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SCI 135 - Second Exam Spring 2017
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.
Once sugar has been stirred
into a cup of water, the sugar is the
____C____
a. Solvent b. Solution
c. Solute
d. Osmont e. Tasty bits
...the stuff that dissolves into the solvent
2.
The phospholipid bilayer
includes molecules with A) hydrophobic ends and B) hydrophilic ends,
arranged how in a cell membrane?
____B_____
a. A faces outside, B faces the inside space
b. B faces outside and inside, with A
sandwiched in between
c. B faces outside, A faces the inside space
d. A
faces outside and inside, with B sandwiched in between
e. Could we just sing the alphabet song instead?
...hydrophilic likes the water (around and inside
the cell).
3.
Different varieties of
particular genes are known as
____D_____
a. Varienes b. Codelles
c. Proteases d. Alleles
e. A Levi's outlet
...match the definition with the term.
4. Flourine, element 9 in Column 7,
has an atomic mass of 19. Its most chemically-stable form
would be as
____B______
a. A +1 ion
b. A -1 ion
c. An uncharged atom d.
A 7 isotope
e. I didn’t think we really had to know this…
...the 7 tells you the outer shell has 7
electrons, 1 shy of the stable number of 8; it picks up an
electron (and an extra negative charge) to get stable.
5.
The pH of a local pond
was 6, now it's 5, which is
____C_____
a. Twice as acidic b. Twice as basic
c. Ten times as acidic
d. Ten times as basic
e. Much more than I really wanted to know...
...going down the scale is more acidic (more H+),
and each number jump is a 10X change.
6.
What sort of organic
molecules are steroid hormones?
____B_____
a. Proteins
b. Lipids
c. Starches d. Antibodies
e. Muscular
...it's one of the possible lipid uses.
7.
Large organic molecules are
assembled using which process?
____A_____
a. Dehydration synthesis
b. Polymer fusion c. Hydrolysis
d. Mineralization
e. Gluing and stapling
...synthesis = making;
a new bond forms where an H was on one side and an OH
on the other. H + OH gives water coming out = dehydration.
8.
The molecule alcohol
dehydrogenase would be made up of
____A_____
a. Amino acids b. Nitrogenous bases
c. Sugars d. Fatty acids e.
Not alcohol, huh-?
...this is multi-level tricky; the -ase
ending says enzyme, which means protein, which means
amino acids.
9. The basic pieces of lipid
molecules are
_____C____
a. Amino acids b. Glycerol and amino acids
c. Glycerol and fatty acids
d. Alleles
e. All special-order import items - very expensive
...just the bits. This gets asked again,
accidentally, later.
10. If a chemical reaction moves an electron, the participant
(not the technical term) that receives an electron is
___D___
a. Electrified b.
Neutralized c. Oxidized
d. Reduced
e. One electron up-?
...picking up a negatively-charged electron makes
the original charge go down / reduce.
11.
Which group does NOT have cell walls?
___A___
a. Animals
b. Fungi c. Plants
d. Bacteria e. Homeless
organisms
...we wouldn't do well with our cells locked
structurally together.
12. The “pull” in muscles is generated by
____C_____
a. Lipids b. Nucleic
acids
c. Proteins
d. Carbohydrates e.
Microscopic horsies
...namely, the proteins actin and myosin.
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.
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1. What are two different things
found in non-coding DNA that are still
sort of codes? |
Old unused & degraded genes
Virus genes |
Bacterial genes
Codes for functional RNAs |
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2. What are two structures that can
commonly be found in both
eukaryotes and prokaryotes? |
Membranes
Chromosomes |
Cell walls
Ribosomes |
3. What produces
hydrogen bonds? (No, it’s not hydrogen)
...partial charges in or on a
molecule attracting each other.
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4. Label the following chemical reaction
with the general terms for each part – |
A +
B
x
>
C
_Reactant_ or
___Substrate__
__Contributor__
__Product___ |
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5. What are two different uses for
lipids? |
Waterproofing
Membranes |
Longterm Energy Storage
Insulation
Hormones |
6. What is a hydration shell?
...when water molecules surround ions or
molecules (holding on with hydrogen bonds) to make them
dissolve. |
7. What particular feature
of protein molecules makes it possible for them
to have so many different uses?
...they have potentially an infinite
number of shapes. |
8. The Fluid Mosaic Model
is used to describe what structure?
...a cell membrane (phospholipids = fluid,
embedded proteins = mosaic). |
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9. The two pieces of a
lipid molecule: (asking it twice was a mistake) |
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(1) Glycerol |
(3) Fatty Acids |
10a. In the lab, what is
sectioning?
Slicing
specimens very thin. |
10b.
Why is sectioning necessary?
So
the microscope beam can come through them. |
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11. What are two different types of jobs
that might be done by molecules embedded in the cell
membrane? |
Channels / Pores
Pumps / Carriers
Receptors |
Connectors
Enzymes
Markers |
12. What, technically, is a gene?
...a DNA code for a particular type of
protein. |
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13. Show the nucleotides on the
other strand of the DNA - |
DNA
A A T G C T A C
C G T A T T G G
C G A G T C A T
Other DNA
Strand: T
T A C G A T G G
C A T A A C C G
C T C A G T A
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14. Give a set of differences
between - |
PROKARYOTE
CHROMOSOMES |
EUKARYOTE
CHROMOSOMES |
Only one
Loop-shaped |
Come in pairs
2-ended |
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15. Name two different types
of organic molecules that are polymers. |
Starches (polymer of sugars)
Proteins (polymer of amino acids) |
Nucleic acids (polymer of nucleotides) |
16. What is meant by the
resolution of an imaging system?
...how clearly it can focus (based on the
smallest gap that can be seen). |
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.
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1. Give four rules from the
Cell Theory. |
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All living things are made up of at least one cell. |
A
cell is the smallest thing considered alive. |
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Cells only come from other related
cells. |
Cells are more alike then different. |
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2. Name and give a brief
description for the four levels of protein
structure. |
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PRIMARY |
Order of amino acids is the string. |
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SECONDARY |
Local patterns within the molecule. |
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TERTIARY |
Overall 3-dimensional shape. |
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QUATERNARY |
If protein has more than 1 string, how they fit together. |
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3. For three basic
properties of water - |
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PROPERTY |
What’s happening
on the molecular level |
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COHESION |
Molecules attract each other with hydrogen bonds. |
| ADHESION |
Molecules attract other materials with hydrogen bonds. |
| SURFACE TENSION |
Molecules pack together at surface and are held by molecules
below them. |
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COOLING EVAPORATION |
Only very fast / hot molecules can get free, taking lots of heat
with them. |
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HEAT STABILITY |
Cohesion makes it hard to get everything moving faster / slower. |
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EXPANSION ON FREEZING |
When packed too closely, molecules repel into expanded crystal
form. |
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GREAT SOLVENT |
Molecules surround many particles and hold them with hydrogen
bonds. |
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4. Microscopes can be split into
two main groups based upon either listed feature.
For each feature, name the groups. |
Nature of the
Imaging Beam |
Light |
Electron |
Interaction of Beam
with specimen |
Transmission
(goes through) |
Scanning
(reflects off surface) |
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5. Using the numbers of bonds
as a guide, fill in the symbols for either
Carbon, Hydrogen, Nitrogen, or Oxygen. |
Can't recreate
the original hand drawing.
Remember HONC: H-1
bond, O - 2, N - 3, C - 4.
O O
O
O
O O
O
O
O O
O
O |
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5. What are four different types of proteins
involved in signaling? |
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Hormones |
Alarmones |
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Receptors |
Pheromones |
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Neurotransmitters |
Antibodies |
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6. For carbohydrates - |
Process that makes
most of them -
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Photosynthesis |
Two main
forms - |
Sugars |
Starches |
Organisms
that
make them -
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Plants |
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.
What makes local ponds and lakes “turn over” in the
fall? Three Points.
If hydrogen bonds are not specifically only found
on hydrogen, why are they called that? Three Points.
You needed to know what the pH scale numbers mean,
but where did the numbers used on the scale come from? What do they
really represent? Three Points.
In which type of organic molecule is most of the
Nitrogen in an organism? Three Points.
What’s the benefit to the plants of producing
digestible starches? Three Points.
Actin shows very little variability across a wide
range of living groups. Why? Three Points.
Which molecule has just recently been shown to be a
major cell player, when it was previously thought to have just a couple
of roles? Three Points.
Some microscope prep involves completely drying
specimens. Why? Three Points.
What clarification was added to the Cell Theory?
Three Points.
What’s the problem with the volume-to-surface
limitation hypothesis? Three Points.
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