Unit 9: What is Heredity?

the father of genetics

Mendel is know for ____?

trait

a physical characteristic of an organism.

F1 (first filial) generation

all offspring were tall.

organism traits

controlled by the alleles it inherits from its parents. Some alleles are Dominant the other Alleles are recessive.

allele

different forms of a gene

Mendel's 2nd conclusion

factors that control each trait occurs in pairs. The female parent contributes one factor, while the male parent contributes another.

pollination

fertilization in plants.

recessive allele

hidden whenever the dominant allele is present.

Mendel's 1st conclusion

individual factors, or set of genetic information must control the inheritance of traits in peas.

fertilization

occurs when sperm and egg cells join.

Mendel's 3rd conclusion

one factor in a pair can mask, or hide, the other factor

dominant allele

one whose traits always shows up in an organism when the allele is present.

hybrid

organism that has two different alleles for a trait.

purebred

organisms that are "pure" for a specific trait

P (parent) generation

purebred tall plants were crossed with purebred short plants.

F2 (second filial) generation

three fourths of the offspring were tall; one fourth were short.

mendel found that only one form of the trait appeared in the F1 generation. In the F2 generation the "lost" form of the trade always reappeared in about one fourth of the plants

what happened in Mendel's crosses?

gene

a factor that controls traits

a dominate a allele is represented by an uppercase letter (T) and it's recessive a allele is represented by the same letter but lower case (t). A dominant and recessive a allele is represented by an uppercase letter and a lowercase letter (Tt).

symbols used to represent the alleles?

heredity

the passing of physical characteristics from parent to offspring.

genetics

the scientific study of heredity.