2. INHERITANCE or HEREDITY- The genetic transmission of characteristics from parent to offspring, such as hair, eye, and skin color.

3. GENOTYPE- the genes present in the DNA of an organism. There are always 2 letters in the genotype because (as a result of sexual reproduction) 1 gene from MOM + 1 gene from DAD = 2 genes (2 letters) for offspring

4.  HOMOZYGOUS: GENOTYPE has 2 capital or 2 lowercase letters (ex: TT or tt) ("homo" means "the same")  Sometimes the term "PUREBRED" is used instead of homozygous.

5.  HETEROZYGOUS: GENOTYPE has 1 capital letter & 1 lowercase letter (ex: Tt) ("hetero" means "other")  A heterozygous genotype can also be referred to as HYBRID.

6.  PHENOTYPE- how the trait physically shows-up in the organism; it is the observable traits present in an organism What the organism LOOKS like Examples of phenotypes: blue eyes, brown fur, striped fruit, yellow flowers

7. ALLELES- alternative forms of the same gene. Alleles for a trait are located at corresponding positions on homologous chromosomes called loci. A b C d e A B c d E Chromosome from MOM Chromosome from DAD ALLELES

8.  When 1 allele masks (hides) the effect of another, that allele is called DOMINANT and the hidden allele is called RECESSIVE.  Dominant alleles are represented by a CAPITAL letter  Recessive alleles are represented by a LOWERCASE letter

9.  Vocabulary Review: Define  Genotype: Phenotype:  Allele:  Genes:  Homozygous:  Heterozygous

10.  Genetics is the scientific study of heredity.  Gregor Mendel was an Austrian monk. His work was important to the understanding of heredity.  Mendel carried out his work with ordinary garden peas.

11.  Mendel knew that the male part of each flower produces pollen, (containing sperm). the female part of the flower produces egg cells.

12.  During sexual reproduction, sperm and egg cells join in a process called fertilization.  Fertilization produces a new cell.  Pea flowers are self-pollinating.

13.  Mendel had true-breeding pea plants that, if allowed to self-pollinate, would produce offspring identical to themselves. Cross-pollination Mendel was able to produce seeds that had two different parents.

14.  Genes and Dominance A trait is a specific characteristic that varies from one individual to another.  Mendel studied seven pea plant traits, each with two contrasting characters.  He crossed plants with each of the seven contrasting characters and studied their offspring.

15.  Each original pair of plants is the P (parental) generation.  The offspring are called the F1, or “first filial,” generation.  The offspring of crosses between parents with different traits are called hybrids. Mendel’s F 1 Crosses on Pea Plants

16.  Mendel's first conclusion biological inheritance is determined by factors that are passed from one generation to the next  Today, scientists call the factors that determine traits genes.

17.  Each of the traits Mendel studied was controlled by one gene that occurred in two contrasting forms that produced different characters for each trait. The different forms of a gene are called alleles.  Mendel’s second conclusion principle of dominance some alleles are dominant and others are recessive

18.  Segregation Mendel crossed the F1 generation with itself to produce the F2 (second filial) generation. The traits controlled by recessive alleles reappeared in one fourth of the F2 plants.

19.  The reappearance of the trait controlled by the recessive allele indicated that at some point the allele for shortness had been separated, or segregated, from the allele for tallness.

20.  Mendel suggested that the alleles for tallness and shortness in the F 1 plants segregated from each other during the formation of the sex cells, or gametes.

21.  Genes are passed from parents to their offspring.  If two or more forms (alleles) of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive.  In most sexually reproducing organisms, each adult has two copies of each gene. These genes are segregated from each other when gametes are formed.

22.  The likelihood that a particular event will occur is called probability.  The principles of probability can be used to predict the outcomes of genetic crosses.

23.  The gene combinations that might result from a genetic cross can be determined by drawing a diagram known as a Punnett square.  Punnett squares can be used to predict and compare the genetic variations that will result from a cross.

24.  A capital letter represents the dominant allele for tall.  A lowercase letter represents the recessive allele for short.  In this example, T = tall t = short

25.  Organisms that have two identical alleles for a particular trait are said to be homozygous.  Organisms that have two different alleles for the same trait are heterozygous.  Homozygous organisms are true- breeding for a particular trait.  Heterozygous organisms are hybrid for a particular trait.

26.  All of the tall plants have the same phenotype, or physical characteristics.  The tall plants do not have the same genotype, or genetic makeup.  One third of the tall plants are TT, while two thirds of the tall plants are Tt.

27.  The plants have different genotypes (TT and Tt), but they have the same phenotype (tall).

28. Now, it’s time for you to practice!!!