Chapter 11 - Genetics

The Essential Question

Who is Gregor Mendel and what did he have to do with alleles, chromosomes, traits, or this topic called genetics?

Name _______Block _______Date _______

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Chromosomes Homologous chromosomes

Two nearly identical copies of each chromosome in an organism. One set is donated by the mother and the other set by the father.

Sister chromatids After a chromosome has replicated during interphase they consist of two identical chromatids which are called sister chromatids.

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ChromosomesGene

The basic unit of heredity. The sequence of DNA nucleotides on a chromosome encodes for the manufacturing of proteins and thus the traits of the organism.

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Important terms and concepts

• Gene: controls one characteristic

• Alleles: alternative forms of a gene

• Dominant: an allele that is

phenotypically expressed regardless of the other allele

• Recessive: an allele that is only

phenotypically expressed when the dominant allele is not present

• Locus: location of a gene on a

chromosome

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Important terms and concepts

• Heterozygous: contains two different alleles

for the trait being studied

• Homozygous: contains identical alleles for the

trait being studied

• Genotype: the collection of alleles in an

individual

• Phenotype: the physical expression of the

alleles (appearance & behaviour)

Gregor Mendel

• He was a High School Biology teacher that gave up teaching to become a monk.

• For his work in genetics, he earned the title of being know as: The Father of Genetics.

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Mendels first law• the Law of Segregation

• Each organism has two hereditary factors for each trait, which are called ___________. And during meiosis, gamete (egg or sperm) formation, the two factors separate (segregate) into different gametes so that each gamete has only one type of each factor.

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Mendel's second law• the Law of Independent Assortment

•Genes located on different chromosomes assort independently of one another.

Punnett Squares

• Monohybrid Cross• TT x tt