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.

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)

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.

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.

2. Cellulose synthase is an enzyme located in the: (A) Vacuole. (B) Cell wall. (C) Mitochondria. (D) Chloroplast. (E) Lysosome.

3. Which of the following is NOT part of protoplast? (A) Nucleus. (B) Cytoplasm. (C) Cytosol. (D) Cell wall. (E) Plastid.

4. Which of the following statement about transposons is FALSE? (A) They are movable genetic elements. (B) They are also called 'jumping genes'. (C) They may lead to mutation. (D) They occur only in algae. (E) Plasmids can function as transposons.

5. In the Ti plasmid of Agrobacterium tumefaciens, the vir region is essential for the: (A) Synthesis of opine. (B) Synthesis of cytokinin. (C) Transfer of T-DNA. (D) Synthesis of auxin. (E) Utilization of nitrogen and carbon.