Genetics and Plant breeding Pointers 1
Genetics is the study of gene operation and heredity from parents to offspring.The term genetics was coined by W. Bateson in 1905.Gregor John Mendel is known as the 'father of modern genetics.'The cell is recognized as the functional unit of life.The cell was discovered by R. Hooke in 1665.The cell theory was proposed by M.J. Schleiden and T. Schwann in 1939.Protoplasm is known as the physical basis of life.There are two types of cells found in the living world: eukaryotic and prokaryotic.A plant cell is classified as a eukaryotic cell.Ribosomes are the cell organelles found in both prokaryotic and eukaryotic cells.Cells without a cell wall are called protoplasts.The nucleus serves as the controlling center of the cell.The nucleus was discovered by Robert Brown in 1831.The organelle known as the “powerhouse of the cell” is the mitochondria.Mitochondria were discovered by Hollicker.The term mitochondria was coined by Benda in 1897.The term endoplasmic reticulum was introduced by Porter in 1948.The organelle known as the engine of the cell is the ribosome.Rough ER is associated with ribosomes.The main site of protein synthesis is the ribosome.70S ribosomes are found in mitochondria.The prokaryotic organism that does not contain mitochondria is bacteria.The term lysosome was first used by Dave in 1955.The organelle known as the suicidal bag of the cell is the lysosome.The main function of the Golgi body is the packing and transport of food materials.The organelle known as the dustbin of the cell is the vacuole.The non-living organelle of the cell is the cell wall.The material contained in vacuoles is called cell sap.Plastids are self-replicating, extra-chromosomal genetic materials found in plant cells.The term plastids was introduced by Lederberg.The organelles found only in plants are plastids and spherosomes.The plastid responsible for photosynthesis in plants is the chloroplast.The plastid responsible for color in plants is the chromoplast.The plastid that stores starch and fat in plants is the leucoplast.The leucoplast that functions as the storage of oil is called lipoplast.Thread-like bodies that carry genes are called chromosomes.Strasburger was the first to discover chromosomes in 1875.The term chromosome was coined by Waldeyer in 1888.The chromosomal theory of inheritance was proposed by Sutton and Boveri.The fundamental unit of a chromosome is chromatin.The part of the chromosome known as primary constriction is called the centromere.The major genetic constituent of a chromosome is DNA.One cycle of mitosis produces two daughter cells.The term mitosis was coined by Walter Flemming in 1882.Mitosis occurs in somatic cells.The longest phase of mitosis is prophase.The shortest phase of mitosis is anaphase.The middle stage of mitosis, where chromosomes are arranged at the equatorial plate, is called metaphase.The stage of DNA synthesis in mitosis occurs during interphase.One cycle of meiosis produces four daughter cells.The term meiosis was first given by J.B. Farmer in 1905.Meiosis occurs in reproductive cells.Crossing over and recombination occur during meiosis division.The pachytene stage is when crossing over takes place.Chiasmata occurs during the diplotene stage.Spindle formation takes place during metaphase I.The process of separation of chromatids is called disjunction.Mendel was born on July 22, 1822.Mendel worked on the seven contrasting characters of the garden pea.The rediscovery of Mendel’s work was done by Hugo de Vries, Erich Correns, and Erich Tschermak in 1900.The accepted theory of Mendel is the Law of Segregation.A Mendelian population is also known as a random mating population.A tall pea plant (DD) and a tall pea plant (Dd) share the same phenotype.The double helix model of DNA was proposed by Watson and Crick in 1953.The process of using information from DNA to construct mRNA is called transcription.The transfer of genetic material from mRNA to protein is known as translation.An expression of one gene depends on the presence or absence of another gene, known as epistasis or gene interaction.The phenotypic ratio of a monohybrid cross is 3:1.The phenotypic ratio of a dihybrid cross is 9:3:3:1.The triplet sequence found in mRNA that codes for a single amino acid is called a codon.The triplet sequence in tRNA is known as an anticodon.5 inbred lines will lead to 10 single crosses.The term genomics was coined by Thomas Roderick in 1986.The concept of pangenesis was developed by Darwin.The theory of evolution through natural selection was proposed by C. Darwin and A.R. Wallace in 1858.The theory of acquired characteristics was developed by Lamarck.The chromosomal theory of heredity was proposed by W. Sutton in 1902.Genes for sex-linked traits are located on the Y chromosome.Humans have 23 pairs of homologous chromosomes.