Modern Biology study guide answers ch.14

Section 14-1
VOCABULARY REVIEW
1. Biogenesis is the principle that all living things
come from other living things.
2. Spontaneous generation is the supposed origin of
living things from nonliving things.
3. Vital force was the force that according to sup-
porters of spontaneous generation, caused life to
appear spontaneously.
MULTIPLE CHOICE
1. b
2. c
3. a
4. b
5. c
SHORT ANSWER
1. Observations with the microscope revealed the
existence of microorganisms that are simple in
structure, numerous, and widespread. Investigators
of that time concluded that microorganisms arise
spontaneously from a “vital force” in the air.
2. Spallanzani reasoned that boiling the broth would
kill all of the microorganisms in the broth, on the
inside of the glass, and in the air inside the flask.
3. Instead of sealing the flask in the experimental
group after boiling, Pasteur used a flask with a
curved neck, which allowed air inside and outside
the flask to mix but prevented microorganisms
from entering the body of the flask.
4. Pasteur’s experiment permitted air from the out-
side to mix with air from the inside, which would
have allowed any “vital force” to enter and cause
the broth to become cloudy if there were such a
“vital force.”
5. Believers in spontaneous generation could have
argued that the meat Redi used was somehow
unable to develop into maggots, regardless
whether flies were present or absent. The control
group showed that this was not the case.
STRUCTURES AND FUNCTIONS
Control group: c, e, a. Experimental group, c, b, d.
Section 14-2
VOCABULARY REVIEW
1. A radioactive isotope is an isotope whose nucleus
tends to release particles, radiant energy, or both;
radioactive dating is a technique for determining
the age of a material by measuring the amount of a
particular radioactive isotope the material contains.
2. The release of particles, radiant energy, or both by
a radioactive isotope is called radioactive decay;
half-life is the time it takes for one-half of any size
sample of a particular isotope to decay.
3. A microsphere is a spherical collection of many
protein molecules organized as a membrane; a
coacervate is a collection of droplets that are com-
posed of different types of molecules, including
amino acids and sugars. Both structures are cell-
like and form spontaneously in the laboratory
from simple organic molecules.
MULTIPLE CHOICE
1. d
2. c
3. b
4. a
5. a
SHORT ANSWER
1. Isotopes with short half-lives are most useful for
dating relatively young fossils, while those with long
half-lives are most useful for dating older fossils.
2. Some scientists think that the atmosphere of early
Earth contained large amounts of CO
2
, a gas that
interferes with the production of organic com-
pounds in laboratory simulations of proposed
early-Earth conditions.
3. Their discovery showed that some aspects of cel-
lular life can arise without direction from genes.
4. No, this method estimates the age of the oldest
unmelted surface rocks on Earth. Since the surface
of Earth probably melted many times as the planet
was formed, the Earth should be older than
these rocks.
STRUCTURES AND FUNCTIONS
1. An isotope content of 1/16 will occur after
four half-lives; 4 × 75,000 years = 300,000 years.
Section 14-3
VOCABULARY REVIEW
1. A ribozyme is an RNA molecule that can act as
an enzyme.
2. Chemosynthesis is the synthesis of organic
compounds using energy contained in inorganic
molecules.
3. Cyanobacteria are a group of photosynthetic
prokaryotes.
4. Endosymbiosis is the mutually beneficial relation-
ship that is hypothesized to have existed between
large prokaryotes and the smaller prokaryotes
that invaded them and eventually gave rise to
mitochondria and chloroplasts.
MULTIPLE CHOICE
1. a
2. d
3. c
4. b
5. d
SHORT ANSWER
1. Each RNA molecule might have competed with
slightly different RNA molecules for nucleotides.
An RNA molecule that was more successful in
getting nucleotides would have an advantage, and
it would pass that advantage on to the new RNA
molecules it created by replicating.