Help with microbiology review sheet, please?

[stephxbee]

So, after countless hours of working on my review sheet, I have finally thrown in the towel and decided to ask for help, but not from my professor because he's not very helpful and he's been using the same exam since 1994, and yet there has never been an answer key posted anywhere. So, the students could be doing the review sheet completely wrong and we'd never know.. but, that's a complaint for a different forum.

 

I did 39/50 questions, but I'm stumped on 11 of them. Help would be much appreciated. Thanks!

 

 

The exact code needed for the synthesis of all the enzymes a cell or an organism can make is ORIGINALLY found in:

A. all of the genes possessed by that cell or organism

B. the genome and all of the plasmids of that cell or organism

C. all of the proteins of that cell or organism

D. both A and B

E. A,B and C

 

Put the following into the correct sequence for gene expression and protein synthesis in a eucaryote:

1. Peptide bonds are formed between amino acids on adjacent tRNA's

2. Introns are cut out and the exons are spliced together

3. Polymerase binds to the promotor

4. AUG is recognized both by the ribosome and by the tRNA with a methionine attached to it

5. DNA binding protein binds to the enhancer

A. 1,2,3,4,5

B. 2,1,5,3,4

C. 5,3,2,4,1

D. 5,2,4,1,3

E. 4,1,3,2,5

 

 

Differences in the procaryotic and eucaryotic ribosomes allow some antibiotics to selectively inhibit the synthesis of bacterial:

A. proteins
B. enzymes
C. DNA binding proteins
D. all of the above since all are made by translation E. none of the above

 

 

16. Nucleic acid hybridization, like what happens between the primer and the template strand in DNA replication, is based on which property of DNA?

A. Hybridization has to do with single-stranded pieces of nucleic acid binding to each other if and only if there is proper base pairing.

B. Hybridization has to do with DNA binding proteins like RNA polymerase and restriction enzymes recognizing specific DNA base sequences

C. Hybridization has to do with fact that double stranded DNA is composed of paired DNA strands which are covalently bound to each other through the bases

D. all of the above E. none of these

Antibiotics like chloramphenicol, erythromycin and tetracycline inhibit translation in procaryotes but not in eucaryotes. The most likely target of these antibiotics would be the:

1. they would interfere with the activity of the enzymes of replication

2. they would interfere with the activity of the enzymes of theribosome

3. they would interfere with the activity of the enzymes of the electron transport system

4. they would interfere with the activity of the enzymes which synthesize peptidoglycan and teichoic acid

5. none of the above

 

Which of the following statements is false about oxygen and bacterial cells

A. Oxygen could be used as a disinfectant against obligate anaerobes since these organisms are killed by oxygen.

B. Oxygen could be used to promote bacterial growth since some organisms, like obligate aerobes, absolutely require oxygen.

C. Metabolism in the presence of oxygen can generate toxic forms of oxygen like peroxide, therefore aerobic organisms need protective enzymes like catalase to destroy these toxic compounds.

D. Oxygen is often used as the terminal electron acceptor by those organism which metabolize with respiration.

E. Facultative anaerobes ferment; they do not respire even in the presence of oxygen.

 

 

Many simple eucaryotic genes can be transcribed and translated by procaryotes like E. coli. However some eucaryotic genes cannot be expressed by procaryotes. Which of the following might be a reason for this failure?

1. eucaryotic genes often have unique bases which are not found in procaryotes

2. Since procaryotic genes are not segmented, procaryotes are not able to cut out the introns nor are they able to splice the exons together

3. the procaryotic genetic code is very different from the eucaryotic genetic code

4. eucaryotes do not use tRNA during the translation process

E. prokaryotes do not use tRNA during the translation process

Which of the following statements is true about alleles

1. a diploid individual who inherited one copy of a gene from each parent could have at most 2 alleles of that gene

2. alleles are different varieties of a particular gene

3. the phenotype of an individual will be determined by the alleles of the genes which that person possesses

4. all of the above are true about alleles

5. only A and B are true

Pseudomonas aeruginosa is an obligate aerobe. What is true about this organism?

A. It probably produces organic waste products.
B. It regenerates NAD from NADH2 by making alcohol and lactic acid
C. It has an electron transport chain with an inorganic final electron

acceptor
D. It will make at most 4 ATP's from a molecule of glucose E. None of the above are true

 

 

Which of the following is mismatched

A. DNA polymerase - uses a DNA template to make the message which is read by the ribosome.

B. RNA processing - removes introns (non-coding sequences) from the mRNA of eucaryotes

C. Reverse transcriptase - makes DNA from the RNA genome of the retroviruses

D. Restriction endonuclease - cuts DNA and gives the pieces sticky ends E. RNA polymerase - makes the primer needed for the DNA polymerase to

work

 

[Xalatan]

That's a lot of work for you if there is no answer key. The answer to the second question should be C - enhancer first, then polymerase then mRNA processing, followed by protein synthesis.

 

There may be rules here about posting homework etc, maybe ask a moderator to see if the content can be posted this way?

Edited March 10, 2016 by Xalatan

[CharonY]

Not a mod, but we discourage simply providing answers to homework as it does not help understanding the subject. Rather we expect to see some thoughts towards answering them and someone is usually wiling to guide a long the way.

[Genecks]

Why can't I argue E. for #1?

I mean, I think it's B if I remember correctly, because genes on different parts of the genome might help synthesize that enzyme. But then, I can possibly equivocate about what "code" is, and no... the code does not generally unravel itself and start punching out proteins. Is the answer: "It's a microbio class, not a molecular bio class"? Maybe, then, it's A, because it's a microbio class.

 

Anyway, the inability for the original poster to answer most of the questions shows a lack of studying the material. A little research is needed, I think, but there has been a lack of studying the material. That is the difference between a letter-grade, I think, especially observing one alleged question from a higher percentage bracket. In a situation like this, use a study group.

Edited March 11, 2016 by Genecks

[Juno]

Anyway, the inability for the original poster to answer most of the questions shows a lack of studying the material. A little research is needed, I think, but there has been a lack of studying the material.

Put it this way - I spent twenty minutes or so with Wikipedia and came to the same conclusion as Xalatan on the second question, and I'm a maths/physics student with no biology background. More effort required, I would say. (Unless Xalatan is wrong, of course!)

[Essay]

Put it this way - I spent twenty minutes or so with Wikipedia and came to the same conclusion as Xalatan on the second question, and I'm a maths/physics student with no biology background. More effort required, I would say. (Unless Xalatan is wrong, of course!)

 

Good going! And if you were already studying biology, you should probably notice how, in that second question, choice #1 described the last step in protein synthesis. Without even reading the other four choices, for the steps in the sequence (for which we're supposed to select the correct order), a quick glance at the answers reveals only one, (answer C), has #1 listed as the last step in the sequence. That trick saved a lot of time, on that question for me, now; but that's only because of a lot of time, in the past, spent studying biology.

 

~

[Xalatan]

Question about P. aeruginosa - question talks about it being an obligate aerobe, so C may be the best answer. An obligate aerobe would need an ETC and the inorganic final electron acceptor likely refers to molecular oxygen. Generating NADH2 from NAD by making alcohol and lactic acid is a property of anaerobes, so B is incorrect. Since alcohol and lactic acid are not produced, A may also be incorrect. A molecule of glucose produces 38 molecules of ATP under obligate aerobic conditions so D is also incorrect.

Last question - A; DNA polymerase carries out DNA replication; RNA polymerase is what is responsible for transcription.