topic: genetics aim: describe how to use punnett squares. do now: next slide hw: study for...

TOPIC: GeneticsAim: Describe how to use punnett squares.

Do Now: next slide

HW: Study for tomorrow’s Reproduction test!

BRING YOUR TEXTBOOK TO CLASS!Pedigree Chart Reading notes due Wednesday!Genetic Engineering Reading notes due

Thursday!

Identify each structure described.1.Where pollen tube forms2.Produces pollen3.Where pollination occurs4.Will turn into fruit5.Where fertilization occurs6.Will turn into seeds

B - Style

F - Anther

A - Stigma

D - Ovary

C - Ovule

C - Ovule

Seed coat

Cotyledon

Embryo

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?

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

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?

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

dominant

yellow

Homozygous

recessive

green

Heterozygous

green

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

Punnett Square

•Shows possible gene combinations of offspring bw 2 organisms

Example:1. T = tall t = short TT x tt

T T

t

t

T

T

T

T

t t

t t

T T

t

t

T

T

T

T

t t

t t

Phenotype=

100% heterozygous

100% tall

Genotype=

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

B b

B

b

B

B

B

b

B b

b b

B b

B

b

B

B

B

b

B b

b b

Phenotype=Genotype=25% homozygous

dominant25% homozygous recessive

75% black, 25 % white

50% heterozygous

Example #3:Red is dominant in flowers & white is recessive. Cross a heterozygous flower with a homozygous dominant flower.

•R = red r = white

•Rr x RR

Rr x RRR r

R

R

R

R

R

R

R r

R r

Phenotype=

100% red

Genotype = 50%

homozygous dominant50%

heterozygous

TOPIC: GeneticsAim: Practice using punnett squares.

Do Now: next slide

HW: Pedigree Chart Reading notes due

Monday.Study for Tuesday’s Reproduction test.

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

b

b

B

B

b

b

b b

b b Answer: 50% chance of having a puppy with black fur

The phenotype of an organism1. represents its genetic

composition2. reflects all the traits that are

actually expressed3. 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

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 tissue2.making new sex cells3.meiosis4.sexual reproduction

The pistil of the flower includes the1.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.

2.Where does this occur?

3.Describe what happens to the chromosome number.

4.Compare the daughter cells to each other.

Meiosis

Gonads

Splits in half

Not genetically similar to each other

The blockages shown at A and B would most likely interfere with the ability to1.transport gametes 2.produce mature gametes3.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 formed1.cell 1, only2.cells 1 and 23.cell 3, only4.cells 2 and 3