Dr. Reichleršs Bio 301L  M-F 11:30am-1pm         Print Name:_______KEY______________

Exam #1   June 17, 2003


            Answer each question as succinctly as possible in the space provided.  If needed, continue on the back.  If you use a drawing as part of your answer, be sure to also include a written explanation.  Read each question carefully and donšt hesitate to ask if a question seems unclear.  These questions have specific answers, although for some, more than one answer is possible.  To receive full credit you must clearly and fully answer the question being asked.  Each question is worth 6 pts, unless otherwise noted, for a total of 100 points possible for this exam.


1.     If I want to demonstrate that Bio 301L students who attend discussion sessions get higher grades, and I show that all of the students who attend discussion sessions earn Ašs, have I followed Strong Inference?  Why or why not?

No, for any one of these reasons, I am using proof, only one hypothesis is presented, and/or the experiment is not done well- maybe all of the students made Ašs.



2.     What are structural proteins doing in the nucleus?

Packaging DNA.



3.     A protein called throttlemonger is comprised of 200 amino acids.

a.     What is the minimum number of RNA nucleotides needed to code for this protein? (2pts)




b.     If the coding region is actually 800 nucleotides long, what could account for this? (2pts)




c.     The entire gene is 1300 nucleotides.  What accounts for the gene being longer than the coding region? (2pts)

The gene encodes the coding region and the promoter and terminator.



4.     In some cases a gene can be disrupted and made non-functional, but the cell will continue to survive without any problems.  Explain how this might happen?

There may be multiple copies of the gene, so one non-functional copy may be ok.  OR  in that cell, this gene product may not be needed, and so its disruption has no effect.  (only a small percent of genes are expressed in each cell)



5.     Are proteins needed for DNA replication?  Why or why not?

Yes, for any of these reasons, they are needed- to make the covalent bonds between the nucleotides, to separate the DNA strands, for DNA repair.

Dr. Reichleršs Bio 301L  M-F 11:30am-1pm  Exam #1   June 17, 2003  Print Name:________Key___________


6.     Why is continuous DNA replication disadvantageous?

Every DNA replication means more mutations.



7.     Why is human DNA more different between genes, and not in the genes themselves?

Mutations in genes are commonly disadvantageous, mutations between genes have little or no effect.  So cells with mutations in genes die, cells with mutations between genes are ok.



8.     For the sickle-cell mutation to give resistance to malaria without causing sickle-cell anemia, a person must have one copy of the normal hemoglobin gene and one copy of the sickle-cell hemoglobin gene.  How is this possible?

Each chromosome comes in pairs, so someone could have one mutant allele (version), and one normal allele (version).



9.     Why can viruses not replicate themselves?

They lack either the genes or proteins to replicate DNA.



10.  What two things might happen to viral DNA after it enters a cell?

It is used to make more virus (it is transcribed/translated and replicated) or it is integrated into the host cellšs DNA.



11.  How could you eliminate viruses as the cause of brain encephalopathy (Mad Cow Disease, Scrapie, CJD)?

Any of:  Eliminate nucleotides from a sample and see if it is still transmissible.  Filter out virus sized particles and see if it is still transmissible.


Dr. Reichleršs Bio 301L  M-F 11:30am-1pm  Exam #1   June 17, 2003  Print Name:_______Key____________


12.  PRP is the normal gene in mice that can be a prion.  When normal mice are exposed to prion PRP, they get sick.  But mice lacking the PRP gene do not get sick when exposed to prions.  Why?

The spread of prions involves the transformation of normal proteins into misfolded ones by contact with the misfolded prion.  So in mice without the PRP gene there is no normal protein to be misfolded, and they are immune.



13.  Could genes play a role in your grade for this class?  Give one reason why they might, and one reason why they might not.

For each any one of:  Genes play a role- Genes determine the structure of the brain, which plays a role in determining ability to learn, to listen, to see, or etc.  Genes also play a role in determining our interests; how interested one is in a subject mat help determine how well they do.

Genes may NOT play a role-  Outside factors, like a family situation etc, may influence how well one can study, learn, etc.  Exposure to various subjects can influence interest and therefore aptitude.



14.  If you were pregnant, and you knew that there was a history of Huntingtonšs disease in your family, would you genetically screen the fetus?  Why or why not?

Either yes or no with support.  For example:  Yes- To decrease potential suffering of offspring, to prepare individual, os that they can get treatment.

No, there is no cure so why know, to big of decision to decide the fate of fetus,



15.  Depression may have both genetic and environmental causes in humans.  Is it important to know whether genes or the environment have a greater influence on determining the cause of depression in humans? (8pts)

Either yes or no with support.  For example:  Yes- Knowing the cause may help with treatments.  Knowing the cause may alleviate anxiety for those with depression. 

No- The cause may be so complex, that knowing will not help treat it.  Greater information may lead to screenings and discrimination.



16.  Using rules one and two of Strong Inference, answer the following question:  How much of someonešs ability to dance is genetically determined? (8pts)

Must use Strong Inference and make multiple hypotheses and experiments to eliminate hypotheses.  Ex:  hypošs- Ability to dance is genetic.  Ability to dance is not genetic.  expt- Study identical twins separated at birth and determine their ability to dance.