Genetics The Study of Heredity

Genetics Genetics is the study of heredity. Heredity is the study of how characteristics, or traits, are inherited . Genetics is the study of heredity. It involves characteristics, or traits, that are passed down from generation to generation.

Mitosis and Meiosis Review: Mitosis is ______ reproduction that results in ___ cells ( ); Important for what three things? Meiosis is used only for ______ reproduction. This process produces ________ cells!  Important in making what? asexual 2 diploid repair, growth, & development sexual Mitosis is the asexual reproduction of cells where all the DNA in the cell is duplicated to form two separate cells with the same DNA. Meiosis is a form of cell division where the DNA of an organism is split between two sex cells known as gametes. 4 haploid gametes – egg and sperm

DNA’s ‘home’ 5.

Deoxyribonucleic Acid DNA contains the ______ material for the ______ organism. It is passed on from _________ to generation and from cell to ___. genetic entire generation cell DNA contains all of the genetic information needed to produce a cell. Every time a cell divides using Mitosis the DNA in the cell replicates and is placed in both new cells making them identical. Based on this information, why do some of us have characteristics of our grandparents, aunts, uncles, cousins, etc.

Mendel Once upon a time, there live an ________ monk named ______ ______. He worked in the monastery's garden, paying special attention to ____ ______. He studied how ______ _____ were passed from generation to generation. He did wonderful things in Genetics, and that is why he is called the “______ of ________”! Austrian Gregor Mendel pea plants genetic traits Mendel was an Austrian monk. He was one of the first scientists to study genetics and is referred to the “Father of genetics.” Mendel first studied genetics using pea plants and tested his theories regarding heredity with the plants. Father Genetics

Mendel loved his peas! cross Mendel _____-pollinated pea plants. {What does this mean?} Pollination the male pollen grains are transferred to the female and the ovule is fertilized!

More info. on our man, Mendel! Mendel observed many different traits that showed up in his pea plants. What is a “trait?” An “observable” inherited characteristic containing at least one pair of genes Example: hair & eye color

10. Mendel’s 7 traits

Some Vocab.: Monohybrid = hybrid for ___ trait P = _____ generation F = ____ generation: F 1 = ______ generation (_______) F2 = _______ generation (__________) F3 = _______ generation (_____ ___________) Dihybrid = organism hybrid for __ traits one parent filial 1st filial children 2nd filial grandchildren 3rd filial great grandchildren 2

Other Genetic Terms Homozygous = ____ is defined as 2 like symbols in a gene pair. Ex: TT or tt Heterozygous = _____ is defined as 2 unlike symbols in a gene pair. Ex: Tt pure hybrid

Mendel's Important Experiment In his first cross, Mendel crossed true breeding tall pea plants with true breeding short pea plants. *Stop and do demo. for tall vs. short corn plants (similar to Mendel’s pea plants).

Cross of F1 generation When Mendel crossed 1 of his “______________” the next generation showed: 3 tall: 1 short pea plant (ratio). How did that happen? Tt x Tt We now use “_____________” to help us predict what the offspring may look like. hybrid pea plants Punnett Squares

Mendel concluded from his experiments that each _______ has __ factors for EACH _____! We now call them _____ which are found on __________. organism 2 trait genes chromosomes

Alleles ______ are different gene forms for a ____ of an organism. Example: There are __alleles for human blood types (IA, IB, & i), but a person only inherits for blood type. A parent can pass _ gene from each pair: Alleles trait 3 2 alleles Alleles are different forms of the same gene. 1

Dominant and Recessive Genes ________ genes are “stronger” than ________ genes (weaker). ________ genes only require __ allele for a trait to be present. Ex: TT or Tt = tall plant Recessive genes require __ alleles for a trait to be present. Ex: __ = short plant Dominant recessive Dominant 1 Dominant genes are stronger genes than recessive genes. Unlike recessive genes which only show up as a trait when two alleles are present, dominant genes will show up as a trait with only one allele present. 2 tt

Genotype & Phenotype: symbols Genotype refers to the _______ which represent the genes. Ex: Tt or tt Identical twins have the same genotype. The ________ refers to the “_______ appearance” of a gene pair. Ex: Tall plant or short plant phenotype physical

Complete Dominance Complete Dominance: Dominant gene is stronger (B) than the weaker recessive gene (b). When together, the dominant gene expresses the phenotype (recessive gene trait is “hidden” ). Ex: Bb The law of complete dominance states that one gene (the dominant gene)is “stronger” than the weaker gene (the recessive gene). The recessive trait will disappear to the dominant trait. The law of incomplete dominance states that two genes are equal in strength. B b Bb +

Incomplete Dominance Incomplete Dominance: states that when __ alleles are ____ in strength; there is a _______ of their phenotypes. Ex: red + white = pink 2 equal blending +

Red, white, & pink!

Codominance Similar to Incomplete Dominance _________ state that ____ phenotypes will show up together. Codominance both + Ex: Black feathers + white feathers both show up!

Codominance A joint & distinct expression of both alleles in a heterozygote! Ex: blood type {ABO blood groups} The IA & IB behave dominantly over IO (i), but codominantly to each other.

26. Application of Genetics Food production to produce better, healthier plants & animals Genetic engineering Genetic disorders & diseases Cloning: pros & cons? Human Genome Project (worldwide effort): To map all 46 human chromosomes Completed in June of 2001 (13 years)

Summary Genetics is the study of heredity. Gregor Mendel is the “Father of genetics.” Mitosis and meiosis are types of cell reproduction. Chromosomes contain genes which have DNA (heredity).

Possible science fair experiment?

Punnett Square Practice