Genetics Part 2 Notes: 1) BEFORE, You Learned: The function of chromosomes. The difference between DNA, Chromosome, and Gene The role chromosomes play in heredity. The process of Meiosis. The purpose of Meiosis. Identifying the different stages of Meiosis. 2) NOW, You Will Learn: The differences between DNA and RNA The discovery of DNA (Watson and Crick) The structure of DNA/RNA Chargaffs Rule Mendels Laws of Inheritance Who is Gregor Mendel? What is a Punnett Square? Mendels Laws 3) Discovery of the Double Helix Watson and Crick- (James and Francis) predicted the structure of DNA, a double helix, in They were able to figure out the 3-D shape of DNA by putting together and building off of many other scientists work. Challenge: Who discovered the double helix structure of DNA? A)Gregor MendelB) Erwin Chargaff C) Watson and Crick 4) Structure of DNA DNA- Deoxyribonucleic Acid. (double stranded) Double Helix is like a twisted ladder with two main parts: Sugar phosphate backbone sides of ladder Nitrogen Base Pairs rungs of ladder Challenge: What does DNA stand for? If DNA is like a twisted ladder, then what makes up the sides of the ladder? What about the rungs? 5) Nitrogen Bases There are 4 different Nitrogen Bases in DNA: Adenine- A Thymine- T Guanine- G Cytosine- C Challenge: How many different Nitrogen Bases are in DNA? What do each of these letters stand for in DNA? : A, T, G, C 6) Chargaffs Rule Erwin Chargaff- discovered that across different species DNA, #A = #T and #G = #C. Chargaffs Rule- In DNA, Adenine always binds with Thymine. Guanine always binds with Cytosine. A-T, G-C All Tigers Can Growl 7) Challenge: Using Chargaffs Rule, create a complimentary strand of DNA for the given sequences of nitrogen bases: 1.GAT-TAC-ACG 2.TAT-TAG-CCT CTA-ATG-TGC ATA-ATC-GGA 8) Structure of RNA RNA- Ribonucleic Acid. (single stranded) Contains 4 different Nitrogen Bases: Adenine- A Uracil- U ( Not Thymine!) Cytosine- C Guanine- G Challenge: What are 2 differences between DNA and RNA? 9) DNA vs. RNA DNA Name- Deoxyribonucleic Acid Strand- Double Stranded T or U- Uses Thymine RNA Name- Ribonucleic Acid Strand- Single Stranded T or U- Uses Uracil. 10) Gregor Mendel Gregor Mendel- known as the father of genetics. He studied the inheritance of traits in pea plants. Challenge: Who is known as the father of genetics? A)Gregor MendelB) Erwin Chargaff C) Watson and Crick 11) Mendels Laws: Law of Segregation- the two parts of a gene pair separate during the formation of sperm and egg cells. Law of Independent Assortment- genes for different traits assort independently from each other during the formation of sperm and egg cells. 12) Mendel Key Terms Allele- one of two or more forms a gene may take. Represented using letters. Example: Blue and Brown are 2 alleles for eye color. Dominant- an allele that overpowers another form of the same gene. Uppercase letter. Example: The brown eye allele is dominant over the blue eye allele. Recessive- an allele that is hidden in offspring by the dominant allele in the pair. Lower case. Example: The blue eye allele is recessive to the brown eye allele. Brown Eyes: BBlue eyes: b 13) BB, bb, and Bb Homozygous- When two alleles for the same gene are the same. Example: Anyone that has blue eyes (recessive) bb for blue or BB for brown. Heterozygous- When two alleles for the same gene are different. Example: Anyone that has brown eyes, and one parent with blue eyes. Bb (eyes will be brown) Practice Punnett Square A man with blue eyes (homozygous recessive) wants to have kids with his wife with brown eyes (homozygous dominant). What color eyes will their children have? b BBBB Bb Practice Punnett Square A man with blue eyes (homozygous recessive) wants to have kids with his wife with brown eyes (heterozygous dominant). What color eyes will their children have? b BbBb Bb bb