12. Which environment is most dangerous to an ectotherm? a. one above its critical temperature b. one that matches its critical temperature c. one below its critical temperature d. A and B e. none of the above 13. Metabolic homeostasis concerns the thyroid gland. The thyroid is regulated by feedback loops involving which of the following? a. the pituitary gland b. the hypothalamus, pancreas and four hormones c. the hypothalamus, the pituitary gland and three hormones d. the islets of Langerhans and three hormones e. the pituitary gland and two hormones 14. The sodium pump operates in which part of the nephron? a. Bowman's capsule b. collecting tubule c. adipose capsule d. proximal convoluted tubule e. loop of Henle 15. Plants are able to build glucose during photosynthesis. Which is the best description of this process? a. catabolic, exothermic, and endergonic b. anabolic, endothermic, and exergonic c. catabolic, endothermic, and endergonic d. anabolic, endothermic, and endergonic e. none on the above 16. Where are excess hydrogen ions removed from the body? a. in the distal tubules after a reaction with glucose b. in the distal tubules after a reaction with urea c. in the nephron during a reaction with aldosterone d. in the lungs during a reaction with aldosterone e. in the lungs after reaction with bicarbonate ions 17. A segment of DNA is read to make a protein. If the original segment reads 3'-GGACCTA -5", the anti-codon segment will read: a. 5'-AUCCAGG-3' b. 3'-GGACCTA-5' c. 3'-AUCCAGG-5' d. 5'-UAGGUCC-3" e. 5'-GGACCUA-3' 18. Identify 'K' on the following graph. a. exponential growth b. carrying capacity c. logistic growth d. geometric growth 19. Which of the following mutations would be expected to have the most harmful effect on the resulting protein? a. a three-base addition near the stop codon b. a base deletion near the start codon c. a base deletion near the stop codon d. a base substitution 20. What happens to the electrons that are released as a result of light absorption by chlorophyll? a. they combine with H ions and oxygen to form water b. they are used directly in the fixation of carbon during the Calvin cycle c. they reduce photosystem I chlorophyll molecules d. they reduce photosystem II chlorophyll molecules e. A and B 21. Suckerfish attach themselves onto the underbellies of sharks while they swim. What is the term for this type of relationship? a. mutualism b. parasitism c. predation d. commensalism e. there is no relationship