SCI 135 - Fourth Exam Spring 2015
Links connect to relevant parts of the online book.

Answer Key



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.  Differentiation involves

___C___   a. The same enzyme doing different jobs
                b. How members of groups do different jobs

                c. Embryo cells using different genes to do different jobs
                d. Air for respiration moving between different pressure zones
                e. A really terrible way to lead off an exam

            ...they begin to become different tissues and structures after just being general dividing cells.

        2.  When sperm and egg cell nuclei fuse, that cell is now

___D___   a. An egg         b. A fetus         c. An embryo        d. A zygote         e. Headed for trouble

            ...that's the first cell of the new offspring.

        3.  What part of a population really changes during evolution?

___A___    a. Gene pool         b. RNA types        c. Organelles         d. Environment
                                        e. Where they order their pizza

            ...selection is really "choosing" the most useful alleles for current conditions.

        4.  Which would use heat as a main energy source?

___C___    a. Embryo development             b. Enzyme action             c. Chemosynthesis
                d. Photosynthesis                e. That thing your brother does to your wrist

            ...where superheated water is mixing with lots of organic molecules, such as at hydrothermal vents.

        5.  A reaction that releases enough energy to keep itself going is

___D___    a. Metabolic             b. High-efficiency             c. Endergonic
                 d. Exergonic                             e. Always bragging about it

            ...match the term with the definition.

        6.  The most likely "staging areas" for the invasion of the land from the water:

___B___    a. Fresh water and hydrothermal vents                b. Fresh water and tidal zones
                c. Tidal zones and hydrothermal vents                 d. Fresh water and underground
                                                            e. Atlantis and Venice

            ...adaptations to osmosis and the shallowness' response to the atmosphere kind of "pre-adapted"
                    organisms for being out in the air.

        7.  When a small group migrates away and has only those alleles present to pass on to their
this is

___B___    a. Genetic drift         b. Founder effect         c. Mutation        d. Habitat isolation         e. Tough luck

            ...that group is the founder of the new population.

        8.  A layer of rusty sediments in the ancient fossil record marks when

___B___    a. Life went onto land                 b. Photosynthesis spread                c. People first appeared
                d. Dinosaurs disappeared                                e. Atlantis' junkyards sank

            ...the release of oxygen combined with iron dissolved in the water produced much less soluble
                iron oxide (rust), which settled to the bottom and accumulated there.

        9.  When people compare the efficiency of different types of respiration, they are generally measuring

___A___    a. ATP production         b. Oxygen use        c. Glucose production         d. Nitrate use
                                                e. Aren't they measuring the efficiency???

            ...ATP is the usable fuel, so the question is, how much can you get from one glucose molecule?

        10.  When a group goes almost extinct, reduced to a small fractional group, this is

___B___    a. Genetic drift         b. Bottleneck effect         c. Mutation        d. Habitat isolation         e. Tough luck

            ...that squeezing of the population size is the bottleneck.

        11. The early oceans had an oily "scum" on the surface that contributed to the development of

___A___    a. Protocells         b. DNA         c. Digestion        d. Flotation         e. Politics

            ...complexes that captured a bubble of that scum around themselves had an extra layer of protection -
                    this eventually became the cell membrane.

        12. Which are vitamins?

___D___    a. Carbohydrates             b. Minerals            c. Lipids             d. Coenzymes
                        e. Do they have letters? They need letters...and sometimes numbers...

            ...specifically, they are coenzymes that humans can't make, that they need to get in their diet.


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. Fill in for one of the embryonic cell layers -
An organ /
structure / system
derived from that layer -
Ectoderm Skin, Nervous System
Mesoderm Muscles, Circulation, Reproduction, Excretion, skeleton (if internal), other systems.
Endoderm Digestive, Respiratory System.

2.  Describe (don't just give a term for) two different types of reproductive isolation that can split off a subgroup living in the same place as the main group.
A subgroup begins to specialize in a different job (Niche) A subgroup become active during a different time period (temporal)
A subgroup times its reproduction at a different time (also temporal) A subgroup prefers a different reproductive behavior
A subgroup becomes physically incompatible for mating (mechanical) A subgroup develops a rejection for some reproductive molecules (chemical / immunological)
3.  What are two different types of nitrogenous wastes?

Uric Acid
4.  What does it mean if an enzyme has high specificity?

            ...its active site is very particular about what substrate it will attach to.
5.  What are two different groups of living things that would contain many species of decomposers?
Bacteria Fungi

Possibly Insects
6.  In every mass extinction event, the trigger has to make something happen early to actually bring about the extinctions - what's the something?

            ...most of the plants die (taking out the bottom of the food chain)
7.  According to theory, when the Earth's "living things" were just big organic molecules, what are two abilities those molecules had to have to lead on to current forms of life?
Ability to self-organize

Ability to reproduce
Ability to evolve
8.  According to theory, what are two abilities the first truly "living" systems needed eventually to lead on to current forms of life?

Protein-based chemistry
DNA-based coding system
9.  According to the Hardy-Weinberg rule, what are two different non-selection-related features that must apply to keep an allele's presence steady over time? Remember, some features are "must be" and some are "must not be".
No mutation

No migration in or out
Population must be very large
10.  What are two different ways that carotenoids get used?
Capture of some light frequencies for photosynthesis Used to color flowers, fruits, etc.
11.  Briefly, what is the panspermia?

            ...the idea that the first Life on Earth originated somewhere else and was somehow brought here.
12.  As energy moves, level-by-level, up a food chain, the laws of thermodynamics apply to things that happen. Give the law (name or number) for each of these -
Some energy gets
lost as random motion /       Second / Entropy
heat at every transfer.
There's less energy
in every level, but                    First / Conservation
the rest has to be somewhere.
13. When enzyme activity is graphed for pH, the rates drop off on either side of the optimum. Why?

            ...too many charged particles (H+ or OH-) disrupt the hydrogen bonds holding the enzymes in their working shapes.
14a. What sort of organism helpers were probably essential to plants being able to move onto land?

              Fungi (possibly bacteria)

14b. What function do these organisms perform for the plants?

     "Fix" nitrogen from air into molecules plants can use to make amino acids and proteins.


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.  What are four different ways that anaerobic organisms impact humans?
Produce alcohol
Dairy products
Dairy spoilage
Rising dough
Intestinal symbionts Diseases

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.
Major animal groups

First real Life


Primordial Soup
Development of Lifelike systems


Life on Land
The last major movement

After photosynthesis made oxygen common

"Snowball" Period
Intense competition leads to animal diversity

Needed as soup materials ran out

Molecular Evolution
Happened in the Soup

3.   Briefly describe the three different ways that
        enzyme inhibition
can work.
Inhibitor molecule attaches in active site so substrate can't
Inhibitor attaches near active site in way that keep substrate from getting into it.
Inhibitor attaches to enzyme and changes its shape, including shape / "fit" of active site.

4.  For oxygen debt -
Tissue it
happens in -
Conditions it
happens during
When oxygen supply can't keep up with activity level
What is
System does anaerobic stage for some energy.  Accumulation of glycolysis product must be "paid off" with oxygen processing eventually.

5.  At the points labeled with the stars, attach the appropriate labels from this list:
                  Violet. X-Ray. InfraRed. Red. Blue. Ultraviolet.
    High Energy                                You can see these                                                     Low Energy
High Frequency          \                        Visible Range                       /                                  Low Frequency                  

    *                        *   /   *         *                                                *   \   *
X-Ray     Ultraviolet     Violet    Blue                                      Red       Infrared

6.  For the main photosynthesis reactions:
Light- Dependent Reaction Light-Independent Reaction
Exact Materials or Energy Used Light, Water ATP (used to build glucose from...), Carbon Dioxide
Exact Materials Produced Oxygen (from the water), ATP Glucose

7.  Answer the questions on the graph for the relationship between enzyme activity and temperature. A. Why is the rate dropping off here?   B. What is this point called?    C. Why is the rate rising here?


                        Particles move faster         *                *          Extra heat shakes enzymes so more and more
                   with rising temps                *                        *         are denatured (not in working shape).
Reaction                                      C    *                             *   A
Rate                                                 *                                   * 
                                                       *                                       *
                                                  *                                                    *
                                         *                                                                       *
                          *****                                                                                         ******
                                                                           B  Optimal temperature                                  

                                                                    Temperature ---->


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.

One of the first HOX genes was discovered in fruit flies, then an equivalent found in mice. What feature were those genes associated with? Three Points.

Embryos go through a “ball” stage that isn’t a ball in humans – what shape is it (3 Points) and why is it that shape (3Points)?

When hybrid vigor was first discovered, it connected what two diseases? Three Points Each.

What species have gone through a bottleneck? Three Points each.

What surprising discovery was made about populations that had been inbreeding for a long time? Three Points.

The optimal temperature of what human process is about 93o F? Three Points.

What's the difference (not counting the capitalization) between calories and Calories? Three Points.

If a pet doesn’t need a particular vitamin in their food, what is probably true of their metabolism? Three Points.

Why do trees change color in the fall? What happens? Five Points.




SCI 135 

Michael McDarby


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