final exam Flashcards
A cell undergoes a series of divisions such that its daughter cells are 1/10 the radius of the parent cell. In these daughter cells, the surface/area volume has
A. Decreased by 10 X
B. Increased by 10 X
C. Decreased by 10^2 X
D. Increased by 10^2 X
E. Decreased by 10^3 X
b
The term “allometry” refers to
a the limitation imposed by the time of diffusion
b the ability of cells to undergo biological changes to speed up diffusion
c the ability of an enzyme to speed up a given reaction
d the growth of body parts at different rates, resulting in a change of body proportions
e the measurement of osmotic pressures under different temperature conditions
d
As the radius of a particle increases, the time it takes to diffuse a certain distance
goes up as the square of the radius goes down as the square of the radius goes up as the cube of the radius goes down as the cube of the radius goes up linearly with the radius of the particle
e
As the radius of a particle increases, the diffusion coefficient for that particle
goes up as the square of the radius goes down as the square of the radius goes up as the cube of the radius goes down as the cube of the radius goes down linearly with the radius of the particle
e
Glucose, which has a diffusion coefficient of about 5 * 10^-6 cm2/sec in a watery medium, moves about 1 micron in about 1 msec. How long would it take for glucose to move the length of a typical mammalian cell body, which is about 10 microns?
A. 10 msec
B. 100 msec
C. 1000 msec
D. 10,000 msec
E. 100 sec
b
Hemoglobin has a diffusion coefficient that is approximately 10 times that of glucose. How long would it take for a single molecule of hemoglobin to move the length of a typical mammalian cell body, which is about 10 microns?
10 msec 100 msec 1000 msec 10,000 msec 100 sec
a
The microvilli present on the epithelial cells of the small intestine are thought to
a Decrease the amount of time for molecules to diffuse across a membrane
b Significantly increase the surface area/volume ratio of a cell
c Decrease the diffusion coefficient for molecules diffusing across a cell membrane
d Increase the total amount of molecules that flow across the cells membrane each second
B&D
e
Catalase is an enzyme that breaks down H2O2 into H20. Each catalase molecule can maximally convert 10^6 molecules of H2O2 to H20 per second. Imagine that there are 1000 molecules of catalase in a peroxisome, the organelle where it is normally located. What would be the Vmax for breakdown of H2O2 in this situation?
A. 10^6 molecules/sec
B. 10^7 molecules/sec
C. 10^8 molecules/sec
D. 10^9 molecules/sec
E. 10^12 molecules/sec
d
Researchers examine the characteristics of catalase using 1 uM of the enzyme in their test tubes and discover in their experiments that in a solution mimicking the normal cytosol of a cell at a pH of 7.0, the Km is found to be 2.5 * 10-4 M. If the researchers then increase the concentration of catalase to 100 uM, the value for Km is likely to be
A. 2.5*10-4M
B. (2.5*10-4)2 M
C. 25*10-4M
D. 250 * 10-4M
E. 2.5*10-2M
a
The “V” in the Michaelis-Menton equation is
A. the maximum velocity that can be achieved
B. the concentration at which 1⁄2 maximal velocity can be achieved
C. the rate at which a given product is formed at a given concentration of substrate
D. the minimum rate at which a product can be detected
E. the rate at which an individual enzyme can form a product ?
c
An investigator is examining the properties of the enzyme carbonic anhydrase, and prepares a Lineweaver-Burke plot from the experiments she performed examining the rate of production of HCO3 when different concentrations of CO2 are added to a number of test tubes. She finds that the data can be fit by a straight line, and that the line, if extended from the data points, would cross the X axis at a value reading 0.1. This reading would mean that
A. The Vmax for the reaction is 1
B. The Vmax for the reaction is 0.1
C. The Vmax for the reaction is 10
D. The Km for the reaction is 0.1
E. The Km for the reaction is 10.
e
The investigator above notes that the line also happens to cross the Y axis at a value of 0.1 This would indicate that
A. The Vmax for the reaction is 1 The Vmax for the reaction is 0.1 The Vmax for the reaction is 10 The Km for the reaction is 0.1 The Km for the reaction is 10.
c
The investigator does a control series of experiments examining the production of HCO3 when different concentrations of CO2 are added to a number of test tubes lacking the enzyme. What should the investigator expect the graph of the data to look like when plotted as typical Michaelis-Menton plots are drawn?
A. A hyperbolic curve with a Vmax near 10 ?
B. A flat line
C. A straight line with a positive slope
D. A straight line with a negative slope
E. A hyperbolic curve that has no Vmax
b
The enzyme phosphofructokinase plays an important role in the glycolytic pathway, converting fructose 6 phosphate to fructose 1,6 bisphosphate. Stimulation of this pathway leads to the production of pyruvic acid, which ultimately produces high levels of ATP. ATP can bind to the enzyme phosphofructokinase and slow down its activity. This type of regulation is likely to result in
A. an increase in Vmax
B. a decrease in Km
C. a decrease in Vmax and Km
D. a decrease in Vmax
E. Vmax and Km are likely to remain the same
d
The effects of the binding of ATP onto the enzyme phosphofructokinase could be referred to as
A. feedback inhibition
B. competitive inhibition
C. allosteric regulation
D. enzyme denaturation
E. A&C
a
AMP (adenosine mono phosphate) can bind to the enzyme phosphofructokinase and significantly increase the amount of fructose 1,6 bisphosphate that is produced. This type of regulation is likely to result in
A. an increase in Vmax
B. a decrease in Km ?
C. a decrease in Vmax and Km
D. a decrease in Vmax
E. Vmax and Km are likely to remain the same
a
An investigator is examining the pressures associated with osmosis. She adds 30 millimoles of MgCl2 to water, bringing the volume of water up to 100 ml (milliliters). The solution is at normal room temperature. The investigator would now have a solution with what level of osmolarity?
A. 30 mosm
B. 60 mosm
C. 90 mosm
D. 300 mosm
E. 900 mosm
c
The investigator now heats the solution to 75oC. What will happen to the osmotic pressure associated with this solution?
A. it stays the same
B. it increases linearly with the rise in temperature
C. it decreases linearly with the rise in temperature
D. it increases as the square of the rise in temperature
E. it decreases as the square of the rise in temperature
b
The plasma osmolarity of a skipjack tuna is close to 400 mosm. The ocean water the fish is swimming in is estimated to be about 1 osmolar. The osmotic pressure difference is likely to be close to
A. 1atm
B. 5atm
C. 10 atm
D. 24 atm
E. 48 atm
c
For the skipjack tuna, a significant physiological problem that it needs to solve is
A. excess water flowing into its blood
B. water flowing out of its body into the water it is swimming in
C. excess salt flow into its blood
D. salt flow out of its blood into the water it is swimming in
E. B&C
e
A hammerhead shark is now chasing the skipjack tuna, hoping to have it for dinner. What major physiological problem does the hammerhead shark face as it devours its prey?
A. excess water flowing into its blood
B. water flowing out of its body into the water it is swimming in
C. excess salt flow into its blood
D. salt flow out of its blood into the water it is swimming in
E. B&C
c
The hammerhead shark is not satisfied after eating the skipjack tuna and spots a stingray gliding close to the ocean floor. It now devours the stingray, and notices that this meal tastes quite a bit different than when it ate the tuna. In what way would the blood of the stingray be expected to differ from the skipjack tuna?
A. It would have high levels of urea
B. it would have high levels of TMAO (trimethylamine oxide)
C. it would have higher levels of chloride
D. It would have high levels of all of the above
E. it would actually not be very different from the tuna.
d
The transporter associated with the movement of vitamins across the cell membrane in the basolateral membrane of epithelial cells of the proximal tubule
A. Moves both Na and vitamins against their concentration gradient
B. Moves Na against its concentration gradient but vitamins moves with its concentration gradient
C. Pumps vitamins against its concentration gradient but Na moves with its concentration gradient
D. Pumps both Na and vitamins down along their concentration gradient
E. Does not use Na when transporting vitamins
e
Which animal would be expected to have particularly short loops of Henle?
A. Rattlesnake
B. Frog
C. Giraffe
D. Desert rat
E. lion
b
High levels of antidiuretic hormone (ADH) in the blood
A. result in water leaving the lumen of the collecting duct and entering the extracellular fluids
B. results in an increase in the movement of salt from the extracellular fluids to the lumen of the collecting duct
C. increases the permeability of cells in the collecting duct to water
D. results in increases in the activity of the Na/K ATPase in the epithelial cells of the collecting duct
E. A&C
e
Stimulation of an epithelial cell in the collecting duct by antidiuretic hormone (ADH)
A. promotes the fusion of vesicles in the cytoplasm to the plasma membrane of epithelial cells
of the collecting duct
B. reduces the number of aquaporins in the plasma membrane of these cells
C. reduces the amount of cAMP in the cell
D. turns off the activity of a G protein in the cells
E. results in the insertion of glucose transporters into the plasma membrane
a
The reabsorption of sodium occurs in which part of the nephron?
A. glomerulus
B. ascending limb of the loop of Henle ?
C. proximal tubule
D. descending limb of the loop of Henle
E. B&C
e
A competitive inhibitor of antidiuretic hormone (ADH) would result in which of the following if an individual had been drinking plenty of water for the past several days?
A. More salt leaving the urine than normal
B. Less salt leaving the urine than normal
C. A significantly higher permeability of the collecting duct to water
D. A significantly lower permeability of the collecting duct to water
E. Not much of a change to either salt or water excretion
e
A non-competitive inhibitor of cAMP or protein kinase C (PKC) would result in which of the following if an individual had been walking in the dessert with little water for the past several days?
A. More total salt leaving the urine than normal
B. Less total salt leaving the urine than normal
C. A significantly higher permeability of the collecting duct to water
D. A significantly lower permeability of the collecting duct to water
E. Not much of a change to either salt or water excretion
d
he cell of a goldfish muscle is placed in a solution mimicking the blood plasma of the fish. In this case, the solution surrounding the cell could be considered to be ________ compared to the solution on the inside of the cell.
A. hypotonic
B. hypertonic
C. isotonic
D. hydrophobic
E. Hyperphobic
c
Which of the following is found in the apical membrane of a cell from a serous acinar salivary gland epithelial cell?
A. Na/K ATPase
B. K+ channel
C. carbonic anhydrase
D. protein kinase C
E. Cl- channel
e
Amylase acts to
A. break down proteins into mono- and di-peptides
B. increase the activity of protein kinase C
C. release calcium from intracellular organelles
D. break down starch
E. increase levels of cAMP
d
Thapsigargin is a pharmaceutical agent that will eliminate the release of calcium from the endoplasmic reticulum. When added to salivary gland epithelial cells stimulated by acetylcholine and noradrenaline, it will likely result in
A. a decrease in the amount of amylase released
B. an inability to increase the insertion of chloride channels into the plasma membrane
C. an inability to increase water accumulation into the lumen
D. an inability to increase sodium accumulation into the lumen
E. B,C&D
c
The basolateral membrane of the epithelial cells of the small intestine are likely to
A. have high levels of Na/K ATPase
B. have high levels of Na-coupled transporters
C. have high levels of Na-coupled amino acid transporters
D. have close associations with blood capillaries
E. A&D
e
The G-protein associated with noradrenaline activation of epithelial cells of the salivary gland most directly
A. activates adenylate cyclase
B. increases cAMP levels
C. increases protein kinase A activation
D. results in the insertion of chloride channels into the plasma membrane
E. leads to the insertion of aquaporins into the cell membrane
a
The effects of acetylcholine on potassium channel permeability in the salivary gland could best be described as
A. an increase in Vmax
B. an increase in Km
C. a decrease in Vmax
D. a decrease in Km
E. an increase in Vmax and a decrease in Km
a
The regulatory effects of thyroid hormones on Na/K ATPase activity in many cells can best be described as
A. an increase in Vmax
B. an increase in Km
C. a decrease in Vmax
D. a decrease in Km
E. an increase in Vmax and a decrease in Km
a
he regulatory effects of Aldosterone on Na/K ATPase activity in many cells can best be described as
A. an increase in Vmax
B. an increase in Km
C. a decrease in Vmax
D. a decrease in Km
E. an increase in Vmax and a decrease in Km
a
ATP-driven calcium pumps can be found in
A. the plasma membrane of many cells
B. mitochondria
C. endoplasmic reticulum
D. all of the above
E. none of the above
d
Channel proteins that will selectively allow calcium to move from high to low concentrations can be found in
A. the plasma membrane of many cells
B. mitochondria
C. endoplasmic reticulum
D. all of the above
E. none of the above
d
The ratio of outside calcium concentration to inside calcium concentration in many cells is approximately
A. 10
B. 0.1
C. 100
D. 0.01
E. 1000
d
The resting membrane potential of many cells in the body is due most immediately and directly to
A. primary active transport
B. secondary active transport
C. carrier mediated transport
D. facilitated transport through channel proteins
E. diffusion directly across the lipid membrane of cells
a
A researcher examines the voltage across the inside of a neuron from a fish previously unknown to science. She places one electrode inside the cell and has a second electrode in the extracellular solution. She sets the extracellular potassium concentration equal to 1 mM. She measures a transmembrane potential of -60 mV at room temperature. What is the likely concentration of potassium on the inside of this cell?
A. 0.1 mM
B. 1mM
C. 10mM
D. 100 mM
E. 1000 mM
c
The researcher then evokes an action potential in this strange neuron. She sets the extracellular sodium concentration to 100 mM. At the peak of the action potential, the researcher records a transmembrane voltage of 0 mV. What is the likely concentration of sodium on the inside of the cell?
A. 0.1 mM
B. 1mM
C. 10mM
D. 100 mM
E. 1000 mM
d
There are two solutions adjacent to one another in a beaker. Compartment A contains 100 mM NaCl. Compartment B has 10 mM NaCl. An experimenter defines side A as being at ground potential (that is, 0 V). Under these conditions, the calculated value for the Nernst equilibrium potential for sodium would be __ and the Nernst equilibrium potential for chloride would be ___
A. ENa=+60mV,ECl=-60mV
B. ENa=-60mV,ECl=+60mV
C. ENa=+60mV,ECl=+60mV
D. ENa=-60mV,ECl=-60mV
E. 0, 0
b
An investigator changes extracellular and intracellular chloride levels so that the outside concentration is 1 mM and the inside concentration is 100 mM. If chloride channels were forced to open up in this condition, they would drive the cell to what voltage value?
A. +120 mV
B. +60 mV
C. 0mV
D. -60mV
E. -120 mV
E
A nerve cell is associated with the following parameters:
PNa=100 Naout =100mM Nain =1mM
PCl=1mM PClout= 100mM PClin =1mM
PK=100 Kin =100mM Kout =1mM
What is the voltage of a cell that has these values close to?
-120 mV
-60 mV
0mV
+60 mV
+120 mV
0mv
A diseased cell has an intracellular calcium concentration of 0.1 mM. The extracellular solution has a normal amount of calcium. The mitochondria has its normal level of internal
calcium. If many calcium channels were opened in a mitochondria were opened up, what would the voltage of the interior of the mitochondria likely be compared to the cytoplasm of the cell?
A. –90mV
B. -60mV
C. -30mV
D. 0 mV
E. +60mV
b
