exam 2 (practice questions) Flashcards
what is parthenogenesis
an egg develops without being fertilized
what part of the body does the excretory and reproductive system share in male mammals
the urethra
peaks of LH and FSH occur during
the period just before ovulation
during what trimester do rudiments of all organs develop
in the first trimester
the endometrial lining is ______ in menstrual cycles but ________ in estrous cycles
shed; reabsorbed
for which of the following is the number the same in human males and females?
functional gametes produced by meiosis
true or false: the earliest stages of spermatogenesis occur closes to the lumen of the seminiferous tubules
false
true or false: fertilization occurs in the oviduct
true
true or false: an oocyte completes meiosis after a sperm penetrates it
true
what are the seminiferous tubules
specialized structures within the testes that house spermatogenesis
- where human sperm cells first arise
what is a similarity between oogenesis and spermatogenesis?
both oogenesis and spermatogenesis lead to the production of gametes from germ cells
when does oogenesis and spermatogenesis begin in males and females?
oogenesis begins before birth but is stopped until puberty
spermatogenesis begins at puberty
advantage of internal fertilization that external fertilization does not get
the smaller number of offspring produced often receive a greater amount of parental investment
for water feels of the genus daphnia, switching from a pattern of asexual reproduction to sexual reproduction coincides with
periods of temperate or food stresses on adults
sexual can produce can produce _________
diverse phenotypes that may enhance survival of a population in a changing environment
asexual reproduction results in greater reproductive success than does sexual reproduction when
a species is in a stable and favorable environment
genetic mutations in asexually reproducing organisms lead to more evolutionary changes than do genetic mutations in sexually reproducing ones because
asexually reproducing organisms, but not sexually reproducing organisms, pass all mutations on to their offspring
in an animal that switches between sexual and asexual reproduction, when is sexual reproduction more likely to occur?
when conditions for survival are unfavorable
environmental cues that influence the timing of reproduction generally do so by ________
direct effects on hormonal control mechanisms
on a submarine to the ocean you discover population of fish that are only female. what type of reproduction does this fish most likely use?
parthenogenesis
what type of organisms reproduce by fission
primarily single-celled organisms like hydra, bacteria, yeast, protists, corals
what process makes sexually reproduced offspring genetically different from their parents?
genetic recombination during meiosis
regeneration, the regrowth of lost body parts, normally follows
fragmentation
Hans Spemann and colleagues developed the concept of the “organizer” in amphibian embryos while studying the ________
dorsal lip of the blastopore
If an amphibian zygote is manipulated so that the first cleavage plane fails to divide the gray X crescent, then ________.
only the daughter cell with the gray crescent will develop normally
Which of the following is common to the development of birds and mammals?
the formation of an embryonic epiblast and hypoblast
Cells move to new positions as an embryo establishes its three germ tissue layers during ________.
gastrulation
An embryo with meroblastic cleavage, extraembryonic membranes, and a primitive streak must be that of ________
a bird
The cortical reaction of sea urchin eggs functions directly in ________.
the formation of a fertilization envelope
why is sperm necessary for reproduction?
sperm trigger egg activation
The first cavity formed during frog development is the ________.
blastocoel
Which of the following correctly displays the sequence of developmental milestones?
cleavage → blastula → gastrula
The vegetal pole of a frog zygote differs from the animal pole in that ________.
the vegetal pole has a higher concentration of yolk
In mammalian eggs, the receptors for sperm are found in the ________.
egg plasma membrane
In an egg cell treated with a chemical that binds calcium and magnesium ions, the ________
fertilization envelope would not be formed
During fertilization, the acrosomal contents ________
digest the protective jelly coat on the surface of the egg
A reproductive difference between sea urchins and humans is ________.
the sea urchin egg completes meiosis prior to fertilization, but meiosis in humans is completed after fertilization
Fertilization of an egg without activation is most like ________.
placing the key in the ignition of a car but not starting the engine
The plasma membrane of the sea urchin egg ________.
has receptor molecules that are specific for binding acrosomal proteins
Contact of a sea urchin egg with signal molecules on sperm causes the egg to undergo a brief ________.
membrane depolarization
The formation of the fertilization envelope requires an increase in the cystosolic concentration of ________.
calcium ions
Most of the neurons in the human central nervous system are ________
interneurons
The point of connection between two communicating neurons is called the ________.
synapse
The motor (somatic nervous) system can alter the activities of its targets, the skeletal muscle fibers, because ________.
its signals bind to receptor proteins on the muscles
In a simple synapse, neurotransmitter chemicals are released by ________.
the presynaptic membrane
In a simple synapse, neurotransmitter chemicals are received by ________
dendrites
Although the membrane of a “resting” neuron is highly permeable to potassium ions, its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also ________.
slightly permeable to sodium ions
The operation of the sodium-potassium pump moves ________
sodium ions out of the cell and potassium ions into the cell
In a resting potential, an example of a cation that is more abundant as a solute in the cytosol of a neuron than it is in the interstitial fluid outside the neuron is ________.
K+
Two fundamental concepts about the ion channels of a “resting” neuron are that the channels ________.
are open or closed depending on their type, and are specific as to which ion can traverse them
If you experimentally increase the concentration of Na+ outside a cell while maintaining other ion concentrations as they were, what would happen to the cell’s membrane potential?
The membrane potential would become more positive.
The concentrations of ions are very different inside and outside a nerve cell due to ________
sodium-potassium pumps
Which ion is most likely to cross the plasma membrane of a resting neuron?
K+
The membrane’s permeability to sodium ions is greatest at ________
rising stage
After the depolarization phase of an action potential, the resting potential is restored by ________.
the opening of voltage-gated potassium channels and the inactivation of sodium channels
The “undershoot” phase of hyperpolarization is due to ________
sustained opening of voltage-gated potassium channels
Why are action potentials usually conducted in one direction?
The brief refractory period prevents reopening of voltage-gated sodium channels.
If you experimentally increase the concentration of K+ inside a cell while maintaining other ion concentrations as they were, what would happen to the cell’s membrane potential?
The membrane potential would become less negative.
Which of the following statements about action potentials is correct?
Action potentials are propagated down the length of the axon.
An example of ligand-gated ion channels is ________.
acetylcholine receptors at the neuromuscular junction
If excitatory postsynaptic potentials (EPSPs) are produced nearly simultaneously through two different synapses on the same postsynaptic neuron, the EPSPs can also add together creating ________.
a spatial summation
When two excitatory postsynaptic potentials (EPSPs) occur at a single synapse so rapidly in succession that the postsynaptic neuron’s membrane potential has not returned to the resting potential before the second EPSP arrives, the EPSPs add together producing ________.
temporal summation
The amino acid that operates at most inhibitory synapses in the brain is ________.
gamma-aminobutyric acid (GABA)
The heart rate of a vertebrate will decrease in response to the arrival of ________
acetylcholine
which event occurs first following a depolarizing stimulus applied to the presynaptic membrane of an axon terminal?
Voltage-gated calcium channels in the membrane open.
How could you increase the magnitude of excitatory postsynaptic potentials (EPSPs) generated at a synapse?
Increase Na+ permeability.
At the neuromuscular junction, the neurotransmitter acetylcholine (ACh) is degraded by acetylcholinesterase. If a neurophysiologist applies the naturally occurring acetylcholinesterase inhibitor, onchidal (produced by the mollusc Onchidella binneyi), to a synapse, what would you expect to happen?
convulsions due to constant muscle stimulation
What happens when a resting neuron’s membrane depolarizes?
The neuron’s membrane voltage becomes more positive.
A common feature of action potentials is that they
are triggered by a depolarization that reaches threshold.
Where are neurotransmitter receptors located?
the postsynaptic membrane
Why are action potentials usually conducted in one direction?
The brief refractory period prevents reopening of voltage-gated Na+ channels.
Which of the following is the most direct result of depolarizing the presynaptic membrane of an axon terminal?
Voltage-gated calcium channels in the membrane open.
Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that
cells X and Y express different receptor molecules for this particular neurotransmitter
The stretch sensors of the sensory neurons in the human knee-jerk reflex are located in the ________.
quadriceps muscles on the front side of the thighs
Choose the correct match of glial cell type and function.
astrocytes—promote blood flow and regulate ion concentrations
The human knee-jerk reflex requires an intact ________
spinal cord
Cerebrospinal fluid can be described as which of the following
I) functioning in transport of nutrients and hormones through the brain
II) a product of the filtration of blood in the brain
III) functioning to cushion the brain
The divisions of the nervous system that have antagonistic, or opposing, actions are ________.
sympathetic and parasympathetic systems
Preparation for the fight-or-flight response includes activation of the ________ nervous system
sympathetic
The activation of the parasympathetic branch of the autonomic nervous system is associated with ________.
resting and digesting
After narrowly escaping a mountain lion attack, which of the following reactions would your nervous system initiate?
increased heartbeat
In humans, control of balance and coordinated movements are associated with increased activity in the ________.
cerebellum
Central coordination of vertebrate biological rhythms in physiology and behavior reside in the ________.
hypothalamus
The regulation of body temperature derives from the activity of the ________
hypothalamus
If you were writing an essay, the part(s) of your brain that would be actively involved in this task is/are the ________.
frontal lobes
Wernicke’s area ________
is active when speech is heard and comprehended
Patients with damage to Broca’s area have difficulty ________.
generating speech
An injury to the temporal lobe will likely impair the function of the ________
sense of hearing
One of the fundamental processes by which memories are stored and learning takes place ________
involves changing the responsiveness of postsynaptic neurons to neurotransmitter
Forming new long-term memories is strikingly disrupted after damage to the ________
cerebral cortex
For long-term potentiation to occur in the hippocampus, ________.
NMDA receptors must be unblocked so that they can respond to glutamate
One of the complications of Alzheimer’s disease is an interference with learning and memory. This disease would most likely involve ________.
molecular and structural changes at synapses
The cerebral cortex does not play a major role in
circadian rhythm
(other choices were short term memory, long term memory, and breath holding)
The correct sequence of sensory processing is ________
stimulus reception → sensory transduction → sensory perception → sensory adaptation
The conversion of a stimulus into an action potential by a receptor cell is called ________.
transduction
Immediately after putting on a shirt, your skin might feel itchy. However, this perception soon fades due to ________.
sensory adaptation
The structure of the mammalian middle ear is adapted to convert ________.
air pressure waves to fluid pressure waves
During an auditory transduction, ion flow varies across the ________
hair cell membrane
A patient is hospitalized with muscle spasms caused by failure of back muscles to relax after contraction. Which of the following would be most likely to help?
Induce tropomyosin and troponin to bind to the myosin binding sites on actin.
The transduction of sound waves into action potentials occurs
when hair cells are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons.
