12. Lipid-soluble signaling molecules, such as aldosterone, can diffuse across the cell membranes but affect only target cells because?
(A) Only target cells have responsive DNA segments
(B) Intracellular receptors are present only in target cells
(C) Only target cells have enzymnes that convert aldosterone to active form
(D) Aldosterone-responsive genes are only present in the target cells

8. Thomas Hunt Morgan's choice of Drosophila melanogaster (fruit fly) has been proven to be useful even today. Which of the following is the most important character that makes fy one of the most useful and powerful model organisms in research? (A) They have compound eyes (B) They have large and transparent embryos that can be easily studied (C) They have genome that is more than 90% similar to the human beings (D) They have short life cycle with large number of offspring

9. Which of the following is the most important factor that determine the resolution of a light microscope? (A) Magnification (B) The wavelength of light (C) Contrast (D) Price

10. Which of the following statement about anacrobic and aerobic respirations is NOT TRUE? (A) Both use glycolysis (B) Both use NAD+ as electron carrier (C) Both use oxygen as final electron acceptor (D) Aerobic respiration produces about 30-32 ATP, whereas anaerobic respiration produces 2 ATP

11. About genetic mutation, which of the following statement is TRUE? (A) Silent mutations usually do not have observable effects on phenotypes because they are in-frame mutations (B) Missense mutations change a codon into a stop codon leading to a truncated protein (C) Nonsense mutation is a point mutation in which a single nucleotide change resulted in a change in an amino acid (D) Insertions and deletions are additions or losses of nucleotides in a gene that usually alter the reading frame producing frame-shifted mutations

13. The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data? (A) Forelimb evolution was adaptive in people and bats, but not in whales (B) Whales are not properly classified as mammals (C) Genes mutate faster in whales than in humans or bats (D) Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy

14. Which of the following is the correct description of the tropical rain forest? (A) Long summers and mild winters (B) Low temperature, rain uniform during the year (C) Warm temperatures and continual rains allow plant growth year-round (D) Low rainfall and dry weather

15. Chemoautotrophs? (A) Use inorganic compound (such as methane) as energy source and CO2 as a carbon source (B) Use light as energy source and organic compound as a carbon source (C) Use organic compound as energy source and organic compound as a carbon source (D) Use light as energy source and CO2 as a carbon source

16. Which of the following is a density-independent factor in a population? (A) Food (B) Weather (C) Habitat (D) Carrying capacity

17. Gymnosperms? (A) Ovary becomes the fruit after fertilization (B) Undergo double fertilization (C) Do not have vascular tissues (D) Bear seeds on exposed surfaces of spore-bearing structures

18. Which of the following tools of DNA technology is incorrectly paired with its use? (A) DNA polymerase_polymerase chain reaction to amplify specific DNA fragments (B) Electrophoresis_separation of DNA fragments by size (C) DNA ligase_ cutting DNA to create DNA segments with specific ends (D) Reverse transcriptase_use mRNA to synthesize DNA