|In most stable freshwater environments,|
populations of Daphnia are almost entirely female and reproduce asexually. However, males are observed in low oxygen environments or when food is scarce. Based on these observations, a researcher suggests that male Daphnia develop in response to unfavorable environmental conditions. This is an example of a
|Two students were testing the amount of|
fertilizer that would best promote the growth of strawberries in a garden. Which of the following could be an unavoidable source of experimental error?
A length of the study
B variation in the strawberry plants
C the cost of watering the plants
D fertilization during the study
|D fertilization during the study|
| Which of the following best describes the use of|
population models in biology?
A They are generally easy to construct.
B They can represent reality precisely.
C They are used when no observations have
been made. D They can help predict outcomes.
|A They are generally easy to construct|
|A computer model of cellular mitosis|
can simulate the aspects of cellular division quite well. However, microscopic observation of actual cellular mitosis can improve understanding because actual observations
A may reveal greater unknown complexities.
B are easier than a computer model to view.
C are the same each time.
D may provide division events in sequence.
|A may reveal greater unknown complexities.|
| After a volcanic eruption has covered an area|
with lava, which of the following is the most likely order of succession in the repopulation of the area?
A lichens →grasses →shrubs →trees
B mosses →grasses →lichens →trees
C grasses →trees →mosses →lichens
D shrubs →grasses →trees →lichens
| Which information was most important to the development of genetic engineering techniques?|
A the observation of nondominant alleles
B the discovery of lethal genes
C the formulation of Punnett squares
D the structure of a DNA molecule
|D the structure of a DNA molecule|
| The cell membrane of the red blood cell|
will allow water, oxygen, carbon dioxide, and glucose to pass through. Because other substances are blocked from entering, this membrane is called
|The plasma membrane of a cell consists of|
A protein molecules arranged in two layers with polar areas forming the outside of the membrane.
B two layers of lipids organized with the nonpolar tails forming the interior of the membrane.
C lipid molecules positioned between two carbohydrate layers.
|B two layers of lipids organized with the nonpolar tails forming the interior of the membrane|
|What causes tomatoes to ripen much more|
slowly in a refrigerator than they do if left on a table at room temperature?
A Tomatoes need sunlight to ripen.
B Humidity accelerates the ripening process.
C Low temperatures reduce the action of
D Enzymes produced by bacteria inhibit ripening.
|C Low temperatures reduce the action of ripening enzymes|
|There are many different enzymes located in|
the cytoplasm of a single cell. How is a specific
enzyme able to catalyze a specific reaction?
A Different enzymes are synthesized in specific areas of the cytoplasm.
B Most enzymes can catalyze many different reactions.
C An enzyme binds to a specific substrate (reactant) for the reaction catalyzed.
D Enzymes are transported to specific substrates (reactants) by ribosomes.
|C An enzyme binds to specific substrate (reactant) for the reaction catalyzed.|
| Some snake venoms are harmful because they|
contain enzymes that destroy blood cells or tissues. The damage caused by such a snakebite could best be slowed by
A applying ice to the bite area.
B drinking large amounts of water.
C inducing vomiting.
D increasing blood flow to the area.
|A applying ice to the bite area|
| Maltose can be broken down into glucose|
molecules by the enzyme maltase. Which of the following would slow the reaction rate?
A adding maltase
B adding maltose
C removing glucose
D diluting with water
|D diluting with water|
| Eukaryotic cells are differentiated from|
prokaryotic cells because eukaryotic cells
A are much smaller.
B have permeable membranes.
C have a higher rate of reproduction.
D have nuclei.
|D have nuclie.|
| Which cellular organelle is responsible for|
packaging the proteins that the cell secretes?
B cell membrane
D Golgi apparatus
|D Golgi apparatus|
| Which molecule in plant cells first captures|
the radiant energy from sunlight?
B carbon dioxide
D adenosine triphosphate
| The first stage of photosynthesis in a|
| A cell from heart muscle would probably|
have an unusually high proportion of
D Golgi bodies.
| In aerobic respiration, the Krebs cycle|
(citric acid cycle) takes place in
|Which of the following statements correctly|
A Cells divide only once during meiosis.
B Meiosis does not occur in reproductive cells.
C The cells produced at the end of meiosis are genetically identical to the parent cell.
D The cells produced at the end of meiosis contain half the number of chromosomes as the parent cell.
|D The cells produced at the end of meiosis contain half the number of chromosomes as the parent cell.|
| Which of the following best describes meiosis?|
A It is carried out in all tissues that require cell replacement.
B It occurs only in cells in the reproductive structures of the organism.
C It happens in all tissues except the brain and spinal cord.
D It is the first stage of mitosis.
|B It occurs only in cells in the reproductive structures of the organism.|
| If a corn plant has a genotype of Ttyy,|
what are the possible genetic combinations that could be present in a single grain of pollen from this plant?
A Ty, ty
B TY, ty
C TY, Ty, ty
D Ty, ty, tY, TY
|A Ty, ty|
| Which of the following sequences represents|
chromosome number during fertilization?
B 2n →n+n
C n →n
D 2n →2n
| Based only on the sex chromosomes in typical|
human egg and sperm cells at fertilization, the
probability of producing a female is
| In fruit flies, the gene for red eyes (R) is|
dominant and the gene for sepia eyes (r) is recessive. What are the possible combinations of genes in the offspring of two red-eyed heterozygous flies (Rr)?
A RR only
B rr only
C Rr and rr only
D RR, Rr, and rr only
|D RR, Rr, and rr only|
| In certain breeds of dogs, deafness is due|
to a recessive allele (d) of a particular gene, and normal hearing is due to its dominant allele (D). What percentage of the offspring of a normal heterozygous (Dd) dog and a deaf dog (dd) would be expected to have normal hearing?
|If a human baby boy inherits a recessive allele|
from his mother, in which circumstance would he most likely show the trait coded for by the recessive allele?
A The baby inherits the dominant allele from his father.
B The allele is on an autosomal chromosome and the baby is a twin.
C The allele is on the X chromosome.
D The allele is on the Y chromosome.
|C The allele is on the X chromosome.|
|Mendel hypothesized that reproductive|
cells have only one factor for each inherited trait. This hypothesis is supported by the observation that
A haploid cells are produced by mitosis.
B diploid cells are produced by mitosis.
C haploid cells are produced by meiosis.
D diploid cells are produced by meiosis.
|C haploid cells are produced by meiosis|
| Complete burning of plant material returns carbon primarily to the|
| Which of these organisms are most helpful in preventing Earth from being covered with the bodies of dead organisms?|
C parasites and viruses
D fungi and bacteria
|D fungi and bacteria|
| Which of these organisms would most likely be found at the top of an energy pyramid?|
| Which of these organisms would most likely be found at the bottom of a biomass pyramid?|
A giant squids
B sand sharks
C sea cucumbers
D green algae
|D green algae|
| Which of these would have the least effect on|
natural selection in a subspecies of giraffes that is geographically isolated from other subspecies of giraffes?
A available niches
B existing predators
C chromosome number
D available food resources
|C chromosome number|
|In carrier pigeons there is a rare inherited|
condition that causes the death of the chicks before hatching. In order for this disease to be passed from generation to generation there must be parent birds that
A are heterozygous for the disease.
B have the disease themselves.
C produce new mutations for this disease.
D are closely interbred.
|A are heterozygous for the disease.|
|A healthy individual is a carrier of a lethal|
allele but is unaffected by it. What is the probable genotype of this individual?
A two dominant normal alleles
B one recessive lethal allele and one dominant lethal allele
C one recessive lethal allele and one dominant normal allele
D one dominant lethal allele and one recessive normal allele
|C one recessive lethal allele and one dominant normal allele|
|A genetic disorder due to a recessive allele (a)|
is lethal in homozygous individuals (aa), whereas heterozygous individuals (Aa) have no symptoms. Based on this information, which of the following is likely to result?
A The disorder will quickly be eliminated since no recessive homozygotes will survive to reproduce.
B The disorder will be maintained in the population through the reproduction of heterozygotes.
C Only homozygous dominant (AA) individuals will survive.
D The prevalence of the disorder will increase over time.
|B Te disorder will be maintained in the population through the reproduction of heterozygotes.|
| Mutations within a DNA sequence are|
A natural processes that produce
B natural processes that always affect the phenotype.
C unnatural processes that always affect the phenotype.
D unnatural processes that are harmful to genetic diversity.
|A natural processes that produce genetic diversity.|
|Which of these best illustrates natural|
A An organism with favorable genetic variations will tend to survive and breed successfully.
B A population monopolizes all of the resources in its habitat, forcing other species to migrate.
C A community whose members work together utilizes all existing resources and migratory routes.
D The largest organisms in a species receive the only breeding opportunities.
|A An organism with favorable genetic variations will tend to survive the breed successfully.|
|A species of finch has been studied on one of|
the geographically isolated Galapagos Islands for many years. Since the island is small, the lineage of every bird for several generations is known. This allows a family tree of each bird to be developed. Some family groups have survived and others have died out. The groups that survive probably have
A interbred with other species.
B inherited some advantageous variations.
C found new places on the island to live.
D been attacked by more predators.
|B inherited some advantageous variations.|
|A population of termites initially consists of|
darkly colored and brightly colored members. After several generations, the termite population consists almost entirely of darkly colored members because the brightly colored termites are easier for a predatory species of insectivores to locate. This situation is an example of
A the evolution of a new species.
B natural selection.
C artificial selection.
D adaptive radiation.
|B natural selection.|
|Earth has undergone some catastrophic|
changes from time to time. Which of these most likely explains why life on Earth continued following these catastrophes?
A Dominant species had a slow mutation rate.
B Many species filled the same niche.
C A strong species had many different
D A wide diversity of species existed.
|D A wide diversity of species existed.|
|A small population of chimpanzees lives in a|
habitat that undergoes no changes for a long period. How will genetic drift probably affect this population?
A It will accelerate the appearance of new traits.
B It will promote the survival of chimpanzees with beneficial traits.
C It will increase the number of alleles for specific traits.
D It will reduce genetic diversity.
|D it will reduce genetic diversity.|
| A small portion of a population that is|
geographically isolated from the rest of the population runs the risk of decreased
A genetic drift.
B mutation rate.
C natural selection.
D genetic variation.
|D genetic variation.|
|A single species of squirrel evolved over time|
into two species, each on opposite sides of the Grand Canyon. This change was most likely due to
A higher mutation rates on one side.
B low genetic diversity in the initial population.
C the isolation of the two groups.
D differences in reproductive rates.
|C the isolation of the two groups.|
|Fossil evidence suggests that a number of|
members of one fish species from an ancient lake in Death Valley, California, became several isolated species. Each of these new species lived in a different pond. Which of the following best explains the cause of this speciation?
A episodic isolation
B temporal isolation
C geographic isolation
D behavioral isolation
|C geographic isolation|
|If a paleontologist finds fossils of many|
different species existing in the same area
at approximately the same time, the paleontologist can conclude that the ecosystem in this area had a high degree of
A climatic variation.
B episodic speciation.
C biological diversity.
D geographic isolation.
|C biological diversity|
| In order for the body to maintain homeostasis,|
the chemical decomposition of food to produce energy must be followed by
A water intake.
B muscle contractions.
C waste removal.
D nervous impulses.
|C waste removal.|
| Carbon dioxide is produced as cells break down|
nutrients for energy. Which of the following pairs of systems would participate in removing the carbon dioxide from the body?
A endocrine and circulatory
B circulatory and respiratory
C respiratory and endocrine
D reproductive and excretory
|B circulatory and respiratory|
| The respiratory system depends on the nervous|
system for signals to
A enhance the amount of available oxygen in the lungs.
B coordinate muscles controlling breathing.
C release enzymes to increase the exchange of gases.
D exchange gases with the circulatory system.
|B coordinate muscles controlling breathing.|
| Striking the tendon just below the kneecap|
causes the lower leg to jerk. Moving an object quickly toward the face can cause the eyes to blink shut. These are examples of
A learned responses.
B short-term memory.
C reflex reactions.
D sensory overload.
|C reflex reactions.|
| The fight-or-flight response includes greater|
heart output and a rise in blood pressure. This response is due to
A insulin secreted by the pancreas.
B thyroxine secreted by the thyroid gland.
C oxytocin secreted by the pituitary gland.
D adrenaline secreted by the adrenal glands.
|D adrenaline secreted by the adrenal glands.|
| Which of these secretes a hormone that|
regulates the rate of metabolism of the body?
| The homeostatic mechanism in humans that|
regulates blood pH depends on the feedback of
A stretch receptors.
B chemical receptors.
C hormone receptors.
D thermal receptors.
|B chemical receptors.|
| Which of the following is a function of the|
A releasing ATP into contracting muscle tissues
B signaling muscle tissues to contract
C producing lactic acid in fatigued muscle tissues
D increasing cellular respiration in muscle tissues
|B signaling muscle tissues to contract|
| A signal that the bladder is full is sent to the|
central nervous system by
A feedback loops.
B sensory neurons.
C nephron tubules.
D receptor proteins.
|B sensory neurons.|
| What is the greatest danger to a patient who|
has had damage to the skin?
A loss of oils produced by the skin
B excessive muscle contractions in the
C infections in uncovered tissues
D damaged tissue entering the blood stream
|C infections in uncovered tissues|
|Sweat and skin secretions contain a mixture of|
molecules that kills or limits the growth of many
types of microbes. This control of microbes is an example of
A a nonspecific defense against infection.
B an enzyme-catalyzed biochemical reaction.
C a feedback loop to maintain homeostasis.
D a specific immune response to infection by
|A a nonspecific defense against infection.|
| The Sabin vaccine is a liquid containing|
weakened polio viruses. Vaccinated individuals become protected against polio because the weakened viruses
A prevent further viral invasion.
B induce an inflammatory response.
C promote production of antibodies.
D are too weak to cause illness.
|C promote production of antibodies.|
|Injecting a person with a killed-bacteria vaccine|
can protect that individual from a disease because the proteins of the killed bacteria
A remain in the body, and live bacteria later prey on them instead of live tissues.
B bind with receptors in the body, so that live bacteria cannot bind with them later.
C stimulate the production of antibodies which can be manufactured later in response to infection.
D give the person a mild form of the disease, which conditions the body not to respond to later infection.
|C stimulate the production of antibodies which can be manufactured later in response to infection.|
| Which of the following require a host cell|
because they are not able to make proteins
on their own?
A blue-green algae
|How do human diseases caused by bacteria and|
diseases caused by viruses react to antibiotics?
A Neither responds to antibiotics.
B Both respond to antibiotics.
C Viral diseases respond to antibiotics;
bacterial diseases do not.
D Bacterial diseases respond to antibiotics; viral diseases do not.
|D Bacterial diseases respond to antibiotics; viral diseases do not.|
|Individuals with HIV sometimes contract a|
pneumonia infection that is rare in the rest of the population because people with HIV
A are unable to fight off these pneumonia-causing organisms.
B are more often exposed to these pneumonia-causing organisms.
C release pheromones that attract the pneumonia-causing organisms.
D release substances that increase the strength of the pneumonia-causing organisms.
|A are unable to fight off these pneumonia-causing organisms.|