Which of the following characterizes parthenogenesis?
A. An individual may change its sex during its lifetime.
B. Specialized groups of cells grow into new individuals.
C. An organism is first a male and then a female.
D. An egg develops without being fertilized.
E. Both mates have male and female reproductive organs
An egg develops without being fertilized
In male mammals, excretory and reproductive systems share
A. the testes.
B. the urethra.
C. the seminal vesicle.
D. the vas deferens.
E. the prostate.
Which of the following is not properly paired?
A. seminiferous tubule—cervix
B. Sertoli cells—follicle cells
E. vas deferens—oviduct
Which of the following is a true statement?
A. All mammals have menstrual cycles.
B.The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.
C. Estrous cycles occur more often than menstrual cycles.
D. Estrous cycles are not controlled by hormones.
E. Ovulation occurs before the endometrium thickens in estrous cycles.
The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.
Peaks of LH and FSH production occur during
A. the menstrual flow phase of the uterine cycle.
B. the beginning of the follicular phase of the ovarian cycle.
C. the period just before ovulation.
D. the end of the luteal phase of the ovarian cycle.
E. the secretory phase of the menstrual cycle.
the period just before ovulation.
For which of the following is the number the same in spermatogenesis and oogenesis?
A.interruptions in meiotic divisions
B. functional gametes produced by meiosis
C.meiotic divisions required to produce each gamete
D.gametes produced in a given time period
E. different cell types produced by meiosis
meiotic divisions required to produce each gamete
During human gestation, rudiments of all organs develop
A. in the first trimester.
B. in the second trimester.
C. in the third trimester.
D. while the embryo is in the oviduct.
E. during the blastocyst stage.
in the first trimester.
Which statement about human reproduction is false?
A. Fertilization occurs in the oviduct.
B. Effective hormonal contraceptives are currently available only for females.
C. An oocyte completes meiosis after a sperm penetrates it.
D. The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.
E. Spermatogenesis and oogenesis require different temperatures.
The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.
The cortical reaction of sea urchin eggs functions directly in
A. the formation of a fertilization envelope
B.the production of a fast block to polyspermy.
C.the release of hydrolytic enzymes from the sperm
D.the generation of an electrical impulse by the egg.
E. the fusion of egg and sperm nuclei.
the formation of a fertilization envelope
Which of the following is common to the development of both birds and mammals?
B. epiblast and hypoblast
D. yolk plug
E. gray crescent
epiblast and hypoblast
The archenteron develops into
A. the mesoderm.
B. the blastocoel.
C. the endoderm.
D. the placenta.
E. the lumen of the digestive tract.
the lumen of the digestive tract
In a frog embryo, the blastocoel is
A. completely obliterated by yolk.
B. lined with endoderm during gastrulation
C.located in the animal hemisphere.
D. the cavity that becomes the coelom.
E. the cavity that later forms the archenteron.
located in the animal hemisphere
What structural adaptation in chickens allows them to lay their eggs in arid environments, rather than in water?
A. extraembryonic membranes
E.development of the brain from ectoderm
In an amphibian embryo, a group of cells called neural crest cells
A. rolls up and forms the neural tube.
B. develops into the main sections of the brain.
C. produces cells that migrate to form teeth, skull bones, and other structures in the embryo.
D. has been shown by experiments to be the organizer region of the developing embryo.
E. induces the formation of the notochord.
produces cells that migrate to form teeth, skull bones, and other structures in the embryo
In the early development of an amphibian embryo, Spemann's "organizer" is located in the
A. neural tube.
C. archenteron roof.
D. dorsal ectoderm.
E. dorsal lip of the blastopore.
dorsal lip of the blastopore
What happens when a neuron's membrane depolarizes?
A. There is a net diffusion of Na+ out of the cell.
B.The equilibrium potential for K+ (EK) becomes more positive.
C. The neuron's membrane voltage becomes more positive.
D. The neuron becomes less likely to generate an action potential.
E. The inside of the cell becomes more negative relative to the outside
The neuron's membrane voltage becomes more positive.
Why are action potentials usually conducted in only one direction along an axon?
A. The nodes of Ranvier can conduct potentials in only one direction.
B. The brief refractory period prevents reopening of voltage-gated Na+ channels.
C. The axon hillock has a higher membrane potential than the terminals of the axon.
D. Ions can flow along the axon in only one direction.
E. Voltage-gated channels for both Na+ and K+ open in only one direction.
The brief refractory period prevents reopening of voltage-gated Na+ channels
A common feature of action potentials is that they
A. cause the membrane to hyperpolarize and then depolarize.
B. can undergo temporal and spatial summation.
C. are triggered by a depolarization that reaches the threshold.
D. move at the same speed along all axons.
E. result from the diffusion of Na+ and K+ through ligand-gated channels.
are triggered by a depolarization that reaches the threshold
Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?
A. Voltage-gated calcium channels in the membrane open.
B. Synaptic vesicles fuse with the membrane.
C. The postsynaptic cell produces an action potential.
D. Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft.
E. An EPSP or IPSP is generated in the postsynaptic cell.
Voltage-gated calcium channels in the membrane open
Where are neurotransmitter receptors located?
A. on the nuclear membrane
B. at nodes of Ranvier
C. on the postsynaptic membrane
D. on the membranes of synaptic vesicles
E. in the myelin sheath
on the postsynaptic membrane
Temporal summation always involves
A. both inhibitory and excitatory inputs.
B. synapses at more than one site.
C. inputs that are not simultaneous.
D. electrical synapses.
E. multiple inputs at a single synapse.
multiple inputs at a single synapse
Wakefulness is regulated by the reticular formation, which is present in the
A. basal nuclei
E. spinal cord.
Which of the following structures or regions is incorrectly paired with its function?
A. limbic system—motor control of speech
B. medulla oblongata—homeostatic control
C. cerebellum—coordination of movement and balance
D. corpus callosum—communication between the left and right cerebral cortices
E. hypothalamus—regulation of temperature, hunger, and thirst
limbic system—motor control of speech
What is the neocortex?
A. a primitive brain region that is common to reptiles and mammals
B. a region deep in the cortex that is associated with the formation of emotional memories
C. a central part of the cortex that receives olfactory information
D. an additional outer layer of neurons in the cerebral cortex that is unique to mammals
E. an association area of the frontal lobe that is involved in higher cognitive functions
an additional outer layer of neurons in the cerebral cortex that is unique to mammals
Patients with damage to Wernicke's area have difficulty
A. coordinating limb movement.
B. generating speech.
C. recognizing faces.
D. understanding language.
E. experiencing emotion.
The sympathetic division of the autonomic portion of the PNS does all of the following except
A. relaxing bronchi in lungs.
B.inhibiting bladder emptying.
C. stimulating glucose release.
D. accelerating heart rate.
E. stimulating the salivary glands.
stimulating the salivary glands
The cerebral cortex plays a major role in all of the following except
A. short-term memory.
B. long-term memory.
C. circadian rhythm.
D. foot-tapping rhythm.
E. breath holding.