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Micro
homework questions
59
Biology
Undergraduate 2
11/10/2013

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Term
It relies on the use of special dideoxyribonucleotide bases that can be inserted into a growing DNA strand by DNA polymerase, but block the insertion of further nucleotides.
Definition
Describe the Sanger method of sequencing
Term
Whole genome shotgun sequencing is the strategy of choice for determining the sequence of bacterial genomes.
Definition
What is shotgun sequencing?
Term

Bioinformatics allows us to process large quantities of biological data, and has developed in tandem with advances in DNA sequencing.


Definition
What is bioinformatics?
Term

It is a process in which DNA is extracted directly from microbial communities and sequenced or cloned into vectors to make libraries.


Definition
What is meant by the term “metagenomics”?
Term
The DNA sequences were then compared to DNA sequence databases. In many cases, the sequenced SSU rRNA gene matched an existing sequence in the database.
Definition
How can DNA isolated from a community be analyzed?
Term
clone DNA fragments into vectors - synthesize new DNA strands – separate newly synthesized DNA strands by gel electrophoresis.
Definition
The correct sequence of steps in the Sanger sequencing method is? 
Term
True
Definition
True or False: Pyrosequencing takes its name from the fact that this technique detects light that is emitted each time a new nucleotide base is added to the growing DNA strand. 
Term
Constitutive expression involves the expression of specific genes all of the time whereas inducible expression involves expression of specific genes when they are needed only.
Definition
What is the difference between constitutive and inducible expression?
Term
To regulate the transcription of genes that code for the enzymes is the most efficient method.
Definition
Microbial cells can regulate the amount of protein produced. At what level is this control most efficient?
Term
True
Definition
True or False: The initiation of transcription can be regulated by affecting the ability of RNA polymerase to bind to DNA.
Term
Negative control refers to regulatory mechanisms involving a repressor that blocks transcription. The repressor binds to the operator as a dimer and inhibits binding of RNA polymerase to the promoter.
Definition
Describe the process of negative control of gene expression. What is role of the repressor proteins play in this process?
Term
During positive control, regulatory molecules lead to increased transcription. For these operons, an activator molecule increases the affinity of the RNA polymerase to promoters that otherwise do not bind them very strongly.
Definition
Describe the process of positive control of gene expression. What is the role that activator proteins play in this process?
Term
lac operon, cAMP is the effector, and allolactose is an inducer
Definition
What role does lactose play in lac operon regulation? 
Term

It binds to the operator and blocks transcription.


Definition
What role does the LacI repressor play in lac operon regulation?
Term
A regulon is a collection of genes in which expression has been altered due to environmental changes.
Definition
What is a regulon?
Term
Glucose shuts down operons that produce enzymes utilizing a number of other nutrients in a process called catabolite repression. This ensures that E. coli preferentially utilizes glucose in the lac operon.
Definition
How is catabolite repression involved in the actions of the lac operon?
Term
True
Definition
True or False: The SOS repair system uses alternative DNA polymerases that can fill in missing DNA strands but lacks the ability to proofread. This mechanism repairs the structure of the chromosome, but results in a high rate of mutation.
Term
True
Definition
True or False: The term “quorum sensing” refers to the number of members of a group that must be present in order to conduct business (a quorum). When microbes achieve a quorum, enough cells are present to accomplish a task that one cell alone cannot perform. Quorum sensing involves the release of specific signal molecules, known as autoinducers, into the environment by bacterial cells.
Term

motility and conjugation 

biofilm formation and seconary metabolite production 

pathogenesis 

Definition
Quorum sensing in bacteria is used to control _____.
Term
Typically, these systems involve a sensor kinase, commonly histidine protein kinase (HPK), for detecting the environmental stimulus, and a response regulator (RR) that regulates transcription.
Definition
What are the two types of protein components involved in a two-component regulatory system? What are their roles?
Term

Enzymes that are in constant demand.


Definition
What types of enzymes are typically constitutively expressed?
Term

negative control involves the action of a repressor molecule; positive control does not.


Definition
A difference between positive and negative control is
Term

Autoinducers are species specific.


Definition
In complex microbial communities consisting of many species, how do individual bacteria differentiate among autoinducers?
Term
True
Definition
True or False: Quorum sensing is an example of a two-component system.
Term
an inducer molecule binds to the lac repressor molecule.
Definition
In the presence of lactose
Term

increase the affinity of RNA polymerase to the promoter.


Definition
In positive control, the function of the activator molecule is to
Term

a chemical signaling system 

individual microbes working cooperatively 

the cumulative impact of the response of a large number of individual cells 

 

Definition
Quorum sensing is an example of
Term
True
Definition
True or False: Allosteric inhibition is also sometimes referred to as feedback inhibition. 
Term
cell membrane
Definition
The electron transport chain (ETC) or electron transport system is located in the _____ in bacteria.
Term
True
Definition
True or False: Electrons enter the ETC when NADH transfers them there.
Term
use the energy of the proton motive force to change ADP into ATP.
Definition
The role of ATP synthase is to:
Term
These steps help construct a proton gradient to be used by ATP synthase for ATP production.
Definition
Why are so many small steps required in the ETC to ultimately donate electrons from NADH to oxygen to form water?
Term

Oxygen


Definition
A facultative aerobe is capable of living with or without oxygen. In conditions where it might need as much ATP as possible, what might it use as a final electron acceptor in its ETC?
Term
Both pathways make ATP using substrate level phosphorylation and construct reduced NADH for use in ETC and ATP production
Definition
What role does glycolysis and the Krebs cycle play in metabolism?
Term

glycerol and three fatty acids


Definition
A triglyceride is composed of:
Term
pyruvic acid
Definition
Glycerol can be converted to:
Term

amino acids


Definition
Proteins must be broken down into ____ before they can used for energy.
Term

movement 

secretion 

protein synthesis 

active transport 

Definition
Glucose can be used for _____.
Term
Glycolysis, Formation of acetyl coenzyme A, Krebs cycle, Electron transport chain
Definition

Select the correct sequence of steps.

Formation of acetyl coenzyme A, Electron transport chain, Krebs cycle, Glycolysis

Glycolysis, Formation of acetyl coenzyme A, Krebs cycle, Electron transport chain

Krebs cycle, Glycolysis, Electron transport chain, Formation of acetyl coenzyme A

Glycolysis, Electron transport chain, Krebs cycle, Formation of acetyl coenzyme A

Term
proteins
Definition
Amino acids are joined by ribosomes to make _______.
Term
none of these choices
Definition

Select the incorrect statement.

Enzymes are proteins.

Enzymes catalyze reactions.
Some enzymes are composed of a protein and non-protein part.
The non-protein part or cofactor can be a metal ion or coenzyme.
None or these choices 
Term
True
Definition
True or False: An enzyme is never consumed in a chemical reaction.
Term
smaller molecules
Definition
Anabolism is the production of larger molecules from _____.
Term
catabolism and anabolism
Definition
Metabolism is:
Term
Anabolism is a series of degradative chemical reactions that break down complex molecules into smaller units.
Definition

Select the incorrect definition. 

Catabolism and anabolism are examples of metabolic events.

Metabolism defines all the biochemical reactions happening in a living cell.
Anabolism is a series of degradative chemical reactions that break down complex molecules into smaller units.
Anabolism is the synthesis of large molecules, using energy.
Catabolism involves the breakdown of larger molecules to produce energy.
Term
Enzymes enhance reaction rates by lowering the activation energy. This typically occurs when the enzyme binds to the substrate of the reaction and modifies its structure to make it easier for the reaction to go through.
Definition
How do enzymes enhance reaction rates?
Term
All of these statements are correct. 
Definition

What are cofactors and coenzymes? What are their roles in enzymatic reactions?

Cofactors and coenzymes are chemicals that can be inorganic ions.

Cofactors and coenzymes are chemicals that can be organic molecules.
Cofactors and coenzymes can assist enzymes in their reactions by transferring functional groups.
None of these statements is correct.
All of these statements are correct. 
Term
Heterotrophs obtain carbon from inorganic molecules, such as elemental sulfur.
Definition

Select the incorrect statement.

Organotrophs remove electrons from organic molecules, such as glucose.

In chemotrophs, the energy is derived from the oxidation of chemical substrates and is termed oxidative phosphorylation.
Phototrophs acquire energy by capturing photons of light to raise electrons to higher energy levels that can drive otherwise unattainable redox reactions.
Heterotrophs obtain carbon from inorganic molecules, such as elemental sulfur.
of these statements are correct.
Term
The plasma membrane of both Gram positive and Gram negative cells is a sufficient barrier to allow a proton motive force to be established.
Definition
How do prokaryal cells establish a proton motive force in the absence of a membrane system like that found in the mitochondria of eukaryal cells?
Term
oxygenic produces oxygen and anoxygenic does not.
Definition
The difference between oxygenic photosynthesis and anoxygenic photosynthesis is
Term
increasing the rate of respiration, thereby consuming more oxygen.
Definition
Nitrogenase, the enzyme responsible for fixing dinitrogen, is inhibited by the presence of oxygen, and yet requires the products of the light reactions of photosynthesis that generate oxygen by splitting water. Nitrogen fixing organisms solve this problem by
Term
True
Definition
True or False: Substrate level phosphorylation produces ATP by the transfer of a phosphate group from a reactive intermediate to ADP.
Term
False
Definition
True or False: Because fermentation is an anaerobic process, only obligate anaerobes use this pathway.
Term
False
Definition
True or False: Some bacteria are capable of aerobic respiration, but ferment instead with the production of large quantities of lactic acid which is then metabolized further to produce ATP.
Term
2 net, 4 gross ATP per glucose molecule.
Definition
The average net and gross ATP production from the EMP pathway is
Term
the tricarboxycylic acid (TCA) pathway.
Definition
All of the following are glycolytic pathways except

the Embden-Meyerhof-Parnas (EMP) pathway.
the pentose phosphate pathway.
the tricarboxycylic acid (TCA) pathway.
the Entner-Doudoroff (ED) pathway.
Term
heterocysts.
Definition
In cyanobacteria, nitrogen fixation takes place in specialized cells called
Term
False
Definition
True or False: Respiration always uses oxygen as a terminal electron acceptor.
Term
True
Definition
True or False: The proton motive force is created by transporting protons across membranes to establish a concentration gradient.
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