Molecular Biology of the Cell, 7th Edition

Test Bank - Molecular Biology of the Cell, 7th Edition (Alberts, 2023) https://tinyurl.com/37pb8ccs Downloaded by Prolearner ([email protected]) c. The evolutionary history of the eukaryotic cell d. The accidental duplication of a small region of a bacterial chromosome followed by cell division e. Introduction of plasmids into bacteria in a laboratory 19. Gene duplication can give rise to homologous genes that are part of gene families. For example, there are six actin genes in the genome of most mammalian species. In humans, the ACTB gene, which encodes a cytoskeletal actin, is expressed ubiquitously, while ACTC1 is expressed mainly in cardiac cells. Although bacteria lack the eukaryotic cytoskeletal organization, the bacterial MreB gene bears recognizable sequence similarity to mammalian actin genes and codes for a protein that is similar to actin in structure and function. Which statement about these genes is true? a. ACTB is homologous to ACTC1 but not to MreB. b. ACTB is orthologous to ACTC1 but not to MreB. c. ACTB is paralogous to ACTC1 but not to MreB. d. MreB is orthologous to ACTB but not to ACTC1. e. ACTB is paralogous to both ACTC1 and MreB. 20. Out of nearly 5000 protein-coding gene families, there is a set of nearly 300 conserved gene families that are found in species from all domains of life. What is one of the general functions assigned to these gene families? a. The majority of them function in cell-to-cell signaling. b. The majority of them are poorly characterized. c. More than one-third of them are involved in translation or amino acid transport and metabolism. d. More than one-half of the shared families are involved in DNA replication and transcription. e. Nearly all of them are involved in energy production and carbohydrate