Heredity & Genetics Mrs. Green

Bell Work What is another term for characteristics? What is the process of passing on traits from one generation to the next? Hair color and skin color is an example of what kind of trait?

The work of Gregor Mendel Gregor Mendel was an Austrian monk, who discovered important facts about heredity using garden peas. Garden peas produce male and female sex chromosomes called gametes. Fertilization occurs when the male and female reproduce cells that join together forming a zygote. The zygote becomes part of a seed. Genetics = is the scientific study of heredity. Heredity = the passing on of inherited traits from one generation to the other. Traits = the characteristics passed down from parents to offspring.

The work of Gregor Mendel Mendel used true-breeding peas, meaning if they were allowed to self-pollinate they would produce offspring identical to themselves. Mendel studied 7 traits of pea plants, but only studied 1 trait at a time. For example, to see how height was passed from parent to offspring, Mendel took pollen from a true-breeding tall pea plant and cross-pollinated it with a true- breeding short pea plant. Purebred = is the offspring of many generations that show the same form of a trait. This created a Hybrid pea plant. Hybrid = offspring of parents that have different forms of a trait. Since only one trait was different the offspring is called a Monohybrid.

Phenotype OR Genotype Mendel concluded that biological inheritance is determined by factors that are passed from one generation to the next. These factors that determine traits are called Genes. Alleles = are different forms of genes, such as genes for height can either produce genes for tall plants or genes for short plants. Law of Segregation = every organism has 2 alleles of each gene and when gametes are produced the alleles separate (mendel) Phenotype = the way an organism looks and behaves (tall or short) Genotype = the allele combination of the organism (Tt, TT)

Gregor Mendel activity

Bell work What is Genotype and phenotype? Who was the father of heredity? What did he use to study genetics? Don’t forget we need to finish our vocabulary today!

Punnett Square T t TT Tt tt Reginal Punnett came up with the Punnett Squares to predict the proportions of possible genotypes in offspring. One parent’s genotype One parent’s genotype T t TT Tt tt Punnett Square for a single trait

Pedigrees Pedigree = is a chart or “family tree” that shows the presence or absence of a trait according to the relationships within a family across several generation. Doctors use pedigrees to trace and diagnose genetic disorders.

Punnett Square Activity

Homozygous OR Heterozygous An organism is Homozygous in a trait if the 2 alleles for the trait are the same. (TT homozygous dominant or tt homozygous recessive) An organism is Heterozygous in a trait of its 2 alleles for the trait are different (Tt) Dominant = Is one whose traits always show up in the organism when the allele is present Recessive = is one trait that is hidden whenever the dominant allele is present. Probability = is the number that describes how likely it is that an event will occur.

Probability Each time you toss a coin there are 2 possible ways it can land – heads up or tails up. You have a 50/50 chance for either way Probability = is s number that describes how likely it is that an event will occur. The law of probability predicts what is likely to occur, not what will occur. If you toss a coin 20 times you may expect it will land heads up 10 times and tails up 10 times. But you actually get 11 heads up and 9 tails up or less. The more tosses you make the closer your results will be to those predicted by probability.

Dohickey Bug Activity