The term steroid describes both hormones produced by the body and artificially produced medications that duplicate the action for the naturally occurring steroids. All of the following describe steroid hormones EXCEPT
They bind with receptor proteins in the plasma membrane to trigger cellular responses.
All of the following statements about ligand-receptor complexes are true EXCEPT
Ligand-receptor complexes are most often formed in cell communication pathways in which participating cells are in direct contact.
Cell signaling involves converting extracellular signals to specific responses inside the target cell. Which of the following best describes how a cell initially responds to a signal?
The cell experiences a change in receptor conformation.
The dashed arrows indicate the pathway taken by chemical signals. Which of the following statements best describes this type of cell communication?
Cells communicate with each other through direct contact.
Which of the following molecules act as a second messenger in the cascade by which epinephrine stimulates the activation of the enzyme glycogen phosphorylase?
Cyclic AMP
Which of the following represents the CORRECT ORDERING of the molecules that are activated by a single molecule of epinephrine, from HIGHEST number of molecules to LOWEST number of molecules?
Glycogen phosphorylase, phosphorylasekinase, protein kinase A, cAMP
Which of the following would likely NOT be observed in a person injected with epinephrine?
Decreased production of cAMP in liver cells
Which of the following best describes a benefit of the many steps involved in a protein kinase cascade?
(all of the above) it allows for the activation or inhibition of many enzymes, it allows for the amplification of the signal, it allows for the distribution of the signal throughout the inside of the cell
All of the following are enzymes involved in the signal transduction pathway shown EXCEPT
epinephrine
Investigations into the causes behind symptoms in Alzheimer's patients have led to the hypothesis that the disease may be caused by excessive activity of IP^3 second messengers in brain cells. When comparing cell samples of Alzheimer's patients to those t
A higher concentration of calcium ions in the cytosol of the Alzheimer cell samples.
Which of the following best describes the role in which the G protein is most intimately involved in the process shown above?
Transduction of the signal.
Blood calcium plays a role in the processes of blood clot formation, muscle contraction and signal conduction in neurons. Negative feedback mechanisms regulate the release of the paired hormones that maintain the blood calcium levels. Which of the followi
Parathyroid glands release PTH which stimulates the release of calcium from the bones when the blood calcium levels are lower than the set point.
...ideally, a relatively steady level of blood glucose is maintained by the body's regulatory mechanisms. The data shown above was collected during an investigation comparing two insulin therapy medicine, Insulin Glargine and NPH insulin. Which of the fol
The rate of glucose uptake produced by Insulin Glargine remains constant for more than 18 hours after injection.
In his research on cell signaling involving epinephrine, E.W. Sutherland determined glycogen phosphorylase was activated by epinephrine. Sutherland found that in vitro, in the lab setting, epinephrine was unable to activate phosphorylase. The reaction req
Cell membrane proteins and molecules inside the cell must be involved in transmitting the signal.
Insulin, epinephrine, testosterone, follicle stimulating hormone, and estrogen are all capable of triggering the flow of communication in a signal transduction pathway. Which of the following terms best describes such molecules?
ligands
A transmembrane protein is a protein that goes from one side of a membrane through to the other side of the membrane. Which model pictured in the image above depicts a membrane protein serving as a ligand receptor in a signal transduction pathway?
II only
Each of the following numbered processes are involved in signal transduction pathways:
I. Response
II. Amplification
III. Reception
IV. Transduction
III, IV, II, I
...liver tissue was homogenated and used to make three test solutions: a whole homogenate, a fraction containing plasma membrane, and a fraction containing cytoplasm but no plasma membrane. Which of the following would be a reasonable conclusion based on
A soluble second messenger, produced by hormone-activated membranes, is present in the solution and activates enzymes in the cytoplasm.
Which of the characteristics listed below best describe a steroid hormone?
I. Induce a rapid response
II. Result in a slow change
III. Composed of amino acids monomers
IV. Synthesized from cholesterol
V. Act as long distance chemical messengers
II, IV, and V only
Which of the following explains why organisms with the adrenal gland arterial arrangement have a selective advantage over those with fewer arteries connected to the adrenal gland?
This arrangement allows adrenalin, a protein hormone, to enter the bloodstream quickly to be distributed throughout the body producing a rapid release of energy.
At which point on the graph above are insulin receptors on glucose carrier proteins least likely to contain the ligand?
Q
Which kingdoms contain organisms that employ cell-to-cell communication?
I. Eubacteria
II. Fungi
III. Animalia
IV. Plantae
I, II, III, and IV
When epinephrine binds to cardiac (heart) muscle cells, it speeds their concentration. When it binds to muscle cells of the small intestine, it inhibits their contraction. Which of the following best accounts for the fact that the same hormone can have di
The two types of muscle cells have different signal transduction pathways for epinephrine and thus have different cellular responses.
Which of the following best explains the difference between a hormone and a pheromone?
Pheromones are chemical signals between organisms while hormones communicate among the parts within the organism.
Four different types of signaling mechanisms are listed below.
I. Quorum sensing
II. Pheromone signaling
III. Endocrine signaling
IV. Paracrine signaling
Which signaling mechanism is exemplified by food trail marking behaviors in insects such as ants and
II
I and II
Which of the following statements is true regarding testosterone?
Testosterone is a steroid hormone involved in endocrine signaling.
Which of the following statements is supported by the information depicted in the stress hormone feedback loop shown above?
Increased cortisol production by the adrenal cortex will result in decreased corticotropin releasing hormone.
Transmission sequence at the synapse:
I. Action potential depolarizes the presynaptic membrane
II. Sodium ions rush into neuron's cytoplasm
III. Synaptic vesicles release neurotransmitter into the synaptic cleft
IV. Neurotransmitter binds with receptor
V. Ion channel opens to allow particular
What would be a likely result of an increase in the amount of acetylcholine present in the synaptic cleft?
Fewer sodium/potassium ion channels would be opened in the postsynaptic dendrite.
Which of the following best describes the function of acetylcholinesterase in neurotransmission?
It breaks down acetylcholine, preventing neurotransmission.
If a stimulus on the receptor portion of a sensory neuron is above the threshold level, a further increase in the intensity of this stimulus will most likely cause the
frequency of the impulse production to increase
Which of the following best explains the relationship between the action potential and the strength of the stimulus?
A strong stimulus increases the frequency of the action potentials.
Which of the following best describes why Lidocaine is an effective anesthetic?
Lidocaine decreases sodium influx, which decreases the propagation of the action potential.
Which of the neurological conditions would be most likely improved by stimulating Schwann cells to work more effectively?
Multiple Sclerosis
Which of the structures shown is located in the spinal cord?
Interneuron
Which of the following describes the adaptive advantage of hyper polarization?
During hyper polarization, an action potential cannot be generated which prevents the resending of same action potential.
Which of the following best describes the action of the sodium-potassium pumps in the membrane of a motor-neuron?
Sodium is pumped out and potassium is pumped into the neuron using energy supplied by ATP.
Which of the following best describes the role of olfactory cells?
They convert sensory stimuli into changes in membrane potential.
The appearance of a fertile, polyploidy individual within a population of diploid organisms is a possible source of a new species. If this individual is capable of reproducing to form a new population, scientists would consider this to be an example of?
sympatric speciation
The different species of finches on the Galapagos Islands are believed to have arisen as a result of the natural selection acting on populations of finches that had experienced
the bottleneck effect
Which of the following is such a post-zygotic isolating mechanism?
developlmental isolation
Which of the following statements best expresses the concept of punctuated equilibrium?
Evolutionary changes consist of rapid bursts of speciation alternating with long periods in which species remain essentially unmodified.
Which of the following pathways for the transformation of cellular energy most likely evolved first?
Individuals that possess the most favorable variations have the best chance of reproducing.
Which of the following principles is NOT part of Darwin's theory of evolution by natural selection?
Mutations are the ultimate source of genetic variation.
It has been proposed that eukaryotic cells are actually hybrids of archaean and bacterial cells. Which of the following statements does NOT support this idea?
The DNA of eukaryotes is enclosed in a nucleus like that of Archaea.
Which of the following traits is likely to be unsuitable for phylogenetic analysis?
learned behavior
Th eastern coral snake, is poisonous and brightly colored with distinctive red, black, yellow, and white alternating bands. The nonpoisonous scarlet king snake resembles the coral snake and also has red black, and white bands. This is an example of
mimicry
Tigers and lions will interbreed in captivity and produce viable offspring, but they do NOT interbreed in Asia where their geographic ranges overlap. Which of the following isolating mechanisms account for this?
behavioral isolation
Which of the following adaptation is LEAST likely to have evolved in response to water shortages?
development of large leaf surfaces to absorb water
Which of the following experimental procedures would most likely reduce transpiration while allowing normal growth of a plant?
increasing the level of carbon dioxide around the plant
Plants do not have a circulatory system like that of some animals. If a given water molecule did "circulate" (that is, go from one point in a plant to another and back), it would require the activity of
BOTH the xylem and the phloem
When the water vapor in the atmosphere is lower than that in the apoplast of a leaf, water vapor will diffuse from the intercellular spaces of the leaf and through the stomata to the outside air in a process known as transpiration. Which of the following
cohesion of water molecules
Most plants and some fungi display alternation of generations which includes both a multicellular diploid stage and a multicellular haploid stage. Which of the following represents the first cell of the sporophyte generation in the life cycle of a pine tr
zygote
What adaptations should one expect of the seed coats of angiosperm species whose seeds are dispersed by frugivorous (fruit-eating) animals, as opposed to angiosperm species whose seeds are dispersed by other means?
The seed coat should be able to withstand low pH's; the seed coat should be resistant to the animals' digestive enzymes.
The seeds of orchids are among the smallest known, with virtually no endosperm and with minuscule seed leaves. Consequently, what should one expect to be true of such seeds?
They germinate very soon after being released from the ovary.
In onions, cells of the sporophyte have 16 chromosomes within each nucleus. Match the number of chromosomes present in each of the onion tissues listed below.
How many chromosomes should be in the tube cell nucleus?
How many chromosomes should be in an en
8
24
16
The value for (E) in root tissue was found to be -0.15MPa. If you take the root tissue and place it in a 0.1M solution of sucrose (E) = -0.23, net water flow would
be from the tissue into the sucrose solution
Accumulation of K+ by guard cells results in water uptake, and the turgid condition of the cells keeps the stomata open. All of the following are cues for stomatal opening EXCEPT
increased humidity in the leaf's environment
A certain short-day plant flowers only when days are less than 12 hours long. Which of the following would cause it to flower?
a 13-hour night and 11-hour day with 1 minute of darkness after 6 hours
Plants produce auxin in the apical merstems at the tips of shoots at different concentrations, auxin stimulates or inhibits the elongation of shoots and roots. Auxin can cause a shoot to bend toward light
stimulating growth on the dark side of the shoot
The genus Atriplex, saltbush, is worldwide in saline shortline and inland habitants. Which of the following is an adaptation that would help Atriplex to survive in such saline conditions?
Glands that actively collect salt into vacuoles which is then released into the environment.
An experiment is performed where plants are exposed to a mixture of gases for several house and then analyzed. One of the gases included in the mixture is radioactive CO2 that contains the C-14 isotope of carbon rather than the C-12 isotope. Which of the
phloem
Which of the following mechanisms is most likely responsible for the rapid uptake of this nutrient into the plant's root tissue?
active transport