BIOS 256 Final Exam Questions and Answers with Rationales |
CHAMBERLAIN UNIVERSITY
Question 1. Which feature is most characteristic of countercurrent multiplication?
A. opposing flow in nephron loops plus selective water and salt permeability establish progressively higher
medullary osmolarity
B. it is released by atrial cardiac muscle during volume expansion
C. renin initiates a hormone cascade that forms angiotensin II and stimulates aldosterone
D. clearance depends on urine concentration, urine flow, and plasma concentration
Correct Answer: A. opposing flow in nephron loops plus selective water and salt permeability establish
progressively higher medullary osmolarity
Explanation: The identifying feature is that opposing flow in nephron loops plus selective water and salt permeability
establish progressively higher medullary osmolarity. That characteristic is consistent with countercurrent multiplication
and its normal role: creates the corticomedullary osmotic gradient that allows urine concentration. The other findings are
characteristic of different items and do not identify countercurrent multiplication as precisely.
Question 2. Which change is the most direct prediction when respiratory compensation is markedly
abnormal?
A. CO2 transport and bicarbonate reabsorption would become less efficient if the enzyme were strongly inhibited
B. respiratory compensation cannot fully normalize pH while the primary metabolic disturbance persists
C. a normal pH does not prove the absence of an acid-base disorder when compensation is present
D. chronic acid loads would be difficult to correct without kidney function
Correct Answer: B. respiratory compensation cannot fully normalize pH while the primary metabolic
disturbance persists
Explanation: The most direct consequence is that respiratory compensation cannot fully normalize pH while the primary
metabolic disturbance persists. That prediction follows because respiratory compensation normally has this role: changes
alveolar ventilation to partially offset a primary metabolic acid-base disorder. The distractors reflect dysfunction of other
structures or processes rather than the most direct consequence here.
Question 3. Which option gives an internally consistent description of glycogenesis?
A. It stores excess glucose as glycogen; this is enabled because a sequence of enzyme reactions splits one
six-carbon glucose into two three-carbon pyruvate molecules.
B. It stores excess glucose as glycogen; this is enabled because digestion and metabolism convert nutrients into
usable molecules, cofactors, and stored fuels.
C. It stores excess glucose as glycogen; this is enabled because insulin favors glucose uptake and enzyme activity
that links glucose units into glycogen.
D. It stores excess glucose as glycogen; this is enabled because coupling energy-releasing reactions to
energy-requiring reactions supports synthesis, repair, and cellular work.
Correct Answer: C. It stores excess glucose as glycogen; this is enabled because insulin favors glucose uptake and
enzyme activity that links glucose units into glycogen.
Explanation: The correct pairing links glycogenesis to this role: stores excess glucose as glycogen, and to this
mechanism: insulin favors glucose uptake and enzyme activity that links glucose units into glycogen. A correct function
paired with the wrong mechanism is still an incorrect description. The other options deliberately mix the role of
glycogenesis with mechanisms that belong to different components.
,Question 4. When reviewing normal anatomy and physiology, which feature belongs to glomerular net
filtration pressure?
A. glomerular hydrostatic pressure favors filtration while capsular hydrostatic pressure and plasma oncotic pressure
oppose it
B. it has a brush border, abundant mitochondria, and extensive transport machinery
C. myogenic responses and tubuloglomerular feedback adjust afferent arteriolar resistance
D. it is relatively permeable to water and less permeable to many solutes
Correct Answer: A. glomerular hydrostatic pressure favors filtration while capsular hydrostatic pressure and
plasma oncotic pressure oppose it
Explanation: The identifying feature is that glomerular hydrostatic pressure favors filtration while capsular hydrostatic
pressure and plasma oncotic pressure oppose it. That characteristic is consistent with glomerular net filtration pressure
and its normal role: drives fluid from glomerular capillaries into capsular space. The other findings are characteristic of
different items and do not identify glomerular net filtration pressure as precisely.
Question 5. Which process provides the best mechanistic explanation for
hypothalamic-pituitary-gonadal axis in males?
A. nitric-oxide-mediated vasodilation increases erectile blood flow, followed later by muscular propulsion of semen
B. LH acts on Leydig cells and FSH acts mainly through Sertoli cells
C. their secretion lubricates the urethra and helps neutralize residual acidity
D. when sperm production and Sertoli activity are adequate, inhibin provides negative feedback to the anterior
pituitary
Correct Answer: B. LH acts on Leydig cells and FSH acts mainly through Sertoli cells
Explanation: The correct mechanism is that LH acts on Leydig cells and FSH acts mainly through Sertoli cells. It
explains the normal function of hypothalamic-pituitary-gonadal axis in males: coordinates testosterone production and
spermatogenesis. The other mechanisms belong to different structures or processes in the same broad system.
Question 6. A student is distinguishing closely related structures and processes. Which finding best
identifies distal convoluted tubule?
A. it follows the nephron loop and participates in regulated sodium and calcium handling
B. it acts mainly on principal cells in late distal tubules and collecting ducts
C. it is a major diluting segment of the nephron loop
D. ADH is released from the posterior pituitary when plasma osmolarity rises or effective circulating volume falls
Correct Answer: A. it follows the nephron loop and participates in regulated sodium and calcium handling
Explanation: The identifying feature is that it follows the nephron loop and participates in regulated sodium and calcium
handling. That characteristic is consistent with distal convoluted tubule and its normal role: fine-tunes electrolyte
composition of tubular fluid after most bulk reabsorption is complete. The other findings are characteristic of different
items and do not identify distal convoluted tubule as precisely.
Question 7. Which structure or process is best identified by this description: a carrier with two X
chromosomes can pass an altered X-linked allele to sons or daughters?
A. meiosis and chromosome number
B. autosomal dominant inheritance
C. polygenic and multifactorial traits
D. X-linked recessive inheritance
Correct Answer: D. X-linked recessive inheritance
Explanation: The description identifies X-linked recessive inheritance because a carrier with two X chromosomes can
pass an altered X-linked allele to sons or daughters. Its key role is that it often affects males more frequently because
they have only one X chromosome. The alternative options have different defining features and do not best fit the
, description.
Question 8. Consider this case: A patient retains large amounts of sodium over several days and gains
extracellular fluid volume. What is the best physiologic explanation?
A. water follows retained sodium, expanding the extracellular compartment
B. the higher extracellular osmolarity draws water out of cells
C. water moves between ICF and ECF according to osmotic gradients
D. altered potassium balance can disturb membrane potentials in excitable tissues
Correct Answer: A. water follows retained sodium, expanding the extracellular compartment
Explanation: The best interpretation is that water follows retained sodium, expanding the extracellular compartment.
This scenario centers on sodium balance, whose normal physiologic role is described as follows: provides the major
extracellular cation and strongly influences extracellular fluid volume. That relationship is more directly supported by
the stated findings than the alternative explanations.
Question 9. Which process provides the best mechanistic explanation for progesterone in the luteal
phase?
A. LH initially supports it, and hCG preserves it in early pregnancy until the placenta assumes steroid production
B. rapid LH elevation completes key oocyte and follicular changes leading to follicle rupture
C. FSH promotes follicular development, and increasing estradiol eventually contributes to the midcycle LH surge
D. progesterone transforms estrogen-primed endometrium into a nutrient-rich implantation-supporting tissue
Correct Answer: D. progesterone transforms estrogen-primed endometrium into a nutrient-rich
implantation-supporting tissue
Explanation: The correct mechanism is that progesterone transforms estrogen-primed endometrium into a nutrient-rich
implantation-supporting tissue. It explains the normal function of progesterone in the luteal phase: maintains a secretory
endometrium and reduces uterine contractile activity after ovulation. The other mechanisms belong to different
structures or processes in the same broad system.
Question 10. Which change is the most direct prediction when protein buffers is markedly abnormal?
A. enzyme and membrane function become disturbed when pH deviates substantially from normal
B. renal elimination of nonvolatile acid would be less effective without urinary buffers such as phosphate
C. pH regulation would be less effective if bicarbonate concentration or carbon dioxide control were severely
impaired
D. buffer capacity would fall if major protein buffering sites were unavailable
Correct Answer: D. buffer capacity would fall if major protein buffering sites were unavailable
Explanation: The most direct consequence is that buffer capacity would fall if major protein buffering sites were
unavailable. That prediction follows because protein buffers normally has this role: buffer hydrogen ions through
ionizable groups on plasma and intracellular proteins. The distractors reflect dysfunction of other structures or processes
rather than the most direct consequence here.
Question 11. Which function is the best match for saliva?
A. coordinates ingestion, propulsion, mechanical and chemical digestion, absorption, and defecation
B. lubricates food, begins digestion, protects oral tissues, and helps dissolve molecules for taste
C. coordinates much of gastrointestinal motility and secretion locally
D. provide a common structural plan for movement, secretion, absorption, support, and external covering
Correct Answer: B. lubricates food, begins digestion, protects oral tissues, and helps dissolve molecules for taste
Explanation: The correct choice describes this function: lubricates food, begins digestion, protects oral tissues, and helps
dissolve molecules for taste. This is the primary role associated with saliva, and it is supported by the mechanism that
parasympathetic stimulation promotes a large watery secretion that moistens food and supports oral processing. The
other choices describe functions performed by different components within the same course domain.
CHAMBERLAIN UNIVERSITY
Question 1. Which feature is most characteristic of countercurrent multiplication?
A. opposing flow in nephron loops plus selective water and salt permeability establish progressively higher
medullary osmolarity
B. it is released by atrial cardiac muscle during volume expansion
C. renin initiates a hormone cascade that forms angiotensin II and stimulates aldosterone
D. clearance depends on urine concentration, urine flow, and plasma concentration
Correct Answer: A. opposing flow in nephron loops plus selective water and salt permeability establish
progressively higher medullary osmolarity
Explanation: The identifying feature is that opposing flow in nephron loops plus selective water and salt permeability
establish progressively higher medullary osmolarity. That characteristic is consistent with countercurrent multiplication
and its normal role: creates the corticomedullary osmotic gradient that allows urine concentration. The other findings are
characteristic of different items and do not identify countercurrent multiplication as precisely.
Question 2. Which change is the most direct prediction when respiratory compensation is markedly
abnormal?
A. CO2 transport and bicarbonate reabsorption would become less efficient if the enzyme were strongly inhibited
B. respiratory compensation cannot fully normalize pH while the primary metabolic disturbance persists
C. a normal pH does not prove the absence of an acid-base disorder when compensation is present
D. chronic acid loads would be difficult to correct without kidney function
Correct Answer: B. respiratory compensation cannot fully normalize pH while the primary metabolic
disturbance persists
Explanation: The most direct consequence is that respiratory compensation cannot fully normalize pH while the primary
metabolic disturbance persists. That prediction follows because respiratory compensation normally has this role: changes
alveolar ventilation to partially offset a primary metabolic acid-base disorder. The distractors reflect dysfunction of other
structures or processes rather than the most direct consequence here.
Question 3. Which option gives an internally consistent description of glycogenesis?
A. It stores excess glucose as glycogen; this is enabled because a sequence of enzyme reactions splits one
six-carbon glucose into two three-carbon pyruvate molecules.
B. It stores excess glucose as glycogen; this is enabled because digestion and metabolism convert nutrients into
usable molecules, cofactors, and stored fuels.
C. It stores excess glucose as glycogen; this is enabled because insulin favors glucose uptake and enzyme activity
that links glucose units into glycogen.
D. It stores excess glucose as glycogen; this is enabled because coupling energy-releasing reactions to
energy-requiring reactions supports synthesis, repair, and cellular work.
Correct Answer: C. It stores excess glucose as glycogen; this is enabled because insulin favors glucose uptake and
enzyme activity that links glucose units into glycogen.
Explanation: The correct pairing links glycogenesis to this role: stores excess glucose as glycogen, and to this
mechanism: insulin favors glucose uptake and enzyme activity that links glucose units into glycogen. A correct function
paired with the wrong mechanism is still an incorrect description. The other options deliberately mix the role of
glycogenesis with mechanisms that belong to different components.
,Question 4. When reviewing normal anatomy and physiology, which feature belongs to glomerular net
filtration pressure?
A. glomerular hydrostatic pressure favors filtration while capsular hydrostatic pressure and plasma oncotic pressure
oppose it
B. it has a brush border, abundant mitochondria, and extensive transport machinery
C. myogenic responses and tubuloglomerular feedback adjust afferent arteriolar resistance
D. it is relatively permeable to water and less permeable to many solutes
Correct Answer: A. glomerular hydrostatic pressure favors filtration while capsular hydrostatic pressure and
plasma oncotic pressure oppose it
Explanation: The identifying feature is that glomerular hydrostatic pressure favors filtration while capsular hydrostatic
pressure and plasma oncotic pressure oppose it. That characteristic is consistent with glomerular net filtration pressure
and its normal role: drives fluid from glomerular capillaries into capsular space. The other findings are characteristic of
different items and do not identify glomerular net filtration pressure as precisely.
Question 5. Which process provides the best mechanistic explanation for
hypothalamic-pituitary-gonadal axis in males?
A. nitric-oxide-mediated vasodilation increases erectile blood flow, followed later by muscular propulsion of semen
B. LH acts on Leydig cells and FSH acts mainly through Sertoli cells
C. their secretion lubricates the urethra and helps neutralize residual acidity
D. when sperm production and Sertoli activity are adequate, inhibin provides negative feedback to the anterior
pituitary
Correct Answer: B. LH acts on Leydig cells and FSH acts mainly through Sertoli cells
Explanation: The correct mechanism is that LH acts on Leydig cells and FSH acts mainly through Sertoli cells. It
explains the normal function of hypothalamic-pituitary-gonadal axis in males: coordinates testosterone production and
spermatogenesis. The other mechanisms belong to different structures or processes in the same broad system.
Question 6. A student is distinguishing closely related structures and processes. Which finding best
identifies distal convoluted tubule?
A. it follows the nephron loop and participates in regulated sodium and calcium handling
B. it acts mainly on principal cells in late distal tubules and collecting ducts
C. it is a major diluting segment of the nephron loop
D. ADH is released from the posterior pituitary when plasma osmolarity rises or effective circulating volume falls
Correct Answer: A. it follows the nephron loop and participates in regulated sodium and calcium handling
Explanation: The identifying feature is that it follows the nephron loop and participates in regulated sodium and calcium
handling. That characteristic is consistent with distal convoluted tubule and its normal role: fine-tunes electrolyte
composition of tubular fluid after most bulk reabsorption is complete. The other findings are characteristic of different
items and do not identify distal convoluted tubule as precisely.
Question 7. Which structure or process is best identified by this description: a carrier with two X
chromosomes can pass an altered X-linked allele to sons or daughters?
A. meiosis and chromosome number
B. autosomal dominant inheritance
C. polygenic and multifactorial traits
D. X-linked recessive inheritance
Correct Answer: D. X-linked recessive inheritance
Explanation: The description identifies X-linked recessive inheritance because a carrier with two X chromosomes can
pass an altered X-linked allele to sons or daughters. Its key role is that it often affects males more frequently because
they have only one X chromosome. The alternative options have different defining features and do not best fit the
, description.
Question 8. Consider this case: A patient retains large amounts of sodium over several days and gains
extracellular fluid volume. What is the best physiologic explanation?
A. water follows retained sodium, expanding the extracellular compartment
B. the higher extracellular osmolarity draws water out of cells
C. water moves between ICF and ECF according to osmotic gradients
D. altered potassium balance can disturb membrane potentials in excitable tissues
Correct Answer: A. water follows retained sodium, expanding the extracellular compartment
Explanation: The best interpretation is that water follows retained sodium, expanding the extracellular compartment.
This scenario centers on sodium balance, whose normal physiologic role is described as follows: provides the major
extracellular cation and strongly influences extracellular fluid volume. That relationship is more directly supported by
the stated findings than the alternative explanations.
Question 9. Which process provides the best mechanistic explanation for progesterone in the luteal
phase?
A. LH initially supports it, and hCG preserves it in early pregnancy until the placenta assumes steroid production
B. rapid LH elevation completes key oocyte and follicular changes leading to follicle rupture
C. FSH promotes follicular development, and increasing estradiol eventually contributes to the midcycle LH surge
D. progesterone transforms estrogen-primed endometrium into a nutrient-rich implantation-supporting tissue
Correct Answer: D. progesterone transforms estrogen-primed endometrium into a nutrient-rich
implantation-supporting tissue
Explanation: The correct mechanism is that progesterone transforms estrogen-primed endometrium into a nutrient-rich
implantation-supporting tissue. It explains the normal function of progesterone in the luteal phase: maintains a secretory
endometrium and reduces uterine contractile activity after ovulation. The other mechanisms belong to different
structures or processes in the same broad system.
Question 10. Which change is the most direct prediction when protein buffers is markedly abnormal?
A. enzyme and membrane function become disturbed when pH deviates substantially from normal
B. renal elimination of nonvolatile acid would be less effective without urinary buffers such as phosphate
C. pH regulation would be less effective if bicarbonate concentration or carbon dioxide control were severely
impaired
D. buffer capacity would fall if major protein buffering sites were unavailable
Correct Answer: D. buffer capacity would fall if major protein buffering sites were unavailable
Explanation: The most direct consequence is that buffer capacity would fall if major protein buffering sites were
unavailable. That prediction follows because protein buffers normally has this role: buffer hydrogen ions through
ionizable groups on plasma and intracellular proteins. The distractors reflect dysfunction of other structures or processes
rather than the most direct consequence here.
Question 11. Which function is the best match for saliva?
A. coordinates ingestion, propulsion, mechanical and chemical digestion, absorption, and defecation
B. lubricates food, begins digestion, protects oral tissues, and helps dissolve molecules for taste
C. coordinates much of gastrointestinal motility and secretion locally
D. provide a common structural plan for movement, secretion, absorption, support, and external covering
Correct Answer: B. lubricates food, begins digestion, protects oral tissues, and helps dissolve molecules for taste
Explanation: The correct choice describes this function: lubricates food, begins digestion, protects oral tissues, and helps
dissolve molecules for taste. This is the primary role associated with saliva, and it is supported by the mechanism that
parasympathetic stimulation promotes a large watery secretion that moistens food and supports oral processing. The
other choices describe functions performed by different components within the same course domain.
