23. Which of the following is not directly associated with photosystem II?
(A) photophosphorylation
(B) splitting water
(C) release of oxygen
(D) harvesting light energy by chlorophyll
(E) P680

19. Mark found an organism in a pond, and he thinks it’s a freshwater sponge. His friend Ralph thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus? (A) See if it can swim. (B) See if it is a eukaryote or a prokaryote. (C) Look for cell walls under a microscope. (D) Determine whether it is unicellular or multicellular. (E) Figure out whether it is autotrophic or heterotrophic.

20. DNA replication occurs in (A) meiosis. (B) mitosis. (C) G1 phase. (D) G2 phase. (E) S phase.

21. A major difference in the mechanism of action between steroid and peptide hormones is that (A) steroid hormones mainly affect the synthesis of proteins, whereas peptide hormones mainly affect the activity of proteins already in the cell. (B) target cells react more rapidly to steroid hormones than they do to peptide hormones. (C) steroid hormones enter the nucleus, whereas peptide hormones stay in the cytoplasm. (D) steroid hormones bind to a receptor protein, whereas peptide hormones bind to G protein. (E) steroid hormones affect metabolism, whereas peptide hormones affect membrane permeability.

22. Which of the following pairs of body systems primarily regulates the activities of the other systems? (A) nervous and endocrine systems (B) endocrine and lymphatic systems (C) circulatory and muscular systems (D) integumentary and nervous systems (E) lymphatic and integumentary systems

24. A man who carries an X-linked allele will pass it on to (A) all of his sons. (B) half of his sons. (C) all of his daughters. (D) half of his daughters. (E) all of his children.

25. Which of the following best illustrates homeostasis? (A) All the cells of the body are about the same size. (B) Most adult human beings are between 5 and 6 feet tall. (C) The lungs and intestines have large surface areas for exchange. (D) When oxygen in the blood decreases, you may feel light-headed. (E) When blood salt concentration goes up, the kidney expels more salt.

26. A technique used in molecular systematics relies on the comparison of cytochrome c in different animals. This technique is referred to as (A) DNA-DNA hybridizatioin. (B) protein comparison. (C) restriction mapping. (D) electron transport. (E) gene cloning.

27. Countercurrent exchange in the gills of a fish (A) maintains a gradient that enhances diffusion. (B) speeds up the flow of water through the gills. (C) interferes with the efficient absorption of oxygen. (D) means that blood and water flow in the same direction. (E) enables the fish to obtain oxygen while swimming backward.

28. Which of the following is a characteristic of all organisms, but not of viruses? (A) genetic information stored as nucleic acid (B) ability to control metabolism (C) ability to reproduce (D) structure includes proteins (E) plasma membrane

29. Researchers suspect that cytotoxic T cells are usually able to find and attack cancer cells because (A) B cells help them. (B) cancer is induced by bacteria. (C) cancer is an autoimmune disease. (D) cancer cells release antibodies into the blood. (E) cancer changes the surfaces of cancerous cells.