BIO 2A03 FINAL EXAM | ACTUAL 217 QUESTIONS AND ANSWERS | WITH COMPLETE
SOLUTIONS - 2026 UPDATE.
Marine (saltwater) environments - (answer)animals tend to gain salts and lose water
Freshwater environments - (answer)animals tend to lose salts and gain water
Terrestrial environments - (answer)animals tend to lose water
The role of epithelial tissues - (answer)form the boundary between animal and environment
Elasmobranchs - (answer)osmoconformers but are strict ionic regulators. Salt levels maintained at low
levels. Osmotic concentrations largely due to organic solutes.
Teleosts - (answer)are osmoregulators and can counter passive water and ion fluxes to maintain
homeostasis
Terrestrial organisms - (answer)first line of defence against water loss is the integument (body covering)
and the ability to resist passive water loss to the environment. Amniotes (mammals, birds and reptiles)
have a specialization of the integument, the keratinized stratum corneum, which creates a waterproof
layer. Keratinocytes differentiate to form part of this thickened external layer
Transcellular transport - (answer)movement through the cell, across membranes
Paracellular transport - (answer)movement between cells
The kidney and urinary system of mammals - (answer)filtration, reabsorption, secretion, excretion
Plasma volume - (answer)regulation, thus influencing our mean arterial pressure
Osmotic balance - (answer)kidneys determine the volume of urine to produce, and therefore water
balance
, BIO 2A03 FINAL EXAM | ACTUAL 217 QUESTIONS AND ANSWERS | WITH COMPLETE
SOLUTIONS - 2026 UPDATE.
Ion balance - (answer)extracellular fluid osmolarity; controls loss of ions that have important roles
pH balance - (answer)by retaining or excreting H+ or HCO3-
Excretion - (answer)of metabolic nitrogenous wastes and water soluble toxins
Hormone production - (answer)renal hormones, renin which controls blood pressure, erythropoietin
which regulates red blood cell synthesis
Gluconeogenesis - (answer)leading to glucose production during fasting
Mammalian kidney - (answer)it has two layers: the outer cortex and the inner medulla. As urine is
produced, it is collected by minor calyces which join together to form major calyx. Urine leaves the
kidney via the ureter, and passes into urinary bladder for storage. Urine leaves the animal through the
urethra
Mammalian nephron - (answer)individual tubular structure that produces urine. There may be millions
of nephrons across our 2 kidneys. By the time urine leaves the nephron, it is fully formed. Main nephron
vasculature is the glomerulus
Cortical nephrons - (answer)make up 85% of our nephrons
Juxtamedullary nephrons - (answer)make up 15% of our nephrons
Glomerular filtration - (answer)blood pressure forces water and solutes across the wall of the
glomerular capillaries and into the capsular space
Reabsorption - (answer)the removal of water and solutes from the filtrate and their movement across
the tubular epithelium and into the peritubular fluid
SOLUTIONS - 2026 UPDATE.
Marine (saltwater) environments - (answer)animals tend to gain salts and lose water
Freshwater environments - (answer)animals tend to lose salts and gain water
Terrestrial environments - (answer)animals tend to lose water
The role of epithelial tissues - (answer)form the boundary between animal and environment
Elasmobranchs - (answer)osmoconformers but are strict ionic regulators. Salt levels maintained at low
levels. Osmotic concentrations largely due to organic solutes.
Teleosts - (answer)are osmoregulators and can counter passive water and ion fluxes to maintain
homeostasis
Terrestrial organisms - (answer)first line of defence against water loss is the integument (body covering)
and the ability to resist passive water loss to the environment. Amniotes (mammals, birds and reptiles)
have a specialization of the integument, the keratinized stratum corneum, which creates a waterproof
layer. Keratinocytes differentiate to form part of this thickened external layer
Transcellular transport - (answer)movement through the cell, across membranes
Paracellular transport - (answer)movement between cells
The kidney and urinary system of mammals - (answer)filtration, reabsorption, secretion, excretion
Plasma volume - (answer)regulation, thus influencing our mean arterial pressure
Osmotic balance - (answer)kidneys determine the volume of urine to produce, and therefore water
balance
, BIO 2A03 FINAL EXAM | ACTUAL 217 QUESTIONS AND ANSWERS | WITH COMPLETE
SOLUTIONS - 2026 UPDATE.
Ion balance - (answer)extracellular fluid osmolarity; controls loss of ions that have important roles
pH balance - (answer)by retaining or excreting H+ or HCO3-
Excretion - (answer)of metabolic nitrogenous wastes and water soluble toxins
Hormone production - (answer)renal hormones, renin which controls blood pressure, erythropoietin
which regulates red blood cell synthesis
Gluconeogenesis - (answer)leading to glucose production during fasting
Mammalian kidney - (answer)it has two layers: the outer cortex and the inner medulla. As urine is
produced, it is collected by minor calyces which join together to form major calyx. Urine leaves the
kidney via the ureter, and passes into urinary bladder for storage. Urine leaves the animal through the
urethra
Mammalian nephron - (answer)individual tubular structure that produces urine. There may be millions
of nephrons across our 2 kidneys. By the time urine leaves the nephron, it is fully formed. Main nephron
vasculature is the glomerulus
Cortical nephrons - (answer)make up 85% of our nephrons
Juxtamedullary nephrons - (answer)make up 15% of our nephrons
Glomerular filtration - (answer)blood pressure forces water and solutes across the wall of the
glomerular capillaries and into the capsular space
Reabsorption - (answer)the removal of water and solutes from the filtrate and their movement across
the tubular epithelium and into the peritubular fluid
