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WorksheetsAP Biology Physiology Test REVIEW
Total questions: 117
Worksheet time: 10hrs 41mins
On a hot summer day in a temperate forest, the water potential at the root of a tree is -0.05 MPa. The water potential of the air is -200.5 MPa. An afternoon storm hits, and the water vapor in the air increases tremendously after the storm passes and the heat and sun return. Which of the following is a logical prediction of what will happen to the rate of transpiration and why?
The rate of transpiration will stay constant. Plants continue to transpire as long as it is hot.
The rate of transpiration will increase. Since there is more water in the soil, there is more water available to move up the plant stem.
The rate of transpiration will decrease. The amount of water vapor in the air will increase the water potential, making it closer to the roots water potential.
The rate of transpiration will decrease. The amount of water vapor in the air means the plants have no need to do transpiration to move water out of the tree.
A human kidney filters about 200 liters of blood each day. Approximately two liters of liquid and nutrient waste are excreted as urine. The remaining fluid and dissolved substances are reabsorbed and continue to circulate throughout the body Antidiuretic hormone (ADH) is secreted in response to reduced plasma volume. ADH targets the collecting ducts in the kidney, stimulating the insertion of aquaporins into their plasma membrane and an increased reabsorption of water. If ADH secretion is inhibited, which of the following would initially result?
The number of aquaporins would increase in response to the inhibition of ADH.
The person would decrease oral water intake to compensate for the inhibition of ADH.
Blood filtration would increase to compensate for the lack aquaporins.
The person would produce greater amounts of dilute urine.
The human body uses a number of processes to repair damage to blood vessels. After vasodilation and prior to coagulation, a platelet plug forms: platelets adhere to exposed collagen and degranulate releasing ADP and thromboxane. These two chemicals in turn help attract more platelets to the area of damage. This is an example of:
Negative feedback
Endocrine control
Positive feedback
set point feedback
Researchers conducted a controlled experiment to investigate the effect of diet on the health of beef cattle. The initial hypothesis was that an abrupt change in diet will benefit the beef cattle by reducing the sizes of bacterial populations living in the digestive systems of cattle. In the experiment, the researchers determined the relative abundance of two bacterial species found in the rumen of cattle. The rumen is a part of the stomach that acts as a fermentation chamber in cattle and other ruminants. Shown in the table are the results from before and after an abrupt change in the cattle's diet. Based on the results, which of the following best explains why the initial hypothesis should be revised?
The diets were too similar, since cellulose and starch are both carbohydrates obtained from eating plants.
The abundance of one of the bacterial species increased in response to the change in diet.
The change in the diversity of microorganisms had no observable effect on cattle physiology.
The ability of rumen fluid to resist changes in pH counteracted the changes in microorganism diversity.
The equation above shows one of the reversible reactions that occur in blood. After exercise, an athlete's blood pH has dropped below the normal level. How will normal blood pH be restored?
An increase in O2 concentration in the plasma will lead to an increase in H+ concentration.
an increase in temperature will lead to an increase in H+ concentration.
An increase in sweating will lead to a decrease in OH- and H+ concentration.
An increase in breathing rate will lead to a decrease in blood CO2 and H+ concentration.
In most fresh water fish, nitrogenous waste is primarily excreted as ammonia, which is highly soluble in water and is toxic at low concentrations. In terrestrial mammals, ammonia is converted to urea before it is excreted. Urea is also highly soluble in water but is less toxic than ammonia at low concentrations. Which of the following best explains why freshwater fish do not convert ammonia to urea for excretions?
The metabolic pathway of fish do not normally involve nitrogen consumption.
The dilution of ammonia by direct excretion into freshwater conserves energy.
Ammonia is concentrated in tissues, where it is stored prior to excretion.
The nitrogen in ammonia is recycle for use in protein and nucleotide synthesis.
Both myoglobin and hemoglobin are proteins that bind reversibly with molecular oxygen. The graph below shows the oxygen-binding saturation of each protein at different concentrations of oxygen.
Which of the following statements is correct?
At 10 mm Hg partial pressure, hemoglobin binds oxygen but myoglobin does not.
At 20mm Hg partial pressure, myoglobin and hemoglobin bind oxygen in equal amounts.
At 40mm Hg partial pressure, myoglobin has a greater affinity for oxygen than hemoglobin has.
at 80mm Hg partial pressure, myoglobin binds twice as much oxygen as hemoglobin binds.
Both myoglobin and hemoglobin are proteins that bind reversibly with molecular oxygen. The graph below shows the oxygen-binding saturation of each protein at different concentrations of oxygen.
Strenuous exercise lowers the blood pH, causing the curves for both hemoglobin and myoglobin to shift to the right. This shift results in
An unloading of O2 at higher partial pressures
An increase in the number of O2 binding sites
The capture of more O2 by hemoglobin
The capture of more O2 by myoglobin
Both myoglobin and hemoglobin are proteins that bind reversibly with molecular oxygen. The graph below shows the oxygen-binding saturation of each protein at different concentrations of oxygen.
Which of the following best describes the physiological significance of the different binding capabilities of hemoglobin and myoglobin?
They present muscles from depleting oxygen levels in the blood.
They cause muscles to become anaerobic.
They prevent glycogen depletion in muscles.
They enhance movement of oxygen from the blood into the muscles.
Most of the water that enters the digestive system is absorbed across the lining of the small intestine into capillaries. This happens because
The small intestine is lined with villi and microvilli that increase surface area.
Many hydrolysis reactions take place in the lumen of the small intestine.
The water potential is higher in the blood than in the lumen of the small intestine.
Water molecules are actively transported into the blood by aquaporins.
What is the main force by which most of the water within xylem vessels moves toward the top of a tree?
Active transport of ions into the steele.
Atmospheric pressure on roots
Evaporation of water through the stoma
The force of root pressure
Action potentials are normally carried in only one direction: from the axon hillock toward the axon terminals. If you experimentally depolarize the middle of the axon to threshold, using an electronic probe, then
an action potential will be initiated and proceed only back toward the axon hillock.
two action potentials will be initiated, one going toward the axon terminal and one going back toward the axon hillock.
no action potential will be initiated
an action potential will be initiated, but it will die out before it reaches the axon terminal.
Assume that excessive consumption of ethanol increases the influx of negative chloride ions into "commonsense" neurons whose action potentials are needed for you to act appropriately and not harm yourself or others. Thus, any resulting poor decisions associated with ethanol ingestion are likely due to
more action potentials in your "commonsense" neurons
more EPSPs in your "commonsense" neurons
increased membrane hyperpolarization of "commonsense" neurons
fewer IPSPs in your "commonsense" neurons
The accompanying diagram represents the steps that occur during the production of an action potential in a neuron. Refer to the figure and select the best description of the sequence of events that occur with a nerve impulse is transmitted along a neuron.
An action potential is created when Na+ ions enter a neuron and trigger more Na+ ions to enter the neuron to repolarize the neuron.
An action potential is created when vesicles in the neuron release neurotransmitters and resting potential restored when neurotransmitter is degraded.
An action potential is created when voltage-gated channels open to allow Na+ into the cell, and resting potential is restored when K+ channels open
An action potential is created when Na+K+ pumps are activated and resting potential is restored when all ion channels open.
When an action potential arrives at the presynaptic membrane, depolarization occurs, opening voltage-gated channels. This allows an influx of Ca2+ ions that are needed to trigger the release of neurotransmitter into the synapse. If a calcium channel blocker, such as cadmium, is injected into the presynaptic cell, which explanation best describes cadmium's effect on the transmission of the impulse?
Blocking the voltage-gated channels causes the synaptic vesicles to release their neurotransmitters within the presynaptic cell thus reversing the direction of the impulse.
Elevated levels of cadmium block the ligand-gated ion channels on the postsynaptic membrane that prevents neurotransmitters from binding.
Elevated cadmium levels cause synaptic vesicles to fuse with the presynaptic membrane thus releasing their neurotransmitters into the synapse triggering an impulse
Elevated cadmium levels prevent the influx of Ca2+ ions into the postsynaptic cell that prevents the release of neurotransmitters into the synapse.
The myelin sheath plays an important role in neuron structure and function. However, when the myelin sheath is missing or fully intact, there are consequences. There are many conditions that cause demyelination of neurons, some are autoimmune disorders, such as multiple sclerosis, and others are heredity. The symptoms of these conditions vary, but often include speech impairment and difficulty coordinating movement. Which of the following correctly connects the symptoms of demyelination with the process of nerve impulse transmission?
Demyelination prevents the formation of an action potential in sensory neurons that transmit signals from the environment to the central nervous system.
Demyelination slows nerve impulse transmission
Demyelination targets the central nervous system
Demyelination prevents the uptake of neurotransmitters reacted to propagate a message to the next neuron
What happens if a neuron is stimulated enough midway in an exon to trigger an action potential?
The nerve impulse could not be transmitted because it must be initiated at the dendrite end of a neuron.
Since neuron transmission is one-way, the nerve impulse would only be transmitted to the end of the exon and then through neurotransmitters to the next neuron.
The nerve impulse would go both directions from the stimulus point, but only the axon end could transfer the message through neurotransmitters to another neuron
The nerve impulse would go both directions and the dendrite end would be stimulated to send a second message through this neuron.
C. elegans is a model organism and was the first eukaryotic organism to have its genome sequence. The free-living nematode is often used in laboratories investigating reproduction, particularly egg laying. There are 16 muscles, 2 types of neurons, and multiple receptors involved in the process of laying eggs in C. elegans and there are mutations in all of these structures for the study of process. One particular mutation that prevents the laying of eggs by the worm is rescued by the neurotransmitter, serotonin. the rescue suggests that the mutation is most likely in which of the following?
one of the muscles needed for egg-laying
a postsynaptic . neuron involved in egg laying
a pre-synaptic neuron involved in egg laying
a receptor for serotonin on cells needed for egg laying
The point of connection between two communication neurons is called the
dendrite
synapse
cell body
axon hillock
In a simple synapse, neurotransmitter chemicals are released by
the dendritic membrane
axon hillock
the presynaptic membrane
ducts on the smooth endoplasmic reticulum
For a neuron with an initial membrane potential of -70mV, an increase in the movement of potassium ions out of their neuron's cytoplasm would result in
replacement of potassium ions with calcium ions
hyperpolarization of the neuron
neuron switching on its sodium-potassium pump to restore the initial conditions
replacement of potassium ions with sodium ions
A toxin that binds specifically to voltage gated sodium channels in axons would be expected to
have most of its effects on the dendritic region of a neuron
increase the release of neurotransmitter molecules
prevent the depolarization phase of the action potential
prevent graded potentials
The somatic nervous system can alter the activities of its targets, the skeletal muscle fibers because
its signals bind to receptor proteins on the muscles
it is connected to the internal neural network of the muscles
its signals reach the muscles via the blood
it is electrically coupled by gap junctions to the muscles
In a simple synapse, neurotransmitters chemicals are received by
the presynaptic membrane
the dendritic membrane
ducts on the smooth endoplasmic reticulum
cell bodies
The observation that the acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is an example of
ligand gated sodium channel
chemical that inhibits action potentials
voltage-gated sodium channel
voltage gated potassium channel
The following steps refer to various stages in transmission at a chemical synapse
- Neurotransmitter binds with receptors associated with the postsynaptic membrane.
- Calcium ions rush into the neuron's cytoplasm
- An action potential depolarizes the membrane of the axon terminal
- The ligand gated ion channels open
- The synaptic vesicles release neurotransmitter into the synaptic cleft
Which sequence of events is correct?
3->2->5->1->4
5->1->2->4->3
2->3->5->4->1
4->3->1->2->5
Neurotransmitters categorized as inhibitory are expected to
open sodium channels
hyperpolarize the membrane
close chloride channels
close potassium channels
Taste and smells are distinct kinds of environmental information in that
odorants bind to receptor proteins, but none of the tastant stimuli will bind to receptors
neural projections from taste receptors reach different parts of the brain than the neural projections from olfactory receptors
distinguishing tastant molecules requires learning, whereas smell discrimination is an innate process
instant molecules are airborne, whereas odorant molecules are dissolved in fluids
An injury to the occipital lobe will likely impair the function of
sense of taste
sense of touch
thalamus
primary visual cortex
Choose the correct sequence of the following events leading to the sensory processing of a stimulus
- transmission
- transduction
- integration
- amplification
2->4->1->3
1->4->2->3
3->4->1->2
3->1->2->4
Immediately after putting on a shirt, your skin might feel itchy. However, this perception soon fades due to
reduced motor unit recruitment
the increase of transduction
reduced receptor amplification
sensory adaptation
A given photon of light may trigger an action potential with thousands of times more energy because the signal strength is magnified by
an enzyme-catalyzed reaction
sensory adaptation
a G protein
triggering several receptors at once
Umami perception would be stimulated by
salt water
sugar water
chocolate milk
a savory and rich cheese
It can be very difficult to select an angle for sneaking up to a grasshopper to catch it because grasshoppers have
a camera like eye with multiple lenses
binocular vision
compound eyes with multiple ommatida
excellent hearing for detecting predators
A rod exposed to light will
undergo a graded hyperpolarization that will decrease the release of glutamate
fire action potentials that will increase its release of glutamate
undergo a graded hyperpolarization that will increase its release of glutamate
undergo a graded depolarization that will decrease the release of glutamate
Our understanding of mental illness has been most advanced by discoveries involving the
evolution of the telecephalon
nature of blood brain barrier
sequence of developmental specialization
chemicals involved in brain communication
Birds secrete uric acid as their nitrogenous waste because uric acid
requires little water like for nitrogenous waste disposal, thus reducing body mass
is readily soluble in water
is metabolically less expensive to synthesize than other excretory products
excretion allows birds to live in desert environments
Adaptive immune response can be either antibody-mediated or cell-mediated. Both processes use cell-signaling mechanisms to defend the body. Helper T cells are central to the immune response and trigger both types of adaptive responses as noted in the diagram.
Select the best explanation of how a Helper T cell uses either cell to cell contact or chemical signaling to enhance the activities of the immune system.
The Helper T cell stimulates the antigen-presenting cell to release chemicals called cytokines to stimulate the cytotoxic T cells.
The pathogen is engulfed by a helper T cell and its antigenic markers are displayed on its surface.
Chemicals called cytokines are secreted from Helper T cells to signal production of antibodies by B cells.
The second exposure of the antigen causes the Helper T cells to activate memory Helper T cells
In a humoral or antibody mediated response, specific B cells are stimulated by Helper T cells to transform into plasma cells that secrete antibodies. What would be an important feature added to B cells in this transition process?
increased rough endoplasmic reticulum in order to have the surface area needed for antibody production
An increased cell size with more plasma membrane to increase the surface to volume ratio of the cell
Duplication of lysosomes in order to store the antibodies before transport
Duplication of specific gene sequences for the appropriate antibody
Histamines trigger dilation of nearby blood vessels as well as an increase in their permeability, producing
all of the signs of a major infection
swelling only
pain
redness, heat, and swelling
A newborn who is accidentally given a drug that destroys the thymus would most likely......
be unable to differentiate and mature T cells
lack humoral immunity
have a reduced number of B cells and be unable to form antibodies
lack class I MHC molecules on cell surfaces
Immunological memory accounts for
the observation that some strains of the pathogen that causes dengue fever cause worse disease than others.
the ancient observation that someone who had recovered from the plague could safely care for those newly diseased.
the ability of the immune system to present antigen fragments in association with MHC antigens
the human body's ability to distinguish self from nonself
For a successful development of a vaccine to be sued against a pathogen, it is necessary that
the surface antigens of the pathogen do not change
the pathogen has only one epitope
the MHC molecules are heterozygous
all of the surface antigens on the pathogen be identified.
The switch of one B cell from producing one class of antibody to another antibody class that is responsive to teh same antigen is due to
a switch in the kind of antigen-presenting cell that is involved in the immune response.
the rearrangement of immunoglobulin heavy chain C region DNA
the rearrangement of V region genes in that clone of responsive B cells
mutation in the genes of that B cell, induced by exposure to the antigen
A person who can produce antibodies against some bacterial pathogens, but not against viral infections, probably has a disorder in his
natural killer cells
B cells
plasma cells
T cells
Select the pathway that would lead to the activation of cytotoxic T cells
complement is secreted--> B cell contacts antigen--> helper T cell activated--> cytokines released
body cell becomes infected with a virus--> new viral proteins appear--> class I MHC molecule-antigent complex displayed on cell surface
B cell contact antigen--> helper T cell activated--> clonal selection occurs
cytotoxic T cells--> Class II MHC molecules-antigen complex displayed--> cytokines released--> cell lyse
Arrange these components of the mammalian immune system as it first responds to a pathogen in the correct sequence.
I. Pathogen is destroyed
II. Lymphocytes secrete antibodies
III. Antigenic determine from pathogen bind to antigen receptors on lymphocytes
IV. Lymphocytes specific to antigenic determinants from pathogen become numerous
V. Only memory cells remain
III--> IV--> II--> I-->V
I-->III-->II-->IV-->V
IV-->II-->III-->I-->V
III-->II-->I-->V-->IV
An individual who has been bitten by a poisonous snake that has a fact-acting toxin would likely benefit from
injection of interleukin 1
injection of antibodies to the toxin
injection of interferon
injection of interleukin 2
A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane's cousin Bob), even though Jane has previously given blood for one of Bob's needed transfusions because
Bob's immune response has been made inadequate before he receives the transplant
a blood type match is less stringent than a match required for transplant because blood is more tolerant of change
even though Jane's blood type is a match to Bob's, her MHC proteins may not be a match
for each gene, there is only one blood allele but many tissue alleles.
An immune response to a tissue graft will differ from an immune response to a bacterium because
a bacterium cannot escape the immune system by replicating inside normal body cells
the tissue graft, unlike the bacterium, is isolated from the circulation end will not enter into an immune response
MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules
the graft will stimulate an autoimmune response in the recipient.
The ability of some viruses to remain inactive (latent) for a period of time is exemplified by
herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host
the virus that causes a form of the common cold, which recurs in patients many times in their lives
influenza, a particular strain of which returns every 10-20 years
Kaposi's sarcoma, which causes skin cancer in people with AIDS, but rarely in those not infected by HIV.
Which of the following immune system components is correctly matched to its function?
macrophage: produces antibodies
cytotoxic T cell : activates plasma B cells
Helper T cell : activates B cells
Memory B cell: engulfs pathogens
Multiple sclerosis is a degenerative disease that is caused by the immune response attacking the myelin sheath that surrounds the nerves of the central nervous system. How would an immunologist classify this disease?
an opportunistic disease
an autoimmune disorder
an acquired immunodeficiency
a genetic immunodeficiency
All of the following are examples of nonspecific defense except
skin
mucus
hypersensitive response
production of antibodies
According to the graph, naive B cells will produce effector cells
between 0 and 7 days
between 7 and 14 days
between 28 and 35 days
between 0 and 7 days and between 7 and 14 days
In active immunity, but not passive immunity there is
acquisition and activation of antibodies
proliferation of lymphocytes in bone morrow
the transfer of antibodies from the mother across the placenta
the requirement for direct exposure to a living or simulated pathogen
When someone is vaccinated, the purpose of the vaccine is to stimulate which of the following responses without making the individual sick?
passive immunity
anaphylactic shock
the primary immune response
inflammation
Immune responses are initiated when
macrophages present antigens to helper T cells
skin blocks the entry of pathogens into the body
killer T cells attack infected cells
mucus traps invading pathogens
The rapid production of B lymphocytes after a specific antigen binds to them is known as
antigenic determination
clonal selection
a cytokine storm
an autoimmune response
Is an allergy (to pollen, bees, peanuts, etc) a normal body function or a disruption of body function?
An allergy is a normal body function that returns the immune system to homeostasis
An allergy is a disruption of normal body function when the immune system overreacts to a particular antigen
An allergy is a disruption of normal body function when the immune system is inactivated and cannot fight a particular antigen.
An allergy is a disruption of normal body function when the immune system identifies a foreign antigen as one of the body's own self proteins.
Douglas and Kevin are sitting next to each other in the lunch room. Conrad sits down across from them and then sneezes hard, spraying droplets of viral infected saliva over both Douglas and Kevin's faces. By the next week, Douglas is feeling awful, sneezing everywhere, and stays sick for about two weeks. On the other hand, Kevin has a few minor symptoms for a couple days but recovers quickly. Which is NOT a possible reason why Douglas gets sicker than Kevin?
There is a genetic variation between people in regards to their immune system cells; Kevin had genes that could make the correct immune system response to fight this particular virus.
Kevin had already been exposed to a similar virus before, and had memory B cells that were primed to produce an appropriate antibody.
Kevin's nonspecific immune system, including his skin and antiviral proteins in his own saliva, may have prevented most of the virus from entering his respiratory cells.
Kevin doesn't have any allergies, so he doesn't sneeze or show or any symptoms of viral disease.
When B cells are developed in the bone marrow, an undifferentiated stem cell divides and differentiates to form a specific type of B cell. During differentiation, segments of antibody genes are linked together by a type of genetic recombination, generating a "new" gene for each polypeptide within the new antibody. This process, which occurs before any contact with foreign antigens, creates an enormous variety of B cells is the body, each with the capability of making a different type of antibody. Which is the best description of why this variety of B cells is helpful to human beings?
When exposed to an antigen, a B cell will mutate to form the antibody to fight that antigen.
If an individual human is infected with an antigen, they will probably already have a specific B cell prepared to attack that particular antigen.
The B cells are active in the nonspecific defense system, and this variety prevents a wild range of antigens from entering the body.
Each B cell can make hundreds of different shaped antibodies, to fight different possible sources of infection.
The rhinovirus- or common cold- is made up of single stranded RNA. HIV is also composed of single stranded RNA, yet colds are not life threatening and are usually cleared from a human body within a week or two, while HIV persists for the life of the person. Which of the following is a reasonable conclusion for the differences of these two viruses?
The RNA of a cold virus begins replication immediately to produce more RNA and proteins, whereas the HIV RNA is converted to DNA and joins with the host cell's DNA.
The RNA of a cold virus can join directly to the DNA of the host cell, but it is rejected quickly by the host, whereas the RNA of HIV does the same and has a method to avoid the defenses of the host cell.
The RNA of HIV is transported directly to teh nucleus and incorporated into the host cell's DNA, but the cold virus stays in teh cytoplasm as RNA, eventually degraded by the host cell's defenses.
Both viruses convert their RNA to DNA and join with the host cell's DNA, but the cold virus DNA degrades over time and is thus removed from the host cell naturally.
Prior to going to college, students are required to be checked for Tuberculosis (TB)- an infection of the lungs by bacteria that is highly resistant to antibiotics. The test is done by injecting a purified protein that is associated with the bacteria under the skin and looking for an inflammatory response. Josie if from the Bahamas where TB is more common and was vaccinated with BCG- a weakened form of the bacteria. She has never contracted TB. Josie decides to attend school in Florida and must do a TB test. Which of the following is a logical prediction of the results she should expect?
She will have no inflammatory reaction to the protein since she has been vaccinated once and has never contracted TB.
She will have no inflammatory reaction to the protein since the strains of TB in the islands are different than the bacterial strains in Florida.
She will have an inflammatory reaction to the protein since her body has made antibodies to the TB protein that she was vaccinated with as a child.
She will have an inflammatory reaction to the protein because even after being vaccinated as a child, she was around people with TB.
In the primary immune response to an antigen by an antigen presenting cell (such as a macrophage), the helper T cell secrete chemicals called IL-2 (Interleukin-2) that cause other immune cells to increase in number. A new strain of bacteria is infecting humans and it blocks the IL-2 from interacting with the immune system cells. Which of the following is a prediction of what would happen if this bacterium were to get into a human?
The macrophage would not be able to present the antigen to the helper T cell, so IL-2 would build up in the body and no immune response would occur.
The helper T cell would be unable to receive the signal from the macrophage, and IL-2 it produced would simply build up inside the body without causing an immune response.
The T8 and B cells would not be able to interact with the helper T cell, but would recognize the macrophage and cause their own cell division to fight the bacterium.
The helper T cell would produce IL-2, but the surrounding cells would no longer bind with the ligand as it would not fit their receptors and no immune response would occur.
Independent of whether an organism is an ectoderm or endotherm, the LEAST reliable indicator of an animal's metabolic rate is the amount of
water consumed in one day
heat generated in one day
food eaten in one day
oxygen used in mitochondria in one day
Hypoglycemia, or low levels of glucose in the blood of a healthy human, is "corrected"
by an increase in the secretion of insulin
by an increase in the secretion of both insulin and glucagon
by a decrease in the secretion of both insulin and glucagon
by an increase in the secretion of glucagon.
Small swollen areas in the neck, groin, and axillary region are associated with
sodium depletion
blood sugar that is abnormally high
a broken limb
increased activity of the immune system
A paleontologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, well formed, and had four chambers, with no connection between the light and left sides. A reasonable conclusion supported by these observation is that the
species had little to no need to regulate blood pressure.
animal was endothermic and had a high metabolic rate
animal was likely an invertebrate animal
animal was most closely related to alligators and crocodiles.
A group of students was designing an experiment to test the effect of smoking on grass frogs. They hypothesized that keeping the frogs in a smoke-filled environment for defined periods would result in the animals developing lung cancer. However, when they searched for previously published information to shore up their hypothesis, they discovered they were quite wrong in their original assessment. Even though they were never going to go ahead with their experiment (so as not to harm frogs needlessly), they knew that a more likely outcome of putting carcinogens in the air would be the development of
gill abnormalities in the next generation of tadpoles
diminished absoprtion of oxygen
skin cancer
the amphibian equivalent of hypertension.
Homeostasis typically relies on negative feedback because positive feedback
acts within, but not beyond, a normal range
drives processes to completion rather than to a balance point
requires a response but not stimulus
can decrease but not increase a variable
Organisms maintain dynamic homeostasis (internal balance) through behavioral and physiological mechanisms. Which of the following statements is an accurate explanation of a negative feedback mechanism used by animals to regulate body temperature?
Desert jackrabbits have unusually large ears that serve as solar heat collectors to enable them to maintain their body temperatures.
A ground squirrel's hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.
A goldfish slows its movements when the water temperature is lower.
Squirrels are able to cool themselves during warmer months by producing more brown fat, which contains abundant mitochondria and a rich blood supply.
Correct and appropriate signal transduction processes are generally under strong selective pressure and are determined by the properties of the molecules involved, the concentration of signal and receptor molecules, and the binding affinities between signal and receptor. Therefore, a hormone action is very specific in a species at any one point in time. However, there are examples of very diverse functions of a specific hormone between groups of organisms. For example, thyroxin, which is produced in all vertebrates and many invertebrates can trigger growth, differentiation, metamorphosis, maturation, reproduction, behavior, temperature tolerance, osmoregulation, or seasonal adaptation depending on the organism in which it is produced. What is the most logical explanation for such different responses triggered by thyroxin in organisms?
Receptor molecules for thyroxin are located on different tissues in different organisms.
Thyroxin and its receptor molecules have a different binding affinity in different organisms.
The concentration of thyroxin varies in different organisms, invertebrate organisms do not have as much thyroxin as vertebrate organisms.
The structure of thyroxin is substantially different in different organisms.
The accompanying figure illustrates the action of both steroid hormones and peptide hormones. Select the figure and explanation that best describes why steroid hormones typically act slowly.
Figure (b) Target cells prefer to interact with steroid hormones since the chemical group of hormones can easily pass through cell membranes. Since steroid hormone molecules are larger in size, it takes longer to get through these membranes.
Figure (b) Steroid hormones pass through the cell membrane, enter the nucleus, and interact with the DNA to turn in genes
Figure (a) Peptide hormones act via a signal transduction pathway that carries the hormone into the nucleus of the cell resulting in quicker responses than does directly interacting with the cell's DNA.
Figure (a). The steroid and peptide hormones are too large to enter a cell and must first bind to a plasma membrane receptor before entering the cell and having an effect on its metabolism of the proteins it has made.
Penguins, seals, and tuna have body forms that permit rapid swimming because
all share a common ancestor at some point in the past
the shape is a convergent evolutionary solution to the need to reduce drag while swimming.
this is the only shape that will allow them to maintain a constant body temperature in water.
all of their bodies have been compressed since birth by intensive underwater pressures.
Food moves along the digestive tract as the result of contractions by
smooth muscle
cardiac muscle
striated muscle
voluntary muscle
An example of a properly functioning homeostatic control system is seen when
the cored body temperature of a runner rises gradually from 37°C to 45°C
the blood pressure increases in response to an increase in blood volume
the kidneys excrete salt into the urine when dietary salt levels rise
a blood cell shrinks when placed in a solution of salt and water
In a survivably cold environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm
has greater insulation on its body surface
invests little energy in temperature regulation
maintains a higher basal metabolic rate
metabolizes its stored energy more readily than can the endotherm.
A necropsy (postmortem analysis) of a marine sea star that died after it was mistakenly placed in a fresh water tank would likely show that it died because
its cells dehydrated and lost the ability to metabolize
it was stressed and needed more time to acclimate to the new conditions
it was so hyperosmotic to the fresh water that it could not osmoregulate
The sea star's kidneys could not handle the change in ionic content presented by the fresh water.
Which of the following statements about transport in plants is false?
Hydrogen bonding between water molecules, which results in the cohesion of the water, is essential for the rise of water in tall trees.
Although some angiosperm plants develop considerable root pressure, this is not sufficient to raise water to the tops of tall trees.
Water bonding between water molecules and the walls of xylem vessels or tracheids helps support the columns of water in the xylem.
Gymnosperms can sometimes develop especially high root pressure, which may account for the rise of water in tall pine trees without transpiration pull.
All of the following normally enter the plant through the roots except
calcium
potassium
carbon dioxide
nitrogen
Plants do not have a circulatory system like that of some animals. If a water molecule did "circulate" (that is, go from one point in a plant to another and back in the same day", it would require the activity of
only the phloem
only the endodermis
both the xylem and phloem
only the xylem
Given that early land plants most likely share a common ancestor with green algae, the earliest land plants were most likely
plants with well developed leaves
species that did not exhibit alternation of generations
vascular plants with well defined root systems
nonvascular plants that grew lealfless photosynthetic shoots above the shallow fresh water in which they lived.
The value for Ψ in root tissue was found to be -0.15MPa. If you take the root tissue and place it in a 0.1 M solution of sucrose (Ψ= -0.23 MPa), the net water flow would
be from the sucrose solution into the tissue
occur only as ATP was hydrolyzed in the tissue
be in both directions and the concentrations would remain equal
be from the tissue into the sucrose solution
Which of the following statements is false concerning the xylem?
Xylem tracheids and vessels fulfill their vital function only after their death.
in the morning, sap in the xylem begins to move first in the twigs of the upper portion of the tree, and later in the lower trunk
The cell walls of the tracheids are greatly strengthened with lignin and cellulose fibrils forming thickened rings or spirals.
Movement of materials is by mass flow, solutes in xylem sap move due to a positive turgor pressure gradient from source to sink.
If ΨP= 0.3 MPa and ΨS= -0.45MPa, the resulting Ψ is
-0.15 MPa
-0.75 MPa
0.15 MPa
-0.42 MPa
In which plant cell would the pressure component of water potential most often be negative?
stem phloem
root epidermis
root cortex cell
stem xylem
Compared to a cell with few aquaporins in its membrane, a cell containing many aquaporins will
have a higher water potential
be flaccid
have a lower water potential
have a fast rate of osmosis
Water flows into the source end of a sieve tube because
sucrose has been actively transported into the sieve tube, making it hypertonic.
water pressure outside the sieve tube forces in water
the companion cell of a sieve tube actively pumps in water
sucrose has been transported . out of the sieve tube by active transport.
Photosynthesis begins to decline when leaves wilt because
CO2 accumulates in the leaves and inhibits the enzymes needed for photosynthesis
there is insufficient water for photolysis during the light reactions
chloroplasts within wilted leaves are incapable of photosynthesis
stomata close, restricting CO2 entry into the leaf
Which of the following has the lowest (most negative) water potential?
root cortical cells
root xylem
leaf cell walls
leaf air spaces
Which two elements make up more than 90% of the dry weight of plants?
carbon and nitrogen
nitrogen and oxygen
oxygen and hydrogen
carbon and oxygen
Why is nitrogen fixation an essential process?
Nitrogen fixation is very expensive in terms of metabolic energy
Nitrogen- fixing capacity can be genetically engineered
Fixed nitrogen is often the limiting factor in plant growth
Nitrogen fixers are sometimes symbiotic with legumes
You are weeding your garden when you accidently expose some roots of your pea plants. You notice swellings (root nodules) on the roots and there is a reddish tinge to the ones you accidently damaged. Most likely your pea plants
are developing offshoots from the root
are benefitting from a mutualistic bacterium
are infected with a parasite
contain developing insect pupa.
A reproductive hormone that is secreted directly from a structure in the brain is
astradiol
follicle stimulating hormone
progesterone
gonadotropin releasing hormone
Labor contractions can be increased by the medical use of a synthetic drug that mimics the action of
prolactin
oxytocin
inihibin
vasopressin
Two contraceptive methods that are generally irreversible and that block the gametes from moving to a site where fertilization can occur are
the male condom and female condom
coitus interruptus and the rhythm method
the diaphragm and the subcutaneous progesterone implant
vasectomy and tubal ligation
Fertilization of an egg without activation is most like
walking to the cafeteria and eating lunch
dropping a rock off a cliff and watching it land in the valley below
resting during halftime of a basketball game
placing the key in the ignition of a car but not starting the engine
During the early part of the cleavage stage in frog development, the rapidly developing cells
skip the S phase of the cell cycle
rapidly increase the volume and mass of the embryo
skip the G1 and G2 phase of the cellc ycle
skip the mitosis phase of the cell cycle
If gastrulation was blocked by an environmental toxin, then
the blastopore would form above the gray crescent in the animal pole
embryonic germ layers would not form
fertilization would be blocked
the blastula would not be formed
Thalidomide, now banned for use as a sedative in pregnancy, was used in the early 1960s by many women in their first trimester of pregnancy. Some of these women gave birth to children with arm and leg deformities, suggesting that the drug most likely influenced
determination of the polarity of the zygote
morphogenesis
organogenesis
early cleavage divisions
Changes in both cell shape and cell position occur extensively during
gastrulation, but not organogenesis or cleavage
gastrulation, organogenesis, and cleavage
gastrulation and organogenesis, but not cleavage
organogenesis, but not gastrulation or cleavage
Select the choice that correctly associates the organ with its embryonic sources
brain- mesoderm and endoderm
thyroid gland- mesoderm and ectoderm
skin- endoderm and mesoderm
adrenal gland- ectoderm and mesoderm
The first cavity formed during sea urchin development is the
blastopore
mouth
anus
blastocoel
Human trophoblasts
are of embryonic origin and function in embryo nutrition
form from ectoderm
are of maternal origin and function in embryo gas exchange
form the inner cell mass
Assume that successful reproduction in a rare salamander species, wherein all the individuals are females, relies on those females having access to sperm from males of another species but that the resulting embryos show no signs of a genetic contribution from the sperm. In this case, the sperm appear to be used only for
egg activation
the creation of a diploid cell
cell differentiation
epigenesis
Across a range of animal species, embryonic development involves common stages. The figure below illustrates these stages. In addition some organisms go through metamorphosis, as illustrated by the life cycle of the frog. Use the information in the figure to select the statement that justifies how embryonic induction in development results in the correct timing of the events that occur in a set order.
The process of gastrulation produces a blastula through mitosis producing more cells.
The process of fertilization and cleavage will initiate embryonic development.
At various times in development, individual cells may be engulfed by neighboring cells.
Organogenesis in animals involve the movement of parts of a cell to change the cell shape.
Embryonic induction, the influence of one group of cells on another group of cells, plays a critical role in embryonic development. In 1924, Hans Spermann and Hilde Mangold transplanted a piece of tissue that influences the formation of the notochord and neural tubes, from the dorsal lip of an amphibian to the ventral side of another amphibian embryo. If embryonic induction occurred, which of the following observations justifies the claim of embryonic induction?
The transplanted tissue inhibited normal cell division on the dorsal side of the recipient embryo that lead to its death.
The transplanted tissue had no effect on either the ventral or dorsal side of the recipient embryo so it continued to develop normally
The transplanted tissue induced the formation of a second notochord and neural tube on the ventral side of the developing embryo
The transplanted tissue induced multiple limbs to develop on the ventral side of the recipient embryo.
Regeneration, the regrowth of body parts, normally follows
fission
parthenogenesis
all types of sexual reproduction
fragmentation
Asexual reproduction results in greater reproductive success than does sexual reproduction when
a species has accumulated numerous deleterious mutations
pathogens are rapidly diversifying
a species is in stable and favorable environments
there is some potential for rapid overpopulation
Environmental cues that influence the timing of reproduction generally do so by
increasing the body temperature
providing access to water to external fertliziation
causing direct effects on gonadal structure
causing direct effect on hormonal control mechanisms.
The surgical removal of the seminal vesciles would likely
greatly reduce the volume of semen
cause the testes to migrate back into the abodominal cavity
enhance the fertilization potency of sperm in the uterus
cause sterility because sperm would not be protected.
Increasing the temperature of the human scrotum by 2°C (i.e. near the normal body temperature) and holding it there would
reduce the man's sexual interest
reduce the fertility of the man by impairing spermatogenesis
have no effect on male reproductive processes
increase the fertility of the affected man by enhancing the rate of steroidogenesis
In vertebrate animals, spermatogenesis and oogenesis differ in that
spermatogenesis is not completed until after fertilization occurs, but oogenesis is completed by the time a girl is born
oogenesis ends at menopause, whereas spermatogenesis is finished before birth
oogenesis begins at the onset of sexual maturity, whereas spermatogenesis begins during embryonic development
cytokinesis is unequal in oogenesis, whereas it is equal spermatogenesis
At the time of fertilization, the complete maturation of each oogonium has resulted in
four primary oocytes
four secondary oocytes
two primary oocytes
one secondary oocyte
The primary difference between estrous and menstrual cycles is that
most estrous cycles are of much longer duration compared to menstrual cycles.
copulation normally occurs across the estrous cycle, whereas in menstrual cycles copulation only occurs during the period surrounding ovulation
season and climate have less pronounced effects on estrous cycles than they do on menstrual cycles
the endometrium shed by the uterus during the estrous cycle is reabsorbed, whereas the shed endometrium of menstrual cycles is excreted from the body
An inactivating mutation in progesterone receptor gene would likely result in
the inability of the uterus to support preganancy
the absence of mammary gland development
the absence of secondary sex characteristics
enlarged and hyperactive uterine endometrium
