Chapter 10: Mendel & Meiosis Week 18 notes Chapter 10: Mendel & Meiosis

Monday/ Tuesday

Warm-Up What is a chromosome? What is one segment of DNA called? What is genetics?

Agenda Section 10.1 (Mendel’s Laws of Heredity) Lesson & Notes Punnett Square Practice Group Research Activity Kahoot! to reinforce concepts (if time allows) Homework: Section 10.1 Assessment Questions #1-5

10.1: Mendel’s Laws of Heredity Genetics: the branch of Biology that studies heredity Heredity: the passing on of traits (characteristics) from parents to offspring Gametes: sex cells (males- sperm; females- eggs) Zygote: fertilized cell (sperm + egg)

10.1: Mendel’s Laws of Heredity Gregory Mendel: guy that first predicted how traits are passed from one generation to the next Mendel used a pea plant for his experiments He often transferred pollen from one plant to another plant with different traits. This is called making a cross.

10.1: Mendel’s Laws of Heredity Allele: different forms of a gene A plant can have 2 alleles for tallness (TT), 2 alleles for shortness (tt), or 1 allele for tallness & one for shortness (Tt) Dominant vs. Recessive: dominant traits overpower recessive ones Dominant alleles are represented by a capital letter; recessive alleles are represented by a lowercase letter

10.1: Mendel’s Laws of Heredity Let’s say… T: dominant allele for tallness t: recessive allele for shortness SHORT OR TALL?? TT tt Tt

10.1: Mendel’s Laws of Heredity

10.1: Mendel’s Laws of Heredity Mendel’s 1st Law… Law of Segregation: Everyone has 2 alleles (versions) of a gene Each gamete (sex cell) receives one of these alleles

10.1: Mendel’s Laws of Heredity Genotype: the genes you have In other words, the allele combination you have Ex: TT, Tt, or tt Phenotype: the genes we see Ex: tall, short, brown eyes Homozygous: 2 of the same allele (TT, tt) Heterozygous: 2 different alleles (Tt)

10.1: Mendel’s Laws of Heredity

10.1: Mendel’s Laws of Heredity Mendel’s 2nd Law… Law of Independent Assortment: Genes for different traits are inherited independently Ex: blonde hair & blue eyes (if you get one, you won’t necessarily get the other)

10.1: Mendel’s Laws of Heredity Punnett Squares!

Punnett Square Practice Right handedness is a dominant gene. Let’s call it “R” Left handedness is a recessive gene. Let’s call it “r” Suppose a mother is right handed (RR) and a father is right handed (Rr). What is the probability that they will have a left handed kid?

Punnett Square Practice Tongue rolling is a dominant gene. Let’s call it “T” Not being able to roll your tongue is a recessive gene. Let’s call it “t” Suppose a mother can’t roll her tongue (she is homozygous recessive). The father can roll his tongue and he is heterozygous. How likely is it that they will have a tongue-rolling kid?

Group Research Activity With your groups, research one of the following genetic disorders. What is it? What causes it? Facts about it? Treatment? Down syndrome Polydactylism Color blindness Tay-Sachs disease Cri du chat syndrome Angelman syndrome