1. According to the fluid mosaic model of cell membranes, phospholipids _____
(A) have hydrophilic tails in the exterior of the membrane
(B) frequently flip-flop from one side of the membrane to the other
(C) occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane
(D) can move laterally along the plane of the membrane
(E) can be rearranged during membrane fusion.

47 According to the passage, what does the word “camouflage” mean? (A) Eliminate. (B) Contain. (C) Restrict. (D) Conceal.

48 According to the passage, which of the following statements can be inferred? (A) Tattoos are viewed as part of a standard cosmetic and medical procedure. (B) People are using tattoos to express their individuality or ideas of beauty. (C) Tattoos are done to further improve the appearance after a plastic surgery. (D) People are using tattoos as a cheaper and safer alternative to cosmetic surgery.

49 According to the passage, which of the following statements is true about Catalano? (A) He had experiences of enduring pain and deformity. (B) He is indifferent to those who are suffering from a disease. (C) His service was in high demand for his artistic healing. (D) His practice in cosmetic surgery boosted his own confidence.

50 Which of the following best describes the tone of the passage? (A) Pessimistic. (B) Suggestive. (C) Cynical. (D) Neutral.

2. The genetic code is essentially the same for all organisms. From this, what can be assumed? (A) The same codons in different organisms translate into different amino acids. (B) A gene from an organism can theoretically be expressed by any other organism. (C) Different organisms have different types of amino acids. (D) DNA was the first genetic material. (E) The abundance of all tRNAs are the same in different organism.

3. Which of the following contradicts the one-gene, one-enzyme hypothesis? (A) Alkaptonuria results when individuals lack a single enzyme involved in the catalysis of homogentisic acid. (B) Sickle-cell anemia results in defective hemoglobin. (C) A mutation in a single gene can result in a defective protein. (D) A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally. (E) Human insulin is encoded by one gene and processed after translation into two conjugated polypeptides for its active form.

4. In 1928, English microbiologist Frederic Griffith demonstrated that DNA is the genetic material to determine the virulence of bacteria cells; what observations helped this conclusion? (A) The heat-killed pathogenic bacteria + live non-pathogenic bacteria -＞ pathogenic. (B) The heat-killed non-pathogenic bacteria+ live pathogenic bacteria -＞ pathogenic. (C) The transformation of bacteria was carried by a heat-stable genetic material. (D) The heat-treated bacteria protein is pathogenic (E) Pathogenicity reflects the action of the capsule gene.

5. What is the mechanism of information transfer in eukaryotes? (A) Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place. (B) Transfer RNA takes information from DNA directly to a ribosome, where protein synthesis takes place. (C) DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis. (D) Proteins transfer information from the nucleus to the ribosome, where protein synthesis takes place. (E) Retrovirus-mediated gene transfer can only occur prenatally during pregnancy

6. Which of the following occurs in prokaryotes but not in eukaryotes? (A) post-transcriptional splicing (B) translation in the absence of a ribosome (C) concurrent transcription and translation (D) gene regulation (E) alanine can be added to polypeptide chain by tRNA with different codons

7. A ribozyme is  _____.(A) a catalyst that uses RNA as a substrate (B) an enzyme that synthesizes RNA as part of the transcription process (C) an enzyme that catalyzes the association between the large and small ribosomal subunits (D) an RNA with catalytic activity (E) an important component of RNA transport from nucleus to cytoplasm.