Introduction to Genetics Chapter 11 Introduction to Genetics Biology 2016
Mitosis The process in cell division by which the nucleus divides, typically resulting in two new nuclei, each of which contains a complete copy of the parental chromosomes Biology 2016
Mitosis Mitosis is a process of cell division which results in the production of two daughter cells from a single parent cell. Biology 2016
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4 Phases of Mitosis Prophase: Each chromosome has duplicated and consists of two sister chromatids. At the end of prophase, the nuclear envelope breaks down into vesicles. Metaphase: The chromosomes align at the equitorial plate and are held in place by microtubules attached to the mitotic spindle and to part of the centromere. Biology 2016
4 Phases of Mitosis Anaphase: The centromeres divide. Sister chromatids separate and move toward the corresponding poles. Telophase: Daughter chromosomes arrive at the poles and the microtubules disappear. The condensed chromatin expands and the nuclear envelope reappears. Biology 2016
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Mitosis Biology 2016
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Meiosis Biology 2016
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Meiosis Meiosis involves two cell divisions: Meiosis I and Meiosis II. Meiosis I separates the matching - or 'homologous' - pairs of chromosomes. Meiosis II divides each chromosome into two copies (much like mitosis). Biology 2016
Meiosis I Biology 2016
Meiosis II Biology 2016
Mitosis Vs. Meiosis Biology 2016
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Comparison Biology 2016
Introduction into Genetics Biology 2016
Introduction to Genetics Back in 1997, a rather bizarre photograph suddenly became very famous. It showed a totally hairless mouse, with what appeared to be a human ear growing out of its back. “Alba”, the green fluorescent bunny, is an albino rabbit. This means that, since she has no skin pigment, under ordinary environmental conditions she is completely white with pink eyes. Alba is not green all the time. She only glows when illuminated with the correct light. Biology 2016
Introduction into Genetic - 2 Biology 2016
Genetics Gregor Mendel – “Father of Genetic” Austrian Monk in the Czech Republic Mendel worked in the monastery garden Mendel worked with ordinary garden peas Mendel studied the structure of the flowers of pea plants Mendel observed the distinct traits of pea plants Biology 2016
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Genetics Traits: specific characteristics that can be passed from parent to offspring that varies from one individual to another Example: the pea plant’s seed shape, color, height, flower position Genetics: is the scientific study of heredity Heredity: transmission of genetic traits from parent to offspring Biology 2016
3 reasons why Mendel studied genetics Mendelian Genetics 3 reasons why Mendel studied genetics He selected the pea because of its distinguishable traits. Example: flower color, seed color, seed shape He knew from prior experiments that one of the traits would disappear in one generation Plant as easy to grow Biology 2016
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Pea Plant Traits Biology 2016
Pea Plant Flower Biology 2016
Mendelian Genetics Fertilization: the process that occurs during sexual reproduction where by male & female reproductive parts join. Fertilization produces a new cell which develops into a tiny embryo. True-Breeding: occurs in both animals & plants where by they produce offspring identical to themselves. Biology 2016
Mendel’s Experiment Gregor Mendel studied garden peas. Pea plants are usually self-pollinating. Self-pollination: a plant fertilizes itself. This means that the pollen (sperm) of one plant will fertilize the egg of the same plant. The seeds produced will inherit all of their characteristics from the single plant that bore them. These self-pollinating pea plants produced true-breeding or pure offspring. They would produce offspring identical to themselves. Biology 2016
Mendel wanted to see what would be the offspring of a tall pea plant X with a short (dwarf) pea plant. TT (Tall) x tt (Short) This is called a monohybrid cross because it only looks at the inheritance of one trait at a time. Mendel expected to find all the offspring to be of medium height (a blending of tall and short plants.) What Mendel found was that all the offspring were tall. Mendel concluded that we have two factors (called genes) that control each trait. Biology 2016
Mendel concluded that we have two factors (called genes) that control each trait. · Each of these genes can be expressed in different forms (alleles). Example: tall and short TT (Tall) x tt (Short) Biology 2016
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Mendel’s Monohybrid Cross Mendel concluded that we have two factors (called genes) that control each trait. Each of these genes can be expressed in different forms (alleles). Example: tall and short Biology 2016
Genetic Terms Gene – section of chromosome that codes for a trait Allele – distinct form of a gene Dominant allele – form of a gene, which is fully expressed Recessive allele – form of a gene, which is not expressed when paired with a dominant allele Biology 2016
Laws of Genetics Law of independent assortment – each member of a pair of homologous chromosomes separates independently of the members of other pairs so the results are random. Law of segregation – each pair of (homologous) genes separates (segregates) during meiosis. Biology 2016
Laws of Genetics Law of dominance – the dominant allele is expressed and the recessive allele can be hidden Probability – likelihood of an event happening Punnet Square – grid for organizing genetic material, shows probabilities not results Biology 2016
Laws of Genetics Monohybrid cross – studying the inheritance of only one trait at a time “cross” refers to mating between male and female Dihybrid cross- studying the inheritance of two traits at a time Test cross – if you don’t know if a trait expression is from genotype which is homozygous dominant or heterozygous, you cross it with a homozygous recessive so expression of recessive trait would occur if it existed Biology 2016
Laws of Genetics Complete dominance: when the one allele completely masked by another allele. Biology 2016
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