45. During gene expression, which molecule carries the genetic code from the nucleus to the ribosomes in the cytoplasm for protein synthesis?
(A) Ribosomal RNA (rRNA)
(B) Transfer RNA (tRNA)
(C) DNA polymerase
(D) Amino acids
(E) Messenger RNA (mRNA)

41. The primary role of oxygen in aerobic cellular respiration is to: (A) directly produce ATP. (B) oxidize glucose during glycolysis. (C) act as an enzyme in the citric acid cycle. (D) serve as the final electron acceptor in the electron transport chain. (E) create a proton gradient across the mitochondrial membrane.

42. Which statement accurately describes a key event or outcome of meiosis? (A) Meiosis produces four genetically identical daughter cells. (B) In meiosis I, sister chromatids separate. (C) Crossing over occurs during prophase II. (D) Meiosis involves two successive cell divisions, resulting in four genetically unique haploid cells. (E) Meiosis's primary purpose is to repair damaged somatic cells.

43. Which statement accurately describes a fundamental concept in Mendelian genetics? (A) Mendel used cross-pollinating peas, which made true-breeding lines easy to establish. (B) Dominant alleles have a higher inheritance frequency. (C) The Law of Segregation states that during gamete formation, alleles for a character separate and end up in different gametes. (D) Repeated self-pollination was not necessary to obtain true-breeding lines. (E) Mendel concluded independent sorting, though his chosen genes were always linked.

44. In a plant species exhibiting incomplete dominance for flower color, a cross between a red-flowered plant (RR) and a white-flowered plant (WW) would produce offspring (RW) with what phenotype? (A) Only red flowers. (B) Only white flowers. (C) Flowers with both red and white patches. (D) Pink flowers (a blend of red and white). (E) Flowers of a completely new color unrelated to parental colors.

46. Which condition violates the assumptions of the Hardy-Weinberg principle? (A) Random mating occurs. (B) No gene flow into or out of the population.. (C) The population size is very large. (D) Natural selection favors certain genotypes. (E) No new mutations occur.

47. If a population is in Hardy-Weinberg equilibrium for a gene, its allele frequencies will: (A) remain constant across generations unless an evolutionary force acts. (B) be perfectly balanced by genetic drift and gene flow. (C) change due to active mate choice based on genotype. (D) significantly deviate from predicted genotypic frequencies. (E) always be significantly altered by new mutations in the short term.

48. Microevolution refers to: (A) small-scale evolutionary changes within a population, observable over short periods, like allele frequency changes. (B) large-scale evolutionary changes that never lead to new species. (C) mechanisms entirely different from those causing macroevolution. (D) changes that cannot lead to macroevolutionary patterns. (E) speciation, as an exclusively macroevolutionary event.

49. Which of the following is a direct cause of microevolution within a population? (A) The formation of a new species over millions of years. (B) A change in the frequency of an allele due to random chance (genetic drift). (C) The large-scale extinction of a taxonomic group. (D) The diversification of life forms into new phyla. (E) The development of complex multicellular organisms from single-celled ancestors.

50. An example of microevolution is: (A) the appearance of the first flowering plants. (B) the diversification of mammals after the dinosaur extinction. (C) the evolution of birds from reptilian ancestors. (D) the formation of a new genus through accumulated genetic changes. (E) an increase in antibiotic resistance in a bacterial population over several generations.

1. Which of the following is NOT a function of membrane proteins? (A) Transport specific molecules or ions into the cell. (B) Act as receptors for chemical signals. (C) Store genetic information. (D) Convert energy from one form to another. (E) Catalyze chemical reactions.