Chapter 3 Genetics: The Science of Heredity

Chapter 3 Genetics: Chapter 3 Genetics: The Science of The Science of

HeredityHereditySection 1: Mendel’s WorkSection 1: Mendel’s Work

Section 1- Objectives:Section 1- Objectives:

To describe Mendel’s genetics To describe Mendel’s genetics experimentsexperiments

To identify the factors that control To identify the factors that control the inheritance of traits in organismsthe inheritance of traits in organisms

To explain how geneticists use To explain how geneticists use symbols to represent alleles.symbols to represent alleles.

VocabVocab

1. trait1. trait

A characteristic that an organism can A characteristic that an organism can pass on to its offspring through its pass on to its offspring through its genes.genes.

2. 2. heredityheredity

The passing of traits from parents to The passing of traits from parents to offspring. offspring.

3. 3. geneticsgenetics

The scientific study of heredity.The scientific study of heredity.

4. 4. purebredpurebred

An organism that always produces An organism that always produces offspring with the same form of a offspring with the same form of a trait as the parent. trait as the parent.

5. 5. genegene

A segment of DNA on a chromosome A segment of DNA on a chromosome that codes for a specific trait.that codes for a specific trait.

6. 6. allelesalleles

The different forms of a gene. The different forms of a gene.

7. 7. dominant alleledominant allele

An allele whose trait always shows An allele whose trait always shows up in the organism when the allele is up in the organism when the allele is present.present.

8. 8. recessive allelerecessive allele

An allele that is masked when a An allele that is masked when a dominant allele is present.dominant allele is present.

9. 9. hybridhybrid

An organism that has two different An organism that has two different alleles for a trait; an organism that is alleles for a trait; an organism that is heterozygous for a particular trait.heterozygous for a particular trait.

NotesNotes

1. _______________________ is 1. _______________________ is

called the “father of genetics”called the “father of genetics”

Gregor Mendel

2. Mendel used peas because:2. Mendel used peas because:

– A. _________________________A. _________________________

– B. _________________________B. _________________________

They have many traits that exist in only 2 forms

Garden peas produce large numbers of offspring in one generation so it is easy to collect large amounts of data to analyze

3. Traits are controlled by 3. Traits are controlled by _________________ of ______________________________ of _____________inheritance

genes

4. Organisms inherit ______ allele 4. Organisms inherit ______ allele from _________ parent.from _________ parent.

oneeach

5. Some alleles are 5. Some alleles are ____________________and others are____________________and others are

__________________________.__________________________.

dominant

recessive

Chapter 3 Genetics: Chapter 3 Genetics: The Science of The Science of

HeredityHereditySection 2: Probability & Section 2: Probability &

GeneticsGenetics

Section 2 -Objectives:Section 2 -Objectives:

To describe the principles of To describe the principles of probability and how Mendel applied probability and how Mendel applied them to inheritancethem to inheritance

To state how geneticists use Punnett To state how geneticists use Punnett squaressquares

To explain the meaning of the terms To explain the meaning of the terms phenotype, genotype, homozygous, phenotype, genotype, homozygous, heterozygous, and codominance.heterozygous, and codominance.

VocabVocab

10. 10. probabilityprobability

The likelihood that a particular event The likelihood that a particular event will occur. will occur.

11. 11. Punnett squarePunnett square

A chart that shows all the possible A chart that shows all the possible combinations of alleles that can combinations of alleles that can result from a genetic cross. result from a genetic cross.

12. 12. phenotypephenotype

An organism’s physical appearance, An organism’s physical appearance, or visible traits. or visible traits.

13. 13. genotypegenotype

An organism’s genetic makeup, or An organism’s genetic makeup, or allele combinations. allele combinations.

14. 14. homozygoushomozygous

Having two identical alleles for a Having two identical alleles for a trait.trait.

15. 15. heterozygousheterozygous

Having two different alleles for a Having two different alleles for a trait. trait.

16. 16. codominancecodominance

A condition in which neither of two A condition in which neither of two alleles of a gene is dominant or alleles of a gene is dominant or recessive.recessive.

NotesNotes

1. Probability is the 1. Probability is the ___________________ that a ___________________ that a ____________________ will occur.____________________ will occur.

likelihoodparticular event

2. _____________________ was the first 2. _____________________ was the first scientist to recognize that the scientist to recognize that the ________________________ of ________________________ of

________________________ can be used ________________________ can be used to predict the result of genetic to predict the result of genetic crosses.crosses.

Mendel

principlesprobability

3. Geneticists use Punnett squares 3. Geneticists use Punnett squares to:to:

– A.A.

– B.B.

Show all the possible outcomes of a genetic cross

Determine the probability of a particular outcome

4. _________________________ is the 4. _________________________ is the physical appearance, while physical appearance, while ________________________ is the ________________________ is the _______________________ make-up._______________________ make-up.

Phenotype

genotype

Genetic makeup

5. Punnett Square 5. Punnett Square practice:practice:

B-BlueB-Blue b-redb-red

Genotype: Genotype:

Phenotype:Phenotype:

B b

B

b

BB Bb

Bb bb1 BB: 2Bb: 1bb

3 Blue, 1 red

5. Punnett Square 5. Punnett Square practice:practice:

G- GreenG- Green g-Yellowg-Yellow

Genotype:Genotype:

Phenotype:Phenotype:

G g

g

g

Gg gg

Gg gg–2 Gg: 2gg

–2 Green: 2 Yellow

Your turn. Practice sheet.Your turn. Practice sheet.

Independent and SilentIndependent and Silent Refer to your notes.Refer to your notes. Go over as a group.Go over as a group.

Chapter 3 Genetics: Chapter 3 Genetics: The Science of The Science of

HeredityHereditySection 3: The Cell and Section 3: The Cell and

InheritanceInheritance

Section 3: The Cell and Section 3: The Cell and InheritanceInheritance

To describe the role of chromosomes To describe the role of chromosomes in inheritancein inheritance

To identify and describe the events To identify and describe the events that occur during meiosisthat occur during meiosis

17. 17. meiosismeiosis

The process that occurs in sex cells The process that occurs in sex cells (sperm and egg) by which the (sperm and egg) by which the number of chromosomes is reduced number of chromosomes is reduced by half.by half.

NotesNotes

1. Sex cells have exactly 1. Sex cells have exactly ____________ the number of ____________ the number of chromosomes as ____________ cells.chromosomes as ____________ cells.

half

other

2. The chromosome theory of inheritance 2. The chromosome theory of inheritance states:states:

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Genes are carried from parents to their offspring on chromosomes

3. During meiosis, the chromosome:3. During meiosis, the chromosome:

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See pg. In textSee pg. In text

The chromosome pairs separate and are distributed to two different cells. The resulting sex cells have only have half as many chromosomes as the other cells in the organism.

4. ____________________ are located 4. ____________________ are located on chromosomes.on chromosomes.

Genes

5. Our bodies have ________ pairs of 5. Our bodies have ________ pairs of chromosomes that contain over chromosomes that contain over __________ genes.__________ genes.

23

60,000

Chapter 3 Genetics: Chapter 3 Genetics: The Science of The Science of

HeredityHereditySection 4: The DNA Section 4: The DNA

ConnectionConnection

Section 4: The DNA Connection -Section 4: The DNA Connection -Objectives:Objectives:

To explain the term “genetic code”:To explain the term “genetic code”:

To describe the process by which a To describe the process by which a cell produces proteinscell produces proteins

To describe different types of To describe different types of mutations and how they affect an mutations and how they affect an organism.organism.

17. 17. messenger RNAmessenger RNA

RNA that copies the coded message RNA that copies the coded message from DNA in the nucleus and carries from DNA in the nucleus and carries the message into the cytoplasmthe message into the cytoplasm. .

18. 18. transfer RNAtransfer RNA

RNA in the cytoplasm that carries an RNA in the cytoplasm that carries an amino acid to the ribosome and adds amino acid to the ribosome and adds it to the growing protein chain.it to the growing protein chain.

NotesNotes

1. The main function of genes is to:1. The main function of genes is to:

Control the production of proteins in the organism’s cells. Proteins help to determine the size, shape, and many other traits in an organism.

2. The _________ of _______________ 2. The _________ of _______________ bases along a _____________ forms a bases along a _____________ forms a genetic code that specifies what type genetic code that specifies what type of ___________ will be produced.of ___________ will be produced.

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order

nitrogen

gene

protein

3. A _____________ is a change in a 3. A _____________ is a change in a ___________ or ____________________.___________ or ____________________.

DNA mutations: DNA mutations: http://www.youtube.com/watch?v=_ajRf8yMBe0http://www.youtube.com/watch?v=_ajRf8yMBe0

mutation

genechromosome

4. Mutations can be:4. Mutations can be:

A. ____________ and an example A. ____________ and an example would be ______________.would be ______________.

B. ____________ and an example B. ____________ and an example would be ______________.would be ______________.

C. ______________________ and an C. ______________________ and an example would be ______________.example would be ______________.

Harmful

Helpful

Neither harmful or helpful

cancer

Antibiotic resistance in bacteria

A white buffalo color on a farm (versus a white buffalo color in the wild)