unit 5 mastering biology – Flashcards
Unlock all answers in this set
Unlock answersquestion
Unlike an earthworm's metanephridia, a mammalian nephron functions in both osmoregulation and excretion. is intimately associated with a capillary network. forms urine by changing fluid composition inside a tubule. has a transport epithelium. receives filtrate from blood instead of coelomic fluid.
answer
receives filtrate from blood instead of coelomic fluid.
question
Which process in the nephron is least selective? secretion salt pumping by the loop of Henle reabsorption active transport filtration
answer
filtration
question
which of the following animals generally has the lowest volume of urine production? a shark inhabiting freshwater Lake Nicaragua a marine bony fish a freshwater bony fish a vampire bat a salmon in fresh water
answer
a marine bony fish
question
The high osmolarity of the renal medulla is maintained by all of the following except diffusion of salt from the descending limb of the loop of Henle. the spatial arrangement of juxtamedullary nephrons. diffusion of salt from the thin segment of the ascending limb of the loop of Henle. active transport of salt from the upper region of the ascending limb. diffusion of urea from the collecting duct.
answer
diffusion of salt from the descending limb of the loop of Henle.
question
Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species? a beaver a river otter a mouse species living in a desert a mouse species living in a temperate broadleaf forest a mouse species living in a tropical rain forest
answer
a mouse species living in a desert
question
African lungfish, which are often found in small stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation? The highly toxic urea makes the pool uninhabitable to potential competitors. Urea takes less energy to synthesize than ammonia. Urea forms an insoluble precipitate. Urea makes lungfish tissue hypoosmotic to the pool. Small stagnant pools do not provide enough water to dilute the toxic ammonia.
answer
Small stagnant pools do not provide enough water to dilute the toxic ammonia.
question
Which of the following is not an accurate statement? Hormones of the same chemical class usually have the same function. Hormones are chemical messengers that travel to target cells through the circulatory system. Hormones are often regulated through feedback loops. Hormones are secreted by specialized cells usually located in endocrine glands. Hormones often regulate homeostasis through antagonistic functions.
answer
Hormones of the same chemical class usually have the same function.
question
An example of antagonistic hormones controlling homeostasis is epinephrine and norepinephrine in fight-or-flight responses. progestins and estrogens in sexual differentiation. oxytocin and prolactin in milk production. thyroxine and parathyroid hormone in calcium balance. insulin and glucagon in glucose metabolism.
answer
insulin and glucagon in glucose metabolism.
question
Growth factors are local regulators that bind to cell-surface receptors and stimulate growth and development of target cells. are modified fatty acids that stimulate bone and cartilage growth. are produced by the anterior pituitary. convey messages between nerve cells. are found on the surface of cancer cells and stimulate abnormal cell division.
answer
bind to cell-surface receptors and stimulate growth and development of target cells.
question
Which hormone is incorrectly paired with its action? ACTH-stimulates the release of glucocorticoids by the adrenal cortex melatonin-affects biological rhythms, seasonal reproduction insulin-stimulates glycogen breakdown in the liver oxytocin-stimulates uterine contractions during childbirth thyroxine-stimulates metabolic processes
answer
insulin-stimulates glycogen breakdown in the liver
question
Steroid and peptide hormones typically have in common the location of their receptors. their requirement for travel through the bloodstream. their reliance on signal transduction in the cell. their solubility in cell membranes. the building blocks from which they are synthesized.
answer
their requirement for travel through the bloodstream.
question
Which of the following is the most likely explanation for hypothyroidism in a patient whose iodine level is normal? a decrease in the thyroid secretion of calcitonin hypersecretion of TSH hypersecretion of MSH hyposecretion of TSH greater production of T3 than of T4
answer
hyposecretion of TSH
question
Shortly after ingesting a big plate of carbohydrate-rich pasta, you measure your blood's hormone levels. What results would you expect, compared to before the meal? low insulin, low glucagon high insulin, low glucagon low insulin, high glucagon high insulin, high glucagon low insulin, no change in glucagon
answer
high insulin, low glucagon
question
The relationship between the insect hormones ecdysteroid and PTTH is an example of competitive inhibition of a hormone receptor. how peptide-derived hormones have more widespread effects than steroid hormones. an interaction of the endocrine and nervous systems. homeostasis achieved by positive feedback. homeostasis maintained by antagonistic hormones.
answer
an interaction of the endocrine and nervous systems.
question
Which of the following characterizes parthenogenesis? Specialized groups of cells grow into new individuals. Both mates have male and female reproductive organs. An egg develops without being fertilized. An organism is first a male and then a female. An individual may change its sex during its lifetime.
answer
An egg develops without being fertilized.
question
In male mammals, excretory and reproductive systems share the urethra. the testes. the vas deferens. the seminal vesicle. the prostate.
answer
the urethra
question
Which of the following is not properly paired? vas deferens-oviduct seminiferous tubule-cervix scrotum-labia majora testosterone-estradiol Sertoli cells-follicle cells
answer
seminiferous tubule-cervix
question
Peaks of LH and FSH production occur during the end of the luteal phase of the ovarian cycle. the menstrual flow phase of the uterine cycle. the beginning of the follicular phase of the ovarian cycle. the secretory phase of the menstrual cycle. the period just before ovulation.
answer
the period just before ovulation.
question
During human gestation, rudiments of all organs develop in the second trimester. while the embryo is in the oviduct. in the third trimester. during the blastocyst stage. in the first trimester.
answer
in the first trimester.
question
Which of the following is a true statement? The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles. All mammals have menstrual cycles. Ovulation occurs before the endometrium thickens in estrous cycles. Estrous cycles are not controlled by hormones. Estrous cycles are more frequent than menstrual cycles.
answer
The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.
question
For which of the following is the number the same in spermatogenesis and oogenesis? gametes produced in a given time period functional gametes produced by meiosis interruptions in meiotic divisions different cell types produced by meiosis meiotic divisions required to produce each gamete
answer
meiotic divisions required to produce each gamete
question
Which statement about human reproduction is false? An oocyte completes meiosis after a sperm penetrates it. Spermatogenesis and oogenesis require different temperatures. Effective hormonal contraceptives are currently available only for females. Fertilization occurs in the oviduct. The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.
answer
The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.
question
The cortical reaction of sea urchin eggs functions directly in the generation of an electrical impulse by the egg. the production of a fast block to polyspermy. the release of hydrolytic enzymes from the sperm. the formation of a fertilization envelope. the fusion of egg and sperm nuclei.
answer
the formation of a fertilization envelope.
question
Which of the following is common to the development of both birds and mammals? epiblast and hypoblast trophoblast yolk plug holoblastic cleavage gray crescent
answer
epiblast and hypoblast
question
The archenteron develops into the mesoderm. the blastocoel. the lumen of the digestive tract. the endoderm. the placenta.
answer
the lumen of the digestive tract.
question
What structural adaptation in chickens allows them to lay their eggs in arid environments rather than in water? development of the brain from ectoderm cleavage gastrulation extraembryonic membranes yolk
answer
extraembryonic membranes
question
In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the fusion of sperm and egg nuclei would be blocked. the acrosomal reaction would be blocked. the fast block to polyspermy would not occur. the fertilization envelope would not form. the zygote would not contain maternal and paternal chromosomes.
answer
the fertilization envelope would not form.
question
In humans, identical twins are possible because early blastomeres can form a complete embryo if isolated. cytoplasmic determinants are distributed unevenly in unfertilized eggs. convergent extension occurs. extraembryonic cells interact with the zygote nucleus. the gray crescent divides the dorsal-ventral axis into new cells.
answer
early blastomeres can form a complete embryo if isolated.
question
Cells transplanted from the neural tube of a frog embryo to the ventral part of another embryo develop into nervous system tissues. This result indicates that the transplanted cells were mesenchymal. determined. apoptotic. differentiated. totipotent.
answer
determined.
question
In an embryonic vertebrate, the apical ectodermal ridge (AER) is a thickened area at the tip of the bud. The cells of the AER secrete protein signals that promote limb-bud outgrowth, and removing the AER blocks growth of the limb along the proximal-distal axis. How would the forelimb of an embryo develop if the AER was removed early or late in limb development? Early removal of the AER would prevent the formation of many distal structures, whereas late removal of the AER would prevent the formation of a few distal structures. Early or late removal of the AER would have the same result: the embryo would not develop a forelimb. Early removal of the AER would prevent the development of a forelimb, whereas late removal of the AER would not have any effect.
answer
Early removal of the AER would prevent the formation of many distal structures, whereas late removal of the AER would prevent the formation of a few distal structures.
question
Select the correct statement about embryonic development in a frog. Development from zygote to blastula involves mitotic division, cell movement, and cell growth. The blastocoel of a developing frog embryo develops into the digestive tract. The reorganization of cell layers during gastrulation allows the layers to interact with each other in new ways.
answer
The reorganization of cell layers during gastrulation allows the layers to interact with each other in new ways.
question
The allantois stores nitrogenous wastes in a reptile egg. What is the function of the allantois in human development? The allantois does not play any role in human development, because the placenta mediates the transfer of nitrogenous wastes from embryonic to maternal circulation. The allantois helps form the umbilical cord in human development. The allantois cushions the human embryo in a private "pond" during development.
answer
The allantois helps form the umbilical cord in human development.
question
Identify the correct statement(s) about Spemann's organizer. Select all that apply. Spemann's organizer is the dorsal lip of the blastopore in frog gastrulation. Spemann's organizer initiates a chain of inductive interactions in frog development. Spemann's organizer is made up of totipotent cells.
answer
Spemann's organizer is the dorsal lip of the blastopore in frog gastrulation. Spemann's organizer initiates a chain of inductive interactions in frog development.
question
In an embryonic vertebrate, the zone of polarizing activity (ZPA) is a block of tissue located on the posterior side of a limb bud. The ZPA provides information about the anterior-posterior axis of the limb. Cells nearest the ZPA form the most posterior of digits (like our little finger); cells farthest from the ZPA form the most anterior digits (like our thumb). How would a vertebrate forelimb bud develop if it had two zones of polarizing activities, one on the posterior side and one on the anterior side of the bud? The forelimb bud would develop into a hind limb. The embryo wouldn't develop a forelimb. The forelimb bud would develop with extra digits, in a mirror image arrangement to the normal digits.
answer
The forelimb bud would develop with extra digits, in a mirror image arrangement to the normal digits.
question
What happens when a resting neuron's membrane depolarizes? There is a net diffusion of Na+ out of the cell. The equilibrium potential for K+ (E K) becomes more positive. The neuron's membrane voltage becomes more positive. The cell's inside is more negative than the outside. The neuron is less likely to generate an action potential.
answer
The neuron's membrane voltage becomes more positive.
question
A common feature of action potentials is that they cause the membrane to hyperpolarize and then depolarize. move at the same speed along all axons. are triggered by a depolarization that reaches the threshold. require the diffusion of and through ligand-gated channels to propagate. can undergo temporal and spatial summation.
answer
are triggered by a depolarization that reaches the threshold.
question
Where are neurotransmitter receptors located? synaptic vesicle membranes the postsynaptic membrane the nuclear membrane the myelin sheath the nodes of Ranvier
answer
the postsynaptic membrane
question
Temporal summation always involves inputs that are not simultaneous. synapses at more than one site. both inhibitory and excitatory inputs. multiple inputs at a single synapse. electrical synapses.
answer
multiple inputs at a single synapse.
question
Why are action potentials usually conducted in one direction? Voltage-gated channels for both Na+ and K+ open in only one direction. The brief refractory period prevents reopening of voltage-gated Na+ channels. Ions can flow along the axon in only one direction. The axon hillock has a higher membrane potential than the terminals of the axon. The nodes of Ranvier conduct potentials in one direction.
answer
The brief refractory period prevents reopening of voltage-gated Na+ channels.
question
Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal? An EPSP or IPSP is generated in the postsynaptic cell. The postsynaptic cell produces an action potential. Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft. Synaptic vesicles fuse with the membrane. Voltage-gated calcium channels in the membrane open.
answer
Voltage-gated calcium channels in the membrane open.
question
Why is an action potential an all-or-none response to stimuli? Because a typical neuron receives signals through multiple dendrites but transmits signals through a single axon Because neurons contain gated ion channels that are either open or closed Because voltage-gated ion channels open when membrane potential passes a particular level
answer
Because voltage-gated ion channels open when membrane potential passes a particular level
question
What causes the falling phase of the action potential? Select the best answer. The opening of voltage-gated sodium channels Inactivation of voltage-gated sodium channels and the opening of voltage-gated potassium channels The opening of voltage-gated potassium channels
answer
Inactivation of voltage-gated sodium channels and the opening of voltage-gated potassium channels
question
If the membrane potential of a neuron decreases, the membrane potential _____. remains unchanged. becomes more negative. becomes more positive.
answer
becomes more positive.
question
The plasma membrane of a neuron has voltage-gated sodium and potassium channels. What is the effect of membrane depolarization on these channels? Membrane depolarization opens sodium and potassium channels at the same time. Membrane depolarization first opens sodium channels and then opens potassium channels. Membrane depolarization opens sodium channels but closes potassium channels.
answer
Membrane depolarization first opens sodium channels and then opens potassium channels.
question
Identify the correct statement(s) about the resting membrane potential of a cell. Select all that apply. Potassium (K+) and sodium (Na+) gradients are maintained by active transport in a resting mammalian neuron. Neurons are the only cells that have a charge difference across their membranes. Concentration gradients of potassium (K+) and sodium (Na+) across the plasma membrane represent potential energy.
answer
Potassium (K+) and sodium (Na+) gradients are maintained by active transport in a resting mammalian neuron. Concentration gradients of potassium (K+) and sodium (Na+) across the plasma membrane represent potential energy.
question
Wakefulness is regulated by the reticular formation, which is present in the spinal cord. limbic system. basal nuclei. cerebral cortex. brainstem.
answer
brainstem.
question
Which of the following structures or regions is incorrectly paired with its function? corpus callosum-communication between the left and right cerebral cortices amygdala-emotional memory limbic system-motor control of speech medulla oblongata-homeostatic control cerebellum-coordination of movement and balance
answer
limbic system-motor control of speech
question
Patients with damage to Wernicke's area have difficulty coordinating limb movement. generating speech. experiencing emotion. understanding language. recognizing faces.
answer
understanding language.
question
The cerebral cortex plays a major role in all of the following except foot-tapping rhythm. long-term memory. circadian rhythm. short-term memory. breath holding.
answer
circadian rhythm.
question
After suffering a stroke, a patient can see objects anywhere in front of him but pays attention only to objects in his right field of vision. When asked to describe these objects, he has difficulty judging their size and distance. What part of the brain was likely damaged by the stroke? the corpus callosum the left parietal lobe the right frontal lobe the left frontal lobe the right parietal lobe
answer
the right parietal lobe
question
Injury localized to the hypothalamus would most likely disrupt executive functions, such as decision making. short-term memory. coordination during locomotion. regulation of body temperature. sorting of sensory information.
answer
regulation of body temperature.
question
Identify the role(s) of glia in the vertebrate brain. Select all that apply. Glia release neurotransmitters. Glia protect the nervous system from pathogens. Glia guide neuron migration during development of the CNS
answer
Glia release neurotransmitters. Glia protect the nervous system from pathogens. Glia guide neuron migration during development of the CNS
question
Which examples correctly illustrate the cooperation between the motor and nervous systems to maintain homeostasis in a vertebrate body? Select all that apply. A drop in body temperature leads to shivering and constriction of surface blood vessels. In response to a sudden fright, the body responds by increasing heart rate, inhibiting digestion, and increasing blood glucose. If you put your hand on a hot burner, a reflex pulls your hand back before you sense pain.
answer
A drop in body temperature leads to shivering and constriction of surface blood vessels.
question
Which of these observations illustrate the developmental plasticity of the human nervous system? Select all that apply. When activity at a synapse correlates with the activity of other synapses, that synaptic connection is reinforced. A person suffering from phantom limb pain following amputation may stop feeling pain after viewing a reflection of the remaining limb in a mirrored box. The brain may ignore certain stimuli and actively process other stimuli.
answer
When activity at a synapse correlates with the activity of other synapses, that synaptic connection is reinforced. A person suffering from phantom limb pain following amputation may stop feeling pain after viewing a reflection of the remaining limb in a mirrored box.
question
Identify the correct statement(s) about glial cells and their functions. Select all that apply. Oligodendrocytes act as stem cells, producing neurons and glia. Schwann cells myelinate dendrites in the PNS. Astrocytes induce the formation of the blood-brain barrier.
answer
Astrocytes induce the formation of the blood-brain barrier.
question
Which of these observations illustrate regional specialization in the human nervous system? Select all that apply. Reading a printed word out loud and then thinking of a related word involves the visual cortex, Broca's area, and the frontal and temporal lobes. Sensory information may be processed in the occipital lobe or the temporal lobe. When the activity of a synapse fails to correlate with that of other synapses, the synaptic connection may become weaker.
answer
Reading a printed word out loud and then thinking of a related word involves the visual cortex, Broca's area, and the frontal and temporal lobes. Sensory information may be processed in the occipital lobe or the temporal lobe.
