BIO 10 Exam 1 KEY
Fall, 2007
PART A (40 pts)
Multiple Choice (2 pts each)
Circle the correct answer. There is only one correct answer in each case.
1.
The best scientific evidence suggests that the Earth is about ________ years old.
A.
B.
C.
D.
E.
2.
Mitochondria
A.
B.
C.
D.
E.
3.
hydrogen bonds
covalent bonds
ionic bonds
hydrophobic bonds
none of the above
Which of the following is NOT a “survival machine” according to Richard Dawkins?
A.
B.
C.
D.
E.
6.
Membrane-bound nucleus
Endoplasmic reticulum
Cell wall
Ribosomes
Plasma membrane
Water molecules are held together by
A.
B.
C.
D.
E.
5.
are a form of small, free-living bacteria
are cellular organelles that synthesize starch
are found inside all prokaryotic cells
contain their own bacteria-like genome
are inherited only from the father
Which of the following is NOT a characteristic shared by all eukaryotic cells?
A.
B.
C.
D.
E.
4.
4,500
450,000
4.5 million
4.5 billion
45 billion
A turtle
An E. coli cell
A computer
A human being
A redwood tree
In the “protein factory” of the eukaryotic cell, the main purpose of the lysosome is
A.
B.
C.
D.
E.
cleaning crew
powerhouse
assembly line
control center
security gate
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7.
Which of the following is a good definition for a scientific theory?
A.
B.
C.
D.
E.
8.
All of the carbon in our bodies
A.
B.
C.
D.
E.
9.
200
2,000
20,000
200,000
2,000,000
Most of the genetic diversity among living organisms on Earth is found among
A.
B.
C.
D.
E.
13.
carbonate ions
starch
water
DNA
nothing; it was an impermeable membrane
The average length of a human gene is about __________ base-pairs of DNA.
A.
B.
C.
D.
E.
12.
the same thing as a chromosome
a region of DNA that is “read” to make an RNA molecule
a region of DNA that codes for a lipid, carbohydrate, or protein
a sequence of nucleotides with no known function
None of the above
The dialysis membrane in lab was permeable to
A.
B.
C.
D.
E.
11.
is very non-reactive
was made in the belly of a heavy star that went supernova
is “trapped” in the form of lipids
is in the form of carbon-dioxide gas dissolved in the blood
none of the above
A gene is
A.
B.
C.
D.
E.
10.
A collection of facts about the Universe and how it behaves
A method of learning about the Universe and its behavior
An idea that has yet to be tested
A set of general principles, supported by facts, that has predictive power
All of the above
the prokaryotes
insects
plants
mammals
fungi
Scientists believe that life on Earth
A.
B.
C.
D.
E.
first appeared about 13.7 billion years ago
arose from non-living matter
arose independently three different times to give rise to bacteria, archaea, and
eukaryotes
evolved from alien life forms that arrived on early comets
was created by God in seven days about 6,000 years ago
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14.
If the pH of a solution is very high, the solution
A.
B.
C.
D.
E.
15.
Which of the following is always true of hydrogen?
A.
B.
C.
D.
E.
16.
It has a single electron
It does not contain any neutrons
It has a single proton
It exists only as a gas
None of the above
Our sun cannot be a “first generation” star because
A.
B.
C.
D.
E.
17.
is acidic
is hydrophobic
contains a low concentration of hydrogen ions
will rapidly evaporate
none of the above
it
it
it
it
it
is too small
is undergoing nuclear fusion reactions
does not appear to be spinning
has rocky planets like the Earth
contains no hydrogen
In the diagram on the right, what element is
represented by the black box?
A.
B.
C.
D.
E.
Helium
Carbon
Neon
Water
None of the above
Note: the correct answer is iron
18.
The “nebular hypothesis” is a theory to explain
A.
B.
C.
D.
E.
19.
The elements in table salt (Na and Cl) are held together by
A.
B.
C.
D.
E.
20.
the formation of the early Universe
how life arose on the early Earth
the formation of the solar system
how nucleated cells evolved
how black holes are formed
the sharing of electrons
an ionic bond
a weak hydrogen bond
a mutual dislike of water (hydrophobicity)
None of the above
Chitin is
A.
B.
C.
D.
E.
a type of polysaccharide
a type of insect
an enzyme important for energy production in cells
found exclusively in plants
a lipid important to maintaining plasma membrane fluidity
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PART B (30 points)
Short Answer.
21.
(10 pts)
An argon atom has 18 protons and 18 electrons. Draw a diagram of this atom, showing the
location of the electrons in their energy shells. Would you expect this atom to be stable or
unstable? Briefly explain.
Nucleus
This atom would be very stable because all of it valence electron shells are filled. Atoms with
filled shells neither seek to share, accept, or donate electrons and so are non-reactive with
other atoms.
22.
(4 pts)
What 2 main functions are served by the plasma membrane of a cell?
23.
a.
Forms a semi-permeable barrier to separate "self" from "other" and to keep
good things in and bad things out.
b.
Enables the cell to communicate with other cells and the environment
(6 pts)
What is the difference between a polypeptide and a protein?
A polypeptide is a long chain of amino acids. Once the polypeptide becomes functional, it is
called a protein. Polypeptides always need to fold into specific 3-D shapes to become
functional and also sometimes need to become modified (e.g. carbohydrate groups added) or
combine with other properly-folded polypeptides to become functional.
24.
(10 pts)
Specialized cells in the human pancreas produce and secrete the protein insulin. Would you
expect these cells to have a lot of rough ER or very little rough ER? Explain.
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These cells would have a lot of rough ER. Proteins that need to be secreted from the cell are
manufactured by ribosomes attached to the ER membrane, and it is the attachment of the
ribosomes that makes the ER look "rough". Cells that do not make a lot of proteins that need
to be secreted or localized within the membranous ER/Golgi/vesicle/plasma membrane system
make most of their proteins on cytoplasmic ("free") ribosomes and thus have a lot of smooth
ER. Thus, the amount of rough ER in the cell is directly related to the types of proteins made
by that cell, and - specifically - to where those proteins need to be localized.
PART C (30 points)
True (T) or False (F)? If the answer is false, cross out the underlined word and
replace it with the correct word.
EXAMPLE:
F
The Cayman Islands
Dr. Ballard recently went to the planet Neptune.
________
Polypeptides are long polymers of amino acids. T
________
Ionic bonds involve the sharing of electrons. F; covalent
________
Saturated fatty acids contain no oxygen. F; double-bonded carbons
________
Steroids are a type of nucleic acid. F; lipid
________
Nucleotides contain a sugar, a nitrogenous base, and a phosphate group. T
________
Proteins account for about nine-tenths of the weight of a cell. F; half
________
Osmosis is the movement of water across a semi-permeable membrane. T
________
Molecules with a higher molecular weight diffuse more quickly than those with
a lower molecular weight. F; slowly
________
In prokaryotes, the genes are found in the nucleus. F; cytoplasm
________
Most enzymes are RNA molecules. F; proteins
________
Animals store carbohydrates in the form of starch. F; glycogen
________
Water has a very high capacity for storing heat. T
________
Redi helped to disprove the theory of biogenesis. F; ambiogenesis
________
The plasma membrane is about 5 billionths of a meter in diameter. T
________
Saturated fats are likely to be liquid at room temperature. F; solid
________
Our sun is currently fusing hydrogen to helium in its core. T
________
Organisms differ from one another primarily by the types of lipids they make.
F; proteins
________
In the Universe as a whole, entropy is always decreasing. F; increasing
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