6. During splicing, which major molecular component of the spliceosome catalyzes the excision reaction?
(A) protein
(B) DNA
(C) RNA
(D) lipid
(E) sugar

2. What causes a differentiating B cell to become committed to producing only one species of antibody molecule? (A) DNA rearrangements in the genome (B) RNA rearrangements in the genome (C) protein rearrangements in the genome (D) DNA rearrangements in the mitochondria (E) RNA rearrangements in the mitochondria

3. Which of the following about neuron is incorrect? (A) It is a polarized cell. (B) Peripheral nervous system includes autonomic and somatic nervous systems. (C) The generation of action potential is related to the electrochemical gradient across the plasma membrane. (D) Myelin sheath is a protein-rich substance that surrounds the axon of some neurons, forming an electrically insulating layer. (E) Neurofilaments are intermediate filaments found in neurons.

4. In the life cycle of an angiosperm, which of the following cells or tissues are diploids? (A) generative cells (B) microsporocyte (C) antipodal cells (D) tube cells (E) polar nuclei of the embryo sac

5. The black dots that cover strawberries are actually individual fruits from a flower with multiple carpels. The fleshy and tasty portion of a strawberry derives from the receptacle of the flower. Therefore, a strawberry is ________. (A) both an aggregate fruit and an accessory fruit (B) both a multiple fruit and an accessory fruit (C) both a multiple fruit and an aggregate fruit (D) both a simple fruit and an aggregate fruit (E) both a simple fruit and an accessory fruit

7. Which of the following statements regarding the body plans of animal is correct? (A) Cnidarian are bilateral symmetry. (B) Nematodes are acoelomate. (C) Platyhelminthes are radial symmetry. (D) Annelids are psudocoelomate. (E) Chordates are deuterostomia.

8. In a phylogenetic tree, a group is composed of some species but not their most recent common ancestor. This is an example of ________. (A) monophyletic group (B) paraphyletic group (C) polyphyletic group (D) polytomy (E) dicotomy

9. Bioluminescence is an important strategy for attracting preys in which of the following marine zone? (A) benthic zone (B) intertidal zone (C) oceanic zone (D) aphotic zone (E) photic zone

10. Which of the following descriptions regarding sensory receptors is correct? (A) Sense of smell is generated through mechanoreceptors. (B) Vision is generated through chemoreceptors. (C) Thermoreceptors detect change of pressures. (D) Nocireceptors detect pain feelings. (E) Photoreceptors detect sense of taste.

11. Which statement is incorrect concerning protein translation? (A) Ribosomes in prokaryotic and eukaryotic cells have two subunits of unequal size. (B) Sequences exist in prokaryotic and eukaryotic rRNA that are so similar, that they likely derive from a common ancestor. (C) Initiator tRNA recognizes AUG codons during initiation at the P site of ribosome. (D) The 30S and 50S ribosomal subunits of E. coli combine to generate an 80S subunit. (E) Polysomes are rich in cells active in protein synthesis.

12. Testosterone is synthesized primarily by the ________. (A) Leydig cells (B) hypothalamus (C) sperm cells (D) anterior pituitary gland (E) seminiferous tubules