Genetics unit

Fertilization

The joining of male and female reproduction cells in sexual reproduction

Traits

Specific hereditary characteristics that varies between individuals

Alleles

The different forms of a gene for one trait

Segregation

A single gene for each trait is passed to offspring

Probability

Mathematical prediction of the likelihood an event will occur used to predict the outcome of genetic crosses

Punnett Square 

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A diagram predicts the probability of genetic outcomes resulting from a cross

Homozygous

An organism with identical alleles from one trait 

Heterozygous

An organism with different alleles for the same trait

Genotype

The genetic makeup of an organism for a trait

Phenotype

The physical characteristics of an organism

Test cross

Determines genotype of an organism with the dominant phenotype

Incomplete dominance

Cases in which the heterozygous phenotype is between either homozygous phenotype

Codominance

A case where both alleles in the heterozygous are seen equally in the offspring

Antigens

Membrane proteins that identify a cell to its immune cells

Antibodies

Proteins that identify foreign cell for removal from the body based on antigens(antibody A removes cells with antigen A)

Polygenic traits

Traits controlled by more than one gene

Multiple alleles

Some genes have more than 2 alleles for a trait

Sex-linked gametes

Genes that do not follow regular patterns of heredity because they are located on the x or Y chromosome

Hemophilia

A disease where the individual cannot control blood clotting

Pedigree

A diagram showing relationships between family and the transmission of an hereditary trait

Karyotype

A diagram of all of the chromosomes in a nucleus to determine the genetic health and sex of an individual

Gene Map

Diagram that shows the location of each gene on a chromosome

Nondisjunction

The unequal separation of chromosome pairs in meiosis 2 resulting in gametes with 22 or 24 chromosomes

Down syndrome

An individual is born with 3 copies of chromosome 21 resulting in mild to impaired mental ability, weaken immunity and a series or other symptoms

Turner’s syndrome

A chromosomal disorder associated with a missing sex chromosome;XO

Klinefelter’s syndrome

Caused by extra sex (X) chromosome

Gene

The chemical factors in organisms that determine the traits