BIO 111 Final Exam Short Answer
Questions
Explain 'exponential' bacterial growth and list the 4 phases of
bacterial growth. - Correct Answers ✅Exponential growth is
when something grows more and more rapidly until it reaches
its peak point. In the case of bacterial growth, bacteria begin
to multiply themselves, doubling in number every few
minutes. They double themselves repeatedly until they reach
their maximum limit and start to die off.
(1) Lag phase- Bacterial growth starts off slow. Since they are
in a new environment, it takes a while for them to get
accustomed to their surroundings. They are also seeking food
and nutrients that will help them grow.
(2) Log phase- Once the bacteria are accustomed to their
new environment, it is time to grow. They multiply
themselves exponentially, doubling in number every few
minutes.
(3) Stationary phase- Since there are so many bacteria now,
there is less food and nutrients for them to feed on. Less
bacteria are formed, and exponential growth stops.
(4) Death phase: Now that almost all the nutrients in the
body are depleted, the bacteria have nothing else to feed on.
Toxic waste also has built up over the previous phases. As a
result, the bacteria die off in this final stage.
Does number of chromosomes correlate to an organism's
complexity. Why or why not? - Correct Answers ✅It does
not. For example, a chicken has 78 chromosomes in its
somatic cells. This means it inherited 39 from each parent.
Meanwhile, humans have 46 chromosomes, inheriting 23
from each parent. Humans are obviously more complex than
, BIO 111 Final Exam Short Answer
Questions
chickens, seeing as we are bigger and more intelligent
beings, and yet chickens still have more chromosomes than
us. Thus, more chromosomes does NOT mean an organism is
more complex.
Explain the normal function of tumor suppressor genes and
proto-oncogenes. If both copies of a tumor suppressor gene is
mutated, what is the effect on the cell? If a copy of a proto-
oncogene is mutated, what is the effect on the cell?
Remember the analogy of the "gas" and "brakes". - Correct
Answers ✅Proto-oncogenes are stimulating proteins that
encode cell cycle regulators. Cell cycle regulators control the
cell as it goes through the cell cycle and can either inhibit or
stimulate cell cycle progression. Thus, without proto-
oncogenes, these cell cycle regulators would not be encoded
to do their jobs and cells wouldn't be controlled as they
moved through the cell cycle.
Like proto-oncogenes, tumor-suppressor genes encode cell
cycle regulators. Their job is to catch mutations in these
regulators which can lead to cancer. Rather than stimulating
the cell cycle like proto-oncogenes, they inhibit it, which
means their job is to STOP mutated genes from forming
rather than make more of them.
Tumor-suppressor genes normally function as "brakes"
because their job is to inhibit any tumorous genes from
growing. Proto-oncogenes function as "the gas" because they
are an accelerator of the cell cycle, contributing to cell
division. When there is a mutation in proto-oncogenes, there
is a gain of function, and a protein is produced that puts the
cell cycle into overdrive. When there is a mutation in a tumor-
Questions
Explain 'exponential' bacterial growth and list the 4 phases of
bacterial growth. - Correct Answers ✅Exponential growth is
when something grows more and more rapidly until it reaches
its peak point. In the case of bacterial growth, bacteria begin
to multiply themselves, doubling in number every few
minutes. They double themselves repeatedly until they reach
their maximum limit and start to die off.
(1) Lag phase- Bacterial growth starts off slow. Since they are
in a new environment, it takes a while for them to get
accustomed to their surroundings. They are also seeking food
and nutrients that will help them grow.
(2) Log phase- Once the bacteria are accustomed to their
new environment, it is time to grow. They multiply
themselves exponentially, doubling in number every few
minutes.
(3) Stationary phase- Since there are so many bacteria now,
there is less food and nutrients for them to feed on. Less
bacteria are formed, and exponential growth stops.
(4) Death phase: Now that almost all the nutrients in the
body are depleted, the bacteria have nothing else to feed on.
Toxic waste also has built up over the previous phases. As a
result, the bacteria die off in this final stage.
Does number of chromosomes correlate to an organism's
complexity. Why or why not? - Correct Answers ✅It does
not. For example, a chicken has 78 chromosomes in its
somatic cells. This means it inherited 39 from each parent.
Meanwhile, humans have 46 chromosomes, inheriting 23
from each parent. Humans are obviously more complex than
, BIO 111 Final Exam Short Answer
Questions
chickens, seeing as we are bigger and more intelligent
beings, and yet chickens still have more chromosomes than
us. Thus, more chromosomes does NOT mean an organism is
more complex.
Explain the normal function of tumor suppressor genes and
proto-oncogenes. If both copies of a tumor suppressor gene is
mutated, what is the effect on the cell? If a copy of a proto-
oncogene is mutated, what is the effect on the cell?
Remember the analogy of the "gas" and "brakes". - Correct
Answers ✅Proto-oncogenes are stimulating proteins that
encode cell cycle regulators. Cell cycle regulators control the
cell as it goes through the cell cycle and can either inhibit or
stimulate cell cycle progression. Thus, without proto-
oncogenes, these cell cycle regulators would not be encoded
to do their jobs and cells wouldn't be controlled as they
moved through the cell cycle.
Like proto-oncogenes, tumor-suppressor genes encode cell
cycle regulators. Their job is to catch mutations in these
regulators which can lead to cancer. Rather than stimulating
the cell cycle like proto-oncogenes, they inhibit it, which
means their job is to STOP mutated genes from forming
rather than make more of them.
Tumor-suppressor genes normally function as "brakes"
because their job is to inhibit any tumorous genes from
growing. Proto-oncogenes function as "the gas" because they
are an accelerator of the cell cycle, contributing to cell
division. When there is a mutation in proto-oncogenes, there
is a gain of function, and a protein is produced that puts the
cell cycle into overdrive. When there is a mutation in a tumor-
