1. (TCO 3) How is work related to energy? (Points : 10)
Work is energy. It’s directly related kinetic energy. In fact, there is a principle in physics
known as the “work-energy principle”, in which we see that the work done by a force on
an object is exactly equal to the change in the object’s kinetic energy. (Kinetic energy is
the of motion, equal to half the product of the mass and the square of the speed of an
object.)
2. (TCO 4) What does an atomic number mean? How does the atomic number identify
the atoms of a particular element? How is the atomic number related to the number of
electrons in an atom? (Points : 10)
Atomic number of an atom is simply the number of protons in the nucleus. This is the
fundamental parameter defining an element. We can change the number of neutrons or
electrons in an atom, and it remains the same element, but changing the number of
protons makes it a different element. So, in effect, the atomic number is what makes an
element that element. Typically there are an equal number of electrons and protons, and
we find the atom with a net zero (neutral) charge. But electrons can be lost or gained,
giving the atom a net charge.
3. (TCO 5) What is the difference between direct and alternating current? (Points : 10)
Direct current produced by a voltage that is not changing in time, and so the current
approaches some steady state value given enough time after turning the voltage on.
Alternating current means just that – the current alternates going first in one direction
then in other, in a wavelike fashion, in response to a similarly alternating voltage. In
typical applications the switching is relatively fast, from one direction to the other and
back in 1/50th or 1/60th of a second or so.
4. (TCO 7) What are the differences between parasitism, commensalism, and mutualism?
Give examples of each kind of interaction. (Points : 10)
Parasitism, commensalism and mutualism are descriptions of the kinds of relationships
two organisms living together can have to each other. In parasitism, such as with
intestinal worms or fleas and mammals, the parasite benefits from the interaction while
the host suffers. In commensalism, such as a barnacle on a mollusk shell, the host is
unharmed but does not benefit, while the other organism benefits. In mutualism, both
organisms benefit from the interaction, such as with honey bees and flowers.
5. (TCO 8) What is the difference between diffusion and osmosis? (Points : 10)
Osmosis is the transport of a solvent through a semi-permeable membrane to an area of
higher concentration of solute, hence in the direction that tends to equilibrate the
concentration. Generally the membrane is impermeable to the solute meanding the solute
cannot move through it, while the solvent can. Osmosis is therefore a type of diffusion,
which is the more general process wherein any particles in a gas or liquid are dispersed
through random motion from higher to lower concentration, again leading to a more
homogeneous distribution.
6. (TCOs 9, 11) Describe the differences between the following mutations: inversion,
duplication, deletion, and point mutation. (Points : 15)
An inversion is a genetic mutation that occurs when a piece of a chromosome is reversed.
This happens when a chromosome breaks and gets reassembled in the reverse order.
Duplication is the mutation associated with a base-pair mistakenly being repeated during
replication, causing an extra pair in the new DNA.
Deletion refers to a base pair being “skipped” and hence not included in the newly
replicated DNA. This is in effect the opposite of duplication.
A point mutation is the replacement of a single nucleotide with another nucleotide. This
could be the insertion or deletion of a single base pair, and like most mutations, generally
occurs during DNA replication.
7. (TCO 10) What is the difference between the systolic and diastolic blood pressure?
What is considered a normal blood pressure? (Points : 10)
Blood is pumped through the body by repeated contractions of the heart. While the heart
contracts, the blood pressure increases to a maximum, or systolic, pressure. When it
relaxes, the pressure drops to a minimum, or diastolic pressure. Normal readings are 120
for systolic, and 80 for diastolic or “120 over 80”. Numbers significantly higher than this
(say 130/90) are a sign of hypertension.
8. (TCO 4) Describe in detail how ionic compounds are formed. What roles do valence
electrons and the octet rule play the the process? (Points : 10)
Ionic compounds are chemicals that are held together by ionic bonds. These are the
electrostatic bonds formed when one atom or molecule has a postitive charge and the
other has a negative. The valence electron structure and the octet rule describe the
tendency of an element or molecule to give up or add an extra electron, hence giving it
the necessary charge to form an ionic bond.