biology exam #1
an artificial cell consisting of an aqueous solution with .5M sucrose is place in an open beaker of distilled water at 22C. calculate the water potential of the artificial cell
-12.26
skin color is polygenic, dependent upon many genes. dominant alles produce darker pigmented skin, where as recessive alleles produce lighter-colored skin. what is the probability that a fair-skinned individual (aabbccDdEeff) and a relatively dark skinned individual (AABbCCDdeeFF) will have a child who is also relatively dark skinned with the specific genotype of (AABBccDdEeFf)?
0
in a population of ground-dwelling finches on the galapagos islands, the allele for wide beaks is dominant to the allele for standard beaks. a drought leads to selection against the standard beaks and only 15% of the remaining finch population exhibits the standard beak phenotype at the end of the drought. assuming the finch population is in hardy-weinberg equilibrium at the end of the drought, what will be the frequency of the wide beak allele in the next generation?
0.61
review the diagram of the food web. according to the 10% rule, determine the energy availability of the beetle relative to the owl?
100
in the peppered moths, the black allele D is dominant to the gray allele d. the following offspring resulted from a cross between a black moth and gray moth
4.94
the data in the table show the number of cells counted in different phased of the cell cycle. what percentage of cells are in the mitosis phase of the cell cycle?
40.7%
which of the following correctly illustrates two amino acids in the optimal physical position to form a dipeptide bond?
a)
based on the eta in the table, the plates that have only transformed bacteria growing include which of the following?
a) III and IV
which of the following best describes the reason for the change in beak size in the finch population?
a) a change in the gene frequencies of CaM and BMP4 due to selective pressure from environmental change
antidiuretic hormone (ADH) is released from the posterior pituitary when blood osmolality (solute concentration) becomes too high. ADH targets tissue in the kidney, causing water to be reabsorbed back into the blood. the consumption of alcohol inhibits ADH release. which of the following would initially occur as a result of ADH inhibition?
a) a person would produce large amounts of dilute urine and possibly become severely dehydrates
a human fetus has webbed hands and feet and sealed eyelids early its developments. later, individual fingers and toes develop and eyelids form an opening. these developmental stages are most likely the result of
a) cells on the eyelids and in the webbing of hands and feet undergo programmed call death and the nutrients are absorbed and recycled by the body
some prokaryotes and chloroplasts share many common proteins. what is some additional evidence that chloroplasts evolved from ancient bacteria?
a) chloroplast and bacteria are similar in size, both are surrounded by a phospholipid bilayer and both replicate via binary fission
habitat loss has occurred within all ecosystems, but concern has centered on tropical rain forests and coral reefs. why are these two ecosystems the "most important" ones?
a) coral reefs and rain forests are particularly rich in biodiversity
the trend in oxygen consumption in rats is the opposite of that in grasshoppers. this difference in trends in oxygen consumption is pst likely due to their
a) difference in mode of body temperature regulation
a laboratory chamber is built in order to model early Earth conditions. the chamber is filled with a mixture of water vapor, hydrogen gas, methane, and ammonia. in order to synthesize organic molecules, which of the following forms of energy should be added?
a) electricity
biosynthetic pathways synthesize many of the amino acids used to make cellular proteins. in E coli, a prokaryote, some species can synthesize the amnio acid tryptophan, while other species of E. coli cannot. what is the most likely source of this genetic variation?
a) errors in DNA replication lead to mutation, a major source of variation in prokaryotes
which of the following explains why the GFP protein is expressed by e. coli cells only in the presence of lactose?
a) lactose in the nutrient agar activates the expression of genes located downstream of the lac operon regulatory gene
which of the following best explains why there is no growth on plate II?
a) lactose was requires to activate the expression of the ampR gene located downstream of the lac operon regulatory gene
there are seasonal and temporal fluctuations in the level of human melatonin, a hormone that is involved in our daily sleep-wake cycle. which of the following conclusions is accurate?
a) light suppresses melatonin production so its duration is longer in winter than summer
using the diagram, which of the following best predicts the outcome and provides the best explanation?
a) option II because body cells are hypertonic to distilled water
the chemical reaction for cellular respiration is C6H12O6 + 6O2 x 6CO2 + 6H2O + ATP if the oxygen gas in this reaction is labeled with a radioactive isotope of oxygen, 18O, then the resulting water also becomes labeled with 18O. how can this best be explained?
a) oxygen gas serves as the final extron acceptor in the electron transport system and combines with protons (H+) to produce water
in the cell respiration, oxygen gas is consumed at the same rate as carbon dioxide gas. what would need to be included in the experimental set up to enable accurate measurements of oxygen gas consumption?
a) potassium hydroxide, KOH, to remove carbon dioxide gas from the respirometer chamber
vaccines against infectious disease are an essential component of modern medicine and vaccination against smallpox was so successful that the disease was eradicated from the planet in 1977. medical researches are now developing vaccines to treat certain types of cancer, and in april 2012, the U.S FDA approved the first therapeutic cancer vaccine. according to the graph, what is the likely reason for the effectiveness of vaccines?
a) primary response to vaccine is minimal and the secondary response shows a dramatic ride in plasma antibody concentration and faster response time
a culture of euglena (a autotrophic protist) is maintained in a water solution with a source of carbon and phosphate but no nitrogen. the mass of several organic compounds found in the euglena culture is measured before and after several weeks in the water solution. which of the organic molecules would likely be lower when measured after being in the solution?
a) proteins and nucleic acids
consider the need for a spherical cell, such as the bacteria Streptococcus sp, to exchange materials with its environment. compare the efficiencies of the following sized cells (r= radius) and choose the one that is the most efficient. the formula for determining the volume of a sphere is (4/3) pi r^3; the formula for determining the surface area of a sphere is 4 pi r^2
a) r=100 u
which of the following best explains the increasing height of the plant community as succession proceeds?
a) taller communities gradually out-compete shorter communities for sunlight
which statement best explains the potential evolutionary benefits of alternative mRNA splicing?
a) the ability to create multiple mRNA molecules from a single gene allows a cell to create a wider variety of proteins whose diversity may positively affect the organisms survival.
look at the data in the table. which of the following is the best interpretation of these results
a) the germination rate of B. naps is related to temperature
the illustration suggests that
a) the gray crescent must contain particular chemical signals that are needed for normal development the the gray crescent was divided equally in the first embryonic cleavage on side I but not on side II
based on your understanding of signal transduction, choose the best definition and description that is most consistent with the information provided in the diagram
a) the process of signaling involves three steps: binding of the signaling molecule, signal transduction and cellular response
plant cells have a strong cell wall that allows water pressure to build up inside cells without causing the cell to burst. the resulting pressure is often called turgor pressure, which is critical because plants depend on it to maintain the turgidity of their bodies. insufficient turgor pressure will cause the plant to wilt, as seen in the illustration. which of the following elaborates on this phenomenon?
a) the water potential in plant A is higher than the surrounding soil, causing water to osmose from root tissue into the soil
the TOP diagram above shows the structures that exist in the thylakoid membrane of a chloroplast. the BOTTOM diagram above shows the structure that exist in the inner membrane of a mitochondrion. the hydrogen ions are depicted as + and the oxygen molecules are depicted as __. what is the best scientific question that can be posed to investigate the similarities in the capture and storage of energy for storage and use?
a) what is the relationship between the hydrogen ions and organelle membranes that is important in both the capture and conversion of energy for storage and use?
information from the cross demonstrates that
a) wing length and body color are in hearted trains and the dominant parent was heterozygous, LlGg
which of the following illustrations best represents the process by which genetic information is copied for transmission between generations?
b)
in nature, there is an amazing diversity of organisms that emit light including bacteria, fungi, crustaceans, mollusks, fishes and insects. this is allied bioluminescence. most bioluminescence mechanisms produce light from the oxidation of organic substrate, luciferin, and are catalyzed by an enzyme called luciferase. this reaction is driven by ATP, which is the biochemical energy source in all living organisms. given this information, which of the following statements is scientifically valid?
b) ATP is a universal energy source and therefore suggests a common ancestor for all forms of life
given that this is a test cross, which of the following represents the correct genotypes of the cross?
b) LlGg X llgg
based on the graph, in addition to types of opportunistic infections, the three categories of HIV are also associated with
b) a decreasing number of helper T cells, TH, cells in the blood
ethylene gas is a plant hormone used extensively in agriculture. it is produces naturally in plants to trigger fruit ripening. recently, tomato plants have been genetically modified to produce no ethylene so that they remain unripe (green) during extended periods of shipping. green tomatoes can then be exposed to ethylene once they arrive at their destination and will ripen at a convenient time for the grocer. how do plant hormones like ethylene coordinate an internal cellular response?
b) a hormone can bind to a plasma membrane receptor on the target cell triggering a signal transduction pathway which results in a change in gene expression
sickle-cell anemia is caused by a point mutation in the b-chain of hemoglobin, causing the hydrophilic amino acid, glutamic acid, to be replaced with the hydrophobic amino acid, valine. this would most likely result in
b) altered protein secondary and tertiary structure as a result of abnormal interactions between amino acid r-groups in hemoglobin
the difference in germination rate was likely due to difference in
b) cellular metabolic and growth rates of the seeds
which of the following statements best explains the increase in finch beak size during the drought?
b) finches with a higher degree of expression of CaM and BMP4 genes have smaller beaks that are better adapted to crack small seeds
during a six-month period in the 1990s, shark fishing in the Atlantic ocean increased from 326 metric tons to 642 metric tons. according to the diagram above, which of the following is most plausible?
b) flounder and salmon populations would decrease
during the six-month period in the 1990's, shark fishing in the atlantic ocean increased from 326 metric tons to 642 metric tons. according to the diagram above, which of the following is most plausible?
b) flounder and salmon populations would decrease
proto-oncogenes are normal genes that trigger progression of cells through the cell cycle. mutant forms of the BRCA1 oncogenes are associated with certain hereditary forms of breasts and ovarian cancer. what is a likely mechanism for the appearance of breast cancer cells?
b) inherited mutant BRAC1 oncogenes produce proteins that continuously promote cell division, regardless of circumstances
what is the best methodology to conduct an experiment to determine the change in beak size over time?
b) measure the beak size in a large number of finches every year for several years
eukaryotic cells have played an essential role in the evolution of complex multicellular organisms. which of the following provides the best explanation of this?
b) membrane-bound organelles allow for the separation of metabolic processes and localization of enzymes, substrates, and produces, which allow eukaryotic cells to become specialized
if a synthetic molecule in the environment mimicked the chemistry and conformation of tryptophan, its presence in the cell would
b) result in a decrease in the level of tryptophan being produced
which of the following statements best explains why there are white colonies on plate I but no colonies on plate II?
b) the bacteria on plate II are not ampicillin resistant in the absence of lactose
the mutation rate among retroviruses like HIV, which use RNA as genetic material, is higher than it is among DNA viruses. this is linked to
b) the extra step in converting viral RNA to cDNA which allows for the introduction of errors in the reverse transcription process
clostridium botulinum is the name of the bacteria that produces botulinum toxin, commonly called Botox. botulinum toxin is responsible for causing the fatal condition known as tetanus but, after studying its mechanism of action several years ago, 2002, botulinum toxin was FDA approved for treatment of facial wrinkles and it now earns billions of dollars in annual sales. botulinum toxin, or boxing, prevents the release of the stimulatory neurotransmitter acetycholine from the axon of motor neurons. which of the following is a likely mechanism of the toxin
b) the toxin alters the function of the synapse
the figure illustrates the difference in nitrogenous waste products between fishes, mammals, and birds. ammonia is highly toxic but soluble in water while urea is also water soluble but less toxic. which of the following best explains the adaptive value of urea excretion over ammonia excretion?
b) urea requires more water to produce than ammonia but is less toxic to tissues
which of the following best illustrates how organisms use negative feedback to maintain their internal environments?
c) after a meal, the hormone insulin, a chemical signal, travels in the cardiovascular system from the pancreas to the liver, where it binds to a receptor and causes liver cells to store glucose as glycogen
tumor suppressor genes like p53 inhibit the cell cycle and prevent damaged cells from dividing uncontrollably. cervical cancer is caused by the human papilloma virus (HPV), which codes for a protein that inactivates the p53 protein in infected cells. what is a direct result of inactivation of the p53 protein?
c) cells fail to stop dividing because the proper stimuli to stop are absent
plate I was included in the experimental design in order to
c) demonstrate the e. coli cultures were viable (alive and vulnerable to transformation)
the molecule/ complex in the figure above will be most useful and active after which event?
c) infection by a virus
the genotype of offspring III is
c) llGg
which of the following statements best supports the evolutionary relationship between organisms?
c) organisms often share some common biochemical pathways, such as glycolysis
what is the most reasonable explanation for the higher oxygen consumption in rats at lower temperatures?
c) rats expend more energy at lower temperatures in order to maintain body temperature
which of the following best explains the impact of HIV on an individuals health?
c) the HIV virus is a product of genetically engineered transduction and is thus only way vulnerable to genetically engineered drugs
antibiotic resistence in disease-causing bacteria is becoming increasingly dangerous to world health. many bacteria that cause ear infections, pneumonia, and tuberculosis have developed antibiotic resistant populations due to the misuse of antibiotics. genes for antibiotic resistance are carried on bacteria plasmids, which can be passed between bacteria by a process known as conjugation. what is the likely explanation for the increase in antibiotic resistant strains of bacteria?
c) when antibiotic are taken in low doses or intermittently, vulnerable bacteria causing the infection are killed but resistant strains survive and reproduce
which of the following best explains how some viruses can "jump" species and start infecting humans?
d) a combining of viral genetic material could occur in a person who is infected with both the bird flu and the human flu viruses, thus leading to recombinant strains that can produce different types of protein spikes
in the absence of drought, it was observed that the average beak size in the finch population declined to pre-drought levels. what is the most likely cause of this reversal?
d) an increase in seed variety led to an increase in beak variation
recent studies show that each regional population of African giraffes represents a unique evolutionary branch of the giraffe family tree. according to the phylogenetic species concept, each of these branches should be recognized as one of six unique giraffe species. based on the information in the diagram, which of the following is the best answer?
d) both a and b are correct
insulin ia hormone released by the pancreas, which causes the liver to store excess glucose as glycogen. failure of the liver to respond appropriately results in a medical condition called diabetes that is a direct result of high blood sugar. what is the best explanation for why cells only respond to certain signaling molecules and not others?
d) signal molecules require receptor proteins and only cells that possess matching receptors can respond to certain signaling molecules
which diagram illustrates the most likely to change in the coloration patters of the snail population after thousands of generations provides a reasonable explanation for the change?
d) the color pattern in the snail population split into two extremes, as in diagram I. the environment helped the camouflage snails from predetors
grey wolves tend to have thicker fur in the winter and shed heavily in the spring when the weather warms. in summer, the wolves' fur thins out significantly. which of the following is most likely responsible for the seasonal change in fur thickness?
d) the decrease in temperature in winter causes a change in gene expression, which results in increased growth of fur
the mitochondrial genome is passed directly from the mother to all her offspring. the number of mutant mtDNA molecules inherited by a specific offspring can vary greatly because of all the following except
d) the number of mitochondria are evenly distributes between every oocyte produced
according to the data, the rats demonstrate greater oxygen consumption at lower temperatures. the most likely explanation for this is that
d) the rats at 15 degrees Celsius had a higher metabolic rate than the rats at 30 degrees celsius
the trp operon
d) uses negative feedback to regulate the expression of the structural gene for tryptophan synthesis
which of the following best supports the claim that free energy is required for living systems to maintain organization, to grow, or to reproduce, but that multiple strategies exist in different living systems
d) while plants are photosynthetic, autotrophic bacteria near hydrothermal vents use hydrogen sulfide (H25) to make organic molecules
