TOPIC Genetics Aim Describe how to use punnett

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

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

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

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

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

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

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

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

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

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. a. What do we call the genotype for TT? Homozygous dominant b. What is the phenotype for TT? Tall c. What do we call the genotype for tt? Homozygous recessive d. What is the phenotype for tt? short e. What do we call the genotype for Tt? Heterozygous f. What is the phenotype for Tt? tall

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. a. What do we call the genotype for gg? Homozygous recessive b. What is the phenotype for gg? yellow c. What do we call the genotype for Gg? Heterozygous d. What is the phenotype for Gg? green e. What do we call the genotype for GG? Homozygous dominant f. What is the phenotype for GG? green

Genetics • The study of how traits are inherited.

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

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

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

T t Tt T Tt t Tt Genotype= 100% heterozygous Phenotype= 100% tall

Example #2: B = Black fur b = white fur Bb x Bb B BB Bb b bb Bb

B B BB b Bb b B b bb Genotype= 25% homozygous dominant 25% homozygous recessive 50% heterozygous Phenotype= 75% black, 25 % white

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

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

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

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

The phenotype of an organism 1. represents its genetic composition 2. reflects all the traits that are actually expressed 3. occurs only in dominant pure organisms 4. cannot be seen

If an individual possesses two recessive alleles for the same trait, the individual is said to be 1. homozygous for the trait 2. haploid for the trait 3. heterozygous for the trait 4. mutated

Identify each structure described. 1. Where pollen tube forms B - Style 2. Produces pollen F - Anther 3. Where pollination occurs A - Stigma 4. Will turn into fruit D - Ovary 5. Where fertilization occurs C - Ovule 6. Will turn into seeds C - Ovule

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

In humans, which cell is produced by mitosis (mitotic cell division)? 1. sperm cell 2. skin cell 3. egg cell 4. zygote cell

What would result if mitosis was not followed by division of the cytoplasm? 1. two cells, each with one nucleus 2. two cells, each without a nucleus 3. one cell with two identical nuclei 4. one cell without a nucleus

The diagram can be used to show a process of: 1. making new body cells for repair of tissue 2. making new sex cells 3. meiosis 4. sexual reproduction

The pistil of the flower includes the 1. stigma, anther, and filament 2. stamen, stigma and anther 3. stigma, style, and ovary 4. petals, sepals and pollen grains

1. Identify the process represented in the diagram. Meiosis 2. Where does this occur? Gonads 3. Describe what happens to the chromosome number. Splits in half 4. Compare the daughter cells to each other. Not genetically similar to each other

The blockages shown at A and B would most likely interfere with the ability to 1. transport gametes 2. produce mature gametes 3. eliminate waste products through the urethra 4. express secondary sex characteristics

Which statement is true of both mitosis and meiosis? 1. Both are involved in asexual reproduction. 2. Both occur only in reproductive cells. 3. The number of chromosomes is reduced by half. 4. DNA replication occurs before the division of the nucleus.

Which statement about the gametes represented in the diagram below is correct? 1. They are produced by females. 2. They are fertilized in an ovary. 3. They transport genetic material. 4. They are produced by mitosis.

The process of meiosis formed 1. cell 1, only 2. cells 1 and 2 3. cell 3, only 4. cells 2 and 3