topic : genetics aim : explain the basic principles of genetics

Topic: GeneticsAim: Explain the basic principles of genetics.

Do Now: Work with your 6 o’clock partner for the do now review questions.

HW: Ditto – Flowers and Seeds Review. Annotate the multiple choice questions.

Don’t forget:CL Sexual Repro due Monday.Repro test on Tuesday!

1. Identify the types of cells above.

2. Where are these cells produced?

3. Identify the process that produces these cells. Describe what occurs to the chromosome number in this process.

4. In humans, how many chromosomes are found in each of these cells?

5. Identify the process in which these 2 cells join. Where does this occur?

Gametes

Gonads

Meiosis Chromosome # splits in half.

23

Fertilization Oviduct

1.Identify structure X. Support your answer.

2.Describe the function of the structure X.

3.Why do the sperm nuclei travel into the ovules?

4.Describe what occurs to the flower once all eggs in the ovary are fertilized.

Pollen tube

•Enables sperm nuclei to travel into the ovary.

•To fertilize the eggs.

•Ovules turn into seeds.

•Ovaries turn into fruit.

A

B

C

embryo

cotyledon

seed coat

1.Identify all structures labeled in the diagram.

2.Describe the function of structure C.

Stores food for embryo

Topic: GeneticsAim: Explain the basic principles of

genetics.

Do Now: next slide

HW: CL Sexual Repro due Monday. Test on Tuesday!

Reading notes:Pedigree Charts due Wednesday.Desirable Traits due Thursday.

The diagram below represents chromosomes in a zygote.

Which best illustrates daughter cells that result from normal MITOTIC cell division of this zygote? Support your answer.

An adaptation for reproduction in most terrestrial organisms is

(1) regeneration

(2) internal fertilization

(3) mitosis

(4) external fertilization

External fertilization occurs most often in

1.mammals and birds2.reptiles and birds3.amphibians and reptiles4.fish and amphibians

Which represents binary fission? Support your answer.

• The passing of traits from parents to offspring

1. Describe the term heredity.

• How traits are inherited through the interactions of alleles.

2. Describe what was studied in the branch of biology called genetics.

• Control an organisms form and function

3. Describe the function of genes.

A

B

CReplicated chromosome

Gene

DNA

• Different forms of a trait that a gene may have

4. Define the term allele.

1.Identify the two alleles for eye color in fruit flies.

2.How many alleles are necessary for this trait?

• Gregor Mendel5. Identify the man considered to be the father of genetics.

• Pea plants6. Identify the type of plant Mendel worked with to study how traits were passed from one generation to the next.

Identify the traits Mendel observed when working with pea plants.

A

B

C

D

E

F

G

• Mathematics of probability7. What did Mendel use to explain heredity.

There are 7 balls on the pool table. If one ball is chosen at random, what is the probability that it is RED? WHITE? BLACK? BLUE? YELLOW?

• Dominant: dominate or covered another form of that trait

• Recessive: covered or dominated by another form of that trait– Seems to disappear

8. Explain the difference between dominant and recessive genes.

The allele for brown eyes is dominant. The allele for blue eyes is recessive.

Why does Bb combination result in brown eyes and not blue?

• To predict results in Mendelian genetics

• To predict traits of offspring

9. Explain what Punnett squares are used for.

•Uppercase

•Lowercase

10. What kind of letters are used to represent dominant alleles?

11. What kind of letters are used to represent dominant alleles?

• Genotype: genetic makeup of organism

• Phenotype: way an organism looks or behaves

12. Explain the difference between genotype and phenotype.

Bb Brown

PhenotypeTall, short, blue eyes, brown eyes, freckles, no freckles'…

Explain the meaning of this statement.

•213. How many alleles do you have for every trait?

Why only 2 alleles?

1 from each parent•

Gene from dad

Gene from mom

• Homozygous: 2 alleles that are alike

• Heterozygous: 2 different alleles for a trait

14. Explain the difference between homozygous and heterozygous.

1.Identify the homozygous pair of alleles. Support your answer.

2.Identify the heterozygous pair of alleles. Support your answer.

• Hybrid15. Identify another name for heterozygous.

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

DOMINANT RECESSIVEF f

DOMINANT RECESSIVEH h

W = widow’s peak w = straight hairline

P = bent pinkiep = straight pinkie (cannot bend inwards)

E = attached earlobese = unattached earlobes

R = Rolling of the tonguer = cannot roll tongue

C = Cleft chinc = smooth chin

D = Dimplesd = Without dimples

Let’s summarize…1. Explain what is studied in genetics.2. Who is the father of genetics? What did

he use in his experiments?3. How many alleles are needed for every

trait?4. Explain the difference between a

dominant and recessive gene.5. Explain the difference between

genotype and phenotype.6. Explain the difference between

homozygous and heterozygous.

Sometimes tens, or even hundreds of genes can play a role in just one trait!

Melanin, a brown pigment, is controlled by the following genes:

• brown-blue gene on chromosome 15

• green-blue gene on chromosome 19

Another brown-type gene was also discovered on chromosome 15.

Recently, a gene for a brownish yellow pigment, lipofuscin, that appears in amber, green and violet irises was discovered.

And there's likely at least one other gene, not yet located, that plays a role in iris color.

Goldfish have 96 chromosomes in each cell while humans only have 46. Dogs have 78 chromosomes. And here’s the real shocker, a fern has 512 chromosomes.

You can easily see that the skin on your fingertips is folded into patterns called dermal ridges. They form whorls, arches and loops. The # of dermal ridges in a fingerprint pattern is determined by genetics, but the pattern can also be changed early in pregnancy. During weeks 6-13, the fetus touches the finger and toe pads to the wall of the amniotic sac which sometimes can alter the ridge pattern. This is why the fingerprints of identical twins are not exactly alike, even though they have identical genes.