142 terms

Bio Test Questions

Why are some reactions exergonic?
•They are spontaneous
•The products have lower potential energy than the reactants
The movement of kinesin along a microtubule track is an ___________ reaction
If in a graph the Products are greater than the Reactants, what type of reaction is it?
What is the most likely result of a endergonic reaction?
•A phosphorylation reaction must be coupled to a hydrolysis reaction to generate the required energy.
•The electrons shared in the chemical bonds are held closer to the nuclei of the atoms with more protons.
Consider the diffusion of O₂ into a spherical single-celled organism. Using Fick's Law of Diffusion, what would yield the greatest decrease in the rate of diffusion?
Double the thickness of the cell membrane
The air is thinner at higher elevations, so there is less O₂ and CO₂ in the atmosphere than at sea level. Using what you know about cellular respiration and Fick's Law, how will gas exchange differ for a person at sea level, compared to the same person at high elevation?
Harder to diffuse O₂, easier to diffuse CO₂ at high elevation
What is NOT a good strategy for increasing the surface area relative to the volume?
Enlarge and make more spherical
Referring to a round organism compared to a stringed out one, assume the volume of each cell is equal, and that the only way in which they differ is their shapes. Which of these organisms has a higher surface-area to volume ratio?
Stringed out organism
What is a true statement about body size and physiology?
Small and Large animals face different physiological challenges because an animal's body mass increases cubically while its surface area increases as a squared function.
Two membranes filled with salt water are placed into separate tanks that are filled with water that has NO dissolved salt. Container 1 is rectangular (h=4, l=2, w=2), SA=2(lw+wh+lh), V=lwh. Container 2 is a cylinder (h=4, r=1), SA=2πrh+2πr², V=πr²h. So From which of these containers will the salt diffuse faster?
Calculate SA of Container 1 and Container 2.
Container 1 is 40, Container 2 is ≈ 31.
Therefore since the SA of Container 1 is greater, salt will diffuse from it faster.
Given the lungs of two species, one lung has more folds than the other, which do you predict will have the higher rate of O₂ uptake?
The lung which has more folds.
Under predicted climate change scenarios, in certain areas local water availability is expected to decrease while CO₂ levels are expected to increase. How could this affect the rate of photosynthesis?
•It could decrease the light dependent reaction
•It could decrease both the light dependent and light independent reactions
Where would you expect to find most of the chlorophyll in a plant?
Why do plants use the ATP from the light dependent reaction for the light independent reaction, instead of using it directly in metabolism?
Plants need to store carbohydrate for times when light energy is not available.
An oak tree starts from a very small acorn and grows to heights of > 60 feet. What is the source of that increase in plant material (e.g., wood, leaves, etc.) as it grows?
What is the flow of energy from solar energy to work done in the cell?
Sun->Photosynthesis->Glucose->Cellular Respiration->ATP
What does light energy do to a chlorophyll molecule that allows the energy to be stored in glucose?
Raises the energy state of its electrons
Imagine a mutation that resulted in an individual plant lacking carotenoids. What do you predict would happen to the rate of photosynthesis in that plant?
Decrease, because less solar energy is passed to chlorophyll
Which of the following best characterizes the effect of carbon fixation by photosynthetic organisms on Earth's atmosphere?
CO₂ content decreased
The stroma is the site of __________
the light independent reactions
What is a difference between plants and animals?
Plants typically possess chloroplasts; most animals do not.
A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen when an athlete exhausts her ATP supply?
Cellular respiration is required to generate more ATP
What most accurately relates glucose and ATP?
Energy stored in glucose is transferred to ATP for use in the cell
In the absence of free CO₂, what reaction would not be possible?
Light Independent reaction of photosynthesis
If aerobic respiration makes the most ATP, why would an organism use something different?
There are places on Earth where O₂ is not available
You have been asked to determine if a specimen represents extraterrestrial life. Given what you know about the characteristics that organisms on Earth share, what would allow you to determine conclusively that the organism was extraterrestrial?
If it was not composed of cells
What feature of the alveoli of mammal lungs maximizes the A term of Fick's Law of Diffusion with respect to O₂ diffusion into the body?
Each lung contains 150 million alveoli
The lungs of mammals have around forty times the SA of the lungs of an equivalently sized frog. Why do mammals need this type of lung?
mammals have a higher mass specific basal metabolic rate
The gills of fish have the same general function as what anatomical structure in humans?
The main difference between respiration in terrestrial insects and in terrestrial vertebrates is that _______
The insects rely on their tracheal system to deliver oxygen in air to their tissues, whereas the vertebrates rely on blood in their circulatory system to deliver oxygen obtained by the lungs to their tissues.
How do lungless salamanders obtain oxygen from their environment?
From the air through their skin
True or False: Epithelial tissue is found in mammals, amphibians, and bacteria.
True or False: The contraction of the diaphragm in mammals decreases the volume of the chest cavity.
Which type of animal tissue consists of cells loosely arranged in an extracellular matrix?
When comparing a mouse to an elephant, the mouse has a _____ SA/V ratio and a _____ mass-specific basal metabolic rate.
higher; higher
An elephant and a mouse are running in full sunlight, and both overheat by the same amount above their normal body temperatures. When they move into the shade and rest, which animal will cool down faster?
The mouse will because it has the higher SA/V ratio.
Which of the following differences would you expect between an ectotherm and an endotherm of equal size?
the ectotherm produces CO₂ at a lower reate than the endotherm
Which of the following is NOT an advantage of having a high-pressure circulatory system?
reduces the thickness of the barrier to diffusion
The pulmonary vein carries _____ blood
low pressure
The left ventricle pumps blood ______
to the body
The interior/superior vena cava carries ____ blood
In a fish, the blood pumped to the cells of the body is generally _________?
low pressure
What statement is False?
The blood in the right atrium has just entered the heart from the lungs
Why do the circulatory systems of land vertebrates have separate circuits: one to the lungs and the other to the rest of the body?
The decrease in blood pressure as blood moves through the lungs may prevent efficient circulation to the rest of the body.
What feature of the capillaries of a mammal CAUSES the rapid decline in blood pressure as blood moves from the arteries to arterioles to capillaries?
The total cross-sectional area of capillaries is much larger relative to that of arteries
With respect to O₂ diffusion into the cells of the body, the heart of which group of organisms best maximizes the (P₂-P₁) term of Fick's Law of Diffusion?
Which of the following groups of organisms have both pulmonary and systemic circuits of their circulatory system?
Both Frogs and Mammals
Which of the following statements is true?
A silent mutation always changes one codon to another
Which statement indentifies a fundamental difference between mitosis and meiosis? (assume no mutation)
Mitosis creates identical daughter cells, meiosis creates new variation
What would not be observed in a diploid organism cell during the normal process of meiosis?
A cell with many chromosomes, while various chromosomes should be connected by the centromere because they are homologous and shouldn't be separated in a single cell.
What distinguishes one chromosome type from another?
the genes they contain
In meiosis 1 what effect on the ploidy level of the cell occurs?
decreases ploidy level
In meiosis 2 what effect on the ploidy level of the cell occurs?
does not change ploidy level
In fertilization what effect on the ploidy level of the cell occurs?
increases ploidy level
When a plant self-fertilizes, why don't the seeds have exactly the same genotype as the parents?
Independent Assortment
What type of error cause trisomy on chromosome 11?
The figure is of a karyotype of a mouse with trisomy 11. During which stage of cell division did the error that lead to this trisomy originate?
•Meiosis I
•Meiosis II
Consider a diploid organism with n=4. What's occurring in a cell that represents a cell of an organism that is just about to begin meiosis II?
A cell with connected homologous pairs of chromosomes.
Two female insects each produce 10 offspring. One does so via asexual reproduction one does so through sexual reproduction. The sexually produced offspring will all have _______ genotypes and the asexually produced offspring will all have ______ genotypes.
different; identical
Which of the following creates combinations of chromosomes in an organism's gametes that are different from the combinations that were present in either the maternal and paternal gametes that united to form the organism in the first place?
independent assortment
What is genetic recombination?
the new combination of maternal and paternal chromosome segments that results when homologs crossover
Between what stage does the ploidy level of a cell change?
Between interphase and prophase, and anaphase and telophase/cytokinesis
How many chromosomes would be present in each gamete if a cell containing 6 chromosomes completed meiosis?
3 unreplicated chromosomes
There is a diploid species of ant that has a single chromosome type (n=1). Given that, which of the following is NOT possible in this ant species?
Independent Assortment
How many distinct combinations of eye-color and hair-color alleles are possible in the gametes of an organism which has four chromosomes, two which contain eye genes, and two which have hair genes?
four combinations
Which of the following is NOT part of an organism's phenotype?
Nucleotide sequence
Why do most mutations occur?
random errors during DNA replication
A substitution changes a single nucleotide from C to T. What effect can this have?
It can cause a nonsense mutation
Which of the following is most likely to have the greatest effect on the protein product of a protein-coding gene?
a nonsense substitution near the beginning of the gene
Father's genotype: AABBCCDDEE
Mother's genotype: aabbccddee
How many UNIQUE genotypes of gametes can the father produce?
Father's genotype: AABBCCDDEE
Mother's genotype: aabbccddee
How many UNIQUE genotypes of offspring can this mating pair produce?
Father's genotype: AABBCCDDEE
Mother's genotype: aabbccddee
How many UNIQUE genotypes of gametes can the offspring of a mating between this pair produce?
What process is responsible for the segregation of alleles (i.e., Mendel's Law of Segregation)?
meiosis I
Genes XRCC6 binding protein 1 and XPA binding protein 2 are both found on the X chromosome of humans. Which statement best describes their relationship?
They are linked to one another and sex-linked
Why are X-linked conditions such as hemophilia more often observed in males than females?
Males only have one X chromosome
A gamete with a single chromosome has two genes on it. Which of the following is NOT possible for alleles of the two genes indicated by the bars?
independent assortment
A male and female both have wet earwax. Both of these individuals have a parent with dry earwax. Wet is dominant to dry. What is the probability that the first child of the couple will have dry earwax?
•Parents have to be hetero, thus a homo rec. will be 1/4. Since dry earwax is recessive, the probability is 0.25
In cats, the Manx (M) allele causes a short or absent tail, while a recessive allele confers a normal, long tail. Cats of genotype MM are never born alive. If two Manx cats mate, what proportion of living offspring will have long tails?
Since MM is dead, there are only 3 possibilities. So a homo rec. is 1/3 chance of occurring in the offspring.
In a chromosome which contains two genes close to another and two farther apart from another, between which pair of genes would you expect to observe the LOWEST frequency of recombination of alleles?
Between genes A and B
A woman is about to deliver triplets. If each child is the product of an independent fertilization event, what is the probability that all of her babies will be of the same gender (i.e., she will deliver EITHER all girls or all boys)?
.5•.5•.5= 1/8 = 0.125
1/2 chance of getting a boy or girl.
On a Punnett square, what do the letters used as column and row headings represent (e.g., TB, Tb, tB, and tb)?
Gamete genotypes
Given parental genotypes of TtBb, in a Punnett square what proportion of the offspring have a phenotype that is DIFFERENT from either parent? Assume that capital letters represent the dominant allele and that the genes are on different chromosome types.

Count phenotypes not similar to parents in Punnett Square
A particular genetic disorder is caused by two separate, unlinked genes (Genes A and B). To have the disorder, a person must be homozygous recessive for BOTH of these genes. A mother is heterozygous for Gene A and homozygous recessive for Gene B. The father is heterozygous for gene Gene A and homozygous dominant for Gene B. If they have two children, what is the probability that one of them will have this disorder?
Do a cross of Aa x Aa, chance of getting aa = 1/4.
Do a cross of BB x bb, chance of getting bb = 0
1/4 x 0 = 0.0
A biologist was studying an organism with only two pairs of homologous chromosomes. This biologist was also studying the inheritance of the following three traits: height (tall or short), color (blue or green) and weight (heavy or light). Assume each trait is controlled by a single, distinct gene. Which of the following could you most confidently conclude about this organism?
Alleles of at least two of these genes will not assort independently.
In a plant, the allele that results in violet flowers (V) is dominant to one that results in white flowers (v); at another locus, the allele that makes prickly seed capsules (P) is dominant to one that results in smooth capsules (p). A plant with white flowers and prickly capsules is crossed with one that has violet flowers and smooth capsules. The resulting seeds were planted and yielded 47 plants with white flowers and prickly capsules, 45 plants with white flowers and smooth capsules, 50 plants with violet flowers and prickly capsules, and 46 plants with violet flowers and smooth capsules. What are the genotypes of the two parents?
Vvpp and vvPp
When a brown male guinea pig was mated with a white female, eight offspring were produced. Six of the offspring were white and the others were brown. The gene controlling fur color (i.e., either brown or white) is located on a single pair of homologous chromosomes. What are the possible genotypes of the eight offspring? (Assume brown is dominant.)
Aa and aa only
Imagine an individual organism with the dominant version of a two different traits. Presuming enough offspring were produced, the genotype of this organism could be determined with certainty by mating it with another individual with what genotype?
homozygous recessive for both genes
A mother and father, who are both carriers for a rare, recessive autosomal disorder, have three children without the disorder. What is the probability their NEXT child will have the disorder?
In birds, sex is determined by a ZW chromosome scheme that is much like the typical XY scheme seen in humans and many other organisms, except that the system is reversed: Males are ZZ (similar to XX in humans) and females are ZW (similar to XY in humans). A lethal recessive allele that causes death of the embryo occurs on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male heterozygous for the lethal allele and a female with the normal phenotype?
2:1 male to female
A father that is homozygous dominant for Gene 1, and heterozygous for Gene 2. The mother is heterozygous for Gene 1, but homozygous recessive for Gene 2. How many unique genotypes and phenotypes are possible in their offspring?
4 genotypes; 2 phenotypes
Consider a cross between two pea plants with the following genotypes: YyPpRrLl x YYPprrll
Y=yellow seeds, y=green seeds
P=purple flowers, p=white flowers
R=round seeds, r=wrinkled seeds
L=long stems, l=short stems
What is the proportion of yellow seeded, purple flower, wrinkled seed, short stemmed offspring?
Consider a cross between two pea plants with the following genotypes: YyPpRrLl x YYPprrll
Y=yellow seeds, y=green seeds
P=purple flowers, p=white flowers
R=round seeds, r=wrinkled seeds
L=long stems, l=short stems
What is the proportion of offspring with all dominant phenotypes?
Consider a cross between two pea plants with the following genotypes: YyPpRrLl x YYPprrll
Y=yellow seeds, y=green seeds
P=purple flowers, p=white flowers
R=round seeds, r=wrinkled seeds
L=long stems, l=short stems
What is the proportion of offspring with all recessive phenotypes?
Which of the following provides an explanation for why natural selection does not produce "perfect" adaptations?
Natural selection is limited by the existing variation within a population
In the United States, about half of the corn crop is genetically engineered to produce a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for the corn borer to evolve resistance to the toxic protein?
The corn borer population must have one or more alleles that convey resistance to the toxic protein.
What causes insecticides (man-made chemicals intended to kill pest insects) to become less effective over time?
Regular use of an insecticide kills almost all individuals except those with alleles that allow them to tolerate the insecticide.
In a field of pea plants, 50% of plants have purple flowers and 50% have white flowers. Flower color is determined by a single gene with two alleles. Homozygous dominant and heterozygous individuals have purple flowers, homozygous recessive individuals have white flowers. A rabbit family that eats just purple flowers, move into the field. When a rabbit finds a purple-flowered plant, it eats all the flowers on that plant. Although the plant survives, it produces no seeds. After many years...
Only white-flowered pea plants remain in the field.
What prevents natural selection from favoring the increase of "self-sacrificing" alleles?
Individuals with alleles for these traits would have low (or zero) fitness
What is an adaptation?
A trait that improves fitness, relative to those without the trait.
What would you expect if an environment changed so that individuals with a snout-vent length of 140 mm were favored, while 170-200mm are currently favored.
Average size would decrease
How would you distinguish heritable variation from variation that is not heritable?
Alleles for variation that is heritable are passed from parents to offspring
In a graph the was a bell curve, and the later the graph had stabilizing selection occur. So what can you conclude regarding relative fitness of individuals in this population?
Individuals of intermediate fur color have the highest fitness.
In a pop. of guppies, body color is genetically determined. You find that the more brightly colored males are more likely to be eaten by predators than those with drab colors. You also find that the most brightly colored individuals have higher fitness than those with drab colors. Which of the following is a likely explanation of why brightly colored males are maintained in this population?
Female guppies prefer to mate with brightly colored males
You are studying a population of flowers where flower color is determined by a single gene. Individuals that are AA have red flowers, Aa individuals have pink flowers and aa individuals have white flowers. By what process did this variation originate?
random mutation
Which of the following is a prediction fo the Hardy-Weinberg principle?
Expected genotype frequencies can be determined from allele frequencies
The Hardy-Weinberg equation is p²+2pq+q²=1. What does the fact that the genotype frequencies add up to 1.0 demonstrate?
That the frequencies of each genotype have been determined correctly
A particular recessive genetic disorder is fatal before birth, so there are no homozygous recessive individuals. In a particular population, one in 15 individuals is a carrier for this disorder. What are the allele frequencies of the dominant (p) and recessive (q) alleles in this population?
p=0.967, q=0.033
What genotype frequencies are expected under Hardy-Weinberg equilibrium for a population with allele frequencies of p=0.81 and q=0.19 for a particular gene?
AA=0.656, Aa=0.308 and aa=0.036
Which of the following is NOT an example of a quantitative trait?
flower color of pea plants (purple or white)
Which of the following (by itself) will NOT change allele frequencies of a single gene within a population?
Sexual Reproduction
Pop. 1 : p=1, q=0
Pop. 2 : p=0.5 q= 0.5
Pop. 3 : p= 0 q=1
Use the information on allele frequencies in three populations to select the correct statement.
Population B has more genetic diversity than does population C
How can fitness (in context of natural selection) be estimated in a real population?
Count the number of offspring produced by different individuals in a population
A particular recessive genetic disorder is fatal before birth. You find the allele frequency for this recessive allele in a population is 0.02. Where are these recessive alleles found in this population?
Heterozygous individuals
Why does natural selection prevent a population from remaining in Hardy-Weinberg equilibrium?
Certain alleles increase in frequency because they increase reproductive success
Which of the following best defines biological evolution within a population?
Change in allele frequencies over time
Monkey flowers living near the sites of copper mines can grow in soil containing high concentrations of copper, which is toxic to most plants. Copper tolerance is a heritable trait, and in several sites near old copper mines, the allele conferring copper tolerance has become fixed. Which statement is correct?
Prior to mining, the population contained both copper-tolerant and copper-intolerant plants.
How do sexual selection and inbreeding differ?
Sexual selection can change allele frequencies, inbreeding cannot
Which of the following is true about inbreeding?
It leads to the gradual loss of the heterozygous genotype
Which of the following increases the amount of gene flow?
Which of the following processes can introduce new alleles into a population?
Gene flow
In a population of an endangered species living in a zoo, genetic disorders have become more common in the past 20 years. to reduce the effect of these genetic disorders on their population, the zoo begins a breeding program with another zoo across the country. The two zoos exchange individuals, with each zoo sending half of their population to the other zoo. Which process makes this a successful program?
Gene flow
Using the biological species concept, new species arise due to
termination of gene flow between populations
A defining characteristic of allopatric speciation is
Geographic Isolation
A species of seagulls exists as a large number of different populations on separate islands of the Azores archipelago. Both black and white gulls are present. The black-colored seagulls is due to a dominant allele (M). Mm and MM individuals are black, and mm individuals are white. During a storm, two males and two females are blown 300 miles West, to an isolated island uninhabited by seagulls. They reproduce and found a new population. They cannot disperse back to the original habitat, nor can any new seagulls cross to the new island. All four original colonists were white-colored gulls.
What is the frequency of the recessive (m) allele in this new population?
The difference in allele frequencies between the new population and the old populations is due to which evolutionary phenomenon?
genetic drift
Over the course of the next 200 years, gulls in this new population evolved mating displays that differ from those of the parent population. When a second group of the original Azores archipelago gulls are introduced to this new island, the two kinds gulls find each other's mating behavior objectionable, and do not interbreed.
What type of isolation mechanism keeps the two species of gulls from interbreeding?
Behavioral Isolation
Over the course of the next 200 years, gulls in this new population evolved mating displays that differ from those of the parent population. When a second group of the original Azores archipelago gulls are introduced to this new island, the two kinds gulls find each other's mating behavior objectionable, and do not interbreed.
What type of evolutionary event has occurred?
Allopatric speciation
Orchids of the genus Cryptostylis produce flowers that look and smell like female wasps. When a male wasp visits and attempts to mate with the flower (thinking it is a female wasp), the mating action results in pollination of the orchid. Different species of Cryptostylis look and smell like different species of wasp. What isolating mechanism has facilitated speciation of Cryptostylis?
Mechanical Isolation
Two populations of birds live on opposite sides of an island. The habitat between the populations is not suitable for these birds. Individuals from the two populations occasionally interbreed with another, but their offspring CANNOT breed with each other, nor with birds from either parent population. The two populations are _______
Reproductively isolated by postzygotic isolation
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. In each case, match various descriptions of frogs below with the appropriate reproductive barrier listed.
Males of one species sing only when its predators are absent; males of another species sing only when its predators are present.
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. In each case, match various descriptions of frogs below with the appropriate reproductive barrier listed.
One species mates at the season when daylight is increasing from 13 hours to 13 hours and 15 minutes; another species mates at the season when daylight is increasing from 14 hours to 14 hours and 15 minutes.
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. In each case, match various descriptions of frogs below with the appropriate reproductive barrier listed.
Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?
hybrid inviability
Which of the following is consistent with sympatric speciation?
A population of ants that live on the branches trees do not interbreed with a population that lives in nests under the tree's roots.
A researcher notices that in a certain moth species, some females prefer to feed and lay eggs on domesticated plants like potatoes and tomatoes. Other females prefer to feed and lay eggs on wild plants. Both male and female moths primarily use scent to find these plants from afar. Females tend to mate where they feed, and the researcher finds a genetic basis for scent preferences in these moths. Based on the above information, what might be occurring in this moth species?
Divergence in sympatry
Two groups of lizards that have long been living in allopatry have recently come into secondary contact. When individuals of one group mate with individuals of the other, the hybrids are almost always inviable. Which of the following could be expected to occur over the long term if the populations remain in sympatry?
Behavioral forms of isolation will develop
Imagine two North American ground cricket species that contact each other as the southern species moves northward during a period of global warming.These two species do not mate much, due to differences in their courtship songs. The northern cricket does not seem to tolerate the warmer temperatures well but is limited in its ability to move north because it does not normally disperse much. Based on this information, which is the most likely outcome?
Extinction of one of the species
Imagine a single population of forest monkeys is physically into two populations by a change in the course of a river. After this physical division occurs, which of these mechanisms can make these two populations into distinct species?
Natural Selection
What is reinforcement?
natural selection against interbreeding and production of hybrid offspring
In which of the following scenarios is the rapid fixation of an allele most likely?
A small population of plants that establish themselves on an island previously uninhabited by this plant
Why does genetic drift violate the assumptions of the Hardy-Weinberg principle?
Genetic drift causes offspring allele frequencies to differ from those of their parents
A small population of wolves was reintroduced to southern New Mexico 20 years ago. Within the population at that time were two different alleles (A₁ and A₂) for a particular gene that affects coat color. A recent analysis shows that there is only one allele (A₂) in that population today, after only three generations. Which of the following mechanisms are potential reasons for this observation?
Natural selection AND/OR genetic drift
A virus killed most the seals in the North Sea (e.g., reduced the population from 8000 to 800). What is this an example of?
Population Bottleneck