TOPIC 22 - HEREDITY Day 1 of 4. Bell Ringer (10 minutes) 1.Grab a Biology EOC Exam Preparation Bell...

TOPIC 22 - HEREDITY Day 1 of 4

Bell Ringer (10 minutes) 1.Grab a Biology EOC Exam Preparation Bell Ringer 2.Provide a GIST of the Question. 3.Bubble your answer. 4.Explain why you believe is the correct answer. 5.BE PREPARED TO PARTICIPATE IN CLASS DISCUSSION. 6.After correcting, reflect on our answer.

Patterns of Inheritance Probability in Genetics

THINK PAIR SHARE

BenchmarkObjectives Students will understand the role of probability in genetics. Students will understand and be able to use the essential vocabulary of genetics. What are we learning today? SC.912.L.16.1 Use Mendels laws of segregation and independent assortment to analyze patterns of inheritance.

What is inheritance? Inheritance is the passing on of characteristics from parents to offspring In 1865, an Austrian monk named Gregor Mendel presented a paper on pea plant inheritance to the Natural History Society of Brnn. The paper was virtually ignored for 30 years. Years after Mendels death, his work was rediscovered. genetics, or the study of heredity These patterns became the basis for a new branch of biology: genetics, or the study of heredity.

What is the essential question? How are fractions, ratios and percentages related to the probability of inheritance? Explain the difference between each pair: gene/allele, dominant/recessive, homozygous/heterozygous, genotype/phenotype.

How can we use probability to predict traits? Probability is the likelihood that a particular event will occur. Probabilities predict the average outcome of a large number of events. Probability can be written as a percent, fraction, or a ratio.

Guided Practice: Marble Probabilities Theoretical probability is the probability that is calculated using the formula. Experimental probability is calculated when the actual situation or problem is performed. The larger the number of outcomes, the closer the results will be to the predicted values.

What essential vocabulary do I need to master? Gene: Section of DNA that determines a trait. Alleles: are different forms of the same gene. Each organism has two alleles for each trait Homozygous: If the two alleles for a trait are the same (AA or aa) Heterozygous: If the two alleles for a trait are different (Aa)

What essential vocabulary do I need to master? Dominant: Trait that is always observed in the offspring, even when a recessive allele is present. Written as an uppercase letter. Recessive: Trait only observed when two recessive alleles are present. Written as a lowercase letter

What essential vocabulary do I need to master? Genotype - the gene combination, or genetic makeup, of an organism Phenotype - the way an organism looks

What essential vocabulary do I need to master? P or Parental generation: When doing genetic crosses, the name we call the original pair of organisms. F 1 or First Filial generation: Offspring.

Collaborative Activity: Heredity Vocabulary TASK CARD MEMORY GAME 1.Working with your partner, use the index cards provided to memorize the meanings of hereditys essential vocabulary. 2.Play Memory with a partner. Show your partner one side of the index cards, and ask them to tell you whats on the other side. SMARTBOARD MEMORY GAME 1.Turn over two cards. If the two cards consist of the term and its definition, your team gets a point, and take another turn. 2.If the two cards do not match, your team loses a turn. 3.Repeat step 3 until no cards remain on the table. The team with the most pairs wins.

What is the essential question? How are fractions, ratios and percentages related to the probability of inheritance? Explain the difference between each pair: gene/allele, dominant/recessive, homozygous/heterozygous, genotype/phenotype.

+ Home Learning Heredity Cross Word Puzzle The same people who never did their homework in high school are still doing that to this very day out in the real world. by Jules Shear

Patterns of Inheritance Monohybrid Crosses

THINK PAIR SHARE 1.How are they similar to one another? 2.How do they differ from one another? 3.What do you think their parents looked like? 4.What does a person mean when he uses the phrases pure-breed and hybrid?

BenchmarkObjectives Students will use a Punnett square to predict the outcome of a monohybrid cross. Students will differentiate between simple dominant/recessive, incomplete dominance, and codominance. What are we learning today? SC.912.L.16.1 Use Mendels laws of segregation and independent assortment to analyze patterns of inheritance.

What is the essential question? Given a cross where T is red and t is white, explain the similarities and differences observed in the offsprings phenotype in simple dominant/recessive, codominance, and incomplete dominance patterns of inheritance. Tt

GIZMOS: MOUSE GENETICS Purpose: Students will distinguish between dominant and recessive traits. Setting: Teacher led discussion. Essential Question: How are traits passed from parents to their offspring?

What did we learn? 1.If two parents of the same color are bred together, do all of their offspring always have that color? 2.How do you know that the trait for white fur is still present in a black-fur hybrid? 3.Why is it impossible to see a hybrid (or heterozygous) white mouse? 4.A black mouse is bred to a white mouse, producing 2 black and 1 white offspring. What is the genotype of the black mouse? 5.An Ff mouse is bred repeatedly to an ff mouse, producing 500 total offspring. In theory, 250 offspring should be black and 250 should be white, but the actual numbers are 237 black and 263 white. Why does this happen?

LETS PRACTICE In roses, a gene that affects flower color has two alleles: red (R) and white (r). Two heterozygous plants are crossed. 1.What would be the genotype and phenotypes of the P and F 1 generations? 2.What is the probability that plants will be white? 3.Determine the ratio of red to white plants. ____

LETS PRACTICE A homozygous German Shepherd with dark eyes (B) is bred with a homozygous German Shepherd with light eyes (b). What is the probability that they will have puppies with dark eyes? Explain your answer. ____

LETS PRACTICE Black color in horses is dominant over chestnut color. If a homozygous black horse is mated to a chestnut horse, what percent of the offspring will be chestnut colored? Use a Punnett square to show how you arrived to your answer. ____

LETS PRACTICE Cystic fibrosis is a recessive genetic disorder. Ron is homozygous dominant (FF) and Nancy is a carrier of cystic fibrosis. Use a Punnett square to predict the probability that one of their children will have cystic fibrosis? ____

LETS PRACTICE In humans widows peak (W) is dominant over straight hairline (w). A heterozygous man for this trait marries a woman who is also heterozygous. What will be the genotype and phenotype of the first generation? ____

What is incomplete dominance? Crosses in which one allele is not completely dominant over another. The heterozygous type is somewhere in between the two homozygous phenotype A blend of the two.

What is codominance? During codominance both alleles are expressed equally in the heterozygous type

How do we use superscripts in codominance patters? Superscripts are not exponents or additional alleles but labels to distinguish the two codominant alleles. Red flower RR C R Pink flower RW C R C W White flower WW C W

Incomplete dominance (A) or Codominance (B) 1)The phenotype of the heterozygote is intermediate from the parents phenotype. 2)Two checkered (black and white) chicken are crossed. They produce offspring with three phenotypes: black, white, and checkered. 3)Two gray rabbits are crossed. They produce offspring with three phenotypes: black, white, and gray. 4)A red-flowered plant is crossed with a white-flowered plant. All of the offspring are pink. 5)A cross between a purebred animal with red hairs and a purebred animal with white hairs produces and animal that has both red hairs and white hairs.

LETS PRACTICE In snapdragons, a gene that affects flower color has two alleles: red and white. In heterozygous individuals, the phenotype is pink. Show a cross between two pink snapdragons and give the expected genotype and phenotype. What is their mode of inheritance? ____

LETS PRACTICE In shorthorn cattle, coat color may be red, white, or roan. In roan cattle, their coats are a mixture of red and white hairs, although the animals appear a light rust color from a distance. Show a cross between two roan cattle and give the expected genotype and phenotype. What is their mode of inheritance? ____

What is the essential question? Given a cross where T is red and t is white, explain the similarities and differences observed in the offsprings phenotype in simple dominant/recessive, codominance, and incomplete dominance patterns of inheritance. Tt

+ Home Learning 1. Patterns of Inheritance Worksheet 2. Study Bio Blitz Words The same people who never did their homework in high school are still doing that to this very day out in the real world. by Jules Shear

Think Pair - Share 1.What is shown in the image below? 2.What is their importance in heredity? 3.What are the parts of one of these chromosomes? 4.Can you see the individual genes on the chromosomes?

Patterns of Inheritance Sex-linked Inheritance Multiple Alleles Inheritance

BenchmarkObjectives Students will describe how an X- or Y-linked gene affects the inheritance of traits. Students will describe multiple alleles patterns of inheritance What are we learning today? SC.912.L.16.1 Use Mendels laws of segregation and independent assortment to analyze patterns of inheritance.

What is the essential question? Colorblindness is a recessive, sex-linked trait. A woman and a man, both with normal vision, have three daughters with normal vision. One of the daughters marries a man with normal vision, and they have a son who is colorblind. Part A Which parent of the son is the carrier of the trait? Explain your answer. Part B What is the likelihood that the children of a woman heterozygous for colorblindness and a colorblind man will express the trait? Explain your answer.

What is a karyotype? A karyotype shows the complete diploid set of chromosomes grouped together in pairs, arranged in order of decreasing size. Two chromosomes are known as the sex chromosomes because they determine an individuals sex. Females have two copies of the X chromosomes. (46,XX) Males have one X chromosome and one Y chromosome. (46,XY)

What is sex-linked inheritance? Traits controlled by genes located on sex chromosome are called sex-linked traits The alleles for sex-linked traits are written as superscripts of the X and Y chromosomes. Hemophilia Alleles Normal (H) X H Affected (h) X h Hemophilia Genotype/Phenotypes X H X H X H X h X h X h X H YX h Y

GUIDED PRACTICE The colorblindness gene (X b ) is recessive to the gene for normal sight (X B ). Construct a Punnett square to show a cross between a father with normal vision and a mother who is a carrier of the colorblindness trait. 1.What percent of the children have normal vision? 2.What percent of the daughters are carriers? 3.What is the probability of having a sick son? 4.What is the probability of having a healthy daughter? ____

LETS PRACTICE Hemophilia is a recessive sex-linked trait (X h ) caused by a defective gene. The blood of individuals with this condition does not clot properly. Without injections of synthetic clotting factors, hemophiliacs are at risk of dying due to excessive bleeding. Make a Punnett square to show a cross between an affected male and a female who is heterozygous. 1.Give the expected genotype and phenotype. 2.How likely are they to have a sick child? ____

What is multiple allele inheritance? In multiple allele inheritance there is more than two possible alleles in a population. This does not mean that an individual can have more than two alleles. The alleles for multiple alleles traits are written as superscripts of the letter used.

How do multiple alleles and codominance determine blood type? There are three alleles for the ABO gene: I A, I B, and i. Alleles I A and I B are codominant. Produce molecules known as antigens on the surface of RBC. The i allele is recessive. Produce no antigens on RBC.

GUIDED PRACTICE Is it possible for a woman with type AB blood and a man with type B blood to have a child with type O blood? What possible blood types can their children have? Use a Punnett square to support your answer.

QUICK LAB: COAT COLOR IN RABBITS In rabbits, there are four alleles for a gene that controls coat color. There is a dominance hierarchy with these alleles: C > c ch > c h > c.

GUIDED PRACTICE c ch c c h c X GenotypeFractionPercentage PhenotypeFractionPercentage

What is the essential question? Colorblindness is a recessive, sex-linked trait. A woman and a man, both with normal vision, have three daughters with normal vision. One of the daughters marries a man with normal vision, and they have a son who is colorblind. Part A Which parent of the son is the carrier of the trait? Explain your answer. Part B What is the likelihood that the children of a woman heterozygous for colorblindness and a colorblind man will express the trait? Explain your answer.

+ Home Learning The Great Hospital Baby Switch The same people who never did their homework in high school are still doing that to this very day out in the real world. by Jules Shear

Patterns of Inheritance Dihybrid Crosses

BenchmarkObjectives Students will use a Punnett square to predict the outcome of a dihybrid cross What are we learning today? SC.912.L.16.1 Use Mendels laws of segregation and independent assortment to analyze patterns of inheritance.

What is the essential question? 1.On the average, each human has about six recessive alleles that would be lethal if expressed. Why do you think that human cultures across the world have laws against marriage between close relative? 2.Why is it possible to have a family of six girls and no boys, but extremely unlikely that there will be a public school with 500 girls and no boys?

What is a dihybrid cross? A dihybrid cross involves a study of inheritance patterns for organisms differing in two traits. Mendel invented the dihybrid cross to determine if different traits of pea plants were inherited independently.

LETS PRACTICE RYRyrYry RY RRYYRRYyRrYYRrYy Ry RRYyRRyyRrYyRryy rY RrYYRrYyrrYYrrYy ry RrYyRryyrrYyrryy Given the following information: Predict the genotype and/or phenotype of the following. ? ? ? ? Shape RSmooth rWrinkled Color YYellow yGreen

CHECK YOUR UNDERSTANDING 1.List all the possible genotypes of a pea plant with smooth (R) and yellow (Y) seeds. What is their percent or fraction? 2.List all the possible genotypes of pea plant with smooth (R) and green (y) seeds. What is their percent or fraction? 3.List all the possible genotypes of pea plant with wrinkled (r) and yellow (Y) seeds. What is their percent or fraction? 4.List all the possible genotypes of a pea plant with wrinkled (r) and green (y) seeds. What is their percent?

LETS PRACTICE AaBb x AaBb ____

LETS PRACTICE In rabbits, the coat color black dominant (B) over brown (b). Short hair is dominant (S) over long (s). In a cross between a homozygous black short-haired male and a brown homozygous long-haired female, what would be the ratios for genotype and phenotype of the F 1 generation? ____

+ Home Learning ADD HOME LEARNING HERE The same people who never did their homework in high school are still doing that to this very day out in the real world. by Jules Shear

TOPIC 22 - HEREDITY Day 1 of 4. Bell Ringer (10 minutes) 1.Grab a Biology EOC Exam Preparation Bell...

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