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136 Cards in this Set

  • Front
  • Back
High surface tension and capillary action are due to which property of water?
water molecules are cohesive and adhesive
the smallest living units capable of carrying out their own basic life functions sometimes even outside the body are called:
what type of gland secretes products into ducts leading to the external environment
exocrine glands
which of the following descriptions INCORRECTLY describes the tissue type
connective tissue is specialized for exchange between the internal and external environments
order of complexity for the components of the body, from least to most complex
cells, tissues, organs, organ systems
homeostasis is a term which describes the process whereby the body:
maintains a constant internal environment
extracellular fluid is composed of
interstitial fluid and plasma
total body water is composed of
intracellular and extracellular fluid
the plasma membrane typically contains
phospholipids, ion channels, glycoproteins
referring to a membrane as 'selectively permeable' describes its ability to
restrict the movement of particular molecules across a membrane
what is the primary mechanism for maintaining homeostasis
negative feedback
an example of negative feedback
when a person stands up, blood pressure decreases due to blood pooling in feet and legs. the heart and blood vessels respond in such a way as to bring blood pressure back toward normal.
thermo-receptors act as the ____ in the thermoregulatory feedback loop
animals whose body temperature changes with environmental temperatures, thereby not maintaining strict thermal homeostasis, are called
when a person walks outside into a colder environment that is still within the thermoneutral zone, which mechanism helps maintain normal body temperature?
blood flow to the face and hands decreases
It is often said that 'the rich get richer' (and presumably, the richer get even richer). This would be an example of...
positive feedback
glycogen is an example of a
____ are lipids that form the core structure of cell membranes.
the ultimate cause of the increase in body temperature associated with an infection (fever) is a...
pyrogen-induced upward movement of the set point
hydrogen bonding links together
molecules of water
cholesterol is...
a lipid, a steroid, and a component of cell membranes
____ is an example of a disaccharide.
when an mRNA is transcribed from a single strand of DNA (3' to 5': ACAGAGTGACAGAAC) after the uncoiling of the double strands, what is the produced mRNA sequence?
What chemical groups will be found in a phospholipid?
fatty acid, phosphate, glycerol
_____ are lipid molecules composed of a glycerol and three fatty acids.
A fatty acid that contains three double bonds in its carbon chain is said to be a ____ fatty acid.
The amphipathic property of phospholipids can be described as...
a polar region that dissolves in water and a nonpolar region that face one another
Alpha-helices and beta-pleated sheets are examples of ____ structure of a protein.
____ are molecules that are composed of one or more phophate groups, a 5-carbon sugar, and a nitrogenous base.
Examples of polymers:
glycogen, nucleic acid, protein
What is an INCORRECT description of a polymer?
ATP is a polymer of phosphates
Which substance contains the most trans fatty acids in the fatty acid parts of the fats?
partially hydrogenated oil
Trans fats are viewed as having a worse effect on human health than animal fats (saturated) because...
they decrease HDL and increase LDL
The process whereby a complementary mRNA is produced from a DNA template is called...
is the formation of proteins from mRNA
Enzymes act as ___ to increase reaction rate.
Enzymes are what class of molecule?
In the induced-fit model for enzyme activity, the substrate alters the ____ of the ____ site on the enzyme.
conformation; active
What would increase the rate of an enzyme-catalyzed reaction?
increasing the affinity of the enzyme for its substrate,

increasing the concentrationi of the enzyme,

increasing the concentration of substrate
Km (Michaelis-Menten constant) is defined as:
the substrate concentration at which the reaction rate is half its maximal value
What is true about Km?
a high Km indicates weak binding between an enzyme and its substrate
In the reversible inhibition of enzyme-catalyzed reaction, which of the following indicates a competitive inhibition?
the inhibitor binds to the active site of the enzyme; it can be reversed by an increase in a substrate concentration,

the inhibitor does not change Vmax but increases Km
An enzyme that catalyzes a particular chemical reaction decreases the...
activation energy
What does not directly determine the rate at which an ion will move passively across a membrane?
amount of ATP available
A particular type of molecule tends to move from the side of a membrane where it is at higher concentration to the side where it is at lower concentration during...
diffusion, facilitated diffusion, osmosis
Which pair of characteristics is more likely to make a substance diffuse through the cell membrane?
small, nonpolar molecule
In facilitated diffusion only, NOT in the secondary active transport...
a molecule is moved down its concentration gradient with the assistance of a protein carrier molecule, and no energy is required.
____ couples the movement of a substance up its concentration gradient to another ion that is moving down its electrochemical gradient which was established earlier using cellular energy (ATP).
secondary active transport
during hemodialysis, if the concentration of glucose in the blood is higher than the concentration of glucose in the dialyzing fluid,
glucose concentration of the dialyzing fluid will increase
During COTRANSPORT of Y with sodium...
Y and sodium both move into the cell
In addition to functioning as a transporter, proteins in primary active transport also function as ___ in order to break ATPs so as to use their energy.
The concentration of an ion inside a cell is 0.3%. The concentration of this ion outside the cell is 0.1%. The cell can obtain more of this ion inside the cell by:
active transport
Which of the following statements about sodium is false?
at the potassium equilibrium potential, there is an electrical force driving sodium ions out of the cell.
A cell is placed into a solution that has the same osmolarity. However, one of the ions inside the cell is able to move across the membrane (the solution the cell was placed into does not contain this ion). After a period of time, the solution into which the cell was placed would become:
A cell is placed in a 5% NaCl solution. This solution is ___ and the cell will ___.
hypertonic; shrink
A membrane permeable to water separates a chamber into 2 compartments: A and B. Compartment A contains a 10mM solution of non-permeating solute, whereas compartment B contains 40mM solution of non-permeating solute. Which of the following statements is true?
water will move from side A to B, but solute will not move
If there is a difference in osmolarity between a cell and its environment, water will move ___ the osmotic pressure gradient.
Of cells with membrane potentials of -70, +20, -90, and +50, which would have a greater electrical driving force for potassium ions to exit the cell?
+50 mV
What type of ion channels in the membrane of neurons allow ions to move across the membrane at rest, and thereby contribute to resting membrane potential?
leak channels
Which of the following best describes the electrochemical forces acting on sodium and potassium ions at the resting membrane potential?
the force on sodium ions is to move into the cell, and the force on potassium ions is to move out of the cell
The presence of the ____ prevents the dissipation of the concentration gradient for Na+.
Na+/K+ pump
A change in a cell's resting membrane potential, such that it becomes more negative, is referred to as a _____.
An example of spatial summation:
2 stimuli from 2 sources produce graded potentials on the same neuron at the same time such that the 2 potentials sum
What ion triggers neurotransmitter release from the presynaptic neuron?
The opening of voltage-gated sodium channels causes a rapid ____ of sodium that ____ the neuron's membrane.
influx; depolarizes
For the voltage-gated sodium channel to open and allow sodium into the cell,
the activation and inactivation gates must both be open
Stimuli A and B are both suprathreshold stimuli that last for one second, but stimulus A is much stronger. What is true about that?
stimulus A will cause a higher frequency of action potentials
The repolarization phase of action potentials in neurons is due primarily to the fact that lots of ____.
potassium flow out of the cell
As an action potential is propagated away from the axon hillock, propagation continues in one direction only because...
the region just behind (more toward the cell body) the action potential is in the absolute refractory period
The term that describes the jumping of an action potential from node-to-node in myelinated nerve fibers is...
saltatory conduction
Which of the following axons would have the fastest conduction velocity?
diameter=20 microns, myelinated
As a membrane's permeability to a particular ion increases, membrane potential will move ____ that ion's ___.
closer to; equilibrium potential
The all-or-none principle, associated with the action potential in a nerve cell, states that:
once membrane potential reaches threshold, an action potential will be generated and that action potential will always look the same (with the same magnitude).
in myelinated nerve fibers, action potentials occur at the...
nodes of Ranvier
when an action potential reaches the presynaptic terminal, ultimately:
neurotransmitters will be released
What type of ion channels in the membrane of neurons open or close in response to a neurotransmitter binding to them?
ligand-gated channels
Given a cation with an equilibrium potential of -55mV. If the plasma membrane of the cell is permeable only to that ion, then which of the following best describes the resting membrane potential?
If a cell is at rest, the electrochemical gradient for sodium across the membrane is such that if more sodium channels are open, the net flux of sodium will be ___, thereby causing the cell's membrane potential to become more ____.
inward, positive
The membrane potential at which there is no net flux of an ion across the membrane is called that ion's:
equilibrium potential
the Na+/K+ pump is called an electrogenic pump because the imbalance between:
Na+ out to K+ in leaves the inside of the cell with a net negative charge
The elecrical potential of a membrane at rest is closest to potassium's equilibrium potential because:
more potassium channels are open, allowing more potassium to move out of the cell.
the opening of an ion channel increases a cell membrane's ____, whereas ____ will decrease.
conductance; resistance
During which of the following states are the majority of voltage-gated sodium channels closed and incapable of opening?
during the absolute refractory period
concerning the length constant (lambda), choose one best correct answer:
length constant is the distance over which an electrotonically conducted signal decays 63%.
Choose the incorrect statement:
a depolarizing PSP is always an EPSP
Slow synaptic transmission involves the binding of a neurotransmitter to a receptor that is:
coupled to G-protein which then stimulates an ion channel
Correct sequence of events during an action potential:
depolarization to threshold or above > increased gNa+ (Na+ conductance) > Na+ influx > increased gK+ > K+ efflux
Correct sequence of events during synaptic transmission:
AP arrives in presynaptic terminal > increased gCa2+ > Ca2+ influx > exocytosis of NT > NT diffuses and binds to receptor in postsynaptic cell membrane > responses in postsynaptic cell
Examples of somatic sensations:
proprioception, touch, pain
decrease in the amplitude of a receptor potential in the presence of a continuing stimulus is called:
the ability to detect the direction from which a sound originates is determined by:
the time delay between that sound reaching the right and left cochlea
in order to focus light on the retina, the lens adjusts its refractive power through a process called:
____ is a condition where light, originating from a distance, is focused in front of the retina
the presence of cGMP in the cytosol of a photoreceptor will directly stimulate the:
opening of sodium channels
in the absence of light, the membrane potential of a photoreceptor is relatively ____ by the presence of open ____ channels.
depolarized; sodium
the closure of sodium channels in mediated by a decrease in the cytosolic concentration of ____ that is degraded by _____.
cAMP; phosphodiesterase
when we enter a dark room, the retinal and opsin molecules within the ____ must first ____ before low light levels can be detected
rods; associate
All of these are FALSE about photoreceptors in the light (relative to the dark):
more sodium channels are open

cGMP levels are elevated

the synaptic terminal is releasing more transmitter

the photoreceptors are more depolarized
disks of a photoreceptor cell are located in the ___ and contain ___.
outer segment; photopigment
which of the following is the correct order of communication of visual information in the retina?
photoreceptor; bipolar cell; ganglion cell
both the auditory and vestibular systems rely upon ___ to detect movement of fluid within the ear.
hair cells
sound waves traveling through the air initiate a vibration of the ___. The sound waves are then transmitted along the ___ to the cochlea.
tympanic membrane; ossicles
a true statement about endolymph and perilymph:
endolymph is similar in composition to intracellular fluid.
the hair cells are embedded within the endolymph, thus, when a potassium channel opens, potassium moves ____ the cell, causing it to ____.
out of; hyperpolarize
bending of the stereocilia on the hair cell can induce either a closure or an opening of a potassium channel based upon the:
direction that the stereocilia move
frequency of sound is coded for by:
the location of the hair cell (in the basilar membrane) stimulated
the transduction of sound waves into neural impulses occurs in the
whether the hair cell in the semicircular canal is depolarized or hyperpolarized is dependent upon the:
directioni toward which the stereocilia are bent relative to the kinocilium
____ is NOT one of the primary tastes
the detection of sweet by taste receptors occurs via the binding of organic molecules to receptors on the cell membrane activating ___ that ultimately causes a ___.
gustducin; potassium channel to close
which taste sensation requires a G protein
taste receptor cells can be depolarized by decreased outward flux of potassium by all of the following primary tastes except one. Which of the following is the exception?
The detection of odorants occurs via the binding of organic molecules to receptors on the cell membrane, activating ___ that ultimately causes the ___.
Golf; cation channel to open
a skeletal muscle is composed of a number of ___, each composed of many muscle fibers
a ____, the fundamental repeating unit of the myofibril that gives skeletal muscle its striated appearance, is bordered by ____.
sarcomere; Z lines
what is the protein component of the thin filament that binds to calcium thereby initiating skeletal muscle contraction?
the shortening of a skeletal muscle fiber during contraction involves:
the sarcomeres shortening
during skeletal muscle contraction, as the muscle shortens, the thick and thin filaments:
slide past one another
the repeated, oscillating interaction between actin and myosin that results in the generation of force by a skeletal muscle cell is called:
crossbridge cycling
the release of an inorganic phosphate from the myosin molecule directly results in the :
power stroke
in order for crossbridge cycling to occur, the actin-myosin complex must be broken by the:
binding of ATP to myosin
the sequence of events that links the action potential to changes in skeletal muscle force development is called:
excitation-contraction coupling
conraction of skeletal muscle fibers is stimulated by:
motor neurons
increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are mediated by the coupling between a ___ on the T-tubule and a ___ on the membrane of the sarcoplasmic reticulum.
dihydropyridine receptor; ryanodine receptor
the binding of calcium to the subunit of troponin will result in
the movement of tropomyosin, thereby exposing the myosin-binding site on the actin molecule
what is the function of the t-tubules
they conduct action potentials from the sarcolemma to the interior or the muscle cell
which of the following best describes the function of transverse (t) tubules and the SR in skeletal muscle contraction?
action potentials in t tubules are detected by dihydropyridine receptors, which are coupled to ryanodine receptors in the SR that are channels for calcium
in order to allow muscle relaxation, calcium is rapidly removed from the cytoplasm via:
Ca2+ pumps (Ca2+ ATPases)
Property of isometric skeletal muscle contraction:
load < force generated by muscle
end plate potentials:
are suprathreshold graded potentials; are a result of acetylcholine binding to nicotinic cholinergic receptors
in an isotonic contraction:
the load is moved,
muscle tension exceeds force of the load,
muscle length shortens
a muscle is stimulated at a frequency that allows the muscle to relax completely between contractions. However, the amount of tension increases with each contraction. What is this called?
as skeletal muscle is further stretched beyond the length where optimum force is developed,
the thin filaments are pulled away from thick filaments, thereby reducing their ability to interact with myosin.
the interaction between actin and myosin in smooth muscle requires:
that the calcium-calmodulin complex activates myosin light-chain kinase, which phosphorylates myosin light chain thereby allowing myosin to bind with actin
What causes some muscle to appear red?
presence of myoglobin
which of the following statements about summation and tetanus is false?
the maximum tension developed during summation and tetanus is treppe.