BSC 108 Exam 3 with Complete Solutions
_________ evolve over time, not individual ___________ - ANSWER-populations;
organisms
As descendants of a common ancestor spread out into various habitats: - ANSWER-
they acquired adaptations to their particular environments through natural selection
Describe the carbon cycle - ANSWER-CO2 is removed from the atmosphere by
photosynthesis, passed along food chain by consumers, returned to the atmosphere by
cellular respiration, decomposers break down carbon compounds in dead matter, CO2
is eventually CO2 is released back into the atmosphere (burning fossil fuels, causing
more to be released than consumed)
DNA makes RNA through: - ANSWER-transcription
Each strand is used as a ______________ to make a new strand. - ANSWER-template
Energy is lost: - ANSWER-as heat at each transfer of energy and nutrients between
trophic levels
Energy: - ANSWER-flows into and out of an ecosystem
How are the nitrogen-containing bases held together? - ANSWER-hydrogen bonds
How can a trait be favored in one situation but not in another? - ANSWER-
environmental factors vary from place to place and time to time
How can new species form without geographic isolation of two populations? -
ANSWER-two distinct gene pools emerge through chromosomal changes due to errors
in mitosis and meiosis, habitat differentiation, or sexual selection
How could a scientist genetically engineer an organism? - ANSWER-1. Isolate a
bacterial plasmid and DNA of interest from another organism
2. Two are joined together, resulting in recombinant plasmids
3. Recombinant plasmids are mixed with bacteria, which "take up" the recombinant
plasmids
4. Each bacterium (carrying the recombinant plasmid) reproduces via cell division to
form a clone
a. The foreign gene carried by recombinant plasmid is also copied
5. Transgenic bacteria with the gene of interest can then be grown in large tanks
6. Final product may be:
a. Copies of the gene itself
b. Product of the cloned gene
, How does an organism's DNA lead to specific traits? - ANSWER-by dictating the
synthesis of proteins
How does DNA replicate? - ANSWER-DNA molecule unwinds and each strand is a
template for complementary base pairing; each daughter helix contains an intact strand
from the parent helix and a newly synthesized strand therefore DNA replication is
semiconservative
How does information flow in a cell? - ANSWER-DNA -> RNA -> Protein
How have humans impacted biodiversity? - ANSWER-through population numbers, use
of land, and lifestyles
How many strands of DNA does a DNA molecule contain? - ANSWER-two
Natural selection can amplify or diminish only ________ traits, not ________ traits -
ANSWER-heritable; acquired
Nutrients: - ANSWER-are recycled within an ecosystem
One parent molecule is composed of two __________________ that separate. -
ANSWER-complementary strands
RNA contains ________ instead of thymine. - ANSWER-Uracil
RNA makes protein through: - ANSWER-translation
The two strands of DNA are: - ANSWER-complementary
Two different species can evolve independently but: - ANSWER-acquire the same traits
as adaptations to similar environments
What are analogies (analogous structures)? - ANSWER-similarities among living
organisms that are due to similar environmental pressures and natural selection
(convergent evolution)
What are consumers? - ANSWER-heterotrophs - consume the food made by producers
What are decomposers? - ANSWER-they break down waste products and the remains
of dead organisms (fungi and bacteria)
What are detritus feeders? - ANSWER-organisms that consume dead organic matter
What are frameshift mutations? - ANSWER-mutations caused by insertions/deletions of
a number of nucleotides not divisible by 3
_________ evolve over time, not individual ___________ - ANSWER-populations;
organisms
As descendants of a common ancestor spread out into various habitats: - ANSWER-
they acquired adaptations to their particular environments through natural selection
Describe the carbon cycle - ANSWER-CO2 is removed from the atmosphere by
photosynthesis, passed along food chain by consumers, returned to the atmosphere by
cellular respiration, decomposers break down carbon compounds in dead matter, CO2
is eventually CO2 is released back into the atmosphere (burning fossil fuels, causing
more to be released than consumed)
DNA makes RNA through: - ANSWER-transcription
Each strand is used as a ______________ to make a new strand. - ANSWER-template
Energy is lost: - ANSWER-as heat at each transfer of energy and nutrients between
trophic levels
Energy: - ANSWER-flows into and out of an ecosystem
How are the nitrogen-containing bases held together? - ANSWER-hydrogen bonds
How can a trait be favored in one situation but not in another? - ANSWER-
environmental factors vary from place to place and time to time
How can new species form without geographic isolation of two populations? -
ANSWER-two distinct gene pools emerge through chromosomal changes due to errors
in mitosis and meiosis, habitat differentiation, or sexual selection
How could a scientist genetically engineer an organism? - ANSWER-1. Isolate a
bacterial plasmid and DNA of interest from another organism
2. Two are joined together, resulting in recombinant plasmids
3. Recombinant plasmids are mixed with bacteria, which "take up" the recombinant
plasmids
4. Each bacterium (carrying the recombinant plasmid) reproduces via cell division to
form a clone
a. The foreign gene carried by recombinant plasmid is also copied
5. Transgenic bacteria with the gene of interest can then be grown in large tanks
6. Final product may be:
a. Copies of the gene itself
b. Product of the cloned gene
, How does an organism's DNA lead to specific traits? - ANSWER-by dictating the
synthesis of proteins
How does DNA replicate? - ANSWER-DNA molecule unwinds and each strand is a
template for complementary base pairing; each daughter helix contains an intact strand
from the parent helix and a newly synthesized strand therefore DNA replication is
semiconservative
How does information flow in a cell? - ANSWER-DNA -> RNA -> Protein
How have humans impacted biodiversity? - ANSWER-through population numbers, use
of land, and lifestyles
How many strands of DNA does a DNA molecule contain? - ANSWER-two
Natural selection can amplify or diminish only ________ traits, not ________ traits -
ANSWER-heritable; acquired
Nutrients: - ANSWER-are recycled within an ecosystem
One parent molecule is composed of two __________________ that separate. -
ANSWER-complementary strands
RNA contains ________ instead of thymine. - ANSWER-Uracil
RNA makes protein through: - ANSWER-translation
The two strands of DNA are: - ANSWER-complementary
Two different species can evolve independently but: - ANSWER-acquire the same traits
as adaptations to similar environments
What are analogies (analogous structures)? - ANSWER-similarities among living
organisms that are due to similar environmental pressures and natural selection
(convergent evolution)
What are consumers? - ANSWER-heterotrophs - consume the food made by producers
What are decomposers? - ANSWER-they break down waste products and the remains
of dead organisms (fungi and bacteria)
What are detritus feeders? - ANSWER-organisms that consume dead organic matter
What are frameshift mutations? - ANSWER-mutations caused by insertions/deletions of
a number of nucleotides not divisible by 3
