SC 135 - Fourth Exam Spring 2011 - Answer Key

 

Links connect to relevant parts of the online book.

 

 

MULTIPLE CHOICE. 

 

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.   Fusion is something that happens to

 

___C___                a.  Electrons during photosynthesis            b.  Light frequencies during photosynthesis            c.  Nuclei during fertilization

d.  Enzymes during inhibition                                                            e.  Stuff that fuses, yo?

 

                                ...the haploid sperm and egg cell nuclei fuse into the diploid zygote nucleus.

 

 

 

2.   The most likely type of molecular complexes to have led to Life:

 

___B___                a.  Carbohydrates                 b.  RNAs                                c.  DNAs                         d.  Water                        e.  Living

 

                                 ...RNA has abilities later taken on by proteins (chemistry) and DNA (coding) - but RNA can do both.

 

 

 

3.   How particular a protein is for attaching to a substrate is called

 

___B___                a.  Selectivity                 b.  Specificity                 c.  Exclusivity              d.  Attachability                    e.  Sluttiness

 

                                 ...they've used an English word, but which one?

 

 

 

4.   The breaking of what usually leads to denaturation?

 

___D___                a.  Amino acids               b.  Covalent bonds             c.  Ionic bonds                 d.  Hydrogen bonds        e.  De nature bonds, mon.

 

                                 ...H bonds are most of what keeps a protein "wrapped up" in the right shape - unwrapping is denaturation.

 

 

 

5.   The critical type of energy for chemosynthesis at hydrothermal vents is

 

___C___                    a.  Ions                       b.  ATP                       c.  Heat                       d. Light                    e.  Enthusiasm 

 

                                ...it's based on heat-energized chemicals.

 

 

 

6.   Which is true?

 

a.  Spindles are made at the centrioles and attach to centromeres

b.  Centromeres are made at the centrioles and attach to spindles

___A___                c.  Centrioles are made at the spindle and attach to centromeres

         d.  Spindles are made at the centromeres and attach to centrioles

e.  The things you read when you don=t have a dartboard...


                                ...it does get pretty confusing.

 

 

7.    Plants require a nitrogen source so that they can

 

___B___                a.  Capture sunlight                          b.  Make proteins                c.  Move water                       d.  Make ATP

                                                e.  Impress the lady plants

 

                                 ...it's used to make amino acids, the components of proteins.

 

 

 

8.   The idea that Life originated elsewhere and was brought to the early Earth is known as

 

___A___                a.  Panspermia                                      b.  Translocation                                       c.  Transplantation              

                            d.  Extrasolar origins                                                    e.  Uninvited guest hypothesis

 

                                 ...from pan = widespread and spermia = seeding.

 

 

 

9.   Evolution changes used to be seen in  _____, but now scientists look for  changes in  _______.

 

___B___                a.  Traits...membranes                  b.  Populations...gene pools                    c.  Genes...mutations

                            d.  Proteins...enzymes                                     e.  Magazines...internet sites

 

                                ...it has to be something that applies to groups, because evolution only happens to groups over time. 

 

 

 

 

10.   The main positive effect of the Snowball Period was probably

 

___D___                a.  Spread plants to land                              b.  Connected land masses                        c.  Allowed mammals to flourish

                             d.  Increased competition                                                            e.  It was really fun

 

                                 ...this massive ice age reduced available resources and living space drastically.

 

 

 

 11.   What runs essentially just like mitosis?

 

___D___                a. Crossing over            b.  Fertilization            c.  Meiosis I            d.  Meiosis II            e.  The Bachelor

 

                                 ...the only difference is that there's only one set of chromosomes to work with.

 

 

 

                      12.   Aerobic respiration is approximately how many more times efficient than anaerobic respiration?

 

___C___                    a.  1000                    b.  100                c.  20                d.  2                e.  I thought that math was off-limits...

 

                                ...most calculations make it 18 times more efficient.
 

 

 

 

SHORT ANSWER.  

 

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.   Briefly explain how a coupled reaction works.

             ...energy released from an exergonic reaction is used to run an endergonic reaction.

2.   What are the three levels of a classic food chain, in order?
Producers Consumers Decomposers
3.   Briefly describe two different types of niche-based isolation.
Two subgroups move gradually into separate niches. A subgroup moves into a similar niche, but is active at a different time.

A niche splits when an ecosystem is physically split by a geographic barrier.

4.   What are two ways, exactly, that cofactors and coenzymes help enzymes work?
Help move electrons Help move substrates

5.   Briefly explain the general idea of the endosymbiont theory.

             ...some eukaryote organelles were originally prokaryote cells taken in and used for their abilities rather than being digested.

6.   What are the two major, different functions of interphase?
Cell performs whatever its basic function is. Cell prepares for mitosis (if it's going to divide).
7.   What are two different nitrogenous waste products?
Ammonia.

Urea.

Uric Acid.
8.   Only two aspects of the Hardy-Weinberg Rule were surprising to people working with evolutionary theory - what were those 2 aspects?
Migration / isolation
(this was known but hadn't been focused on)
Size of population
(rates could be much faster in small populations)

9.   What is found in the fossil record to indicate when photosynthesis first arose?

 

              ...layers of rust (dissolved iron combined with released oxygen) settled into the sediments.

10.   What two things are combined, usually, to make ATP?
ADP
(Adenosine Diphosphate)
Phosphate
11.  As they go through a food chain, what ultimately happens to most of the -

MATTER?    (After breakdown)  Gets recycled 

ENERGY?    Lost (given off at heat in every transfer)
12.   Two completely different uses for carotenoids in plants -
Captures some light frequencies for photosynthesis Used in coloring fruits, flowers, etc.

13.   What is the evolutionary significance of crossing over?

 

             ...when uneven, it provides extra copies of genes whose use can shift without losing the original.

14.   Briefly describe what happens at an enzyme=s regulatory site.


             ...an inhibitor molecule attaches to shut the enzyme off temporarily.
15.    Main uses plants have for glucose -
Energy
(aerobic respiration)
Make starches
(For structure and storage)

 

LONG  ANSWER. 

 

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 (remember, one of the phases is not part of division!), name the phases in order and for each one, describe one thing that occurs only during that phase.
Prophase Spindle forms;  nuclear envelope goes away;  chromatin, then chromosomes become visible in light microscope;  spindles attach to chromosomes;  chromosomes get pulled into equator (middle) of cell
Metaphase Chromosomes line up on cell equator;  centromeres "pop" apart
Anaphase Single-strand chromosomes pulled toward cell poles;  cell plate forms in plants
Telophase Nucleus reforms;  spindles break down;  chromosomes spin to chromatin and become invisible in light microscope.
2.   For each step in the theoretical development of Life on Earth, put them in chronological order, from earliest to latest, 1 - 8 in the boxes to the left.
 7

Cambrian

Explosion
Multicelled Animals

6

Multicelled

Systems 
After eukaryotes

2

Molecular

Competition
In the soup

5

Aerobic

Respiration
Uses available oxygen

 1

Primordial

Soup
Oceans form

8

Movement
onto Land
Last major step

3

Prokaryote

Cells
First cell type

4

Photosynthesis
Uses common energy

3.  For the main photosynthesis reactions:
Name: Materials or Energy Used Materials Produced
Light-Dependent Reaction Water (supplies H to carry electrons)
Light ( energizes electrons)
Oxygen (from water)
ATP (made using energized electrons)
Light-Independent Reaction ATP (from first step)
Carbon Dioxide (to be built into glucose)
Glucose
4.   What are four different ways that anaerobic organisms impact humans? 
Dairy products (cheese, yogurt, etc.) Dairy spoilage
Alcohol production Dough rising
Diseases Digestive helpers
Immune-system helpers  
5.  For mass extinctions -

Common early

step -                      Most of the plants die

 

Possible

cause -                      Asteroid impact

 

Another possible

cause -                         Major volcanic eruption

Another possible

cause -                               Ice Age

6.   Below is a graph showing how enzyme activity, measured through the rate of the reaction catalyzed by the enzyme, reacts to changes in pH (NOT temperature!).  Fill in:  A)  The name given to the pH where the graph peaks; B) Why the graph peaks there;  C) and D) What=s happening to the enzyme molecules as the rate drops off (C) below the peak; and (D) above the peak.
 

                                                                         A   Optimum temperature
                                                                          *
                                                                  *                *
                                                              *                        *
Reaction                                      C    *                             *   D
Rate           OH- disrupts H               *                                   *    H+ disrupts H bonds in enzymes
                 bonds in enzymes          *                                       *
                                                  *                                                    *
                                         *                                                                       *
                          *****                                                                                         ******
                                                                           B   All of the enzyme molecules are active           
 
                                                                               Increasing pH —> 

 

7.   At the points labeled with the stars, attach the appropriate labels from this list:  Violet.  X-Ray.  InfraRed.  Red.   Blue. Ultraviolet.

        High Frequency                                                     \                      Visible Range                   /    Low Frequency            

 

                        *                                                     *     /      *        *                                    *       \     *
               X-Rays                                    Ultraviolet        Violet     Blue                              Red        InfraRed
      (very energetic)            (Energetic, next to violet)                 VISIBLE!!!                             (Less energy - heat - next to red)

 

 

 

BONUS QUESTIONS.

 

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.

 

Animal cell cytokinesis can happen in which stage / stages of the cell cycle?  Three Points.

 

 

 

What structure is present in animal cell mitosis but not supposed to be present in plant cell mitosis?  Three Points.

 

 

 

What organisms actually get a second use out of their polar bodies?  Three Points.

 

 

 

What=s the difference between an embryo and a fetus?  Three Points.

 

 

 

What type of organisms has mechanical isolation been found in?  Three Points.

 

 

 

Folks who claim that Life had to have been created because it breaks the 2nd Law of Thermodynamics are forgetting what important detail about the Law?  Three Points.

 

 

 

Any trait produced by a pathway has to be a multiple-gene trait.  Why?  Three Points.

 

 

 

What are the other terms for substrates?  Three Points Each.

 

 

 

What often produce irreversible enzyme inhibitions?  Three Points.

 

 

 

What are calories actually a measurement of?  Three Points.

 

 

 

Where can the parts of primordial soup still be found?   Three Points Each.

 

 

 

What causes reradiation?  Five Points.

 

 

 

 
 

Michael McDarby.

SC 135

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