Bio 1500 Final Exam Questions And Answers
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What does it mean for a gene to be expressed? - Answer✔When the gene is transcribed into
mRNA and translated into AA
What does it mean for a gene to not be expressed? - Answer✔no protein/amino acids are made
and no transcription occurs
What does it mean for a gene to be turned on? - Answer✔transcription of the gene occurs
What does it mean for a gene to be turned off? - Answer✔Transcription of the gene does not
occur
What does it mean for a gene to be upregulated? - Answer✔the cell increases the quantity of
mRNA/protein in response to external stimulus (more of)
What does it mean for a gene to be downregulated? - Answer✔the cell decreases the quantity
of mRNA/protein in response to external stimulus (less of)
what do regulatory genes do? - Answer✔control the expression of one or more gene
what is a gene family? - Answer✔genes found on a small number of chromosomes (3 for Globin
family)
what is a protein family? - Answer✔proteins that have the same number if on the same
chromosome and are similar in structure
What are the causes of gene duplication? - Answer✔unequal crossing over during meiosis,
duplication of the entire chromosome /chromosome pair, new genes can come from mutations
that replace start codons/viral genes.
What is the function of myoglobin? - Answer✔Stores O2 in endurance muscles, times for high
metabolic demand facilitates oxygen diffusion.
explain how the structure and the o2 binding properties of myoglobin relate to each other -
Answer✔Compared to hemoglobin the O2 dissociation curve is shifted to the left meaning it
has higher O2 affinity.
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how does the binding of molecules other than O2 (e.g. CO, NO, H2O) to hemoglobin
affect the color of meat? - Answer✔CO2 causes smoked meat to turn pink, myoglobin stores
the O2 in muscle cells (responsible for color before during and after cooking depending on how
much myglobin is exposed to gas). Myoglobin brown = H20 binding instead of O2, myoglobin
pink = NO or CO binding.
why is meat color not necessarily an indicator of meat's freshness? - Answer✔Meat in a
packages use nitric acid (NO) for a bright pink color and if the meat stays this color it means it is
fresh because the HB is not binding to anything else.
what is the oxygen environment of the womb? - Answer✔Poor oxygen environment/low Po2,
therefor fetal blood mixes with O2 and deoxygenated blood from mom lowering mom's overall
po2
how does a fetus obtain oxygen? - Answer✔Obtains oxygen from mom's blood being released
to the fetal's umbilical artery and vein
What is the Hb-O2 dissociation curve like compared to adult Hb to fetal hemoglobin? -
Answer✔Fetal Hb has higher O2 affinity than adults (left shift)
How are the developmental changes in Hb related to gene duplication and to changes in gene
expression? - Answer✔Different Hb could be due to different tissue types
How do you interpret evolutionary relationships in a phylogenetic tree? - Answer✔DON'T count
nodes, look at common ancestors for evolutionary relationships. Same distance = same evolving
time
what is a clade? - Answer✔All lineages connect together at a common ancestor
Interpret traits in living species based on hypothesized gains or losses of a trait in a
phylogenetic tree - Answer✔Whether or not species are alive in a phylogenic tree determines
what traits will continue to pass on.
what is convergent evolution? - Answer✔when two different organisms share the same
phenotype/trait because they share similar way of life/pressures.
how do we know that the Hb adaptations of birds living at high altitudes in different parts of
the world is an example of convergent evolution? - Answer✔Different locations but same
adaptions due to same altitude pressures
what is the biological species concept? - Answer✔Species are a group of organisms with the
potential to breed with each other and produce live fertile offspring
What are the steps involved in the most common form of speciation? - Answer✔1. Population
splits into two isolated groups
2. Genetic differences build up between populations due to different selective pressures
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3. Populations become different enough to no longer reproduce successfully.
What are the chemical compounds most strongly implicated in climate change - Answer✔Water
vapor, co2, methane, nitrous oxide, and chlorofluorocarbons
what evidence is there that increased atmospheric temperatures are the result of an increase in
greenhouse gas composition rather than changes in the sun. - Answer✔average amount of
energy from sun has remained constant or slightly decreased since 1750, no increase in energy
emitted from sun.
how is climate change connected to events that occurred during the Carboniferous? -
Answer✔Coal was made when carbon was buried before ligin was decomposable. Burial of coal
formed fossil fuels and when burned releases CO2
what are the unusual features of the Páramo ecosystems of the Andes - Answer✔12,5000 ft
(high alt.), rainy, thin air, and Paramo collect water from environment and store/release it to
the lowlands.
how are molecular changes during o2 binding connected to cooperative o2 binding properties?
- Answer✔Cooperative o2 binding allows for the affinity to increase as each o2 binds to the
heme groups, when no o2 is bonded there is low affinity but when one oxygen binds the
molecules expand for each o2 added.
How is the O2-Hb dissociation curve related to the partial O2 pressure in the lung and body and
explain the advantage of its sigmoidal shape. - Answer✔The lung is where the curve has 100%
Po2, the body is where the steep drop in po2 happens and normal body po2 hemoglobin keeps
70-80% of its oxygen.
how does the O2 affinity of Hb decrease in the body, incl. which factors contribute to this
decrease and how this facilitates the release of O2 in the body. - Answer✔As pH decreases
(more acidic) affinity of Hb decreases, as temp. increases affinity also decreases which allows
for oxygen to be released where it is needed.
how does pH, PCO2, temperature, and 2,3-BPG change the tertiary and
quaternary structure of Hb and thus its O2 affinity. - Answer✔CO2, H+, and 3-BPG are all
charged/polar, so they attach to amino acids outside Hb subunits which changes the structure
of Hb therefore changing the function. (PH increases polar molecules)
why does human Hb does not work sufficiently at high altitudes, by relating PO2 at low and
high altitudes to the O2 Hb dissociation curve. - Answer✔At higher altitudes, PO2 is lower
which means there's less Po2 in the lungs and a smaller percentage of Hb with O2 in the lungs
and therefore the cells cannot get the oxygen they need, and their body cannot create energy.
how does the bird respiratory system differs from that of mammals? - Answer✔Birds have a
single direction of flow of air and a more complicated respiratory system with parabronchi &
little residual volume vs. multiple directions and alveoli in mammals.
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