Nucleic Acids & Protein Synthesis 36. Which of the following statements best describes the structure of DNA? A. Two strands of proteins are held together by sugar molecules, nitrogen bases, and phosphate groups. B. Two strands composed of sugar molecules and phosphate groups are linked together by proteins. C. Nitrogen bases and phosphate groups link together to form the backbone of a strand. Two such strands are linked together by sugar molecules. D. Sugar molecules and phosphate groups link together to form the backbone of a strand. Two such strands are linked together by matched nitrogen bases.

Nucleic Acids & Protein Synthesis 37. The diagram represents an incomplete model of the DNA molecule. Even though the model is not complete, what pattern is evident in this representation of the DNA molecule? A. Every third base pair has a mutation. B. Guanine is always paired with cytosine. C. The model has a repeating base sequence. D. There are two sugars between each phosphate.

Nucleic Acids & Protein Synthesis

Nucleic Acids & Protein Synthesis 38. The genetic code is nearly universal. That is, with few exceptions, the same codons code for the same amino acids in all organisms. What does the near universality of the genetic code suggest? A. All life forms can reproduce with one another. B. All life forms have the same number of genes. C. All life forms have a common evolutionary ancestor. D. All life forms arose about the same time in Earth’s history.

Nucleic Acids & Protein Synthesis 39. During the process of transcription, the strand of messenger RNA shown below is produced. mRNA AACUUAGGACAU What was the original DNA template that produced this strand? A. TTCTTAGGACAT B. UUGTTUCCUGUT C. UUGAAUCCUGUA D. TTGAATCCTGTA

Nucleic Acids & Protein Synthesis 40. The diagram above shows one process that occurs during gene expression. What process does the diagram represent? A. DNA replication B. RNA replication C. Transcription D. Translation

Nucleic Acids & Protein Synthesis 41. Which of the following statements best describes the process of gene expression? A. Messenger, transfer, and ribosomal RNA transcribe information onto a cell’s DNA. B. The information in DNA is transcribed to RNA and then transcribed to amino acids. C. The information in DNA is transcribed to RNA and then translated to make specific proteins. D. The information in DNA is translated by messenger RNA and then translated to make ribosomal RNA.

Nucleic Acids & Protein Synthesis 42. In some cells, gene expression involves mRNA processing. Which of the following best describes where mRNA processing is likely to occur? A. nucleus of prokaryotic cell B. cytoplasm of prokaryotic cell C. nucleus of eukaryotic cell D. ribosome of eukaryotic cell

Nucleic Acids & Protein Synthesis 43. Errors sometimes happen during DNA replication. If guanine is accidentally substituted for thymine in a DNA nucleotide, which of the following will always happen because of the error in DNA replication? A. The cell will die when it divides. B. The cell will become a rapidly dividing cancer cell. C. The cell will produce mRNA with a mutated nucleotide sequence. D. The cell will have a better chance of surviving under different conditions.

Nucleic Acids & Protein Synthesis 44. Most mutations involve a misplacement of a nucleotide on a DNA segment. Which of the following is not a possible result of a mutation? A. The mutation will be passed on to the next generation. B. The mutation will cause immediate death of the individual. C. The gene that contains the mutation will be expressed in a new way. D. The gene that contains the mutation will be expressed in the same way as before the mutation.

Nucleic Acids & Protein Synthesis 45. A section of a nucleic acid is shown below. The process represented in the diagram produces a molecule that is complementary to the template strand of DNA. What type of molecule is produced? A. New DNA B. Polypeptide C. Messenger RNA D. Carbohydrate

Nucleic Acids & Protein Synthesis 46. A model of a DNA molecule is shown below. The arrow indicates — F. the bond between adjacent phosphate and deoxyribose molecules G. the junction of introns and exons in the sense strand of DNA H. the hydrogen bond between complementary nucleotides J. the junction of a codon and a DNA triplet

Nucleic Acids & Protein Synthesis 47. A codon chart is shown below. Which of these changes to the DNA triplet 3’ GCT 5’ will affect the protein produced? A. GTT C. TCC B. TCT D. GCA

Nucleic Acids & Protein Synthesis 48. Characteristics such as a widow’s peak or attached earlobes are determined by the genetic code. Which components of DNA are referred to as the genetic code? F. Phosphate groups G. Nitrogenous bases H. Deoxyribose sugars J. Hydrogen bonds

Nucleic Acids & Protein Synthesis 49. How does DNA in cells determine an organism’s complex traits? A. DNA contains codes for proteins, which are necessary for the growth and functioning of an organism. B. DNA separates into long single strands that make up each part of an organism. C. DNA produces the energy an organism needs in order to grow. D. DNA folds into the nucleus of each of the cells of an organism.

Nucleic Acids & Protein Synthesis 50. A mutation that occurs in the gametes of an organism will most likely be transferred to which of the following? A. The siblings of the organism B. The offspring of the organism C. The other organisms living nearby D. The mating partner of the organism

Nucleic Acids & Protein Synthesis 51. The main function of this process is to A. provide an exact copy of the genetic code B. ensure genetic variation in a species C. synthesize cellular proteins D. produce antibodies to combat disease

Nucleic Acids & Protein Synthesis 52. What does gene expression control? A. the proteins that are made by the cell B. the rate at which DNA replication occurs C. the duration between cell cycles D. the division of the cell nucleus

Nucleic Acids & Protein Synthesis 53. A recent study of the genetic code has determined that the mRNA codons UCU, UCC, UCA, and UCG all code for the amino acid serine. What does this research finding suggest? A. The genetic code is the same for nearly all organisms. B. The genetic code does not dictate the amino acid sequence of proteins. C. A mutation in one base will always have a physical effect on the resulting protein. D. A mutation in one base could have absolutely no physical effect on the resulting protein.

Nucleic Acids & Protein Synthesis 54. There are 64 possible mRNA codons that make up the genetic code. Which of the following is true of the genetic code? A. Codons can be only three amino acids long. B. Codons can be one, two, or three bases long. C. Each codon is linked to only one amino acid. D. Each amino acid is linked to only one codon.

Cell Reproduction 55. Part of a process necessary for reproduction in complex organisms is represented . Step C results in the production of four zygotes that will develop into embryos B. embryonic cells that could unite and develop into an organism C. four cells that will recombine to form two offspring D. gametes that could be involved in the formation of a zygote

Cell Reproduction 56. Which sequence best represents sexual reproduction? A. mitosis → gametes → zygote → fertilization B. gametes →meiosis →mitosis →fertilization C. fertilization → gametes → meiosis → zygote D. meiosis → gametes → fertilization → zygote

Cell Reproduction 57. Cell differentiation is critical during embryonic development. The process of cell differentiation results in the production of many types of cells, including germ, somatic, and stem cells. Cell differentiation is most directly regulated by — A. ATP B. DNA C. lipids D. sugars

Cell Reproduction 58. Construction workers attach ropes and pulleys to wooden timbers on an old bridge. They use the rope and pulley system like the one in the diagram to move the timbers away from each other in order to dismantle the bridge. Which stage of mitosis is similar to this way of dismantling a bridge? A. Prophase B. Anaphase C. Telophase D. Metaphase

Cell Reproduction 59. Which of these statements best explains why meiosis is important for sexual reproduction? A. By involving two cell divisions, meiosis ensures that offspring receive half their genetic information from each parent. B. By involving a single cell division, meiosis ensures that offspring are genetically identical to each other and to the parents. C. Meiosis occurs in those cells that have already undergone DNA replication. D. During meiosis, sister chromatids, which are genetically different from each other, line up along the center of the cell, and then separate into two cells.

Cell Reproduction 60. The diagram to the right represents the cell cycle. When cells leave the cell cycle, they exit during G1 phase and then enter G0 phase, a resting period. Most normal cells can leave G0 phase and reenter the cell cycle at G1 phase before entering S phase. Cancer cells are different because they cannot enter G0 phase and are likely to do which of the following? A. Fail to complete S phase B. Mutate during G1 phase C. Repeat the cell cycle continuously D. Die after completing mitosis 1

Cell Reproduction 61. The diagram below shows four stages of a cell undergoing mitosis. Which of the following is the correct sequence of stages as they occur in the cell cycle? A. 1, 3, 4, 2 B. 2, 1, 3, 4 C. 2, 4, 3, 1 D. 4, 3, 2, 1

2/13 Cell Reproduction 62. A photomicrograph of onion root tip cells during mitosis is shown below. Which phase of mitosis is occurring in the cell indicated by the arrow? F. Prophase G. Metaphase H. Anaphase J. Telophase

Cell Reproduction 63. Crossing-over between nonsister chromatids during meiosis is significant in heredity. This process most likely leads to an increase in which of the following? F. The expression of dominant traits G. Number of gametes H. The occurrence of polyploidy J. Genetic variation

Cell Reproduction 64. Which of these must occur during S phase of the cell cycle so that two daughter cells can be produced during M phase? A. The DNA must be replicated. B. The chromosomes must be joined. C. The cytoplasm must be separated. D. The cell membrane must be expanded.