exam 2 (practice questions) Flashcards by Ayesha Rashid

what is parthenogenesis

an egg develops without being fertilized

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what part of the body does the excretory and reproductive system share in male mammals

the urethra

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peaks of LH and FSH occur during

the period just before ovulation

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during what trimester do rudiments of all organs develop

in the first trimester

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the endometrial lining is ______ in menstrual cycles but ________ in estrous cycles

shed; reabsorbed

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for which of the following is the number the same in human males and females?

functional gametes produced by meiosis

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true or false: the earliest stages of spermatogenesis occur closes to the lumen of the seminiferous tubules

false

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true or false: fertilization occurs in the oviduct

true

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true or false: an oocyte completes meiosis after a sperm penetrates it

true

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what are the seminiferous tubules

specialized structures within the testes that house spermatogenesis

where human sperm cells first arise

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what is a similarity between oogenesis and spermatogenesis?

both oogenesis and spermatogenesis lead to the production of gametes from germ cells

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when does oogenesis and spermatogenesis begin in males and females?

oogenesis begins before birth but is stopped until puberty

spermatogenesis begins at puberty

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advantage of internal fertilization that external fertilization does not get

the smaller number of offspring produced often receive a greater amount of parental investment

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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

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sexual can produce can produce _________

diverse phenotypes that may enhance survival of a population in a changing environment

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asexual reproduction results in greater reproductive success than does sexual reproduction when

a species is in a stable and favorable environment

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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

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in an animal that switches between sexual and asexual reproduction, when is sexual reproduction more likely to occur?

when conditions for survival are unfavorable

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environmental cues that influence the timing of reproduction generally do so by ________

direct effects on hormonal control mechanisms

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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

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what type of organisms reproduce by fission

primarily single-celled organisms like hydra, bacteria, yeast, protists, corals

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what process makes sexually reproduced offspring genetically different from their parents?

genetic recombination during meiosis

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regeneration, the regrowth of lost body parts, normally follows

fragmentation

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Hans Spemann and colleagues developed the concept of the “organizer” in amphibian embryos while studying the ________

dorsal lip of the blastopore

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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.