22. Which structure is NOT part of the endomembrane system?
(A) nuclear envelope
(B) chloroplast
(C) Golgi apparatus
(D) plasma membrane
(E) ER

18. Which of the following accurately gives the distribution of phenotypes produced from a cross of purple dwarf pea plants that are heterozygous for flower color and plant height? (A) 27 purple dwarf; 28 purple tall; 31 white dwarf; 29 white tall (B) 63 purple dwarf; 28 purple tall; 27 white dwarf; 7 white tall (C) 132 purple dwarf; 138 white tall (D) 54 purple dwarf; 6 white tall (E) 100% purple dwarf

19. Which of the following components and conditions increases membrane fluidity? (A) phospholipids with long, saturated fatty acyl chains (B) phospholipids with short, unsaturated fatty acyl chains (C) lower temperatures (D) cholesterol at the usual concentrations found in biomembranes (E) lipid rafts

20. A 400-bp covalently closed circular DNA with a linking number of 35 has 5 negative supercoils. When the linking number of this DNA is changed to 38 by a topoisomerase, this DNA will have (A) 3 positive supercoils. (B) 3 negative supercoils. (C) 2 positive supercoil. (D) 2 negative supercoils. (E) relaxed.

21. When a cell releases a signal molecule into the environment and a number of cells in the immediate vicinity respond, this type of signaling is (A) typical of hormones. (B) autocrine signaling. (C) paracrine signaling. (D) endocrine signaling. (E) synaptic signaling.

23. What is a genome? (A) An ordered display of chromosomes arranged from largest to smallest. (B) A specific set of polypeptides within each cell. (C) A specialized polymer of four different kinds of monomers. (D) A specific segment of DNA that is found within a prokaryotic chromosome. (E) The complete complement of an organism's genes.

24. Why are cattle able to survive on a diet consisting almost entirely of plant material? (A) They are autotrophic. (B) Cattle, like the rabbit, reingest their feces. (C) They manufacture all 15 amino acids out of sugars in the liver. (D) Cattle saliva has enzymes capable of digesting cellulose. (E) They have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs.

25. Which one of the following, if present in a urine sample, would likely be caused by trauma? (A) amino acids (B) glucose (C) salts (D) erythrocytes (E) vitamins

26. The main source of energy for producers in an ecosystem is (A) light energy. (B) kinetic energy. (C) thermal energy. (D) chemical energy. (E) ATP.

27. Trace elements are those required by organisms in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates? (A) nitrogen (B) calcium (C) iodine (D) sodium (E) phosphorus

28. Which of the following pieces of evidence most strongly supports the common origin of all life on Earth? (A) All organisms require energy. (B) All organisms show heritable variation. (C) All organisms reproduce. (D) All organisms use essentially the same genetic code. (E) All organisms have undergone evolution.