ANSWER KEY S.Y.B.Sc. Life Sciences- SEM III - Paper III Q.P.Code: 79543 Exam Date: 2nd November 2018 Marks : 100 Q. 1 Do as Directed: (20mks) .Q. 1. A) Define / Explain the following terms: (07) 1. TCP/IP- It is commonly known as TCP/IP because the foundational protocols in the suite are the Transmission Control Protocol (TCP) and the Internet Protocol (IP). It is a set of networking protocols that allows two or more computers to communicate. 2. WWW- The World Wide Web (WWW), also called the Web, is an information space where documents and other web resourcesare identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and accessible via the Internet. Web pages are primarily text documents formatted and annotated with Hypertext Markup Language (HTML). In addition to formatted text, web pages may contain images, video, audio, and software components that are rendered in the user's web browser as coherent pages of multimedia content. 3. Proteomics- Proteomics is the large-scale study of proteomes. A proteome is a set of proteins produced in an organism, system, or biological context. 4. Human Genome Project-The Genome Project (HGP) was an international scientific research project with the goal of determining the sequence of nucleotide base pairs that make up human DNA, and of identifying and mapping all of the genes of the human genome from both a physical and a functional standpoint. 5. Forward reading frame-An open reading frame starts with an atg (Met) in most species and ends with a stop codon (taa, tag or tga). For example, the following sequence of DNA can be read in six reading frames. Forward frames are in the 5’ to 3’ orientation. 6. Biological database-Biological databases are libraries of life sciences information, collected from scientific experiments, published literature, high-throughput experiment technology, and computational analysis. Information contained in biological databases includes gene function, structure, localization (both cellular and chromosomal), clinical effects of mutations as well as similarities of biological sequences and structures. 7. Bioinformatics-Bioinformatics is an interdisciplinary field mainly involving molecular biology and genetics, computer science, mathematics, and statistics. Data intensive, large-scale biological problems (related to structures and functions of biological micro molecules) are addressed from a computational point of view. Q. 1 B) Match The Columns: (07) a) - v) ;b) – vi) ; c) – vii); d) – iii); e) – i) ; f) – ii); g) – viii) Q.1. C) Explain whether True or False: (06) 1.False 2.False 3.True 4.True 5. False 6.True Q.2. A) Answer any one of the following: (10) 1. Enumerate the characteristics of a population that is in Hardy Weinberg Equilibrium and describe any two characteristics in detail. The Hardy–Weinberg principle, also known as the Hardy–Weinberg equilibrium, model, theorem, or law, states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. These influences include genetic drift, mate choice, assortative mating, natural selection, sexual selection, mutation, gene flow, meiotic drive, genetic hitchhiking, population bottleneck, founder effect and inbreeding. A population must be large enough that chance occurrences cannot significantly change allelic frequencies significantly. To better understand this point, consider the random flipping of a fair coin. The coin is as likely to land on heads as it is on tails. If a coin is flipped 1000 times, it is likely to land on heads almost exactly 50% of the time. However, as you may know from experience, if the same coin is flipped only ten times, it is much less likely that it will land on heads 5 times. The same holds true for allele distributions in populations. Large populations are unlikely to be affected by chance changes in allele frequencies because those chance changes are very small in relation to the total number of allele copies. But in small populations with fewer copies of alleles, chance can greatly alter allele frequencies. In small populations, a change in allelic frequencies and phenotypes based on random occurrences is called genetic drift. No Mutation In order for allelic frequencies to remain constant, there must be no change in the number of copies of an allele due to mutation. This condition can be met in two ways. A population can experience little or no mutation. Alternatively, it can experience balanced mutation. Balanced mutation occurs when the rate at which copies of a given allele are lost to mutation equals the rate at which new copies are created by mutation. No Immigration or Emigration For allelic frequencies to remain constant in a population, individuals must not move in and out of that population. Whenever an individual enters or exits a population, it takes copies of alleles with it, changing the overall frequency of those alleles in the population. Random Mating In order for all alleles to have an equal chance of being passed down to the next generation, mating within the population must be random. Non-random mating can give an advantage to certain alleles, allowing them to be passed down to more offspring than other alleles, increasing their relative frequency in the population. The processes of natural selection, since they usually select for individuals with greatest fitness for a given environment, usually work against random mating: the most fit organisms are most likely to mate. Random Reproductive Success Just as mating must be random, the survival of offspring to reproductive age, or reproductive success, must also be random. Again, natural selection usually works against such randomness. 2. Explain the Comparative, Anatomical and Embryological evidences supporting evolution. Comparative anatomy explores and establishes the correspondences between body parts of organisms from different species. It builds the concepts of the living structures and thus must not be confused with morphology (the study of the forms and their variations) nor with Evo-Devo (the study of the relations between genetics of the development and evolution). Similarities among different species can show two different kinds of relationships, both of which support evolution and natural selection. These similar structures are known as homologous structures and analogous structures.Similarities shared by closely related species (species who share many characteristics) are homologous, because the species have descended from a common ancestor which had that trait. Homologous structures may or may not serve the same function. Example: the forelimbs of mammals, considered homologous because all mammals show the same basic pattern: a single proximal bone joins a pair of more distal bones, which connect to bones of the wrist, “hand,” and digits. With this basic pattern, bats build wings for their lives in the air, whales form fins for their lives in the sea, and horses construct long, hoofed legs for speed on land. Therefore, homologous structures support common ancestry. Similarities shared by distantly related species may have evolved separately because they live in similar habitats. These structures are analogous because they serve similar functions, but evolved independently. Example: compares the wings of bats, bird, and pterosaurs. Bats evolved wings as mammals, pterosaurs as dinosaurs, and birds from a separate line of reptiles. Their wings are analogous structures, each of which evolved independently, but all of which suit a lifestyle in the air. Note that although the wings are analogous, their bones are homologous: all three share a common but more distant vertebrate ancestor, in which the basic forelimb pattern evolved. Because analogous structures are independent adaptations to a common environment, they support natural selection. Haeckel’s influential yet now-infamous biogenetic law, summarized by the phrase “ontogeny recapitulates phylogeny”—in other words, an organism’s embryo progresses through stages of development that mirror its evolutionary history. According to this theory, embryos of more advanced species—humans, for example—would pass through stages in which they displayed the adult characteristics of their more primitive ancestors (such as fish gills or monkey tails). The evidence Darwin presented in The Origin of Species included not only fossils but also detailed comparisons of living species at all stages of life. Naturalists in Darwin’s time were experts in comparative anatomy, the study of the similarities and differences in organisms’ structures (body parts). At different times during his life, Darwin studied the comparative anatomy of closely related species of marine mammals, barnacles, orchids, insectivorous plants, and earthworms. Embryology is a branch of comparative anatomy which studies the development of vertebrate animals before birth or hatching. Like adults, embryos show similarities which can support common ancestry. For example, all vertebrate embryos have gill slits and tails. The “gill slits” are not gills, however. They connect the throat to the outside early in development but eventually close in many species; only in fish and larval amphibians do they contribute to the development of gills. In mammals, the tissue between the first gill slits forms part of the lower jaw and the bones of the inner ear. The embryonic tail does not develop into a tail in all species; in humans, it is reduced during development to the coccyx, or tailbone. Similar structures during development support common ancestry. Q.2.B) Answerany two of the following: (10) 1. Enlist any type of Natural Selection w.r.t. to evolution. Natural selection is the process in nature by which organisms get better adapted to their environment tend to survive and reproduce more than those less adapted to their environment. For example, treefrogs are sometimes eaten by snakes and birds. Gray Treefrogs blend well in dark wooded areas on tree bark and Green Treefrogs blend in well with green vegetation found in marshes and swamps. A Green Treefrog on the bark of a tree is easier for a predator to find, compared to a Green Treefrog on a green leaf.