Biology Test Sophmore Year

Hybrid

An organism that has two different alleles for a trait

Gene

The set of information that controls a trait; code in the DNA

Allele

The different forms of a gene.

Heredity

The passing of traits from patents to offspring

Purebred

The offspring of many generations that have the same traits

Trait

A characteristic that an organism can pass to offspring through genes

Genetics

The scientific study of heredity

Phenotype

An organism’s physical appearance or visible traits

Genotype

An organism’s genetic makeup or allele combinations

Dominant

An allele whose trait always shows up in the organism when it is present

Recessive

An allele that is masked when a dominant allele is present

Heterozygous

Having two different alleles for a trait

Homozygous

Having two identical alleles for a trait

Haploid

1 set of chromosomes (half the “normal” number ie. gametes)

Diploid

2 sets of chromosomes (the normal number- SOMATIC/BODY CELLS)

Codominance

A condition in which neither of two alleles of gene is dominant or recessive

Incomplete Dominance

Cases in which one allele is not completely dominant or recessive

Polygentic “Traits

Traits controlled by two or more genes

Pedigree

A genetic tool that looks at the history of a genetic disorder in a family

Karyotype

A display of the chromosome pairs of a cell arranged by size and shape

Punnett Square

A diagram used in the study of inheritance to show the predicted genotypic results of random fertilization in genetic crosses between individuals of known genotype

Carrier

A person whose genotype includes a gene that is not expressed in the phenotype

Sex-Linked Trait

any trait located on the X chromosome, usually carried by the female and expressed int he male; recessive