Normal Cellular Physiology – 17 July 2012
1. Body fluid volumes are important in physiology. Which of the following statements
is correct?
a. about 1/3 of total body water is extracellular
b. total blood volume can be calculated by multiplying plasma volume by
100 – Hct
c. inulin is used to accurately measure intracellular fluid volume
d. the intracellular component of body water accounts for about 20% of body
weight
2. The principle buffer in interstitial fluid is:
a. carbonic acid
b. haemoglobin
c. phosphate
d. compounds containing histidine
3. Regarding general cell physiology, which of the following is true?
a. osmolarity is the number of osmoles/kg of solvent
b. the exterior of the cell is negative relative to the interior
c. the equilibrium potential of chloride is -90mV
d. sodium contributes little to the value of the resting membrane potential
4. Which of the following characteristics is shared by simple and facilitated diffusion
of glucose?
a. occurs down an electrochemical gradient
b. is saturable
c. requires metabolic energy
d. requires a sodium gradient
5. In error, a patient is infused with large volumes of a solution that causes lysis of his
RBCs. The solution is most likely:
a. isotonic NaCL
b. isotonic mannitol
c. hypotonic urea
d. hypertonic urea
6. Which of the following would occur as a result of the inhibition of Na+K+
ATPase?
a. decreased intracellular sodium concentration
b. increased intracellular calcium concentration
c. increased intracellular potassium concentration
d. increased Na+-glucose co-transport
7. Regarding endocytosis and exocytosis, which of the following is true?
a. exocytosis requires Na+ and energy
b. the constitutive pathway of exocytosis involves prompt transport of proteins
with little or no processing
c. in phagocytosis, ingested substances ingested are in solution
d. constitutive endocytosis plays a major role in synaptic function
8. Which mechanisms does noradrenaline, via α1 receptors act to bring about changes
in cell function?
a. opens/closes ion channels in cell membranes
b. increases cyclicGMP in the cell
c. increases tyrosine kinase activity of the cytoplasmic portions of
transmembrane receptors
d. activation of phospholipase with intracellular production of DAG, IP3 and
other inositol intracellular phosphates
9. Regarding the composition of ECF versus ICF, ECG has:
a. increased potassium compared with ICF
b. increased protein compared with ICF
c. decreased phosphate compared with ICF
d. decreased sodium compared with ICF
10. Which is true regarding membrane transport proteins?
a. active transport of sodium and potassium accounts for about 24% of the
energy utilised by cells
b. N+K+ATPase is an example of a symport
c. a typical voltage gated channel is the acetylcholine channel
d. glucose transport via the glucose transporter into the cell is an example of
active transport
11. All of the following transport processes require energy except which of the
following?
a. hydrogen into the lumen of the distal nephron
b. calcium into the sarcoplasmic reticulum
c. potassium into striated muscle cells
d. glucose into adipose tissue
12. Increasing the extracellular potassium concentration will do which of the
following?
a. increase the threshold for eliciting an action potential
b. hyperpolarise the membrane potential
c. decrease potassium permeability
d. decrease activity of the sodium/potassium pump
13. All of the following are vasoconstricting agents except
a. bradykinin
b. norepinephine
c. endothelin
d. angiotensin
14. Paracrine communication refers to interactions between cells resulting from which
of the following?
a. direct contact of cells at tight junctions
b. release of chemical mediators in localised synaptic junctions
c. release and diffusion of chemical mediators through ECF to target cells
d. release of chemical mediators into blood to act upon specific receptors in
distant target tissues
15. The most plentiful catecholamine in urine is which of the following?
a. norepinephrine
b. dopamine
c. homovanillic acid
d. vanillylmandelic acid
16. Increasing the extracellular potassium concentration will do which of the
following?
a. increase the threshold for eliciting an action potential
b. hyperpolarise the membrane potential
c. decrease potassium permeability
d. decrease activity of the sodium/potassium pump
17. Which of the following is INcorrect?
a. total blood volume = 8% body weight
b. plasma = 5% body weight
c. interstitial fluid = 20% body weight
d. extracellular body water = 20% body weight
18. Water is the ideal solvent due all of the following properties except:
a. high surface tension
b. high heat of evaporation
c. high heat capacity
d. low dielectric constant
19. Which of the following is not an essential amino acid?
a. valine
b. isoleucine
c. tyrosine
d. arginine
20. The membrane potential of a particular cell is at the K+ equilibrium. The
intracellular concentration for K+ is at 150mmol/L and the extracellular concentration
for K+ is at 5.5 mmol/L. What is the resting membrane potential?
a. -70 mV
b. -90 mV
c. +70 mV
d. +90 mV
21. Transcription refers to which of the following statements?
a. the process where an mRNA is used as a template for protein production
b. the process where a DNA sequence is copied into RNA for the purpose of
gene expression
c. the process where DNA wraps around histones to form a nucleosome
d. the process of replication of RNA prior to cell division
22. Regarding second messengers, which is true?
a. are substances that interact with first messengers outside cells
b. are hormones secreted by cells in response to stimulation by another
hormone
c. mediate the intracellular response to many different hormones and
neurotransmitters
d. are substances that bind to first messengers in the cell membrane
23. Which of the following statements is correct regarding G protein coupled
receptors?
a. are intracellular membrane proteins that help to regulate movement within
the cell
b. are plasma membrane proteins that couple the extracellular binding of
primary signalling molecules to activation of small G proteins
c. are plasma membrane proteins that couple the extracellular binding of
primary signalling molecules to the activation of heterotrimeric G
proteins
d. are intracellular proteins that couple the binding of primary messenger
molecules with transcription
24. Which of the following protein kinases is not calmodulin-dependent?
a. mysosin light-chain kinase
b. phosphorylase kinase
c. Ca+2/calmodulin kinase III
d. protein kinase C
25. Which of the following is not an example of local intercellular communication by
chemical mediators?
a. gap junctions
b. synaptic junctions
c. paracrine communication
d. endocrine communication
26. The following is true about exocytosis:
a. in the regulated pathway, there is prompt transport of proteins to the cell
membrane without processing
b. in the constitutive pathway, there is prompt transport of proteins to
membranes without processing
c. only the non-constitutive pathway is regulated
d. there are three pathways for exocytosis
27. Regarding endocytosis, which is true?
a. refers to phagocytosis but not pinocytosis
b. rafts are cell membrane areas rich in sphingolipids
c. clathrin-mediated endocytosis and caveolae-dependent uptake are the same
process
d. substance must be in solution for phagocytosis to occur
28. Which of the following is false regarding membrane permeability?
a. patch clamping is an important method of studying membrane permeability
b. gated ion channels can be opened by ligand binding
c. the relative prevalence of non-gated ion channels determines the membrane
permeability to ions such as potassium
d. polar molecules freely diffuse without need for active transport
29. Which of the following statements about ion channels is correct?
a. there are single subunit transmembrane proteins that allow ions into the cells
b. cystis fibrosis is a condition which involves a sodium channel deficit
c. aquaporins are pentamers
d. ligand gated ion channels are generally made up of 5 subunits
30. Regarding active transport, which of the following statements is false?
a. energy is required for transport to occur
b. Na+/glucose symport is an example
c. Na+ can be transported into the cell via and Na+/Ca+2 antiport
d. Na+/K+ATPase puts out two Na+ for every three K+ that go in
31. Which of the following is true regarding intercellular communication?
a. endocrine communication is not an example
b. a substance can not act as a neurotransmitter and a hormone
c. the number of active receptors decreases in response to excess hormone
d. down regulation refers to chemical modification of receptors
32. Regarding second messengers, which of the following is false?
a. extracellular ligands are primary messengers
b. Ca+2 is a secondary messenger with limited effects
c. Adrenaline and dopamine act via G-proteins secondary messengers
d. insulin works by a second messenger where tyrosine residues are
phosphorylated
33. In a70kg man, which of the following is true with respect to body compartment
composition?
a. total body water = 50 litres
b. interstitial volume = 15 litres
c. blood plasma = 3.5 litres
d. total blood volume = 10%
34. Regarding diffusion, which is incorrect?
a. time to equilibrium is proportionate to the square of the diffusion distance
b. diffusion tendency is proportionate to the cross-sectional area which
diffusion is taking place
c. time to equilibrium is inversely proportionate to the square of the diffusion
distance
d. diffusion tendency is proportionate to the concentration gradient
35. Regarding osmosis, which is correct?
a. osmolality is the number of osmoles/litre of solution
b. osmolarity is the number of osmoles/kg of solvent
c. osmolal concentration of substance is measured by degree to which it raises
the freezing point
d. osmolarity is the number of osmoles/litre of solution
36. Regarding the Nernst equation, which is true?
a. membrane potential of K+ is -70mV
b. Membrane potential of Na+ is +60mV
c. Membrane potential of Cl- is -60mV
d. Resting membrane potential in neurons is -70mV
37. Which of the following statements is incorrect?
a. RNA contains ribose
b. DNA contains 2-deoxyribose
c. a nucleoside consists of purine or pyrimidine and phosphoric acid residue
d. a nucleotide consists of nucleoside and phosphoric acid residue
38. Regarding pH and buffering, which is true?
a. carbonic acid is both a weak acid and an important buffer
b. for each pH unit < 7.0, H+ concentration decreases tenfold
c. pH of a solution is the logarithm to base 10 of the hydrogen concentration
d. the Henderson Hasselbach equation is: pH= pKa + log [HA-]/[A-]
39. Which is true of the distribution of ions across cell membranes?
a. normal cell volume and pressure depends on Na+K+ATPase
b. there are less osmotically active particles in cells compared to interstitial
fluid
c. the Donnan effect relies on the presence of diffusible ions
d. at equilibrium, symmetric distribution of ions across a cell membrane
creates an electrical gradient
40. Select the incorrect statement regarding body compartments
a. The extracellular fluid compartment contributes to 20% body weight
b. 1/3rd of total body water is extracellular
c. Total blood volume is 12% body weight
d. Blood plasma is 5% body weight.
41. Choose the correct statement regarding pH and buffering
a. The pH of water at 25 degrees is 7.4
b. Each pH unit rise above 7.0 indicates 100x decrease in H+ concentration
c. Strong acids and bases dissociate weakly in water
d. A buffer has the ability to bind or release H+ in solution
42. Choose the correct statement
a. Osmotic pressure is the pressure necessary to cause solvent migration in
a solution
b. Osmolarity is the number of osmols per litre of solution
c. Osmolality is affected by the volume of various solutes in the solution
d. One osmol equals the gram molecular weight of a substance multiplied
by the number of freely moving particles that each molecule liberates in
solution
43. Regarding the Donnan Effect, which of the following is TRUE?
a. If it were not for the Na-K-ATPase pump, the presence of negatively
charged proteins inside the cell would cause water to diffuse into the
cells
b. The distribution of ions across the membrane is equal, allowing for an
electrochemical gradient to exist
c. There are equal amounts of proteins in the interstitial fluid and plasma,
meaning the Donnan Effect does not apply across capillary walls.
d. In the presence of diffusible ions, the non diffusible ions reorganise
themselves to maintain electrochemical neutrality.
44. Which is correct regarding tonicity?
a. 5% glucose remains isotonic when infused into an individual.
b. Average tonicity of human blood is 250 mOsm/L
c. The major nonelectrolytes of plasma that contribute to tonicity are Urea
and Haemoglobin
d. The majority of ionic contribution to tonicity of plasma comes from Na
and it’s anions Cl and HCO3
45. Regarding intercellular communication, which is false?
a. Paracrine communication occurs by diffusion in interstitial fluid
b. Endocrine communication is mediated through receptors
c. Gap junctions transmit messages across the synaptic cleft
d. Autocrine transmission occurs back onto the original cell
46. Which is incorrect regarding Chemical messengers?
a. Are called first messengers if they are intracellular
b. Typically starts with interaction of the ligand with a receptor
c. A deficiency may cause 'up-regulation' of the receptors
d. Desensitisation is a form of down regulation
47. Na K ATPase pump:
a. Is an electrogenic pump
b. Is activated by ouabain and digitalis
c. Has a coupling ratio of 4:3
d. Consists of three subunits
48. Cyclic AMP:
a. Is formed from ATP
b. Is inactivated by phosphodiesterase
c. Activates cyclic nucleotide dependent protein kinases
d. All of the above
49. Which is false regarding intracellular Ca2+
a. Concentration is increased by many second messengers
b. Increase of cytosol Ca2+ concentration is slow and declines slowly
c. Ca2+ concentration is many times greater in the interstitial fluid than the
cytoplasm
d. The SERCA pump causes movement into the internal stores of the cell