Midterm 3 More Review Flashcards
If substantial lactic acid were found in a person’s bloodstream, which of the following is likely true?
a
Their cells are producing less ATP per molecule of glucose than they normally would
b
Their cells are using lactic acid fermentation
c
Their cells are not getting as much oxygen as they normally do
d
Two of the above are likely true
e
A, B, and C are all likely true
e
A, B, and C are all likely true
Imagine a plant with a mutated version of the chlorophyll molecule such that chlorophyll can no longer absorb light in the red wavelengths. Which of the following best describes what the consequences of this would be?
a
There would not be any consequences since chlorophyll only absorbs green light
b
Red light is the only color of light absorbed by chlorophyll, so all photosynthesis would stop
c
Most red light is currently absorbed by carotenoids, so there would be minimal effects
d
Chlorophyll would still be able to absorb blue light, but the loss of absorption of red light would decrease rates of photosynthesis
e
The plant’s leaves would likely appear purple or blue
d
Chlorophyll would still be able to absorb blue light, but the loss of absorption of red light would decrease rates of photosynthesis
Imagine that you are using a molecular marker to track oxygen atoms. You would find that the oxygen gas (O2) that is released as a result of photosynthesis is a direct by-product of:
water molecules
Which of the following is not true of photosynthesis?
a
Electrons and some energy are passed from Photosystem II to Photosystem I in the light-capturing reactions
b
The oxygen and carbon atoms found in all of the carbohydrates produced by photosynthesis originally came from carbon dioxide (CO2) molecules
c
The light-capturing reactions and the Calvin cycle are linked by the fact that one produces ATP and NADPH, while the other uses them
d
Antenna pigments transfer energy from photons to the reaction center by transferring electrons from antenna pigment to antenna pigment
e
Just like in cellular respiration, part of photosynthesis involves an electron transport chain that drives the creation of a hydrogen ion (H+) gradient which, in turn, drives the formation of ATP
d
Antenna pigments transfer energy from photons to the reaction center by transferring electrons from antenna pigment to antenna pigment
Energy from sunlight can excite electrons, sometimes kicking them out of their orbitals and creating free radicals. Free radicals are highly reactive atoms or molecules that have unpaired electrons and degrade and destroy other compounds in their vicinity. Carotenoids, one of the pigments present in chloroplasts, can stabilize these free radicals. This suggests that:
a
free radicals induce the synthesis of carotenoids in chloroplasts
b
carotenoids likely protect other molecules, such as chlorophyll, from damage caused by free radicals
c
if carotenoids were not found in chloroplasts, there would be minimal differences in chloroplast function
d
carotenoids communicate directly with the immune system of plants
e
chlorophylls may also be able to stabilize free radicals
b
carotenoids likely protect other molecules, such as chlorophyll, from damage caused by free radicals
Plant growth is affected by the balance of different gasses in the atmosphere. If the amount of oxygen in the atmosphere were to suddenly increase, why would this be a problem for most plants? Are there any plants that would be less affected by this increase in oxygen?
An increase in oxygen gas in the atmosphere would be a problem for most plants because an important enzyme in the Calvin cycle called Rubisco can pick up gaseous oxygen instead of carbon dioxide and fix it into the Calvin cycle. This is called photorespiration and causes the plant to lose energy rather than gain it, making photosynthesis less efficient at higher oxygen concentrations. A plant that fixes carbon dioxide in a different cell type than it carries out the Calvin cycle in (called a C4 plant) would be less affected by increases in oxygen as it already has a mechanism to minimize photorespiration.
You are excited to create your first transgenic organism, but are unsure which method of gene editing to use. Discussing this issue with a colleague, you come up with a list of reasons why to use CRISPR/Cas9 versus one of the older methods of gene editing. Which of the following is incorrect and should not be part of this list?
a
CRISPR/Cas9 tends to be cheaper than most other methods of gene editing
b
In CRISPR/Cas9, the use of the sgRNA allows you to target where in the genome you are editing, whereas you cannot control where a gene is added in many other methods
c
CRISPR/Cas9 can be used on a wider array of organisms than many previous gene editing methods
d
CRISPR/Cas9 can only be used to delete a gene’s function, it cannot be used to create transgenic organisms
e
All of the above are true comparisons of CRISPR/Cas9 and older methods of gene editing
d
CRISPR/Cas9 can only be used to delete a gene’s function, it cannot be used to create transgenic organisms
A gene drive would be most useful under which of the following circumstances?
a
When you are trying to do gene therapy with a retrovirus
b
When you are trying to quickly spread a genetic edit through a wild population of organisms
c
When you are trying to create a new transgenic plant
d
When you are trying to sequence the genome of a new organism
e
When you are comparing DNA between two species
b
When you are trying to quickly spread a genetic edit through a wild population of organisms
Which of the following statements is true concerning an organism’s genome?
a
Each genome codes for one or a few proteins
b
Most organisms have genomes made up of RNA, rather than DNA
c
Humans have 23 pairs of genomes
d
The genome is usually the same in a muscle cell as it is in a neuron or a fat cell of an individual
e
Organisms with larger genome sizes always are more complex than organisms with smaller genomes
d
The genome is usually the same in a muscle cell as it is in a neuron or a fat cell of an individual
In mitosis, which of the following happens before the chromosomes line up along the middle of the cell?
a
The chromosomes de-condense
b
The microtubules begin to shorten, pulling the sister chromatids apart
c
The microtubules attach to the kinetochores of the chromatids
d
The membrane around the nucleus reforms
e
All of the above occur after the chromosomes have finished lining up
c
The microtubules attach to the kinetochores of the chromatids
Describe one way that cells control the rate of cell division. How is this related to the alleles/mutations in genes that we talked about with cancer?
You could talk about cell cycle checkpoints here and how they stop cells from dividing under the wrong conditions. These are related to cancer in that these checkpoints involve tumor suppressor genes. You could instead talk about MPF and other cell signals that stimulate cell division and would be termed proto-oncogenes when related to cancer (or oncogenes if they are mutated)
In aggressive forms of breast cancer, the gene encoding a protein called stathmin is overexpressed increasing cell division. Inhibiting expression of the stathmin gene inhibits mitosis and is being investigated as an alternative therapy for treating cancer. Based on this information, in its normal, non-mutated form, stathmin could be considered:
a
a mutator gene
b
a tumor suppressor gene
c
a proto-oncogene
d
an oncogene
e
an angiogenesis gene
c
a proto-oncogene
which of the following are true of cancer
a
The two characteristics that differentiate cancerous cells from normal cells are that cancerous cells have uncontrolled cell division and have also lost control of cellular differentiation (i.e. a cancerous neuron no longer looks or functions like a normal neuron)
b
One of the reasons that it is hard to find a cure for cancer is that it is hard to target cancer cells without also harming normal, healthy cells
c
Some cancers fool the body into growing new blood vessels that supply the cancer with nutrients
d
Cancer cells can sometimes metastasize, or spread throughout the body
a
The two characteristics that differentiate cancerous cells from normal cells are that cancerous cells have uncontrolled cell division and have also lost control of cellular differentiation (i.e. a cancerous neuron no longer looks or functions like a normal neuron)
b
One of the reasons that it is hard to find a cure for cancer is that it is hard to target cancer cells without also harming normal, healthy cells
c
Some cancers fool the body into growing new blood vessels that supply the cancer with nutrients
d
Cancer cells can sometimes metastasize, or spread throughout the body
A common cellular symptom of coronaviruses, including the current novel coronavirus, is the production of multinucleated cells. What is one plausible explanation for the presence of a cell with more than one nucleus? (note: it may or may not be the correct explanation, just a possible one based on this information)
a
Cells infected by coronavirus are gametic cells
b
Cells infected by coronavirus undergo interphase, but never begin prophase
c
Cells infected by coronavirus undergo mitosis I, but not mitosis II
d
Cells infected by coronavirus complete the steps of mitosis from beginning of prophase through end of telophase, but do not undergo cytokinesis
e
Cells infected by coronavirus undergo meiosis instead of mitosis
d
Cells infected by coronavirus complete the steps of mitosis from beginning of prophase through end of telophase, but do not undergo cytokinesis
The egg cells of a fruit fly has 4 individual chromosomes. Based on this information, which of the following is false?
a
Regular somatic (body) cells of a fruit fly should have 8 chromosomes
b
After interphase, but before cell division, a fruit fly cells should contain 16 chromatids
c
During metaphase I of meiosis, there should be 8 pairs of chromosomes lined up in the center of the cells
d
A haploid fruit fly cell will contain 4 chromosomes
e
All of the above are true
c
During metaphase I of meiosis, there should be 8 pairs of chromosomes lined up in the center of the cells
