Bio 105 canvas quiz questions
Why are fermentation reactions important for cells? A. They produce alcohol used in alcoholic beverages. B. They regenerate NAD+ so that glycolysis can continue. C. They utilize oxygen. D. They generate oxygen.
B
Why are there several structurally different pigments in the reaction centers of photosystems? A. Excited electrons must pass through several pigments before they can be transferred to electron acceptors of the electron transport chain. B. This setup enables the plant to absorb energy from sunlight from a variety of wavelengths. C. They enable the plant to absorb more photons from light energy, all of which are at the same wavelength. D. They enable the reaction center to excite electrons to a higher energy level.
B
A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best describes this observation? A. A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best describes this observation? B. Natural selection caused the pigweed to mutate, creating a new triazine-resistant species. C. Triazine-resistant pigweed has less efficient photosynthesis metabolism. D. Only triazine-resistant weeds survived and reproduced, so each year more pigweed was triazine-resistant.
D
After telophase I of meiosis, what is the chromosomal makeup of each daughter cell? A. Diploid; and the chromosomes are each composed of single chromatids. B. Diploid; and the chromosomes are each composed of two chromatids. C. Haploid; and the chromosomes are each composed of single chromatids. D. Haploid; and the chromosomes are each composed of two chromatids.
D
As a scientist, what would I require to investigate scientifically the existence of Ganesha, Hindu Lord of Obstacles? A. Faith as a Hindu believer B. Eyewitness accounts of Ganesha's actions C. Divine insight D. Quantifiable, testable evidence
D
Assume that a particular human cell is examined under a microscope, and it contains 22 autosomes and a Y chromosome. This cell is most likely to be A. a somatic cell of a male B. a zygote C. a somatic cell of a female D. a sperm cell
D
Assuming independent assortment for all gene pairs, what is the probability that the following parents, AABbCc AaBbCc, will produce an AaBbCc offspring? A. 1/2 B. 1/16 C. 1/8 D. 3/4 E. 9/16
D
At which stage in meiosis is chromosome number typically reduced from 2n to n? A. meiosis II B. metaphase II C. mitosis D. meiosis I
D
Based on what you know about the structure and function of the antenna complex, irradiating a leaf with which of the following light types would be result in the release of the greatest quantities of oxygen? A. red light B. green light C. blue light D. red and blue light
D
Besides sunlight, which would be the most important climatic factor(s) for plants? A. wind B. moisture C. temperature D. temperature and moisture
D
Considering the global nitrogen cycle, what is the limiting portion of the cycle for plants? A. industrial nitrogen fixation B. nitrogen lost to the atmosphere C. internal nitrogen cycling in the oceans D. nitrogen fixation by bacteria
D
During interphase of the cell cycle, just prior to mitosis or meiosis, A. DNA recombines. B. Sister chromatids move to opposite poles. C. The nuclear membrane disappears. D. DNA content essentially doubles.
D
How can a gene be longer than an mRNA produced by that gene? For instance, the gene for Duchenne muscular dystrophy (DMD) is over 2000 kb (kb = kilobases) long, but the mRNA that this gene produces and that is found in polyribosomes is approximately 14 kb long. What causes this discrepancy? A. The exons have been spliced out during mRNA processing. B. The DNA represented a double-stranded structure and the RNA is single stranded. C. There are more amino acids coded for by the DNA than the mRNA. D. The introns have been spliced out during mRNA processing. E. When the mRNA is produced, it is highly folded and therefore less long.
D
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE? A. 32 B. 4 C. 16 D. 8 E. 1/64
D
In a sample of double-stranded DNA from a particular organism, if 15% of the nitrogenous base is thymine, what percentage should be cytosine? A. 15% B. 30% C. 70% D. 35% E. 40%
D
In cells, the activity of enzymes is often regulated by other enzymes or molecules. Why is this necessary? A. because all enzymes require some help from another molecule to function correctly B. because other molecules are necessary to prevent enzymes from denaturing C. because each enzyme has multiple functions D. because it is unlikely that all reaction products are required all of the time
D
In the diagram above, which of the lines represents exponential growth? A. line c B. line b C. line a D. all of the above E. line d
D
In the triplet code, which of the following is true? A. Each DNA base codes for three amino acids. B. Each gene codes for three proteins. C. It takes three genes to code for one protein. D. Each amino acid in a protein is coded for by three bases in the DNA. E. Each triplet has many different meanings.
D
Looking at the above figure, which number would designate the biome with the highest variation in annual temperature? A. 1 B. 2 C. 3 D. 4
D
Looking at the above two figures, which of the following statements is false? A. Area 1 has more average precipitation than area 2 does. B. Area 1 has a higher average temperature than area 2 does. C. Both areas have low variation in precipitation. D. Area 2 has a smaller annual temperature variation when compared to area 1.
D
Looking the data above, what can be said about survival and clutch size? A. Animals with high fecundity tend to live longer. B. Animals with low survival tend to have low clutch sizes. C. High clutch sizes tend to produce animals with low survival. D. Animals with high fecundity tend not to live as long as animals with low fecundity.
D
Meiosis II is similar to mitosis in that: A. Homologous chromosomes synapse. B. DNA replicates immediately before the division. C. The daughter cells are diploid. D. Sister chromatids separate during anaphase. E. The chromosome number is reduced following meiosis II.
D
Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small vertebrates that fly or jump out of the way of the ants. What is the specific benefit relationship? A. Neither birds nor ants benefit from the association. B. Birds do not benefit from the association, but the ants do. C. Birds benefit from the association and harm the ants. D. Birds benefit from the association but have no impact on the ants. E. Birds and ants benefit from the association.
D
The definition of a generation is A. the average time between a father's first offspring and his son's first offspring B. an average of B and C C. 20 years D. the average time between a mother's first offspring and her daughter's first offspring
D
The gametes of a particular roundworm have eight chromosomes. How many chromosomes would be expected in each diploid mitotic metaphase cell? A. 4 B. 2 C. 8 D. 16
D
The number and size of organelles in a cell correlates with that cell's function. Propose a function for cells that contain extensive rough ER. A. rapid cell division in growing bones or muscle tissues B. production and processing of fatty acids and other lipids C. movement via cell crawling D. production of proteins that are secreted from the cell
D
This figure is of A. messenger RNA B. ribosomal RNA C. DNA D. transfer RNA
D
This table gives the results of assays of percentages of bases from nucleic acids isolated from different sources. For each source, what type of nucleic acid (RNA or DNA) is most likely specified? State whether it is likely to be single or double stranded. Source A G T C U (1) 20 30 0 10 40 (2) 20 30 20 30 0 (3) 20 20 30 30 0 The nucleic acid from source #2 is _________ and most likely __________. A. RNA; single stranded B. RNA; double stranded C. DNA; single stranded D. DNA; double stranded
D
Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. What keeps the two populations separate? A. temporal reproductive isolation B. lack of hybrid viability C. gametic barrier D. spatial reproductive isolation E. behavioral reproductive isolation
D
What characteristic of this molecule (ATP) is responsible for its high energy level? A. the nitrogen atoms in adenine B. the phosphorus atoms in the phosphate groups C. the C-H bonds of the ribose sugar D. the closely spaced negative charges associated with the phosphate groups
D
A black guinea pig crossed with an albino guinea pig produced 12 black offspring. When the albino was crossed with a second black animal, 6 blacks and 6 albinos were obtained. What is the best explanation for this genetic situation? A. Albino is recessive; black is dominant. B. Albino is dominant; black is incompletely dominant. C. Albino and black are codominant. D. Albino is recessive; black is recessive.
A
A class of mutations that results in multiple contiguous (side-by-side) amino acid changes in proteins is probably caused by the following type of mutation: A. reading frame shift B. transversion C. transition D. base analogue E. recombinant
A
Assume a particular organism has a diploid chromosome number of 4. How many different chromosome combinations can be normally packaged among the gametes of this organism? (Assume that no crossing over occurs.) A. 4 B. 8 C. 2 D. infinite number E. 0
A
Considering the global nitrogen cycle, how are humans altering this cycle? A. industrial nitrogen fixation B. nitrogen lost to the atmosphere C. reduction of nitrogen available to terrestrial ecosystems D. reduction of nitrogen fixation by bacteria
A
Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In actual fact, it comes from: A. water B. glucose C. hydrogen sulfide D. electrons from NADPH
A
Evolution by natural selection changes the population but not the individual. A. true B. false
A
If a solution surrounding a cell is hypotonic relative to the inside of the cell, how will water move? A. It will move into the cell via osmosis. B. It will move out of the cell via osmosis. C. It will not move, because equilibrium exists. D. It will evaporate from the cell surface more rapidly.
A
If the GC content of a double-stranded DNA molecule is 60%, what are the molar percentages of the four bases (G, C, T, A)? A. G = 30%; C = 30%; A = 20%; T = 20% B. G = 20%; C = 20%; A = 30%; T = 30% C. G = 10%; C = 50%; A = 20%; T = 20% D. G = 0%; C = 60%; A = 0%; T = 40%
A
If the curves on the above diagram continue on their trajectory, what can be said about these populations? A. Population growth is density independent. B. Individual growth is indeterminate. C. Population growth is discontinuous. D. Population growth is density dependent.
A
If you were to compare the base sequences of related genes from different but closely related species, you'd be likely to find that corresponding __________ are usually conserved, but the sequences of __________ are much less well conserved. A. exons; introns B. introns; exons C. introns; chaperons D. chaperons; exons E. introns; proteins
A
Looking at the above figure, which number would designate the biome with the highest variation in annual precipitation? A. 1 B. 2 C. 3 D. 4
A
Metaphase occurs prior to the splitting of centromeres. It is characterized by: A. aligning of chromosomes on the equator (also known as the metaphase plate) B. splitting of centromeres C. cytokinesis D. disassembly of the nuclear envelope
A
Name two evolutionarily significant benefits of meiosis that are not present in mitosis. A. reshuffling of homologous chromosomes and crossing over B. all of the gametes are identical C. maintains the same number of chromosomes in the gametes and adults
A
Phospholipids are the major constituent of cellular membranes. Phospholipids are often drawn like this figure. When phospholipids are placed in an aqueous environment, they assemble into membranes. Which of the following is true about a membrane? A. It contains two layers of phospholipids with the "B" regions facing the inside and the "A" regions facing out. B. It contains two layers of phospholipids with the "A" regions facing the inside and the "B" regions facing out. C. It contains a single layer of phospholipids with the "B" region facing the inside and the A" region facing out D. It contains a single layer of phospholipids with the "A" region facing the inside and the "B" region facing out
A
Select three posttranscriptional modifications often seen in the maturation of mRNA in eukaryotes. A. 5'-capping; 3'-poly(A) tail addition; splicing B. 3'-capping; 5'-poly(A) tail addition; splicing C. removal of exons; insertion of introns; capping D. 5'-poly(A) tail addition; insertion of introns; capping E. heteroduplex formation; base modification; capping
A
Snails typically avoid sunlit areas, but some snails infected with certain parasites become attracted to light and prefer sunlit areas. Which of the following is the most likely hypothesis given the life cycles of many parasites? A. The parasite manipulates the behavior of the snail so that it gets eaten more readily, which allows the parasite to complete its life cycle. B. The snail is dying from the parasite and is therefore looking for the light. C. The parasite must exit the snail in a sunlit area in order to move and find its next host. D. The snail is behaving differently in order to rid itself of the parasite. E. The parasite itself must be exposed to light in order to survive in the snail.
A
Stoma, openings in the leaf, are important to photosynthesis for: A. entry of carbon dioxide that is used in the Calvin cycle B. entry of oxygen that is used in the Calvin cycle C. removal of water and carbon dioxide, the end-products of photooxidation D. removal of nitrogen-containing waste products
A
Suppose you discovered a new amino acid. Its R-group contains only hydrogen and carbon atoms. Predict the behavior of this amino acid. A. It is hydrophobic. B. It is hydrophilic C. Relative to the amino acids found in organisms, its interactions with water will be intermediate D. Relative to the amino acids found in organisms, its interactions with water will be very high.
A
The competitive exclusion principle states that: A. It is not possible for two species with the same niche to coexist. B. It is possible for two species with the same niche to coexist. C. It is not possible for two species with different niches to coexist. D. It is possible for two species with different niches to coexist.
A
The electron transport chain: A. is a series of redox reactions B. is a series of substitution reactions C. is driven by ATP consumption D. takes place in the cytoplasm of prokaryotic cells
A
The proteins of the electron transport chain active in the light-dependent reactions: A. are membrane proteins present in the thylakoid B. are free proteins present in the thylakoid lumen C. are part of the reaction center of photosystem I D. are part of the reaction center of photosystem II
A
Theoretically, which would be the most effective way to disrupt the Hadley cell? A. Remove all equatorial moisture. B. Extensively water the deserts. C. Heat the poles. D. Shift the Sun to apply direct rays 30 degrees south latitude.
A
There are twenty different amino acids. All amino acids have a(n) ________ functional group and a(n) ________ functional group, but vary in their ________ group. A. carboxyl; amino; R- B. R-; carboxyl; amino C. amino; R-; carboxyl
A
There is a great deal of energy in the glucose molecule in its: A. C-H bonds B. C-N bonds C. level of oxygen D. ring structure
A
This table gives the results of assays of percentages of bases from nucleic acids isolated from different sources. For each source, what type of nucleic acid (RNA or DNA) is most likely specified? State whether it is likely to be single or double stranded. Source A G T C U (1) 20 30 0 10 40 (2) 20 30 20 30 0 (3) 20 20 30 30 0 The nucleic acid from source #1 is _________ and most likely __________. A. RNA; single stranded B. RNA; double stranded C. DNA; single stranded D. DNA; double stranded
A
Three populations of birds look very similar, but the males have territorial songs that sound different. What function would this difference in song likely serve if the two populations came in contact? A. a prezygotic isolating mechanism B. a postzygotic isolating mechanism
A
Treehoppers (a type of insect) produce honeydew, which ants use for food. Treehoppers have a major predator, the jumping spider. Researchers hypothesized that the ants would protect the treehoppers from the spiders. In an experiment, researchers followed study plots with ants removed from the system and compared to a control plot. In the above figure, what can you conclude? A. Ants do somehow protect the treehoppers from spiders. B. Ants do not protect the treehoppers from spiders. C. Ants reduce the numbers of treehoppers. D. No specific conclusions can be drawn from this graph.
A
What conclusion can you draw from the above figure? A. Without direct contact, mussels can sense the presence of crabs. B. Mussels can sense the presence of crabs only visually. C. Mussels are increasing their shell thickness in response to water current. D. Shell thickness is a non-inducible defense.
A
What determines the primary structure of a polypeptide? A. its sequence of amino acids B. hydrogen bonds that form between carboxyl and amino groups on different residues C. hydrogen bonds and other interactions between side chains D. the number, identity, and arrangement of polypeptides that make up a protein
A
Which of the following describes the most likely order of events in speciation? A. genetic drift, genetic isolation, divergence B. genetic isolation, divergence, genetic drift C. divergence, genetic drift, genetic isolation D. divergence, genetic isolation, genetic drift E. genetic isolation, genetic drift, divergence
A
Which of the following is not a type of consumption? A. mutualism B. herbivory C. parasitism D. predation
A
Which of the following is not an example of a mutualism? A. fungi residing in plant roots, such as endomycorrhizae B. bacteria fixing nitrogen in plants C. rancher ants that protect aphids in exchange for sugar-rich honeydew D. birds eating insects jumping out of the path of army ants
A
Which of the two graphs above shows a population of organisms that has a strong population cycle? A. B B. A
A
Which terrestrial category has the highest impact on Earth's ecosystem? A. tropical wet forest B. rock, sand, and ice C. tropical seasonal forest D. algal beds and reefs
A
A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed, no matter how often he applies triazine. Which of these actions is most likely to solve the farmer's problem? A. buying triazine from a different company B. trying a different herbicide C. increasing the amount of triazine he puts on his fields D. adding triazine more often to his fields
B
A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation). Albinism is an autosomal (not sex-linked) recessive trait. What is the probability that their first child will be an albino girl? A. 0% B. 1/8 C. 1/2 D. 1/4 E. 100%
B
A parent cell divides to form two genetically identical daughter cells in the process of mitosis. For mitosis to take place: A. The parent cell must first be fertilized. B. The parent cell must replicate its entire genome (i.e., all of its genes) prior to mitosis. C. The parent cell must reproduce its DNA during telophase. D. The parent cell must divide its DNA in half so each daughter cell gets only the genes needed to carry out its functions. In this way, differentiation occurs.
B
Which statement about K (environmental carrying capacity) is false? A. K varies among populations. B. K is specific for a given species C. K varies in space D. K varies in time.
B
At the end of mitosis, each daughter cell has: A. twice the DNA and half the cytoplasm of the parent cell B. identical DNA to that of the parent cell C. half the DNA and half the cytoplasm of the parent cell D. twice the cytoplasm and the same amount of DNA as the parent cell
B
Based on the diagram above, which of the following statements correctly interprets the data? A. Female density is affected by clutch size. B. Clutch size is affected by female density. C. Survivorship is affected by female density.
B
Chlorophyll absorbs light in the ____________ range? A. ultraviolet B. visible C. infrared D. X-ray
B
Considering the global carbon cycle, where is the largest reservoir of carbon? A. terrestrial ecosystems B. oceans C. atmosphere D. beneath the surface of the Earth
B
Early in the evolution of life-forms, there likely were fewer than 20 amino acids. If "primitive proteins" were composed of only 14 different kinds of amino acids, what would be the fewest number of nucleotides needed for a code that could specify the 14 different amino acids? Assume that all four nitrogenous bases are available for coding. A. 1 B. 2 C. 3 D. 4 E. 14
B
Energy from sunlight can excite electrons, kicking them out of their orbitals and creating free radicals. Free radicals are highly reactive atoms or molecules that have unpaired electrons. They degrade and destroy other compounds in their vicinity. Carotenoids, one of the pigments present in most chloroplasts, can stabilize these free radicals. This suggests that: A. Once chloroplasts are destroyed, the free radicals will destroy the cell. B. Carotenoids probably have a protective function in the cell C. Other pigments (besides carotenoids and chlorophyll) are essential for the health of a plant cell. D. Carotenoids communicate directly with the immune system of plants.
B
Given the structure of DNA, what component of that structure is most directly associated with encoding genetic information? A. the sequence of phosphates B. nitrogenous bases and their sequence C. the arrangement of phosphodiester linkages D. the order of the deoxyribose sugars E. all of the above are correct
B
Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. (a) What is the most probable genotype of each parent? (b) Based on your answer in (a) above, what genotypic and phenotypic ratios are expected in the progeny? (Assume the following symbols: G = gray and g = white.) A. (a) GG gg; (b) genotypic = 3:1, phenotypic = 1:2:1 B. (a) Gg Gg; (b) genotypic = 1:2:1, phenotypic = 3:1 C. (a) GG Gg; (b) genotypic = 1:2:1, phenotypic = 2:1 D. (a) gg Gg; (b) genotypic = 1:2, phenotypic = 3:1 E. (a) Gg X Gg; (b) genotypic = 3:1, phenotypic = 9:3:3:1
B
Homologous chromosomes move to opposite poles of a dividing cell during A. mitosis B. meiosis I C. meiosis II D. fertilization
B
How are the light-dependent and light-independent reactions of photosynthesis related? A. They cannot occur in the absence of light. B. The products of light-dependent reactions are used in light-independent reactions. C. The products of light-independent reactions must be present for light-dependent reactions to take place. D. They are not related.
B
I set up an experiment to test the effect of 10 different temperatures on the rate of absorption of a blue dye by the roots of 10 different celery plants. I set up the experiment very carefully, making sure that all of my experimental plants were treated the same, except for temperature, which was varied for each plant. I set the experiment up over night (under lights) and returned in the morning to collect the results. My results revealed that the higher temperatures resulted in more absorption of the dye. Cooler temperatures resulted in very little dye being absorbed. I make the statement, "All plants absorb water and dye faster at higher temperatures because they require more liquid to keep cool". This is a(n): A. Fact B. Hypothesis C. Theory D. A hypothesis and a theory E. None of the above
B
If Earth were to reorient such that the North Pole always received direct sunlight (always faced the Sun), how would that change Earth's climate? A. The equators would not change in climate. B. The South Pole would get colder. C. The equators would get warmer. D. The North Pole would get more wind.
B
In deep water, which of the following abiotic factors would most limit productivity? A. temperature B. light availability C. solute concentration D. They all limit productivity similarly
B
In the diagram above, which of the lines represents the highest per-capita rate increase (r)? A. line B B. line A C. line C D. line D
B
Independent assortment of two genes _________. A. cannot occur if the genes are located on different chromosomes. B. can only happen if the genes are located on different chromosomes. C. has been proven to not occur with genes. D. will result in male offspring if the genes are located on the X chromosome.
B
It has been hypothesized for some time that by having eukaryotic mRNAs spliced (removal of introns), an opportunity exists for alternative splicing (i.e., removal of different combinations of introns/exons) to produce A. more than one polymerase at a replication fork B. more than one mRNA from the same genetic locus C. several RNAs to generate several DNA segments D. many tRNA species to avoid the wobble seen during translation
B
Looking at the above figure, what can be said about productivity in this ecosystem? A. Nothing can be said based on this information. B. Between 80 and 90% of the energy is lost at the next highest trophic level. C. Between 10 and 20% of the energy is lost at the next highest trophic level. D. Productivity increases with each trophic level.
B
Looking at the above two figures, which of the following statements is false? A. Area 1 has more average precipitation than area 2 does. B. Area 1 would be considered a desert because of its high average temperature. C. Area 2 would be considered a desert because of its low average precipitation D. Area 2 has a large annual temperature variation.
B
Looking at the above two figures, which of the following statements is true? A. Area 1 could be called a subtropical desert. B. Area 2 could be called tundra. C. Area 1 could be called a tropical wet forest. D. Area 2 could be called a boreal forest
B
Many songbirds breed in North America in the spring and summer, and then migrate to Central and South America in the fall. They spend the winter in these warmer areas, where they feed and prepare for the spring migration north and another breeding season. Two hypothetical species of sparrow, A and B, overwinter together in mixed flocks in Costa Rica. In spring, species A goes to the east coast of North America, and species B goes to the west coast. What can you say about the isolating mechanisms of these two species? A. They must have strong prezygotic or postzygotic isolating mechanisms in order to spend winter in such close proximity. B. The two species do not breed in the same area, so they are reproductively isolated by allopatry. C. One of the species is probably polyploid, so they are reproductively isolated by genetic incompatibility. D. Reinforcement must be occurring when they winter together
B
Monomers join together to form polymers via: A. hydrolysis B. condensation reactions C. exergonic reactions D. hydrophilic reactions
B
See the diagrams. The four diagrams labeled A, B, C, D should be used to answer the question. A. A B. B C. C D. D
B
The figure above shows the change in population size for whooping cranes (Grus americana) in North America between 1940 and 2000. The population of cranes is much smaller than many other species. This allows for every bird to be ringed and tracked throughout the year. Whooping crane populations grew between 1950 and 1990 because of a reduction in number of predators. This is a(n): A. Fact B. Hypothesis C. Theory D. Estimate
B
The light-independent reactions of plants function to make organic molecules using carbon dioxide as a carbon source. What is the electron source that helps reduce carbon dioxide to sugars and other organic molecules? A. NADH B. NADPH C. ATP D. electrons from oxygen
B
The metabolic pathway, glycolysis is active when cellular energy levels are ____________; the regulatory enzyme, phosphofructokinase is ____________ by ATP. A. low; activated B. low; inhibited C. high; activated D. high; inhibited
B
The projections for Earth's human population by 2050 made in 1992 are much higher than those recently made in 2002. What is the main difference recent history has made in this significant projection alteration? A. All of the above answers apply. B. Deaths from AIDS have significantly increased since 1992 C. Human fertility rates have significantly decreased since 1992. D. The number of developed countries has significantly increased since 1992.
B
The relationship between a gene and a messenger RNA is as follows: A. Genes are made from mRNAs. B. mRNAs are made from genes. C. mRNAs make proteins which then code for genes. D. All genes are made from mRNAs. E. Messenger RNA is directly responsible for making Okazaki fragments.
B
Using the figure above, what result would you expect if you replaced the crabs with broken mussel shells? A. a higher degree of difference than the crab experiment B. no difference in shell thickness C. impossible to hypothesize D. the same result as the experiment with crabs
B
What base pairing arrangement is typically found in double-stranded DNA? A. A pairs with T; G pairs with U. B. A pairs with T; G pairs with C. C. G pairs with A; T pairs with U. D. A pairs with G; C pairs with T. E. There are no base-pairing rules.
B
What is a rain shadow? A. the part of a mountain that receives prevailing winds and heavy rain B. the part of a mountain that does not receives prevailing winds and heavy rain C. the region along the equator where precipitation is abundant D. the region near 30°N and 30°S latitude that receives hot, dry air masses
B
What is the electron carrier that functions in the Krebs cycle? A. NAD+ only B. both NAD+ and FAD C. the electron transport chain D. FAD only
B
What is the main difference between climate and weather? A. Weather typically describes a larger area than climate. B. Climate typically describes longer-term conditions. C. Climate typically describes shorter-term conditions. D. Weather includes temperature, and climate does not.
B
What is the site of synthesis of proteins for export? A. free ribosomes B. ribosomes that attach to the endoplasmic reticulum C. the Golgi complex D. ribosomes that are attached to the outer mitochondrial membrane
B
What is the term used to describe the process shown in the above panels? A. niche realization B. niche differentiation C. species interaction D. competition
B
When does feedback inhibition occur? A. when lack of an appropriate electron acceptor makes an electron transport chain stop B. when an enzyme that is active early in a metabolic pathway is inhibited by a product of the pathway C. when ATP synthase reverses and begins pumping protons out of the mitochondrial matrix D. when cellular respiration is inhibited and fermentation begins
B
When one of the eight Krebs cycle intermediates is added to the respiration medium of living cells, like yeast, what happens to the rates of ATP and carbon dioxide production? A. There would be no change in ATP production but an increased rate of carbon dioxide production. B. The rates of ATP production and carbon dioxide production both increase. C. The rate of ATP production decreases, but the rate of carbon dioxide production increases. D. Rates of both ATP and carbon dioxide production both decrease.
B
Where does the Krebs cycle occur in eukaryotes? A. in the cytoplasm B. in the matrix of mitochondria C. in the inner membrane of mitochondria D. in the intermembrane space of mitochondria
B
Which habitat type covers the largest area on Earth? A. tropical wet forest B. open ocean C. algal beds and reefs D. wetlands
B
Which of the following is not true when comparing an uncatalyzed reaction to the same reaction with a catalyst? A. The catalyzed reaction will be faster. B. The catalyzed reaction will have a different delta G (change in free energy). C. The catalyzed reaction will have lower activation energy. D. The catalyzed reaction will not consume any of the catalyst
B
Which of the following is the best modern definition of evolution? A. descent without modification B. change in allele frequencies in a population over time C. survival of the fittest D. inheritance of acquired characters
B
Why is the electron transport chain also called oxidative phosphorylation? A. Electron carriers are phosphorylated before being oxidized. B. As electrons are transferred, a carrier is oxidized. The process of electron transfer assists in setting up the electrochemical gradient that drives phosphorylation of ATP from ADP. C. Electron transport deals with transport of electrons to carriers of subsequently lower and lower energy levels. The phosphorylation provides the energy for the reactions to take place. D. Water is oxidized and ATP is produced by phosphorylation of ADP.
B
A protein, called pRb (protein for retinoblastoma) is synthesized by a gene (Rb) on chromosome 13 in humans. When mutant or absent in the homozygous state in a retinal cell, there is a high likelihood of developing a cancerous condition of the eye called retinoblastoma. Nonmutant pRb binds with and temporarily inactivates E2F, a transcription factor that stimulates genes to produce proteins that initiate S phase of the mitotic cell cycle (thus, Rb is a negative regulator of cell division). When phosphorylated in response to a variety of normal stimuli, pRb normally releases E2F and cell division is stimulated. Thus, Rb is a tumor suppressor gene. (For a recent review, see H. Liu et al. (2004), "Novel functions of the RB tumor suppressor." Current Opinions in Genetics and Development 14: 55-64. When retinoblastoma occurs in families, the disease tends to have an early onset and express bilaterally (both eyes). When sporadic (spontaneous, not inherited), it tends to show later onset and be unilateral (one eye only). Individuals who inherit a predisposition for the disease are Rb+/Rb- and may get retinoblastoma by having a mutation in the Rb+ allele. Assume that two heterozygous parents have children. One would expect the Rb-/Rb- genotypic combination in a zygote (one-cell stage of an individual) to be characterized as: A. lethal (inviable or lasting a relatively short time) B. completely normal C. having a very low likelihood of developing retinoblastoma D. having unilateral retinoblastoma only
C
As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy? A. It excites electrons of the reaction center of photosystem I and II. B. It is lost as heat. C. It is used to establish and maintain a proton gradient. D. It is used to phosphorylate NAD+ to NADPH, the molecule that accepts electrons from photosystem I and II.
C
Assume that the following polypeptide chain is produced by a wild-type gene in an organism (N and C refer to the amino and carboxyl terminal portions, respectively). The 5' end of the mRNA corresponds to the N or amino terminal portion of the synthesized protein. N-methionine-lysine-tryptophan-leucine-histidine-alanine-glutamic acid-glycine-lysine-C Assume also that a mutation occurred in the coding region of the messenger RNA that coded for this polypeptide such that a base was added between the sixth and seventh bases counting from the 5' end of that mRNA coding region. Without referring to actual codons, what is a likely consequence of such a base addition? A. an alteration of all the amino acids from (and including) glutamic acid through the C terminus B. an alteration of all the amino acids from (and including) glutamic acid through the N terminus C. an alteration of all the amino acids from (and including) tryptophan through the C terminus D. N-methionine-C
C
Assume that you have determined the percentages of bases in DNA samples from a variety of organisms, each having DNA in the customary double-stranded form. What relationships would you expect to find in the percentage data? (Choose all that apply.) A. A = C B. A = G and C = T C. A + C = G + T D. A + T = G + C E. Both B and C are true.
C
Crossing over usually contributes to genetic variation by exchanging chromosomal segments between A. sister chromatids of a chromosome B. chromatids of nonhomologous chromosomes C. non-sister chromatids of homologous chromosomes D. nonhomologous loci of the genome E. autosomes and sex chromosomes
C
DNA is composed of four nucleotides: adenosine, cytosine, thymidine, and guanosine. If scientists introduced radioactive thymidine into the growth medium of the cells, it would be incorporated into the DNA molecule: A. at any point in the cell cycle B. when centromeres split so the two chromosomes can be separated C. during DNA replication D. as the cell enters G1 of interphase
C
Different ratios occur in crosses with single gene pairs or two gene pairs. What types of ratios are likely to occur in crosses dealing with a single gene pair? A. 9:3:3:1, 1:2:1 B. 1:1:1:1, 1:4:6:4:1 C. 3:1, 1:1, 1:2:1 D. 9:7, 12:3:1 E. 15:1, 1:2
C
Double-stranded nucleic acids are said to be antiparallel. What structural configuration is antiparallel? A. The phosphates are attached to the opposite ends of the bases. B. The bases pair A-T in one direction and T-A in the other direction. C. The C-5 to C-3 ribose orientations run in opposite directions on the complementary strands. D. The G-C bases pair in one direction and C-G in the other direction.
C
Fatty acids are typically an even number of carbons. They are catabolized by a process called beta-oxidation. The end-products of the metabolic pathway are two-carbon fragments called acetyl CoA. What is the most likely fate of acetyl CoA? A. It enters the electron transport chain. B. It enters the energy-yielding stages of glycolysis. C. It enters the Krebs cycle. D. It enters the fermentation process.
C
Here is a simplified diagram of several components of the translation machinery. The ribosome is moving from left to right in this figure. Which of the following statements about this diagram is true? A. Letter A points to the mRNA. B. Letter B points to the tRNA. C. Letter C points to the 3' end of the mRNA. D. Letter D points to the ribosome. E. Letter E points to the "N" terminus of the growing polypeptide chain.
C
How many different combinations of maternal and paternal chromosomes can be packaged in gametes made by an organism with a diploid chromosome number of 6 (2n = 6)? A. 2 B. 4 C. 8 D. 16 E. 32
C
If a typical diploid somatic cell has 32 chromosomes, how many chromosomes are expected in each gamete of that organism? A. 32 B. 64 C. 16 D. 0 E. 46
C
In the diagram above, which of the arrows represents the most rapid growth? A. arrow A B. arrow C C. arrow B
C
In the energy-yielding phase of glycolysis, energy is extracted in the form of: A. pyruvate B. carbon dioxide C. NADH and ATP D. phosphorylated intermediates
C
Looking at the figure above, what can be stated about species diversity and latitude? A. As latitude decreases, diversity decreases. B. Species diversity and latitude cannot be compared using this figure. C. As latitude increases, diversity decreases. D. Species diversity is independent of latitude.
C
Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6022 yellow and 2001 green (8023 total). The allele for green seeds has what relationship to the allele for yellow seeds? A. dominant B. incompletely dominant C. recessive D. semidominant
C
Researchers have found fossils of Eocene horse species in Colorado. Deeper deposits contain smaller species, and more recent deposits contain larger species. How does this observation support the theory of evolution? A. It suggests that species are unchanging and of recent origin. B. It proves that environments have changed over time. C. It provides evidence that species change over time. D. It shows that all species are related to each other. E. It does not support the theory of evolution.
C
The absorption spectrum of a plant shows what wavelengths of light the plant absorbs. The absorption spectrum depends on: A. the wavelengths of light that hit the plant B. light that is transmitted by the plant C. the pigments present in the plant D. the thickness of the leaves of the plant
C
This table gives the results of assays of percentages of bases from nucleic acids isolated from different sources. For each source, what type of nucleic acid (RNA or DNA) is most likely specified? State whether it is likely to be single or double stranded. Source A G T C U (1) 20 30 0 10 40 (2) 20 30 20 30 0 (3) 20 20 30 30 0 The nucleic acid from source #3 is _________ and most likely __________. A. RNA; single stranded B. RNA; double stranded C. DNA; single stranded D. DNA; double stranded
C
Twenty different amino acids are found in the proteins of cells. What distinguishes these molecules? A. the location of their carboxyl group B. the location of their amino group C. the composition of their side chains, or R-groups D. their ability to form peptide bonds
C
What is the difference between NAD+ and NADP? A. NAD+ functions as an electron transporter, whereas NADP does not. B. NAD+ functions as a free energy source for cells, whereas NADP does not. C. Both function as electron carriers, but NADP has a phosphate group and NAD+ does not. D. Both transport electrons to the electron transport chain (ETC) found on the inner mitochondrial membrane, but NADP transfers its electrons to the ETC at a higher energy level.
C
What type of interaction is directly responsible for the formation of secondary structure? A. peptide bonds between adjacent amino acids B. peptide bonds between nonadjacent amino acids C. hydrogen bonds between sections of the polypeptide backbone D. hydrogen bonds between side chains of amino acids
C
Which of the following best describes primary structure in proteins? A. It is the number of amino acids present in the complete protein B. It is the number of peptide bonds in the complete protein C. It is the sequence of amino acids in the complete protein D. It is the number of α-helices and -pleated sheets in the complete protein.
C
Which of the following must be true for osmosis to occur? A. Water must be at room temperature or above. B. Solutions with the same concentration of solutes must be separated by a selectively permeable membrane. C. Solutions with the different concentration of solutes must be separated by a selectively permeable membrane. D. Water must be under pressure.
C
Which of the following takes place in the electron transport chain? A. breakdown of glucose to two-pyruvate molecules B. the breakdown of an acetyl group to carbon dioxide C. the extraction of energy from high-energy electrons remaining from glycolysis and the Krebs cycle D. substrate-level phosphorylation
C
Which of these conditions are always true of populations evolving due to natural selection? Condition 1: The population must vary in traits that are heritable. Condition 2: Some heritable traits must increase reproductive success. Condition 3: Individuals pass on all traits they acquire during their lifetime. A. condition 1 only B. condition 2 only C. conditions 1 and 2 D. conditions 2 and 3 E. conditions 1, 2, and 3
C
Why are changes in the global carbon cycle important? A. Carbon is the chief source of food, and burning it reduces available food for primary consumers. B. Global carbon availability is directly related to the water cycle. C. Carbon dioxide is a greenhouse gas, and increasing atmospheric concentrations could alter Earth's climate. D. Carbon can be recycled only a limited number of times.
C
Why don't Na+ ions move across the plasma membrane of neurons and down their concentration gradient all the time? A. The plasma membrane is not permeable to Na+ ions. B. The Na+/K+ pump is required and it only operates when ATP is plentiful C. A Na+ channel is required and it is usually closed. D. A & C. E. A, B, & C.
C
You stumble across a red, yellow, and black banded snake while traveling in Texas. You somehow remember that this could be a poisonous coral snake or a harmless milk snake, but you forget how to differentiate them because they both have similar colors and banding patterns. You wisely decide not to pick up the snake. What defense was successful in preventing you from grabbing the snake? A. constitutive defense B. Müllerian mimicry C. Batesian mimicry D. inducible defenses E. none of the above
C
What event accompanies energy absorption by chlorophyll (or other pigment molecules of the antenna complex)? A. ATP is synthesized from the energy absorbed. B. A carboxylation reaction of the Calvin cycle occurs. C. Electrons are stripped from NADPH. D. An electron is excited.
D
What is the leading hypothesis as to why terrestrial productivity is higher in equatorial climates? A. Productivity increases with temperature. B. Productivity increases with water availability. C. Productivity increases with available sunlight. D. Hypothesis is most likely a combination of A, B, and C.
D
When Mendel crossed yellow-seeded and green-seeded pea plants, all the offspring were yellow-seeded. When he took these F1 yellow-seeded plants and crossed them to green-seeded plants, what genotypic ratio is expected? A. 1:2:1 B. 3:1 C. 9:3:3:1 D. 1:1 E. 1:1:1:1
D
Which is the correct grouping hierarchy for studying ecology of organisms? A. organismal < community < population < ecosystem B. ecosystem < organismal < community < population C. population < organismal < community < ecosystem D. organismal < population < community < ecosystem
D
Which of the following observations is the strongest argument in favor of the hypothesis that protein structure and function are correlated? A. Proteins function best at certain temperatures. B. Proteins have four distinct levels of structure and many functions. C. Enzymes tend to be globular in shape. D. Denatured (unfolded) proteins do not function normally.
D
Which of the following statements regarding altitude and climate is false? A. The presence of mountain ranges tends to produce extremes in precipitation B. Rain shadows may appear on one side of a mountain range C. The higher the altitude, the cooler the climate D. One side of a mountain range always receives large amounts of precipitation
D
Why are the lipid bilayers in cells called "selectively permeable"? A. They are not all that permeable. B. Their permeability changes with their molecular composition. C. Their permeability is temperature dependent. D. They are permeable to some substances but not others.
D
You have a distant cousin, age 4, who is always tired and fatigued and is not able to play games and sports like other healthy children. He is most likely to have an enzyme deficiency or defect associated with which intracellular organelle? A. lysosomes B. Golgi stacks C. smooth endoplasmic reticulum D. mitochondria
D
A bacterial protein is 300 amino acids long. Remembering that DNA is typically double stranded, which of the following could be the number of nucleotides in the section of DNA that codes for this protein? A. 3 B. 100 C. 300 D. 500 E. 1800
E
A particular protein is 400 amino acids long. How many nucleotide base pairs in the template strand of DNA are required to code for this protein? A. 3 B. 100 C. 300 D. 600 E. 1200
E
Detritus can be consumed by which of the following primary decomposers? A. bacteria B. archaea C. fungi D. earthworms E. all of the above
E
In Drosophila melanogaster, vestigial (short) wings (vg) are caused by a recessive gene that independently assorts with a gene pair that influences body hair. Hairy (h) results in a hairy body. A cross is made between a fly with normal wings and a hairy body and a fly with vestigial wings and a normal body. The phenotypically normal F1 flies were crossed among each other, and 1024 F2 flies were reared. What phenotypes would you expect in the F2, and in what actual numbers (not ratio) would you expect to find them? A. phenotypes—all wild; numbers expected—wild (1024) B. phenotypes—hairy, vestigial hairy; numbers expected—hairy (512), vestigial hairy (512) C. phenotypes—wild, vestigial, hairy, vestigial hairy; numbers expected—wild (256), vestigial (256), hairy (256), vestigial hairy (256) D. phenotypes—wild, vestigial; numbers expected—wild (576), vestigial (576) E. phenotypes—wild, vestigial, hairy, vestigial hairy; numbers expected—wild (576), vestigial (192), hairy (192), vestigial hairy (64)
E
In tigers, a recessive allele causes a white tiger (virtual absence of fur pigmentation). If two phenotypically normal tigers that are heterozygous at this recessive gene are mated, what percentage of their offspring are expected to be white? A. 50% B. 75% C. about 66% D. about 90% E. 25%
E
Phenylketonuria is an inherited disease caused by a recessive autosomal allele. If a woman and her husband are both carriers, what is the probability that their first child will be a phenotypically normal girl? A. 1/4 B. 1/16 C. 1.0 D. 3/16 E. 3/8
E
The specific abiotic factors defining a biome are A. maximum annual temperature and moisture levels B. average annual temperature and moisture levels C. annual variation in temperature and precipitation D. both A and B E. both B and C
E
Which of the following is NOT TRUE about Na+ ion channels? A. They are proteins. B. They are embedded in the plasma membrane. C. They allow Na+ ions to move down their concentration gradient. D. They require energy in order to move Na+ ions. E. They undergo a conformational change to open or close
E
Which of the following is NOT TRUE about the Na+/K+ pump? A. It is a protein. B. It moves Na+ ions against their concentration gradient. C. The hydrolysis of ATP results in the Na+/K+ pump changing what side of the plasma membrane it is open to. D. The hydrolysis of ATP results in the Na/K+ pump changing its affinity for Na+ ions. E. The pump has a high affinity for Na+ ions when it is open to the outside of the cell.
E
A human somatic (body) cell normally contains 46 chromosomes. How many chromosomes would be expected in a male's meiotic prophase I cell? A. 23 B. 92 C. 46 D. 46 autosomes plus an X and Y chromosome E. 23 chromosomes plus a Y chromosome
not A
A protein, called pRb (protein for retinoblastoma) is synthesized by a gene (Rb) on chromosome 13 in humans. When mutant or absent in the homozygous state in a retinal cell, there is a high likelihood of developing a cancerous condition of the eye called retinoblastoma. Nonmutant pRb binds with and temporarily inactivates E2F, a transcription factor that stimulates genes to produce proteins that initiate S phase of the mitotic cell cycle (thus, Rb is a negative regulator of cell division). When phosphorylated in response to a variety of normal stimuli, pRb normally releases E2F and cell division is stimulated. Thus, Rb is a tumor suppressor gene. (For a recent review, see H. Liu et al. (2004), "Novel functions of the RB tumor suppressor." Current Opinions in Genetics and Development 14: 55-64. When retinoblastoma occurs in families, the disease tends to have an early onset and express bilaterally (both eyes). When sporadic (spontaneous, not inherited), it tends to show later onset and be unilateral (one eye only). Individuals who inherit a predisposition for the disease are Rb+/Rb- and may get retinoblastoma by having a mutation in the Rb+ allele. Assume that two heterozygous parents have children. One would expect the Rb-/Rb- genotypic combination in a zygote (one-cell stage of an individual) to be characterized as: A. lethal (inviable or lasting a relatively short time) B. completely normal C. having a very low likelihood of developing retinoblastoma D. having unilateral retinoblastoma only
not B or C