Monday, April 23, 2012 Homework: none Plan: 1)Mitosis/Meiosis/Karyotype Checkup 2)Review MendelSim data from Friday 3)MendelSim Questions 4)Heredity/genetics Notes

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

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

Parent 1Parent 2Offspring (after 50 crosses) RedBlue Data Table 1: Pure Red X Pure Blue Parent 1Parent 2Offspring (after 50 crosses) RedBlue Data Table 2: Cross of Two Red Offspring Data Table 3: Cross of Two Blue Offspring Parent 1Parent 2Offspring (after 50 crosses) RedBlue Red Blue Red Blue This one varied 0 50

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

TAPE in these questions and answer them in your logbook 1.What is the trait we observed? 2.What are the results of crossing the red flowers with the blue flowers? 3.Based on the results, what do we know about the flower color gene? 4.What are the results for the second crossing—red crossed with red? 5.The flowers in the second crossing look red— but what do we know about their genetics? 6.What happened to the blue trait and how did it show up again in the third generation?

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

Chromosome structure- DNA Chromosomes = long pieces of DNA

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

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

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

How does your DNA determine your traits? DNAmRNAprotein Observed trait transcription translation 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.

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

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) How many chromosomes?

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 chromosome 3 (from computer simulation) From Dad From Mom flower color gene

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

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