Q.14 What is artificial selection? Explain it. Answer: Definition Artificial selection (or selective breeding) means intentional breeding between individuals for certain traits or combination of traits. Historical Background (a) Abu Rayhan Biruni The term artificial selection was ‘expressed by the Persian scientist Abu Rayhan Biruni in the 11th century. (b) Charles Darwin Charles Darwin also used …
Q.13 What is Biological or Organic Evolution? Explain with the help of Darwin’s theory of natural selection Answer: Biological/Organic Evolution It is a change in the characteristics of a population or species of organisms over the course of generations. The changes in an individual are not considered as evolution because evolution refers to populations and not …
Q.12 Define variations. Discuss their sources and types. Answer: Definition Differences shown by the individual of same species are called as variations. Sources of variations (a) Genetic Recombination The genetic recombination produced through crossing over results in gametes with variations. (b) Mutation Mutation (changes in DNA) are important source of variations. (c) Combination of Sperm …
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Q.11 Define and explain co-dominance and Incomplete dominance with examples. Answer: Co-dominance It is a situation where two different alleles of a gene pair express themselves completely instead of showing dominant-recessive relationship. As a result, heterozygous organism shows phenotype that is different from both homozygous parents. Example ABO Blood Group Gene I The ABO blood …
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Q.10 Derine and Explain Mendel’s Law of Independent Assortment. Answer: Definition Alleles of a gene pair segregate (get separated and distributed to gametes) independently from the alleles of other gene pair. This is called as law of independent assortment. Dihybrid Cross It is a cross in which two contrasting traits are studied at a time. In …
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Q.9 Define and Explain Mendel’s law of segregation. Answer: Definition In each organism, genes are present in pairs. During gamete formation the genes (alleles) of each pair segregate from each other and each gamete receives one gene from the pair. When gametes of male and female parents unite, the resulting offspring again gets the genes in …
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Q.8 What do you know about Gregor Mendel? Why he selected pea plant for his genetic experiments? Answer: Gregor Mendel Gregor Mendel was monk (priest) in Austria, He developed the fundamental principles of genetics. Special factors Mendel proposed that there are “special factors” in organisms which control expression of traits and their transmission to next generations. …
Q.7 What is Genotype? Explain its different types. Answer: Genotype The specific combination of genes in an individual is known as the genotype of that individual. It is of two types: (i) Homozygous . (ii) Heterozygous (i) Homozygous Genotype The genotype in which the gene pair contains two identical alleles (AA or aa) is called …
Q.7 What is Genotype? Explain its different types. Read More »
Q.6 Describe role of genes and alleles. Answer: Gene The part of DNA (sequence of nucleotides) that contains the instructions for the synthesis of a particular protein is known as a gene. Gene Loci DNA of each chromosome contains thousand of genes which are in pairs, one on each homologous chromosome. The locations or positions of …
Q.5 How does DNA of chromosome work? Answer: DNA DNA is the genetic material. It performs its role by giving instructions for synthesis of specific proteins. Cell is actually controlled by its DNA. It is the DNA which makes characteristics or traits of cell or organism Roles of proteins Proteins may have different roles. Some perform …