Exam 3: Bioenergetics, Enzymes, and Metabolism

In the reaction A + B <-> C + D,how might the reaction take place in the cell if the $\Delta$ G is very positive? How might the reaction occur if the $\Delta$ G is slightly positive?

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Question 1

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If $\Delta$ G is very positive,the reaction would probably take place by coupling it to a reaction with a larger - $\Delta$ G so that when the $\Delta$ G values are added up the sum is negative.If the reaction is slightly positive,it may be coupled as well,although it may also be driven forward by increasing the amounts of the reactants and/or decreasing the amounts of products.The Law of Mass Action would be likely to allow the reaction to run under these conditions.

Many bacteria have acquired resistance to penicillin by picking up the gene for -lactamase.However,some have developed resistance without acquiring this gene.How do these bacteria escape the fatal effects of penicillin?

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Some are resistant because they possess modifications in their cell walls that block the entry of the antibiotic.Others are resistant because they are able to selectively export the antibiotic once it has entered the cell.Still others are resistant because they possess modified transpeptidases that fail to bind the antibiotic as a result of mutations in the gene that encodes the enzyme.

Where is S.aureus usually found in humans? What kind of hospitalized patients develop life-threatening S.aureus infections? Distressingly,instead of just showing up in hospitals,methicillin-resistant S.aureus (MRSA)is showing up in other places.What are some examples?

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The skin and nasal passages.Those patients who have open wounds or invasive tubes.It has appeared in community settings,like high school gyms and children's daycare centers.

What strategies are employed to combat the ability of the AIDS (HIV)virus to develop drug-resistant variants?

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Question 4

Why are alcoholic beverages often made in airtight containers?

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Question 5

How does the AIDS virus manage to avoid the effects of drugs that attack its enzymes so effectively?

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Question 6

Do the equations below represent coupled reactions? If not,why not? A + B <-> C + D ( $\Delta$ G = -5.4 kcal/mole) E + F <-> G + H ( $\Delta$ G = +4.4 kcal/mole)

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Question 7

A number of antibiotics attack prokaryotic protein synthesis,but not eukaryotic protein synthesis.Name two common antibiotics that work this way.What is their site of action and why don't they affect eukaryotic protein synthesis?

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Question 8

If ATP is present in relatively high amounts,what is likely to happen to the rate of glycolytic activity in that cell?

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Question 9

You are observing a reaction and discover that the reaction vessel is warm to the touch.The reaction also results in an increase in entropy.Is the reaction spontaneous? How do you know?

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Question 10

There have been two new classes of antibiotics developed and approved since 1963.One of these antibiotics acts specifically on bacterial ribosomes.What is it? Another new group of antibiotics is the cyclic lipopeptides.What is a representative of this group and how does this group of antibiotics work?

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Question 11

The effect of a competitive inhibitor can be reversed by _______.

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Question 12

Glycolysis occurs in the ;the Krebs (TCA)cycle occurs in the of eukaryotes and the of prokaryotes.

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Question 13

What kind of interaction is not involved in the binding of a substrate to a normally functioning enzyme?

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Question 14

If a reaction vessel is cold to the touch and the reaction results in an increase in order in the reaction vessel,is the reaction spontaneous or nonspontaneous? Explain your answer.

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Question 15

Penicillin fits into the active site of transpeptidases and thus acts as what kind of inhibitor? How is the effect of such an inhibitor usually able to be reversed? Why would this approach not work with penicillin?

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Question 16

Why was methicillin developed?

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Question 17

Penicillin is an irreversible inhibitor of the transpeptidases,enzymes that cross-link components of the bacterial cell wall.The cell wall is thus fragile and the bacteria die.Penicillin and its derivatives are structural analogs of the natural substrates of these enzymes.Why doesn't penicillin normally kill humans,unless a severe allergic reaction (anaphylaxis)develops? How does penicillin inhibit transpeptidase?

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Question 18

The presently accepted model of enzyme action was proposed by Daniel Koshland in the 1960s and suggested that the enzyme was a flexible structure with an active site roughly complementary to the substrate that binds it.After its initial interaction with the substrate,the enzyme alters its shape and thus improves the fit of the substrate in the active site)What is the name of this model?

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Question 19

Which property below is not a characteristic of enzymes?

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Question 20

Showing 1 - 20 of 48

In the reaction A + B <-> C + D,how might the reaction take place in the cell if the $\Delta$ G is very positive? How might the reaction occur if the $\Delta$ G is slightly positive?

Many bacteria have acquired resistance to penicillin by picking up the gene for -lactamase.However,some have developed resistance without acquiring this gene.How do these bacteria escape the fatal effects of penicillin?

Where is S.aureus usually found in humans? What kind of hospitalized patients develop life-threatening S.aureus infections? Distressingly,instead of just showing up in hospitals,methicillin-resistant S.aureus (MRSA)is showing up in other places.What are some examples?

What strategies are employed to combat the ability of the AIDS (HIV)virus to develop drug-resistant variants?

Why are alcoholic beverages often made in airtight containers?

How does the AIDS virus manage to avoid the effects of drugs that attack its enzymes so effectively?

Do the equations below represent coupled reactions? If not,why not? A + B <-> C + D ( $\Delta$ G = -5.4 kcal/mole) E + F <-> G + H ( $\Delta$ G = +4.4 kcal/mole)

A number of antibiotics attack prokaryotic protein synthesis,but not eukaryotic protein synthesis.Name two common antibiotics that work this way.What is their site of action and why don't they affect eukaryotic protein synthesis?

If ATP is present in relatively high amounts,what is likely to happen to the rate of glycolytic activity in that cell?

You are observing a reaction and discover that the reaction vessel is warm to the touch.The reaction also results in an increase in entropy.Is the reaction spontaneous? How do you know?

The effect of a competitive inhibitor can be reversed by _______.

Glycolysis occurs in the ;the Krebs (TCA)cycle occurs in the of eukaryotes and the of prokaryotes.

What kind of interaction is not involved in the binding of a substrate to a normally functioning enzyme?

If a reaction vessel is cold to the touch and the reaction results in an increase in order in the reaction vessel,is the reaction spontaneous or nonspontaneous? Explain your answer.

Penicillin fits into the active site of transpeptidases and thus acts as what kind of inhibitor? How is the effect of such an inhibitor usually able to be reversed? Why would this approach not work with penicillin?

Why was methicillin developed?

Which property below is not a characteristic of enzymes?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, Function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cell Signaling and Signal Transduction: Communication Between Cells

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

Exam 3: Bioenergetics, Enzymes, and Metabolism

In the reaction A + B <-> C + D,how might the reaction take place in the cell if the Δ\DeltaΔ G is very positive? How might the reaction occur if the Δ\DeltaΔ G is slightly positive?

Many bacteria have acquired resistance to penicillin by picking up the gene for -lactamase.However,some have developed resistance without acquiring this gene.How do these bacteria escape the fatal effects of penicillin?

Where is S.aureus usually found in humans? What kind of hospitalized patients develop life-threatening S.aureus infections? Distressingly,instead of just showing up in hospitals,methicillin-resistant S.aureus (MRSA)is showing up in other places.What are some examples?

What strategies are employed to combat the ability of the AIDS (HIV)virus to develop drug-resistant variants?

Why are alcoholic beverages often made in airtight containers?

How does the AIDS virus manage to avoid the effects of drugs that attack its enzymes so effectively?

Do the equations below represent coupled reactions? If not,why not? A + B <-> C + D ( Δ\DeltaΔ G = -5.4 kcal/mole) E + F <-> G + H ( Δ\DeltaΔ G = +4.4 kcal/mole)

A number of antibiotics attack prokaryotic protein synthesis,but not eukaryotic protein synthesis.Name two common antibiotics that work this way.What is their site of action and why don't they affect eukaryotic protein synthesis?

If ATP is present in relatively high amounts,what is likely to happen to the rate of glycolytic activity in that cell?

You are observing a reaction and discover that the reaction vessel is warm to the touch.The reaction also results in an increase in entropy.Is the reaction spontaneous? How do you know?

The effect of a competitive inhibitor can be reversed by _______.

Glycolysis occurs in the ________;the Krebs (TCA)cycle occurs in the ______ of eukaryotes and the ______ of prokaryotes.

What kind of interaction is not involved in the binding of a substrate to a normally functioning enzyme?

If a reaction vessel is cold to the touch and the reaction results in an increase in order in the reaction vessel,is the reaction spontaneous or nonspontaneous? Explain your answer.

Penicillin fits into the active site of transpeptidases and thus acts as what kind of inhibitor? How is the effect of such an inhibitor usually able to be reversed? Why would this approach not work with penicillin?

Why was methicillin developed?

Which property below is not a characteristic of enzymes?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, Function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cell Signaling and Signal Transduction: Communication Between Cells

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

In the reaction A + B <-> C + D,how might the reaction take place in the cell if the $\Delta$ G is very positive? How might the reaction occur if the $\Delta$ G is slightly positive?

Do the equations below represent coupled reactions? If not,why not? A + B <-> C + D ( $\Delta$ G = -5.4 kcal/mole) E + F <-> G + H ( $\Delta$ G = +4.4 kcal/mole)

Glycolysis occurs in the ;the Krebs (TCA)cycle occurs in the of eukaryotes and the of prokaryotes.