Biology, Eighth Edition (Raven)

Chapter 50: Temperature, Osmotic Regulation and the Urinary System

Pre Test

True or False: Ectotherms are animals that do not use metabolism to produce heat and have a body temperature that conform to the ambient temperature. Therefore ectotherms are unable to regulate body temperature. (p. 1019)
Most marine vertebrates are hypotonic to their environment. What is/are the consequences of this? (p. 1024)
A)They will gain water by osmosis.
B)They must retain water to prevent dehydration.
C)They must eliminate excess water.
D)They must actively transport inorganic ions into their body.
E)none of the above
Insects have a unique excretory system consisting of Malpighian tubules that branch off the hindgut. Waste molecules and potassium ions are secreted into these tubules from the blood by active transport. What is the result of this? (p 1025 - 1026)
A)Water will be drawn out of the tubules by osmosis.
B)Most of this water is excreted with the wastes.
C)Water will be drawn into the tubules by osmosis.
D)none of the above
Freshwater fish: (p. 1027)
A)are hypertonic to their environment.
B)must excreted large amounts of dilute urine.
C)avoid drinking water.
D)actively transport ions across their gills into the blood.
E)all of the above
In the processing of nitrogenous wastes, why do mammals convert ammonia, the initial by-product of catabolism of amino acids and nucleic acids, into urea? (p. 1028)
A)It is less toxic than ammonia.
B)It is insoluble in water so water is conserved when it is excreted.
C)It is soluble in water so can be excreted in large amounts.
D)both a and c
E)none of the above
The filtering unit of the mammalian kidney is the: (p. 1030)
B)renal medulla.
D)renal cortex.
E)flame cell.
The hormone aldosterone stimulates the kidney to: (p. 1035)
A)excrete Na+.
B)excrete Ca+.
C)reabsorb Na+.
D)reabaorb Ca+.
E)reabsorb K+.
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