Monday, April 23, 2012

1. Monday, April 23, 2012 Homework: none Plan: • Mitosis/Meiosis/Karyotype Checkup • Review MendelSim data from Friday • MendelSimQuestions • Heredity/genetics Notes

2. Checkup Be sure to write your VERSION A or B on your answer sheet. Record all answers #1-18 on the answer sheet.

3. MendelSim Data Review Goes in entry from Friday- Entry 39: MendelSim Simulation- 4/20/12

4. Data Table 1: Pure Red X Pure Blue Red Blue 0 50 Data Table 2: Cross of Two Red Offspring This one varied 38 12 Red Red Data Table 3: Cross of Two Blue Offspring Blue 50 Blue 0

5. 50 (ALL) RED OFFSPRING X = PARENT 2 BLUE PARENT 1 RED = X PARENT 1 RED PARENT 2 RED 38 RED 12 BLUE = 50 (ALL) BLUE OFFSPRING X PARENT 1 BLUE PARENT 1 BLUE

6. TAPE in these questions and answer them in your logbook • What is the trait we observed? • What are the results of crossing the red flowers with the blue flowers? • Based on the results, what do we know about the flower color gene? • What are the results for the second crossing—red crossed with red? • The flowers in the second crossing look red—but what do we know about their genetics? • What happened to the blue trait and how did it show up again in the third generation?

7. Make an entry- Heredity and Genetics 1- 4/23/12 This is a “see attached” entry- First, some information we already know…

8. Chromosome structure- DNA • Chromosomes = long pieces of DNA

9. Chromosomes come in pairs (one from mom and one from dad) Cut out from picture and match each in pairs

10. Chromosomes have genetic information and are passed to offspring Dividing onion cells chromosomes chromosomes cell wall nucelus

11. R Chromosome structure - genes • Parts of chromosomes that code for proteins are called genes • Genes, and specifically the proteins made from them, help determine your characteristics Human chromosome # 7 • Contains about 1,800 genes • Contains over 150 million nucleotides Gene for RED flowers Link to view genes and DNA sequence

12. Observed trait DNA mRNA protein translation transcription How does your DNA determine your traits? Example1: A person has DNA that has instructions to make LACTASE (a protein) which allows them to digest milk Example 2: The Labrador Retriever has DNA that has the instructions to make TRP-1 which converts brown pigment to black—so they have black fur.

13. Trait – a characteristic of an organism • Example: “flower color” Gene – part of a chromosome that helps determine a specific trait • Example: “flower color gene” Allele – a form of a gene • Example: • One allele is the “blue” form of the gene • One allele is the “red” form of the gene

14. How many chromosomes? • Humans = 23 chromosome pairs, or 46 total. We have about 24,000 genes. Some other examples: (do not need to memorize) • Pea flower = 7 chromosome pairs (14 total) • Fruit fly = 4 chromosome pairs (8 total) 13,601 genes identified so far! • Potato = 24 pairs (total 48) • Horse = 32 pairs (total 64)

15. Chromosomes come in pairs (one from Mom and one from Dad) • This pair of chromosomes is called a “homologous pair” because they have the same genes on them - flower color gene Flower chromosome 3 (from computer simulation) From Dad From Mom

16. IMPORTANT: homologous pairs are NOT IDENTICAL, but they have the same genes, • Alleles can be different flower color gene “Blue” allele of flower color gene “Red” allele of flower color gene From Dad From Mom

17. The combination of alleles determines the observed characteristics RED allele BLUE allele RED allele BLUE allele BLUE allele RED allele Chromosome combination Allele combination red, red red, blue (orblue, red) blue, blue Observed characteristic RED RED BLUE