation energy of a cellular process decrease the energy a cellular process uses increase the energy a cellular process uses

Enzyme activity can be positively or negatively modified in a reversible manner by ----- and ----- is a process that involves the reversible association of an enzyme with another molecule.

covalent modification allosteric regulation

Controlling an enzyme by slowing down its activity can be accomplished by which of the following?

end-product inhibition

What two processes are faster and more precise in metabolic regulation over the other modes of metabolic regulation?

enzyme activity and allostery

During growth of a bacteria in a culture, the presence of glutamine in the medium would stop the use of which molecule?

glutamine

unlike their bacterial counterparts, Archaeal phospholipds have...

glycerol 1-phosphate

At high [ATP], ATP-replenishing pathways are _____, and ATP-utilizing pathways are _____ .

inhibited stimulated

Allosteric regulation is controlled by binding of --- metabolites that recognize and bind to a/an --- site on the protein, distinct from the enzyme's --- site.

low molecule weight allosteric catalytic

Under different growth conditions, which two molecules levels change quickly?

mRNA and lipids

What is the molecule in the diagram above?

operon

__________ afford the organism the opportunity to __________ regulate transcription of multiple genes, whose products are active in __________ process.

operons simultaneously the same

What precursor metabolite acts as a positive allosteric effector for Pyruvate Dehydrogenase and a negative allosteric effector for Phosphofructokinase?

phosphoenolpyruvate (PEP)

What factors would change in glycolysis if the ATP concentration was lower than the AMP concentration?

phosphofructokinase & pyruvate kinase would be activated

Which of the following is NOT an example of covalent modifications?

phosphorylation methylation adenylation acetylation modulation

Which step in the Central Dogma of Molecular Biology can be controlled by prokaryotes to regulate the rate of protein synthesis?

post-translational modifications

Experimentally, what molecule was shown to accumulate during the inhibition of tRNA synthesis, inhibition of rRNA synthesis, and inhibition of protein chain elongation?

ppGpp

the synthesis of LPS in G (-) bacteria...

requires energy from the proton motive force

Which of the following is why the stringent response modulon evolved?

response to starvation

Which of the following molecules can directly regulate both transcription initiation and transcription termination?

sRNA

Over the years, researchers have shown that DNA stores the information so it can be inherited by the daughter cells and transcribed into ribosomal and transfer RNAs for protein synthesis, regulatory RNAs for coordination, and mRNA templates to make proteins, the major catalysts of the cell. Which of the following can regulatory RNAs coordinate?

select all that apply transcription initiation enzyme synthesis replication enzyme activity translation allostery transcription termination

Which of the following are fall posttranscriptional mechanisms to control gene expression?

select all that apply (Bolded = right) mRNA stability DNA topology Translational control Transcriptional enhancement Promoter recognition Transcriptional repression Regulatory RNAs Transcriptional activation Proteolysis Transcription termination

Which of the following are fall under Transcriptional control to control gene expression?

select all that apply: (Bolded = right) DNA topology Proteolysis Transcriptional enhancement Regulatory RNAs Transcriptional repression Promoter recognition Translational control Transcription termination Transcriptional activation mRNA stability

At low [ATP], ATP-replenishing pathways are _____, and ATP-utilizing pathways are _____ .

stimulated inhibited

the polymerization of flagellins during the assembly of bacterial flagellum...

takes place at the tip of the filament

which of the following is not true about the synthesis of the peptidoglycan cell wall in bacteria?

the sugar and peptide precursors are transported independently across the cell membrane by dedicated lipid carriers

WHich of the following is true regarding type III secretion systems?

this system evolved from the machinery that builds flagella

What is a simple explanation of why evolution might control the enzyme amount?

to conserve energy

In prokaryotes, which two mechanisms are monitored closely during gene expression?

transcription and translation

What would the response of a microbe be if a specific building block was abundant in its environment?

turn off the pathway leading to the synthesis of that building block

Allosteric enzymes contain at least ___ subunit(s) and can exist in at least ___conformation(s).

two two