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SCI 135 -
Third Exam Fall 2013
Answer Key
Links in each number
connect to the pertinent sections 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. Position effect can change how
___C___ a. Cells reproduce
b. Cells relate to each other in multicelled
systems
c. Genes get expressed
d. Materials get moved through a cell membrane
e. Easily your foot goes to sleep
...
some mutations (translocations) move genes from "loosely-wrapped"
parts of a chromosome to "tighter," harder-to-access parts, and the genes
get used less there (or the opposite happens).
2.
In the fluid mosaic model, the phospholipid molecules
are
___B___
a. Held tightly to each other
b. Freely floating in 2
layers
c. Held in place by proteins d.
Only a small part of the membrane
e. The things that are by the things when the
things are there
...
they are the "fluid" part of the model (embedded proteins are the "mosaic").
3. A cell that specializes in absorbing materials most
likely has
___D___ a. Cilia b. Golgi
bodies c. Ribosomes
d. Microvilli e.
Issues with self-image
...
they increase surface for that absorption.
4.
Mitochondria are found in
___C___ a. Plants but not animals
b. Animals but not plants
c. Both plants and animals
d. Neither plants nor animals
e. Books that only insane
people read
...
99+% of eukaryotes (plants, animals, fungi, protists) do aerobic
respiration, done in mitochondria.
5.
Water moves from soil, where the water is close to pure, to the cells
of
a plant’s roots. This movement
is
___B___ a. Performed by the lining cells of the root
b. Passive transport
c. Active transport
d. Only done if nutrients are carried in the
water.
e. Not particularly interesting
...
the movement is "downhill," from a higher-concentration area to a
lower-concentration one.
6.
Which is an example of apoptosis?
a. A hand forms as a paddle; cells between
the bones die to separate
the fingers
b. Some materials have to be helped to move
through a membrane,
even if they are going in the
“right” direction
___A___ c. After digestion, leftover materials are ejected
from the cell
d. Many places in DNA code for small
functional RNA molecules
e. Somebody drops a really heavy rock on their
bare foot
...
cells dying because they need to, they do it to themselves.
7. Which can change almost the
whole sequence of a coded protein?
___D___ a. Radiation b.
Substitution c. Translocation
d. Deletion
e. Scrambling with a whisk
...
if a nucleotide in a codon is lost, that codon changes and every following
codon
is shifted one spot down, potentially changing them all.
8. Which starts with diploid cells and ends
with haploid cells?
___A___
a. Meiosis b. Transcription
c. Mitosis
d.
Translation e. Is that even legal?
...
2 sets of chromosomes reduced to one set each.
9. A nucleolus would contain a lot of
___C___ a. Membrane b. DNA
c. RNA
d. Carbohydrates e. Cell
slimey stuff
...
that's where a lot of RNA is stored and processed.
10.
Sectioning needs to be done to
___A___
a. Prepare tissues for the microscope
b. Figure out where genes are on a chromosome
c. Position chromosomes for a cell division
d. Subdivide eukaryote cells for different
functions
e. Keep the drunks away from the nice
customers at games
...
it's the thin-slicing so a transmission beam can go through.
11. Recessive traits show up with which
allele combination?
___D___ a. Three recessives and a dominant
b. Four recessives only
c. One dominant and one recessive
d. Two recessives only
e. Time for rock, paper,
scissors, shotgun…
...
alleles work in pairs, and recessives only show if no dominants hide them.
12. Materials are
broken down for recycling in the
___B___ a. Pseudopod b. Peroxisome c. Golgi bodies
d. Nucleus e. Recyclothingy
... one
of those remember the name things.
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 components of the
cytoskeleton? |
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Microtubules |
Microfilaments |
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2. Give
the terms that go with each definition - |
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DIFFERENT GENES
FOUND ON THE SAME Linkage
CHROMOSOME |
TWO CHROMOSOMES
Genetic
CARRYING THE SAME Redundancy
TYPES OF GENES
(one of two types) |
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3.
Give two different things that parts of our noncoding DNA
might be - |
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Help in chromosome structure.
Old unused genes.
Functional RNA codes (not really
non-coding, but not known until recently) |
Regulators of gene expression.
Foreign genes.
DNA mini-parasites. |
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4. Give
the basic structural difference between - |
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SMOOTH ENDOPLASMIC RETICULUM |
ROUGH ENDOPLASMIC RETICULUM |
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Just membrane in lining |
Lining membrane has ribosomes embedded |
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5. What is the function of
histones?
...they
are the proteins that DNA is packaged with to make chromosomes. |
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4.
It’s called a
nuclear envelope, not a nuclear membrane. Give one feature about it
that makes it different from a “regular” membrane (other than it
being around the nucleus).
...it
is 2 membranes thick. |
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7. The two different
medical research areas that are very interested in
telomeres - |
Aging
(telomerase to complete copied chromosome tips made less and less with
aging, compromising repair functions) |
Cancer
(cancer cells require working telomerase to make lots of cells) |
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8.
Give one
set of differences between - |
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PROKARYOTE CHROMOSOME |
EUKARYOTE CHROMOSOME |
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Only one in the cell
Loop-shaped chromosomes
May make plasmids (little partial chromosomes) |
Homologous pair(s)
2-ended chromosomes
Do not make plasmids |
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9.
Explain why HIV escape mutants are so dangerous.
...they
still work to invade and kill cells of the immune system, but existing
HIV antibodies can't attach to altered antigens. By the time new
antibodies are in production, the immune system can be too shut down to
use them. |
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10a. What is a
Barr body? |
10b. Why do
Barr bodies exist? |
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A deactivated X chromosome |
It "equals out" working X chromosomes
between XX genders and XY genders. |
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11. Give two pieces of
evidence that supports the
endosymbiont theory.
- That some cell organelles began as kidnapped
prokaryotes that worked for the bigger eukaryote rather than being
digested. |
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Structures and molecules in organelles
almost identical to known prokaryotes.
Such kidnapping & use is found in some
existing eukaryotes. |
Organelles have partial but clearly
prokaryote-type chromosomes inside them. |
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12. For
a low chromosome number (compared to a high chromosome number) - |
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ADVANTAGE –
Fewer mistakes during cell division |
DISADVANTAGE -
Less variety for sexual reproduction |
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13. Briefly give the most
common explanation for
why cells seem to have a
maximum size limit.
...growing cells
increase volume (working chemistry) at a much faster rate than surface
area (input / outgo for that chemistry). |
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14.
What are two Kingdoms of Life where all of the cells have cell
walls? |
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Plants
Fungi |
Monera
Archaea |
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15. Give the names of
two different types of
vacuoles - |
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Food Vacuoles
Central Vacuoles |
Contractile Vacuoles |
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16. Explain how a
prion can cause the malfunction of an
entire cell.
...since the prions can turn working cell proteins into prions, the
affected proteins stop doing whatever important function they were doing
before being transformed. |
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
three sets of differences (other than the associated genders)
between - |
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EGG CELLS |
SPERM |
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Larger (hold food for offspring) |
Smaller |
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Comparatively fewer made |
Many more made |
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Must be reached by sperm |
Have way of getting to where egg cells
are |
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One starting cell makes on egg cell
and 3 tiny polar bodies |
One starting cell makes 4 working
sperm |
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2. Give
three sets of differences between - |
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FLAGELLA |
CILIA |
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Larger |
Smaller |
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May have add-on structures |
Do not have add-on structures |
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Rarely more than 12 on a cell |
Always very numerous on a cell |
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Not usually very coordinated with
other flagella |
Always highly coordinated with other
cilia |
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Tend to spin |
Tend to stroke |
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3.
Give four rules from
the Cell
Theory. |
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All living things are made up of at
least one cell. |
Cells are the smallest unit considered
alive. |
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Cells only come from pre-existing
related cells. |
Cells are more alike than different. |
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4.
Give the terms for each of
the two groups in each
microscope category - |
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HOW THE BEAM INTERACTS WITH THE
SPECIMEN |
NATURE OF THE IMAGING BEAM |
Transmission
(beam goes through) |
Light |
Scanning
(beam reflects off) |
Electron |
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5.
What are
three different ways that fresh-water organisms deal with
osmosis? Osmosis would continually move
water into cells less dilute than the environmental water. |
Pump excess water
back out |
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Enclose cells to resist expansion |
Waterproof most surfaces |
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6. Using this DNA
code give the messenger RNA sequence and, using
this chart, give the
coded amino acid sequence. |
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Starting_____________________________________________________________________________________
Strand T A C C C A T
G G T A C C G A T G A A A A G C G A T T
Codons marked:
mRNA
A U G -G G U -A C C -A U
G -G C U -A C U -U U U -C G
C -U A A
Amino
Methionine - glycine - threonine - leucine - alanine - threonine -
phenylalanine - arginine (STOP)
Acids (start)
|
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7. Give four different
functions for some of the
proteins found embedded
in cell membranes. |
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Allow materials through small holes
(pores / channels) |
Move materials from one side to the
other (carriers / pumps) |
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Pick up information from outside
(receptors) |
Identification for other cells
(markers) |
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Help bend the membrane to form vacuoles
and pseudopods |
Attach the membrane to surfaces while
crawling |
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.
The resolution on light microscope hits a limit at about 1200X
magnification. Why can’t it be better than that? Three Points.
Why do some specimens need to be
coated with gold or platinum? Three Points.
What common word applies to
almost all prokaryotes (but not eukaryotes)? Three Points.
For two points each, give up to
three different materials that can easily pass through a typical cell
membrane. Three Points.
When a cancer becomes
malignant, it turns on genes for what particular ability? Three
Points.
Cancers
may begin when several different control systems malfunction. For Two
Points each, what systems might those be?
Mendel,
the genetics monk, believed that he was not really successful as a scientist.
Why? Three Points.
What particular feature is
often true of proteins from recessive alleles? Three Points.
What does the term “gender” mean,
biologically? Three Points.
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