A steady-state system is dynamic, whereas a system in equilibrium is not.
What is the main difference between the concepts of "steady-state" and "equilibrium?
A negative feedback response demonstrates a fluctuation around a setpoint.
Which of the following would best describe the concept of negative feedback as it relates to homeostasis?
Integrating center
Which component of a control system initiates an appropriate response to a stimulus?
The ability of living systems to maintain a relatively constant internal environment.
What is the best definition for "homeostasis?
positive feedback
Oxytocin is a hormone that is released in response to cervical dilation. It in turn causes more uterine contractions that will further dilate the cervix. What type of feedback loop does oxytocin trigger?
A teaspoon of salt disappears when stirred into a glass of water.
Which of the following situations BEST demonstrates solubility?
insoluble; nonpolar
Hydrophobic solutes are generally soluble/insoluble (choose one) in water, due to the presence of _____ covalent bonds between the atoms in each solute molecule.
polar covalent
Water readily dissolves ions because the atoms in water molecules are bonded by _____ bonds.
equivalent
For ions in solution, the measurement unit that considers the number of electrical charges carried by each ion is the _____.
solution
You take salt and add it to a beaker containing water. You have just created which of the following?
the number of atoms of each element and the atomic mass of each element
What pieces of information do you need to know in order to calculate the molecular weight of a substance
Microliter (?L)
If you were to measure out 1/1,000,000 of a liter, how would you express and abbreviate this volume measurement?
molarity; percent solutions
Which of the following is a measurement of concentration?
Add 13 g of sodium chloride to a beaker and add water to make a final volume of 100ml; Add 26 g of sodium chloride to a beaker and add water to make a final volume of 200ml.
What would you need to do to make a 13% solution of sodium chloride (NaCl)?
No, using 175 g of sodium chloride in 5 L of solution will give a 3.5% solution.
Sally needs to make a 35% solution of sodium chloride for several different lab groups. To make her time more efficient, she decides to make a stock of 5 L that will last through the whole week. After doing her math, Sally weighs out 175 g of sodium chlor
5983 mM
What is the molarity of the solution that Sally is supposed to make for the lab?
A buffer
What is a substance that can moderate the change in pH of a solution?
10 times higher
Lemon juice has a pH of about 2.0, compared to a pH of about 1.0 for stomach acid. Therefore, the concentration of H+ in stomach juice is ________ than that of lemon juice.
receptors
Proteins that bind signal molecules and initiate cellular responses are called ________.
Forming ions
Electrons have four important roles in biological systems: forming covalent bonds, transferring energy from the environment, free radical formation, and which other function?
those that may be synthesized by human cells
Nonessential amino acids of a human are defined as ________.
Ca2+
Which of the following are examples of cations?
a precursor to steroid hormones and a structural component of cell membranes.
Cholesterol is
anions
Ions with a negative charge are called
Interstitial fluid is extracellular fluid outside the circulatory system and the cells.
Define interstitial fluid, indicating if it is inside or outside cells (intracellular or extracellular).
Lumen
What is the name of the hollow interior of an organ?
Plasma and interstitial fluid
Which two fluid compartments make up the extracellular fluid?
lipids and proteins
Cell membranes are mainly constructed from ________.
Lysosomes
Tay-Sachs disease, which results from accumulation of glycolipids that are normally broken down, is associated with malfunction of which cellular component(s)?
Cardiac muscle
Which tissues would likely have cells with the greatest number of gap junctions?
Smooth muscle
Which tissue can generate electrical signals?
Smooth muscle
Which tissue can generate electrical signals?
multipotent
Undifferentiated cells in a tissue that can become specialized cells of that tissue, but not of other tissues, are ________ cells.
extracellular fluid
The watery medium that surrounds a cell is known as
does not mix with water
Which of the following statements properly defines something that is hydrophobic? A substance that_______.
Phosphate heads and lipid tails would orient away from each other, with the phosphate heads facing either the extracellular or intracellular fluid and the tails facing each other.
If you were to throw many phospholipids into an aqueous solution, which of the following would you observe?
to allow for cell-cell communication; to serve as a channel for the transport of molecules between extracellular and intracellular fluid; to provide structural stability for the cell; to combine with a carbohydrate, providing an immune response and/or cel
The cell membrane is made up of many different kinds of proteins. These proteins can be classified as either peripheral, transmembrane, or lipid-anchored proteins. Regardless of their classification, these proteins all play an important role in the functi
protein
The more metabolically active a cell is, the more ________ it's membrane contains.
the formation of a barrier that is selectively permeable to lipid-soluble molecules and to provide a framework for membrane proteins
What is/are the major role(s) of the phospholipid bilayer?
proteins
Cells that form a tissue are held together by ________.
storing energy reserves
Functions of epithelia include all of the following EXCEPT
controlling permeability.
producing specialized secretions.
movement.
storing energy reserves.
providing physical protection.
a basement membrane, protein filaments embedded in glycoprotein, and a basal lamina.
Epithelia are connected to underlying connective tissues by
increase the cell's surface area.
The function of microvilli, often seen on the apical membrane of transporting epithelia, is to
apoptosis
The term meaning programmed cell death is
To see whether they are carriers of the gene that causes Tay-Sachs disease.
Why do Sarah and David choose to seek out the assistance of a genetic counselor?
Contain enzymes; ensure that debris and/or dead cells are cleaned up..
What is the normal function of lysosomes and why is this function important?
lack of enzymes stored in the lysosome, or ineffective enzymes
How is lysosomal function altered in people afflicted with Tay-Sachs disease?
No. They could still be carriers of the gene and have normal levels of hexosaminidase A
The genetic counselor that Sarah and David are working with tested both of their blood for levels of hexosaminidase A before running the genetic test. Both levels are normal. Does this mean that they do not need to run the genetic test?
increase the rate of chemical reactions
Enzymes ________.
Phosphate
A kinase moves which functional group or molecule?
It is the total of all the chemical reactions in an organism.
What is the definition of "metabolism?
Enzymes lower the activation energy level of a chemical reaction, thus making it so the reaction will proceed.
Which of the following best describes the function of enzymes?
potential energy
The general term that describes energy stored in chemical bonds is
Potential
A molecule positioned on the high-concentration side of a concentration gradient stores ________ energy.
reversible
A chemical reaction that can proceed in both directions is called a ________ reaction.
are enzymes with slightly different structure that catalyze the same reaction.
Isozymes
lowering the activation energy of a reaction.
Enzymes increase reaction rate by
High ATP concentrations in the cell inhibit the action of phosphofructokinase, the third enzyme of glycolysis.
What is the best example of feedback inhibition?
the active site.
A competitive inhibitor binds to
a region of the enzyme other than the active site.
An allosteric modulator binds to
Many vitamins are precursors of coenzymes, which are necessary for metabolic reactions.
Which of the following best describes why vitamins are important in the human body?
Potassium ions are more concentrated inside cells than in the extracellular space.
How does the intracellular fluid compartment differ from the extracellular fluid compartment?
The seawater is hypertonic to the erythrocytes.
If a swimmer cuts his foot on a seashell while wading in the ocean and bleeds into the seawater, his red blood cells (erythrocytes) will shrink. What does this tell us about seawater?
If the concentration of nonpenetrating solutes is less in the solution than in a cell
How can a solution be hyperosmotic but hypotonic?
It allows for the diffusion of chloride across the epithelium of a cell.
What is the mechanism of action of the cystic fibrosis transmembrane conductance regulator (CFTR)?
The CFTR channel is absent.
How is the function of the CFTR altered in someone with cystic fibrosis?
Without the CFTR, mucus cannot be thinned.
Why is the thick mucus in Daniel's lungs a sign that he might have cystic fibrosis?
The CFTR allows for chloride to leave the sweat and re-enter the cells, creating a hypotonic sweat
Why would tasting salty sweat on the foreheads of babies lead a midwife to assume that the baby might be afflicted with cystic fibrosis?
Channel proteins create water-filled passages for small molecules that do not bind to the protein. Carrier proteins transport larger molecules by binding to them.
What is the most important distinction between the membrane transporters known as channel proteins and those known as carrier proteins?
They must be small and/or lipophilic
What properties must a molecule have to pass through a cell membrane by simple diffusion?
The types of solutes and their distribution between the ICF and ECF are not the same
Which of the following statements correctly describes the relationship between intracellular fluid (ICF) and extracellular fluid (ECF)?
Compartment A is hyposomotic to compartment B.
You have prepared a beaker containing two membranes that are permeable only to water. This beaker has three separate compartments each containing the following osmolarities:How would you describe the osmolarity of compartment A relative to compartment B?
Compartment B is hyperosmotic to compartment C
sing the same scenario as Part E, how would you describe the osmolarity of compartment B relative to compartment C?
A voltage-gated channel
What type of membrane transporter would be activated by an action potential?
The question cannot be answered with certainty without knowing the identity of the solutes present in the IV solution.
What will happen to the cells of a patient who is provided with an intravenous solution that is isosmotic to intracellular fluids?
intracellular fluid only
Which body fluid compartment contains high levels of K+, large anions, and proteins?
both plasma and interstitial fluid
Which body fluid compartment contains higher levels of Na+, Cl-, and HCO3-?
plasma and interstitial fluid.
The extracellular compartment(s) in the body is/are
circulatory system
The walls of the ________ separate the two extracellular fluid compartments.
hyposmotic, hyperosmotic
Water will always move from ________ areas to ________ areas, if there are no impermeable barriers.
electrical disequilibrium.
The inside of a resting cell is slightly negative relative to the outside. This is an example of
Plasma
Which body fluid compartment has the smallest volume?
The volume of B will increase
What will occur if solution A (500ml solution containing 400mosmol/L nonpenetrating solute) is separated by a biological membrane from solution B (4L solution containing 600mosmol/L nonpenetrating solute)?
Active transport
Which type of molecular movement requires energy from ATP?
The chemical gradient of sodium ion
What energy is used to power the SGLT (Na+-glucose secondary active transporter)?
Receptor-mediated endocytosis
What process requires clathrin to form coated pits?
Intracellular fluid
Where is most of the water in the body located?
It results, in part, from the concentration gradients for Na+ and K+.
Which of the following statements about the resting membrane potential is TRUE?
-70 mV.
The resting membrane potential in a typical nerve cell is approximately
negatively charged.
Compared to the outside surface, the inside of a resting cell membrane is
Na+
the ion that plays a key role in initiating electrical signals in neurons is
resting membrane permeability for sodium ions greater than potassium ions
Which of the following is NOT involved in creating the resting potential of a neuron?
Most membranes are 40 times more permeable to K+ than to Na+.
Why is the resting membrane potential (Vm) approximately - 70 mV for most cells?
only specific target cells, because nontarget cells lack the appropriate receptors
A given hormone affects ________.
ligands
Extracellular signal molecules are also called
signal transduction.
Conversion of an extracellular signal into an intracellular one is called
second messengers.
Amplifier enzymes produce
It must be lipophilic.
Which specific characteristic must a signaling molecule have in order to bind to a cytosolic or nuclear receptor?
It blocks production of prostaglandins
Administration of ibuprofen can decrease pain. Why would this COX-2 inhibitor have this effect?
causes some blood vessels to dilate and others to constrict, because different vessels have different receptors for norepinephrine
The neurotransmitter norepinephrine ________.
Specificity
Alpha-adrenergic receptors have a higher affinity for norepinephrine than for epinephrine. Beta-adrenergic receptors have a higher affinity for epinephrine than for norepinephrine. Which concept about receptor function do these statements reflect?
Gap junction signaling
Which form of cell-to-cell communication uses the direct transfer of electrical and chemical signals?
targets.
Cells that respond to signals are usually called
paracrine.
A chemical that is secreted by a cell to act on cells in its immediate vicinity is called a(n)
Signal amplification
The binding of a single ligand to its receptor can activate many second messengers. Which characteristic of signal transduction systems is this?
Inositol triphosphate and diacylglycerol
What are the second messengers in the GPCR-phospholipase C signal transduction system?
Protein kinase A
Which molecule of the GPCR-adenylyl cyclase signal transduction system phosphorylates proteins to create the cellular response?
ion channels
The most rapid intracellular responses to signals result from activation of receptors that are also ________.
calcium
The ion that controls the widest variety of intracellular activities is ________.
Some cells lack the necessary receptors.
Why do some normal cells fail to respond to a chemical signal?
in all of these places:
only in the cytosol.
only in the nucleus.
only on the cell surface.
only in the outer cell membrane.
Receptor molecules are located
protein kinase A.
Cyclic AMP activates
the lipid solubility of the ligand.
The most important factor determining which type of receptor a signal molecule will bind to is
is common because it promotes homeostasis
Negative feedback in reflex loops ________.
respond rapidly, but are very brief
Compared to endocrine reflexes, neural reflexes ________.
simple endocrine
The secretion of the hormone insulin in response to changes in blood glucose level is an example of a ________ reflex.
the two hormones bind to different receptors and use a different second messenger.
Both insulin and glucagon are peptide hormones that target liver cells. The response of the target cells to each of these two hormones is opposite. This information implies that
local control
Homeostatic control that takes place at the tissue or cell by using paracrine or autocrine signals is called ________.
cortisol
Which of the following hormones has intracellular receptors?
activation of genes, which increases protein synthesis in the cell
What is the mechanism of action of lipid-soluble hormones?
acts as a transcription factor and binds to DNA, activating a gene
After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do?
thyroid hormone
Which hormone's receptor is always bound to DNA, even when the receptor is empty?
chaperone proteins (chaperonins)
What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor?
A steroid
A new hormone is discovered. Analysis of its synthesis suggests that it is synthesized on demand and has a long half-life in the bloodstream once it is released. It seems to activate gene transcription in its target cells though no cell surface receptors
A pathology in the endocrine gland could prevent negative feedback from working, resulting in hypersecretion.
When might negative feedback fail to regulate hormone production, and how would this affect hormone secretion?
Permissiveness
Norepinephrine and epinephrine cause an increase in heart rate (HR) and stroke volume (SV), which is the amount of blood pumped out during each heart beat, but the effect is enhanced when thyroid hormone (TH) is also present. Oddly, TH has little effect o
The anterior pituitary
A blood sample is found to have low levels of GHRH and excessive levels of GH and IGFs. Where would the pathology be located in this example?
There is a lack of feedback inhibition by thyroid hormone on the anterior pituitary.
Why is elevated TSH sometimes associated with hypothyroidism?
Calcitonin
Which of the following is a peptide hormone?
cell's receptors and the signal transduction pathway used by the cell.
A cell's or tissue's response to a hormone primarily depends on the
They bind to intracellular receptors.
What is the implication of the fact that steroid hormones are lipophilic?
Tyrosine
Most amine hormones are derived from which source?
Epinephrine
Which hormone is classified as an amino acid derivative?
gene transcription may increase or decrease.
Typically, when steroid hormones bind to their receptors,
half-life
The ________ of a hormone is an indicator of how long a hormone is active in the body
Peptide hormones in the bloodstream are always bound to carrier proteins.
Each of the following statements concerning peptide hormones is true except one. Identify the exception.
Peptide hormones are first synthesized as prohormones.
Peptide hormones remain in circulation for relatively short periods of time.
Prohormones can be
cortex
The outer layer of the adrenal gland is called the adrenal
medulla.
The inner portion of the adrenal gland is called the adrenal
aldosterone, cortisol
The adrenal cortex produces a steroid hormone called ________ that controls Na+ and K+ homeostasis and another steroid hormone called ________ that controls blood glucose levels.
to release trophic hormones that stimulate the anterior pituitary
What is the role of the hypothalamus with regard to hormone release and endocrine function?
The anterior pituitary would not release hormones in response to trophic hormone stimulation.
Which loss of function would occur if you were to sever the connection between the hypothalamus and the anterior pituitary?
neurohormone
ow would you classify the type of chemical released by the posterior pituitary (e.g., classic hormone, neurotransmitter etc.)?
oxytocin; vasopressin
Which of the following are released by the posterior pituitary?
in the neuronal cell bodies found in the hypothalamus
Where are the neurohormones released by the posterior pituitary produced?
The neuronal cell bodies in the hypothalamus are damaged.
Mrs. Johnson does goes in to visit her doctor because of some health issues that she has been having. One of the many tests that were run on Mrs. Johnson revealed that she had no circulating concentrations of vasopressin. The doctor does a further analysi
Anterior pituitary is composed of endocrine tissue while the posterior pituitary is composed of neural tissue.
Which of the following statements regarding the anterior and posterior pituitary is correct?
From outside the body
What does the word "exogenous" mean?
Primary
________ pathologies arise in the last endocrine gland in a reflex.
C cells (parafollicular cells) in the thyroid gland
Calcitonin is secreted by which cells?
cortisol
The zona fasciculata of the adrenal cortex produces what steroid hormone?
epinephrine from the adrenal medulla
The sympathetic nervous system directly stimulates which of the following amine hormones?
atrial natriuretic peptide (ANP)
What hormone causes the loss of sodium and water, thus lowering blood pressure.
melatonin
What amine hormone helps coordinate body activities with the light-dark cycle?
insulin
What hormone promotes glycogen synthesis in liver and muscle?
anterior pituitary
Where is thyroid stimulating hormone (TSH) synthesized?