Exam 1 Modules Ch 1-7
__________ allow(s) the body to predict that a change is about to occur and start the __________ in anticipation of the change.
Feed forward control; response loop
Paracrines and autocrines ________.
both depend on diffusion as a means to reach their target cell and differ primarily in their targets
Substances that promote inflammation include __________.
histamine and prostaglandins
In people with diabetes mellitus, glucose is not being transported into cells at the normal rate. This buildup of glucose in the plasma causes the extracellular fluid to become __________.
hypertonic and hyperosmotic
A cell placed in a solution of unknown composition soon swelled up and burst, so the solution must have been __________ to the cell when it was originally placed in the solution.
hypotonic and of an undetermined relative osmolarity
Up regulation allows a target cell to __________.
increase the sensitivity of a target cell to a ligand
A cell that responds to a chemical messenger secreted by another cell is called the ____________.
target cell
Responses to chemical messengers produced by target cells vary in magnitude according to __________.
the amount of the messenger present the number of receptors present for the chemical messenger the affinity of the receptor for the messenger
The rate of diffusion, or flux, of particles across a membrane is dependent on __________.
the membrane permeability the surface area of the membrane the steepness of the concentration gradient across the membrane
Which of the following statements about vesicular transport processes into or out of the cell is (are) true?
-If a cell is to remain the same size, the rate of exocytosis must equal the rate of endocytosis. -Receptor-mediated endocytosis is triggered by the binding of a ligand to the receptor. -Proteins or lipids that have undergone endocytosis can be recycled back to the plasma membrane by exocytosis.
__________ are ligands that bind to receptors but do not produce a response.
Antagonists
Which of the following will always be true of primary and secondary active transport?
At least one substance will move against its concentration gradient.
Which of the following interacts with receptors on the cell surface?
Catecholamines
In the digestive system, Vitamin B12 bound to intrinsic factor (B12-IF) is absorbed through the epithelium of the small intestine and delivered into the extracellular fluid on the basolateral membrane of the epithelium by a process called transcytosis. This process begins on the apical surface of the epithelial cell when the B12-IF binds to receptors, and is engulfed into the cell. What is the type of membrane transport at the apical surface of the epithelium?
Endocytosis
What type of membrane transport is used in the following scenario? Neurons will release signaling molecules called neurotransmitters in order to communicate with other neurons or with organs. In the axon terminal of many neurons are storage vesicles of these neurotransmitters called synaptic vesicles. When an electrical signal known as an action potential is propagated to the axon terminal, the synaptic vesicles fuse with the neuronal membrane and the neurotransmitter is released.
Exocytosis
If many solutes are constantly being pumped into or out of cells, why don't the intracellular concentrations of these solutes change?
For any given solute, the rate of active transport in one direction is equal to the passive movement (leak) of the solute in the opposite direction.
Signal amplification can occur at the level of the __________.
G protein, protein kinase, and second messenger
Which of the following statements about G proteins is(are) false?
G proteins can be stimulatory or inhibitory. Alpha subunits can interact with effector proteins. Beta-gamma subunits can interact with effector proteins. G proteins are also enzymes. Beta-gamma subunits can interact with effector proteins and G proteins are also enzymes.
Which of the following statements provides an accurate comparison between facilitated diffusion and simple diffusion?
In both facilitated and simple diffusion, substances move down their concentration gradient.
Which of the following statements makes an accurate comparison between primary and secondary active transport?
In primary active transport ATP is directly utilized, while in secondary active transport the potential energy of a concentration gradient is utilized
Identify which of the following is the correct definition of primary active transport.
It is mediated by a protein that directly uses ATP energy in order to move a substance against its concentration gradient.
Which of the following statements about dopamine is (are) true?
It is quickly degraded in the ICF after use.
Substances that are going to move against their concentration gradient (from low concentration to high concentration) will use which type(s) of membrane transport?
Primary or secondary active transport
An increase in which of the following would increase the rate of diffusion of oxygen molecules across pulmonary cell membranes?
Membrane surface area, the oxygen concentration inside the lung, and temperature
Which of the following statements about methods of cell-to-cell communication is false?
Most long-distance communication between cells is accomplished via chemicals known as autocrines and paracrines.
Which of the following molecules would not diffuse through cell membranes easily?
Na+ ions and glucose
If a cell's Vm = -70 mV and ENa+ = +50 mV, which way will Na+ ions move across the cell membrane?
Na+ ions will move into the cell.
Which of the organ systems listed below is known for producing more focused, direct and the fastest responses from target cells?
Nervous system
__________ are substances that are released from neurosecretory cells but travel through the bloodstream to target tissues.
Neurohormones
Which of the following does not require the use of ATP?
Osmosis
Which of the following types of molecules would be most likely to pass through the plasma membrane by means of simple diffusion?
Oxygen - nonpolar
Passive membrane transport does not use energy in the form of ATP in order to move substances across biological membranes. That doesn't mean, however, that there is no energy used in the movement of ions across membranes. How would you classify the type of energy required in order for a neutral substance to move via either simple or facilitated diffusion?
Potential
If a cell were to become depleted of its ATP, which type of membrane transport would be most directly and immediately affected?
Primary active transport
In skeletal muscle, the sarcoplasmic reticulum stores a very high concentration of Ca++. When Ca++ is released into the cytosol of muscle to facilitate contraction, it needs to be removed and pumped back into the sarcoplasmic reticulum so that skeletal muscle can return to its relaxed state. The Ca++ is moved from cytosol and pumped back into the sarcoplasmic reticulum where its concentration is much higher. What type of membrane transport does this represent?
Primary active transport
Use the following scenario to answer the question: A cell has an antiport protein on its apical surface. The cell is placed in a solution that contains a high concentration of Na+ relative to the inside of the cell, and a high concentration of Ca++ relative to the inside of the cell. The antiporter will move 3 Na+ into the cell in exchange for one Ca++ leaving the cell. This is an example of what type of transport?
Secondary active transport
Which of the following transport mechanisms may be utilized to move glucose across cell membranes
Secondary active transport and facilitated diffusion
Use the following scenario to answer the question. A beaker containing two fluid compartments separated by a semipermeable membrane is filled with distilled water. In compartment A you place 15 mM of NaCl and in compartment B you place 25 mM of NaCl. The membrane is permeable to both sodium and chloride. Initially, which side has the higher osmotic pressure? As time goes on will the water levels change,and if so how?
Side B has a higher osmotic pressure; the water levels will not change.
Which of the following statements is false with regard to primary/secondary active transport?
Substances will always move down their concentration gradient.
Which of the following statements about epithelial transport in the intestines is(are) true?
The Na+/K+ ATPase is found only in the basolateral membrane of intestinal epithelial cells and the movement of Na+ ions across the apical membrane of intestinal epithelial cells is dependent on the electrochemical gradient created by the Na+/K+ ATPase.
Which of the following statements about lipophilic hormones is false?
The effects of lipophilic messengers are short-lived.
Which of the following effects is (are) produced by epinephrine during exercise?
The heart beats faster and more forcefully.
Which of the following statements about the Na-K pump is(are) true?
The location of the binding sites on the Na-K pump dictates the direction of solute movement
Facilitated diffusion differs from simple diffusion in what way(s)?
The rate of facilitated diffusion depends on the number of carriers in the membrane.
Which of the following statements about facilitated diffusion is(are) true?
The rate of facilitated diffusion is directly dependent on the number of carrier proteins for a solute and the rate of facilitated diffusion is directly dependent on the concentration gradient of the solute across the membrane.
The term used to describe the minimum stimulus to trigger a response in a feedback loop is __________.
The term used to describe the minimum stimulus to trigger a response in a feedback loop is __________.
In which of the following are receptor and transduction mechanisms contained within the same protein?
Tyrosine kinases and fast ligand-gated channels
The greatest electrical driving force on an ion to move into a cell is illustrated by which of the following examples?
Vm = -70 mV, ion = Ca2+ (ECa2+ = +110 mV)
In comparing a solution to a fluid in a cell, a hypertonic solution always has ____________.
a higher concentration of non-penetrating solutes than that in the cell
Which of the following conditions would lead to the fastest rate of oxygen diffusion into a cell?
a large concentration gradient and a thin membrane
What is similar between facilitated diffusion and primary/secondary active transport? In both forms of transport __________.
a membrane transport protein is involved
Autocrine signals __________.
act on the same cell that secreted them
Cholera toxin raises cAMP levels in intestinal epithelial cells by directly __________.
activating G proteins
Due to the similarities in chemical structure of dopamine, epinephrine, and norepinephrine, they can all be classified as __________.
amines and catecholamines
In order for water to be absorbed by epithelial cells, __________.
aquaporins must be present in the cell membranes and the concentration of impermeable solutes must be higher on the inside of the cell
The heart functions as a secondary endocrine organ because it secretes __________, which functions in the regulation of sodium reabsorption by the kidneys.
atrial natriuretic peptide (ANP)
Put the following events in the correct order: a. Chemical messenger binds to receptor on the target cell. b. A response occurs in the target cell. c. Chemical messenger is secreted. d. Signal transduction occurs in the target cell.
c, a, d, b
The difference between carrier and channel proteins is that ________.
channel proteins create a continuous passage between intra- and extracellular compartments
In the process of __________, membrane-bound receptors will recognize and bind to specific structures on a bacterium, which will result in the cell taking that bacteria into a vesicle.
endocytosis
The movement of molecules into a cell in an indentation of the cell membrane and formation of a small vesicle is called __________.
endocytosis
White blood cells engulf bacteria in a process known as __________
endocytosis or phagocytosis
During peptide synthesis, a propeptide may be found in the __________.
endoplasmic reticulum, Golgi apparatus, and secretory vesicle
Water toxicity occurs when __________.
extracellular fluids become hypotonic, causing brain cells to swell
When calcium enters a cell through ligand-gated channels, it may __________.
interact with proteins induce muscle contractions act as a second messenger
A cell containing 300 mOsm of non-penetrating solutes per liter is placed in a solution containing 200 mOsm of non-penetrating solutes per liter and 100 mOsm of the penetrating solute urea per liter. The solution can be said to be __________ with respect to the cell.
iso-osmotic and hypotonic
Examples of eicosanoids include __________.
leukotrienes prostacyclins prostaglandins thromboxanes
Steroid hormones are __________.
membrane permeable synthesized from cholesterol synthesized in the smooth endoplasmic reticulum synthesized on demand and released immediately
If a patient is given an intravenous solution that is 0.9% NaCl (300 mOsm/L NaCl), his or her red blood cells will __________.
not change size or shape
Chemical messengers that may require a carrier protein to move through the bloodstream include __________.
paracrines peptide hormones catecholamines neurotransmitters
Energy released by the hydrolysis of ATP is used to move K+ and Na+ across cell membranes. This process is called __________.
primary active transport
Transport processes that can be saturated include
primary active transport secondary active transport facilitated diffusion movement of ions through some channels
Transport processes that require an energy source include __________.
primary active transport and secondary active transport
In contrast to the nervous system, the endocrine system __________.
produces long-lasting effects, has no direct anatomical link between the site of secretion and the target tissue, and often acts through G proteins
The fastest-acting membrane-bound receptors are __________.
proteins that contain both the receptor and the channel
Overall, Na+ and glucose transport into epithelial cells __________.
requires energy
Examples of active transport may include __________.
the movement of Na+ ions out of cells and the movement of glucose molecules into intestinal epithelial cells
The term simple diffusion can be used to describe __________, from areas of high concentration to areas of lower concentration.
the movement of oxygen molecules across the cell membrane and the movement of oxygen molecules in air
With cystic fibrosis, breathing is difficult because __________.
the osmotic pressure of the fluid on the luminal side of the respiratory surface favors water transport out of cells and the movement of Cl- ions is impeded due to a lack of chloride transporters
As the solute concentration of a solution increases, __________.
the water concentration decreases and the osmotic pressure increases
