Exploring Gene Expression, Population Evolution and DNA Technology

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Biology Questions

Question 1
A. Explain how differential gene expression yields a variety of cell types in a multi-cellular eukaryote.
The subset of genes expressed in the cells of each type is very unique and are specific to allow those cells to conduct their own specific function. As such, the differences between the cell types are not because of different genes being present, but to differential gene expression. This means in other words; the expression of different and specific genes by cells with the same genomic material or genome. The genomic material of multi-cellular eukaryotes then could hold thousands of genes; however; only for a few species. (Alberts, Johnson, & Lewis, 2002).
B. Explain how DNA is packaged into chromosomes. Explain how packing influences gene expression.
The most important function of DNA is to carry genes. In eukaryotic cells, the DNA is divided between a set of different chromosomes of which consists of a single, very long DNA molecule that are associated with proteins that fold and pack the DNA thread into a more compact structure. The DNA is first wrapped around histonic proteins or histones to form beads on a string. The beads form a looped structure which in turn forms the chromosomes. In addition to the proteins involved in packaging the DNA, the chromosomes themselves are also associated with proteins that are required for the processes of the gene expression as well as DNA replication, and repair (Alberts et al., 2002).
C. Explain the process and significance of alternative DNA splicing.
Gene splicing is the literal 'splicing' or cutting of genes into fragments and recombine or rejoining them where and when they are appropriately needed. The two modes by which gene splicing occurs are: post transcriptional modification (the more natural way) and recombinant technology (chemically or artificial way) (Alberts et al., 2002).Gene splicing is important in the diversification of proteins and facilitates single genes to increase their ability to code. This also allows the synthesis of the proteins and allows them to be more distinctly functional and structural. In Eukaryotic cells; gene Splicing is done prior to mRNA translation, and via differential inclusion and/or exclusion of portions of the pre-mRNA. During gene splicing the pre-mRNA gets transcribed from one gene and could result in a maturation of a variety of mRNA molecules that result in the formation of functional proteins (Alberts et al., 2002).

Question 2
A. Choose and describe how three different areas of biology support evolution.
1. Biogeography: which is the study of the geographical distribution of species and their relationships related to evolution seeks to explain how species appear to have colonized different and varying island habitats from mainland areas and how they have been modified through the process of natural selection.

2. Embryology: examines and is concerned with the similarities and differences in different embryological stages which indicate the passage of the evolutionary relationships ...