SC 135 - Third Exam Spring 2012

Links connect to relevant parts of the online book.



On the line to the left, place the letter of the choice that best  answers the question.

Three Points Each.                  NOTE:  "e" answers are never the correct answer.


                        1.    The main purpose of Barr bodies is to

_______                    a.  Determine gender                        b.  Equalize expression of genes

                                    c.  Mark the cells                              d.  Help the cell divide

                                                e.  Make the barr seem popular



                        2.   About how much of human DNA is not coding (not genes)?

_______                    a.  10 - 20%          b.  30 - 40%              c.  40 - 50%         d.  Over 90%

                                          e.   Well, if it’s not working then I’m not paying for it…!



                        3.   A cell whose primary function is absorption might have a lot of

_______                    a.   Ribosomes                       b.   Nucleoli                           c.   Microvilli

            d.   Cytoskeleton                  e.   Reasons to look for a better job



                        4.    Which would be the most potentially dangerous point mutation?

_______                    a.  Substitution                                  b.  Insertion

                                    c.  Reversal                                        d.  Translocation

                                                e.  Mutations can make a point?



                        5.    Rough endoplasmic reticulum combines

_______                    a.  Transcription and translation         b.  Translation and secretion

                                    c.  Structure and waste removal          d.  Production and transport

                                                            e.  A normal word with two scary ones



                        6.   Meiosis produces four cells because it

                                    a.  Has to make diploid cells

                                    b.  Has to make haploid cells

_______                    c.  Replicates its DNA beforehand

                                    d.  Has to make small enough cells

                                    e.  Just can’t stop itself 



                        7.    Centromeres connect to

_______                    a.  Chromatids and spindles           b.  Membranes and chromatids

                                    c.  Membranes and spindles           d.  Nucleolus and spindles

                                                            e.  The centro and the mere




                        8.   In order for something to be a mutation, it must

_______                    a.  Produce a cellular effect                        b.  Change the DNA

                        c.  Change the protein                                  d.  All of these

                        e.  Fill out a short questionnaire first




                        9.    Genetic redundancy shows up in

_______                    a.  Polyploidy and mitosis             b.  Codons and meiosis

            c.  Meiosis and mitosis                    d.  Spindles and telomeres

                     e.  My notes, but I don’t know what it is




                        10.  The most common result of crossing over is

_______                    a.  Point mutations                           b.  Polyploidy

                                    c.  Broken linkage                            d.  Extra chromosome                     

e.  To get to the other side (gotta respect the classics!)




                        11.  In position effects, the position is in the

_______                    a.  Chromosome                    b.  Nucleus                            c.  Cell

                                    d.  Cell cycle                         e.  Well, how flexible are you-?




                        12.   Prokaryote chromosomes do not have

_______                    a.  Telomeres             b.  Homologous pairs           c.  Centromeres

d.  Any of these                                e.  Much self-esteem





Answer any eight of the following questions for 4 Points Each.

            Note:  if you answer more than eight, only the first eight  will be corrected.

            You can get partial credit on these answers.

1.       Explain how dominant and recessive alleles work.


2.    What are two different ways that radiation exposure can result in a cell’s death?






3.   For high chromosome numbers (compared to low numbers) -






4.   Spindle fibers are what type of cell structure?




5.   What two critical abilities must HIV escape mutants have to be dangerous?








6.   Explain how a prion infection causes damage to cells.





7.   What are two main components of cytoskeleton?





8.    Two major ways that Meiosis I differs from mitosis.






9.    What are two phases of the cell cycle when cytokinesis can happen?





10.  For histones -





11.   A cell full of Golgi bodies is most likely doing what function?




12.   What two major areas of medical research are studying telomeres?





13.  Briefly explain why sex-linked diseases are more common in human males than in females.





14.  What is apoptosis?





15.  The two main functions of interphase -








16.  For a cell plate -











Answer any four of the following questions for Eight Points Each.

Note:  if you answer more than four, only the first four will be corrected.

            You can get partial credit on these answers.


1.        Name or give a function (but not both as 2 answers) performed by a vesicle or vacuole.




2.    Using this DNA code give the messenger RNA sequence and, using the chart attached to the back of the exam, give the coded amino acid sequence.


      Strand   T A C  T  C  A  A  G  G  A  A  A  C  C  C  G  T  A  T   T  C  G  C  G  A  C  T


      mRNA   ___________________________________________________________________________________________________






3.   Give, in order, the four steps of actual mitosis (don’t include the stage between mitoses), and for each give one thing that happens just during that stage.








4.   Give three sets of differences, other than the genders involved, between






5.  a.  Two different things that happen during transcription in a cell.  




b.  Two different things that happen during translation in a cell.  




6.   What are three different molecular-complex organelles?




7a.  Briefly explain the endosymbiont theory.



7b.   What two structures are associated with the endosymbiont theory?





Link to Answer Key




Answer as many as you are able.  Wrong answers will not result in points being lost from the main exam.   You can get partial credit on these answers.


Why is the nuclear envelope called an envelope?  Three Points.



There was a non-scientific reason why the endosymbiont theory was not accepted at first – what was it?  Three Points.




Why is mtDNA considered “better” for evolutionary comparisons?  Three Points.



Cancer cells, being damages by mutation, randomly activate different genes, but malignant cancers often activate the same genes.  For four points, briefly explain why.




Why did Mendel wind up doing his research with pea plants?  Three Points.



Why do most cancer treatments have toxic effects on other cells?  Three Points.




Why do some species have extremely efficient DNA repair machinery?  Three Points.



The molecules called chaperonins are in the same class as molecules that do what other function?  Three Points.




What are the two possible things that happen when the nuclear membrane “disappears”?  Three Points Each.




SCI 135 

Michael McDarby





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