TOPIC : Genetics Aim: Describe how to use punnett squares.

1. TOPIC: Genetics Aim: Describe how to use punnett squares. Do Now: Take out your genetics reading notes. HW: Earth Day poster due tomorrow!

2. A B • Mitosis • Meiosis • 4 daughter cells • 2 daughter cells • Sexual repro • Asexual repro • Daughter cells have same # of chromosomes • Daughter cells have half the # of chromosomes • Used to reprilcate somatic cells • Used to make gametes

3. 14. Describe what a homozygouspair of alleles consists of. • 2 alleles or genes that are the same • Ex: BB or bb

4. 15. Identify the pair of alleles that consist of two dominant genes. • Homozygous dominant • Ex: BB

5. 16. Identify the pair of alleles that consist of two recessive genes. • Homozygous recessive • Ex: bb

6. 17. Identify what a heterozygouspair of alleles consists of. • One dominant and one recessive gene • Ex: Bb

7. 18. Identify another term with the same meaning as heterozygous. • Hybrid

8. 19. When will a dominant gene be expressed? • It is always expressed unless there are two recessive genes. • Ex: • BB • Bb

9. 20. When will a recessive gene be expressed? • When there are two recessive genes. • Ex: bb

10. The trait for height in pea plants can be represented by using the letter “T.” T represents the allele for tall and t represents the allele for short. • What do we call the genotype for TT? b. What is the phenotype for TT? c. What do we call the genotype for tt? d. What is the phenotype for tt? e. What do we call the genotype for Tt? f. What is the phenotype for Tt? Homozygous dominant Tall Homozygous recessive short Heterozygous tall

11. The trait for seed color in pea plants can be represented by using the letter “G.” G represents the allele for green seeds and g represents the allele for yellow seeds. • What do we call the genotype for gg? b. What is the phenotype for gg? c. What do we call the genotype for Gg? d. What is the phenotype for Gg? e. What do we call the genotype for GG? f. What is the phenotype for GG? Homozygous recessive yellow Heterozygous green Homozygous dominant green

12. Genetics • The study of how traits are inherited.

13. Probability • The possibility that an event may or may not happen

14. Punnett Square • Shows possible gene combinations of offspring bw 2 organisms

16. T T 1. T = tall t = short TT x tt t t T t T T t t T t

17. T T T t t T t t T t T t Genotype= 100% heterozygous Phenotype= • 100% tall

18. B b Example #2: B = Black fur b = white fur Bb x Bb B B B B b b B b b b

19. B b B b B B B b B b b b Genotype= 25% homozygous dominant 25% homozygous recessive 50% heterozygous Phenotype= 75% black, 25 % white

20. Example #3: Red is dominant in flowers & whiteis recessive. Cross a heterozygous flower with a homozygous dominant flower. • R = redr = white • Rr x RR

21. Rr x RR R r Genotype = R r R R R 50% homozygous dominant R R R R r 50% heterozygous Phenotype= 100% red

22. One dog carries the heterozygous, black fur trait and the other carries homozygous recessive white traits. What are the chances of having a puppy with black fur? B = black, b = white Bb x bb

23. B b Bb x bb b b b B b Answer: 50% chance of having a puppy with black fur b B b b b

24. The phenotype of an organism • represents its genetic composition • reflects all the traits that are actually expressed • occurs only in dominant pure organisms • cannot be seen

25. If an individual possesses two recessive alleles for the same trait, the individual is said to be • homozygous for the trait             • haploid for the trait • heterozygous for the trait           • mutated

26. B - Style Identify each structure described. • Where pollen tube forms • Produces pollen • Where pollination occurs • Will turn into fruit • Where fertilization occurs • Will turn into seeds F - Anther A - Stigma D - Ovary C - Ovule C - Ovule

27. The cell in Diagram 1 contains 4 chromosomes and is undergoing the process of mitosis. What is the total number of chromosomes in each individual cell in Diagram 3? 1. 8 2. 2 3. 16 4. 4

28. In humans, which cell is produced by mitosis (mitotic cell division)? • sperm cell • skin cell • egg cell • zygote cell

29. What would result if mitosis was not followed by division of the cytoplasm? • two cells, each with one nucleus • two cells, each without a nucleus • one cell with two identical nuclei • one cell without a nucleus

30. The diagram can be used to show a process of: • making new body cells for repair of tissue • making new sex cells • meiosis • sexual reproduction

31. The pistil of the flower includes the • stigma, anther, and filament • stamen, stigma and anther • stigma, style, and ovary • petals, sepals and pollen grains

32. Identify the process represented in the diagram. • Where does this occur? • Describe what happens to the chromosome number. • Compare the daughter cells to each other. Meiosis Gonads Splits in half Not genetically similar to each other

33. The blockages shown at A and B would most likely interfere with the ability to • transport gametes • produce mature gametes • eliminate waste products through the urethra • express secondary sex characteristics

34. Which statement is true of both mitosis and meiosis? • Both are involved in asexual reproduction. • Both occur only in reproductive cells. • The number of chromosomes is reduced by half. • DNA replication occurs before the division of the nucleus.

35. Which statement about the gametes represented in the diagram below is correct? • They are produced by females. • They are fertilized in an ovary. • They transport genetic material. • They are produced by mitosis.

36. The process of meiosis formed • cell 1, only • cells 1 and 2 • cell 3, only • cells 2 and 3