question

In the post-synaptic neuron with a resting potential of -70mV and a threshold of -50mV. Two EPSPs decrease the membrane potential by 15mV each and one IPSP increases the membrane potential by with a 15mV. Does this post-synaptic cell fire an action potential?

answer

Yes

question

During sensory adaptation your response to a stimulus

answer

decreases

question

The Central nervous System (CNS) consists of:

answer

brain and spinal cord

question

The somatic division is the parasympathetic portion of the afferent nervous system is the afferent portion of the CNS is under conscious control is under unconscious control

answer

is under conscious control

question

If muscles can only shorten when stimulated how is it possible for you to move your limbs in at least two directions (flexed and extended): -by using a hydrostatic skeleton -your muscles can expand and contract under stimulation -by using another limb to move it in the opposite direction -by using pairs of muscles working in opposition to one another

answer

by using pairs of muscles working in opposition to one another

question

The binding of actin to myosin during muscle contraction is regulated by

answer

Ca++

question

In a normal cell which of the following statements is correct The membrane potential is negative The concentration of Na+ inside the cell is greater than outside The concentration of negative ions is greater outside than inside The concentration of K+ outside the cell is greater than inside

answer

the membrane potential is negative

question

A membrane depolarization is generally caused by

answer

Na+ flowing into the cell

question

Excitable cells differ from other cells in that they have ____ in their membranes

answer

voltage-gated Na+ and K+ channels

question

While membrane depolarizations can be variable, all action potentials are the same.

answer

True

question

Action potentials in myelinated axons propagate smoothly slower than in non-myelinated axons can not propagate using salutatory motion

answer

using salutatory motion

question

Voltage gated Na+ channels have ____ gates.

answer

2 gates

question

The portion of a neuron that transmits membrane potentials to the cell body is usually the:

answer

dendrites

question

A single neuron can synapse with ____ other neurons

answer

many

question

Post-synaptic cells respond to neurotransmitters through the neurotransmitter

answer

binding to a receptor

question

An EPSP is caused by the movement of ____ and results in __________.

answer

Na+, depolarization

question

Which of the following is true of a target cell? It must have a receptor for the chemical signal It must have a second messenger It must use c-AMP It must use a tyrosine-kinase pathway It must use G-proteins

answer

it must have a receptor for the chemical signal

question

A compound that is secreted in one part of the body and travels through the bloodstream to another part of the body where it has an effect is called a(n)

answer

hormone

question

Protein signal molecules are not permeable to the cell membrane but can affect their target cells because -cells, which are the target, transport the signal molecule directly to the nucleus. -all of the other cells quickly destroy the signal molecules. -only the target cells have the appropriate DNA sequence that must be activated. -intracellular receptors are present only in the target cells -the target cells have cell membrane bound receptors specific to the signal molecule.

answer

the target cells have cell membrane bound receptors specific to the signal molecule

question

Which of the following is not one of the major plant hormones? Abscisic acid Brassinosteriods Gibberelins Ethylene Photoxin

answer

photoxin

question

Which hormone promotes seed dormancy?

answer

abscisic acid

question

Which plant hormone stimulates lateral bud developemnt in stems?

answer

cytokinin

question

Which of the following is involved in the regulation of metabolic rate?

answer

thyroxine (T4)

question

Which of the following contains neurosecretory cells?

answer

hypothalamus

question

Which of the following endocrine glands produces the greatest number of different hormones?

answer

anterior pituitary

question

Which of the following endocrine glands secretes steroid hormones?

answer

adrenal

question

Where is the pituitary gland located?

answer

the bottom of the brain

question

In a portal system how many capillary beds does the blood flow through as it travels from the heart back to the heart?

answer

2

question

If the membrane potential of a neuron decreases, the membrane potential _____.

answer

becomes more positive

question

Why is an action potential an all-or-none response to stimuli? -Because neurons contain gated ion channels that are either open or closed -Because a typical neuron receives signals through multiple dendrites but transmits signals through a single axon -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

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 first opens sodium channels and then opens potassium channels. -Membrane depolarization opens sodium channels but closes potassium channels. -Membrane depolarization opens sodium and potassium channels at the same time.

answer

Membrane depolarization first opens sodium channels and then opens potassium channels.

question

What causes the falling phase of the action potential? Select the best answer. -The opening of voltage-gated sodium channels -The opening of voltage-gated potassium channels -Inactivation of voltage-gated sodium channels and the opening of voltage-gated potassium channels

answer

Inactivation of voltage-gated sodium channels and the opening of voltage-gated potassium channels

question

Which structure is not part of a neuron?

answer

myelin sheath

question

Which of the following statements about action potentials in a given neuron is false? -They are propagated down the length of the dendrite. -They are identical in magnitude. -They occur after the threshold potential is reached. -They are identical in duration.

answer

They are propagated down the length of the dendrite

question

True or false? Action potentials travel in only one direction down an axon because potassium channels in the neuron are refractory and cannot be activated for a short time after they open and close.

answer

false

question

Which event triggers the creation of an action potential? -The sodium—potassium pump shuttles ions across the membrane. -Voltage-gated potassium channels open, and K+ ions diffuse out of the neuron. -The membrane depolarizes above a certain threshold potential. -There is an undershoot of the resting potential.

answer

The membrane depolarizes above a certain threshold potential

question

What term describes how a neuronal membrane's potential is altered in the presence of inhibitory signals?

answer

hyperpolarization

question

Where in the neuron do action potentials begin?

answer

axon hillock

question

How is an action potential propagated down an axon after voltage-gated sodium channels open in a region of the neuron's membrane? -Potassium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated sodium channels farther down the axon. -Sodium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated sodium channels farther down the axon. -Potassium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated potassium channels farther down the axon. -Sodium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated potassium channels farther down the axon.

answer

Sodium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated sodium channels farther down the axon.

question

What causes the release of neurotransmitter molecules?

answer

action potential reaching the end of the axon

question

The space between an axon of one neuron and the dendrite of another neuron is called a(n) _____.

answer

synaptic cleft

question

Neurons store neurotransmitter molecules in vesicles located within _____.

answer

synaptic terminals

question

Which type of hormone is lipid soluble?

answer

steroid

question

Which molecules determine the tissue specificity of hormones?

answer

receptors

question

True or false? Lipid-insoluble hormones affect their target cells by binding to receptors inside the cell.

answer

false

question

Which of the following statements about lipid-soluble hormones is true? -They bind to receptors on the plasma membrane. -They act by producing second messengers. -They act by affecting the transcription of genes. -They bind to DNA as soon as they enter a cell.

answer

They act by affecting the transcription of genes.

question

What structure allows hormone-receptor complexes to bind to specific DNA sequences?

answer

Zinc fingers

question

What is the role of cAMP in the signal transduction pathway activated by epinephrine? -It binds to and activates protein kinase A, which then phosphorylates other enzymes. -It catalyzes the breakdown of glycogen to glucose. -It activates adenylyl cyclase. -It binds to the receptor protein on a target cell.

answer

It binds to and activates protein kinase A, which then phosphorylates other enzymes

question

True or false? For a signal transduction pathway to be activated, hormones must be present in the bloodstream at very high concentrations.

answer

false

question

Which of these glands secretes releasing hormones? -hypothalamus -adrenal cortex -thymus -ovaries -testes

answer

hypothalamus

question

Which hormones are responsible for the "fight or flight" response to danger?

answer

epinephrine and norepinephrine

question

Adrenocorticotropic hormone (ACTH) triggers the release of _____ in response to stress.

answer

glucocorticoids

question

_____ are the main male hormones.

answer

androgens

question

What hormone promotes water retention by the kidneys?

answer

antidiuretic hormone (ADH)

question

Which hormone opposes the action of parathyroid hormone?

answer

calcitonin

question

Which hormone stimulates hormone production by the ovaries and testes?

answer

luteinizing hormone (LH)

question

Which hormone stimulates milk production?

answer

prolactin

question

What is the physical basis of the phototropic response?

answer

cell elongation

question

True or false? Auxin is asymmetrically distributed in shoots because the auxin on the side of the plant facing the source of light is destroyed.

answer

false

question

Where does the majority of stem growth in a plant occur?

answer

apical meristem

question

Which of the following statements about hormones is true? -Hormones are small inorganic molecules. -Hormones are produced at the sites where they are needed. -Hormones are produced only in plants. -Hormones can function at very low concentrations.

answer

Hormones can function at very low concentrations

question

Which term describes the direction of auxin transport in a plant?

answer

polar

question

How does auxin produce gravitropism in a plant that is placed on its side? -Auxin accumulates on the side of the leaf opposite the sunlight and inhibits elongation of cells in that region. -Auxin accumulates on the lower surface of the root and stimulates elongation of cells in that region. -Auxin accumulates on the lower surface of the root and inhibits elongation of cells in that region. -Auxin accumulates on the side of the leaf opposite the sunlight and stimulates elongation of cells in that region.

answer

Auxin accumulates on the lower surface of the root and inhibits elongation of cells in that region

question

How does auxin produce phototropism? -Auxin accumulates in cells on the side of the plant facing the source of light and stimulates their elongation. -Auxin accumulates in cells on the side of the plant opposite the source of light and causes them to shorten. -Auxin accumulates in cells on the side of the plant opposite the source of light and stimulates their elongation. -Auxin accumulates in cells on the side of the plant facing the source of light and causes them to shorten.

answer

Auxin accumulates in cells on the side of the plant opposite the source of light and stimulates their elongation.

question

A neuron's nucleus is located in its _____.

answer

cell body

question

A nerve impulse moves toward a neuron's cell body along _____.

answer

dendrite

question

A nerve impulse moves away from a neuron's cell body along _____.

answer

axons

question

An impulse relayed along a myelinated axon "jumps" from _____ to _____.

answer

node of Ranvier ... node of Ranvier

question

Axons insulated by a(n) _____ are able to conduct impulses faster that those not so insulated.

answer

myelin sheath

question

What type of cell makes up the myelin sheath of a motor neuron?

answer

Schwann cell

question

What part of a neuron relays signals from one neuron to another neuron or to an effector?

answer

synaptic terminal

question

Which term describes the difference in electrical charge across a membrane?

answer

membrane potential

question

Resting neurons are most permeable to which of the following ions?

answer

K+

question

True or false? The potential energy of a membrane potential comes solely from the difference in electrical charge across the membrane.

answer

false

question

Which channel is mainly responsible for the resting potential of a neuron?

answer

potassium leak channel

question

Which term describes an electrical signal generated by neurons?

answer

action potential

question

Which channel maintains the concentration gradients of ions across a neuronal membrane? -The sodium leak channel allowing Na+ ions out. -The sodium-potassium pump moving Na+ ions out and K+ ions in. -The sodium-potassium pump moving Na+ ions in and K+ ions out. -The potassium leak channel allowing K+ ions out.

answer

The sodium-potassium pump moving Na+ ions out and K+ ions in.

question

What behavior is observed if the voltage across a neuronal membrane is set to -20 mV? -The sodium channel opens, and Na+ ions flow out. -The voltage-gated sodium and potassium channels both remain closed. -The sodium channel opens, and Na+ ions flow in. -The potassium channel opens, and K+ ions flow in.

answer

The sodium channel opens, and Na+ ions flow in.

question

Which part of the eye is the opening through which light initially passes?

answer

pupil

question

Which of the following statements does not describe a vertebrate eye? -It acquires images by focusing light on receptor cells. -It contains many light-sensing columns called ommatidia. -It contains photoreceptors that are either rod- or cone-shaped. -It contains cells that are sensitive to either dim light or color.

answer

It contains many light-sensing columns called ommatidia.

question

True or false? The "blind spot" in vertebrate eyes is a region of the retina that contains no photoreceptors.

answer

true

question

Which part of the eye contains the densest concentration of cone cells?

answer

fovea

question

Which part of the eye bends light to focus it on the retina?

answer

lens

question

Which of the following statements about photoreception is true? -The retinal molecule changes shape when it absorbs light. -Rhodopsin is found in cone cells. -Rod cells are responsible for color vision. -Cone cells are sensitive to dim light.

answer

The retinal molecule changes shape when it absorbs light.

question

True or false? Cone cells are color photoreceptors that use different retinal molecules to absorb different wavelengths of light.

answer

false

question

The thick filaments of sarcomeres are composed of _____.

answer

myosin

question

The thin filaments of sarcomeres are composed of _____.

answer

actin

question

A single muscle cell is referred to as a _____.

answer

muscle fiber

question

During the course of muscle contraction the potential energy stored in ATP is transferred to potential energy stored in _____.

answer

the myosin head

question

The release of _____ ions from the sarcoplasmic reticulum is required for skeletal muscle contraction.

answer

calcium

question

Myosin heads bind to _____, which they then pull and cause to slide toward the center of the sarcomere.

answer

thin filaments

question

Of these events, the first to occur when a motor neuron stops sending an impulse to a muscle is _____. -the pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum -the release of myosin heads from the thin filament -thin filaments slide back to their relaxed positions -proteins on the thin filaments block actin's myosin-binding sites -all of these events occur simultaneously

answer

The pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum

Mastering Biology Final Exam – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards