Chapter 8 Heredity Heredity is the passing of

Chapter 8 - Heredity

• Heredity – is the passing of traits from parent to offspring. • We call these “inherited traits”.

Inherited Traits • Living things inherit many traits, or characteristics from their parents. • Recall that _____, determine the inherited traits of an organism. • Traits are determined by the genes you receive from your parents.

Genotype vs. Phenotype • Genotype – “genetic makeup” of an organism. • Phenotype –– the way an organism looks and behaves as a result of its genotype ---“physical makeup”. • Genotype DETERMINES phenotype

Chromosomes • Genes are located on structures called chromosomes. • Cells of different kinds of organisms contain a different number of chromosomes. • A human baby receives ______ chromosomes from its mother, and ______ from its father. Human body cells contain _______ chromosomes.

• Each pair of chromosomes are given a number from 1 to 23. • Genes that determine a specific trait are in matching locations on paired ---“homologous” chromosomes.

Check List • 1) _____ is the passing on of traits from parents to offspring. • 2) A trait is contained in a ______? • 3) What is the difference in genotype and phenotype? • 4) How many chromosomes are in the human body cell? How many from dad and mom? • 5) What are homologous chromosomes?

• Traits are controlled by a single gene. • An example of a gene is one that causes earlobes to be attached to the head & another form that causes earlobes to be free from the head.

• Allele – different forms of a trait that make up a gene pair. – “alternate forms of the same gene” • Alleles may be either dominant or recessive for a particular trait.

Dominant vs Recessive Alleles • Dominant allele – is one that is expressed when two different alleles are inherited. • Recessive allele – is not expressed unless an organism inherits two copies of it.

Identifying Genotype and Phenotype • Each pair of genes is part of an individual’s genotype (Ff, Bb, Gg, etc) • Genotype identifies which alleles have been passed on to an organism. • Capital letter – dominant • Lowercase letter – recessive

• Offspring receive two copies of each gene – one from each parent. • 3 possible genotypes: FF, Ff, ff. • Homozygous genotype - is made up of two dominant or two recessive alleles “the same” – Ex: FF or ff • Heterozygous genotype - is made up of one dominant and one recessive allele “not the same” – Ex: Ff

Punnett Square • Punnett Square – is a tool used to predict the results when two organisms mate. • Used to calculate the probability of genotypes and phenotypes in offspring.

Check List • 1) What is the passing on of traits from parent to offspring called? • 2) What is an organism’s genotype? • 3)An organism’s expressed traits make up its ______? • 4) How many total chromosomes are their in a human cell? How many pairs? • 5) _____ is two different forms of the same gene. • 6) An allele can be either _______ or ______?

Father of Genetics • Gregor Mendel – is considered the “father” of genetics. • First experimented with pea plants in 1856. • He was a Austrian monk who was fascinated with crossbreeding plants. • First to develop punnett square to predict probabilities.

Advances in Genetics • Genetic Engineering – where scientist alter the DNA of an organism to benefit. • 3 advantages of genetic engineering: – 1) Gene transfer (out with the bad in with the good) – 2) Genetically engineered plants – 3) Genetically engineered animals

Chapter 8 - Heredity

• Heredity - ______________ • ______ are passed on to future generations

Inherited Traits • Recall that _____, determine the traits of an organism. • Traits are determined by the genes you receive from your parents.

• Genotype – ___________________ • Phenotype – ___________________ • Genotype DETERMINES phenotype

Chromosomes • 23 pairs of chromosomes in each cell = _____ total • Each pair has a chromosome from a mom and a dad. • On each chromosome is an alternating ______.

Chapter 8 Check List • 1) _______ -is the process of passing traits from parents to offspring. • 2) The genetic makeup or genes of an organism is called its _________. • 3) _____ determines the inherited traits of an organism. • 4) _______ - is the way an organism looks and behaves –“expressed or physical makeup” • 5) More complex organisms generally contain ____ chromosomes. • 6) Genes code for certain _______. • 7) Inherited traits means we get our characteristics from our _______. If we have 2 parents, there is _______ in the offspring. • 8) Above in #7, what type of reproduction has been involved?

Section 2

Chromosomes • Genes are located on structures called chromosomes. • Cells of different kinds of organisms contain a different number of chromosomes.

• Traits are controlled by a single gene. • An example of a gene is one that causes earlobes to be attached to the head & another form that causes earlobes to be free from the head.

• Allele ___________________ • Alleles can be either ________ or ________.

• Dominant Allele ___________________ • Recessive Allele ___________________

• Each pair of genes is part of an organism’s _________. (ex: Ff, Dd, Tt) • Genotype shows which alleles have been passed on. • Capital Letter = ______ allele • Lowercase Letter = _____ allele

• Offspring receive two copies of each gene – one from each parent. • 3 possible genotypes: _______, ______ • Homozygous genotype ___________________ – Ex: • Heterozygous genotype ____________________ – Ex:

Section 3 • • • Genotype vs Phenotype Tt vs Tall Homozygous vs Heterozygous Dominant vs. Recessive 3 genotypes

Punnett Square • Punnett Square – ___________. • Used to calculate the _____ of genotypes and phenotypes in offspring.

Task 1 • Draw a punnett square when a heterozygous parent for tallness mates with a homozygous parent for shortness. ( use T and t ).

Task 2 • Draw out a punnett square for two organisms that mate: one is Heterozygous for being athletic, and the other is homozygous recessive for being athletic (Use A or a)

Task 3 • A male eastern fox squirrel is notorious for mating in the winter months and for finding a mate who is always homozygous dominant. If a male eastern fox squirrel is homozygous for being slow and finds a mate draw a punnett square (F=fast; f=slow) and predict these: – What is the probability of the offspring being fast? – What is the probability of the offspring being slow? – What % will be homozygous? – What % will be heterozygous?

Section 3 cont.

Father of Genetics • Gregor Mendel – ___________. • First experimented with pea plants in 1856. • Used the __________ in his studies.

Advances in Genetics • Genetic Engineering – ___________________. • 2 advantages of genetic engineering: – 1) – 2)