SCI 135 - Third Exam Fall 2015

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.  What is the critical change in HIV escape mutants?

_______    a. They become much more highly infective                b. Their antigens change
                c. They are able to survive outside the body                 d. They invade the bone marrow
                                                e. They look like little ninja turtles

            2.  Chromatin is made up of DNA and

_______    a. Spindles         b. Nuclear envelope         c. Histones        d. RNA         e. Um, tin-?

            3.  Crossing over usually happens during

_______    a. Mitosis I         b. Mitosis II         c. Meiosis I        d. Meiosis II         e. Star Wars XXII

            4.  Without chaperonins, cell proteins would

_______    a. Not form their proper shapes                      b. Get recycled
                c. Not get to where they’re used                     d. Not be made
                            e. Do things that would show up in shared phone files

            5. Cytoskeleton has which structures?

_______    a. Microvilli & microfilaments                         b. Microvilli & Cytotubules
                 c. Cytofilaments & microvilli                          d. Microfilaments & Microtubules
                                   e. It’s probably not microbones, huh?

           6. Translocation mutations can often lead to

_______    a. Radiation damage         b. Development of new alleles        c. Cell death
                d. Position effects                   e. Suddenly understanding Swedish

            7. It is now understood that evolution changes

_______    a. A population’s surroundings          b. RNA to DNA         c. Allele ratios
                d. Whatever will be needed later        e. This species-thingee into that species-thingee

            8. A zygote becomes an embryo by

_______    a. Mitosis           b. Differentiation          c. Fusion           d. Meiosis
                                  e. Taking a tough multiple-choice exam

           9.  Pancreas cells that secrete the protein insulin must have

_______    a. Ribosomes         b. Vesicles         c. Golgi bodies        d. All of the above         e. An insulin license

            10. Mice with a right side – left side switch had what kind of mutation?

_______    a. Translocation             b. HOX gene            c. Dominant             d. Recessive
                                    e. Is that where switch-hitters in baseball come from?

            11. Transfer RNA attaches to

_______    a. Messenger RNA & an amino acid                b. Messenger RNA & DNA
                c. DNA & proteins                                         d. DNA & the nuclear envelope
                                            e. Any molecule that pays attention to it

            12. Cytokinesis could happen in

_______    a. Prophase or telophase             b. Metaphase or anaphase            c. Interphase or telophase
                d. Prophase or anaphase              e. Las Vegas – anything can happen there, according to the ads...


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.  What are two different molecular complex organelles?


2a. What are Barr bodies?

2b. Why do Barr bodies exist?

3.  Briefly explain why an addition point mutation should be much more damaging than a substitution.

4. When radiation causes multiple DNA breaks, cells often die for what two common reasons?


5. Embryos eventually form three cell layers that go one to be different parts of the animal. Name a layer and give one system that develops from that layer.


6.  What is a pseudopod?

7.  Give two pieces of evidence supporting the idea that chloroplasts were originally endosymbionts.


8.  What does telomerase do?

9. Briefly explain how a prion infection can kill a cell.

10. Under an electron microscope, why does rough endoplasmic reticulum look rough?

11. For a high chromosome number, compared to a low chromosome number -

12. What, technically, is a gene?

13. Homologous chromosomes are matched pairs. What exactly matches between them?

14. Two different structures that attach at centromeres -


15. During fertilization, only the sperm nucleus gets into the egg cell. What would be bad about other parts entering?

16. Briefly explain the concept of hybrid vigor.


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.  For the four phases of mitosis (so not the one between), name the phases in order and give one specific thing for each that happens particularly in that phase.




2.  Describe (don’t just give a term) four different types of reproductive isolation.



3.  Give three sets of differences between -




4.  Using this DNA code give the messenger RNA sequence and, using this chart, give the coded amino acid sequence.
Strand         T A C C A A A G T A G G C A T C C A T A G T G G A T T

mRNA ____________________________________________________________________________



5.  Give three sets of differences (other than the associated genders) between -




6.  Name or give a function (but not both as 2 answers) performed by 4 vesicles or vacuoles.



7.  Pick two of these three genetics terms, and explain how each one works.




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.

To be successful, cancers have to “turn on” certain genes and abilities the original cells didn’t have activated. One ability / feature makes a cancer malignant – it can spread from the original tumor site. What is that ability / feature? Three Points.

Pick a type of organelle that a cell might not have, and explain why it wouldn’t have it. Three Points.

Why would a single-celled organism not do apoptosis? Three Points.

Postmodernism looks at cultural influences on science. What was postmodern about the resistance put up against the endosymbiosis theory? Three Points.

What is a karyotype? Three Points.

In what group does the unmatched chromosome pair produce females? Three Points.

Give an example of how sexual reproduction with no genders can happen. Three Points.

What sorts of animals do a much better job of DNA repair than we do? Three Points.

Polyploidy if often a non-deadly mutation in what group of living things? Three Points.


Through time, some new genes appear. Where did they probably come from? Three Points.

In the “ball” stage, human embryos are actually disc-shaped. Why? Three Points.



SCI 135 

Michael McDarby