18. Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells because
(A) Only target cells retain the appropriate DNA segments
(B) Intracellular receptors are present only in target cells
(C) Only target cells have enzymes that break down aldosterone
(D) Only in target cells is aldosterone able to initiate thephosphorylation cascade that turns genes on

14. About anaerobic and aerobic respirations, which of the following statement is NOT TRUE (A) Both use glycolysis (B)Both use NAD+ as electron carrier(C)Both use oxygen acceptor (D) Aerobic respiration produces about 32 ATP, whereas anaerobic c respiration produces 2 ATP

15. Which of the following statement is NOT TRUE about photosynthesis (A) Light reactions generate ATP and increase the potentialenergy of electrons by moving them from H2O to NADPH(B) Both ATP and NADPH are produced on the side facing thestroma, where the Calvin cycle takes place(C) The Calvin cycle is a carbon fixation process that generatesoxygen as a by-product(D) Carbon enters the Calvin cycle as CO2 and leaves as glyceraldehyde 3-phospate (G3P)

16. About mutation, which of the following stateme ent is TRUE? (A) Silent mutations usually do not have obser rvable effects on phenotypes becaus se they are in-frame mutations (B) Missense mutations change a codon into a stop codon leading to a trunc cated protein (C) Nonsense mutation is a point mutation in which a single nucleotide change resulted in a a change in an amino acid (D) Insertions and deletions are additions or losses of nucleotide pairs in a gene that alter the reading frame producing out-of-frame mutations

17. FtsZ is a bacterial cytoskeletal protein that forms a co contractile ring involved in binary fission. Its function is similar to (A)1 The cleavage furrow of eukary yotic animal cells (B) The cell plate of eukary yotic plant cells ukaryotic cells (C) The mitotics spindle of eu (D) The microtubule-organizing center of eukaryotic cells

19. Homeotic genes (A) Encode transcription factors that control the expression of genes responsible for specific anatomical structures (B) Are found only in Drosophila and other arthropods (C) Are the only genes that contaln the homeobox domain (D) Encode proteins that form anatomical structures in the fly

20. The upper forelimbs of humans and bats have fairly similar skeletal structures, very different sl shapes and proport s, whereas the corr responding bones in whales have tions. However, genetic data su data suggest that all three kinds of o forganisms div verged 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) Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy (C)Genes mutate faster in whales than in humans or bats (D) Whales are not properly classified as mammals

21. Chemoautotrophs (A) Use light as energy sou urce and CO2 as a carbon source (B) Use organie con ompound as energy source and organic compound as a carbon source (C) Use light as energy source and organic compound as a carbon source (D) Use inorganic compound (such as methane) as energy source and CO2 as a carbon source

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

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

24. Gymnos sperms (A) Bear seeds on e exposed surfaces of spore-bearing structures (B) Undergo double fertilization (C) Do not have vascular tissues (D)After fertillization, ovary becomes the fruit