Study Guide Chemistry

Chapter 4 Study Guide
Mendel’s Work Section 1
Key concepts
* In All of Mendel’s crosses, only one form of the trait appeared in the F1 generation. However, in the F2 generation, the“lost” form of the trait always reappeared in about one fourth of the plant.
* An organism´s traits are controlled by the alleles it inherits from its parents. Some alleles are dominant, while otheralleles are recessive.
Key Terms
* Heredity is the passing of physical characteristics from parents to offsprings.
* Trait is each different form of a characteristic, such as stem height or seedcolor.
* Genetic the scientific study of heredity
* Fertilization is the joining of a sperm and an egg.
* Purebred organism is the offsprings of many generation that have the same trait* Gene is the factor that control a trait
* Alleles are the different forms of a gene
* Dominant allele is one whose trait always shows up in the organism when the allele is present.
*Recessive allele is hidden whenever the dominant allele is present.
* Hybrid is an organism that has two different alleles for a trait.

Probability and heredity Section 2
Key concepts
*Probability is the likehood that a particular event will occur.
* Ina genetic cross, the alleles that each parent will pass on to its offspring is based on probability
* An organism´s phenotypeis its physical appearance, or visible traits. An organism´s genotype is its genetic makeup, or allele combination.
* In condominance, the alleles are neither dominant or recessive. As a result,both alleles are expressed in the offsprings.
Key terms
* Probability a number that describes how likely it is that an event will occur
* Punnett square is a chart that shows all the possiblecombinations of alleles that can result from genetic cross
* Phenotype an organism´s physical appearance or visible traits
* Genotype an organism´s genetic makeup, or allele combination...