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Chapter 13-Genetics
Term | Definition |
---|---|
heredity | the passing of traits from parent to offspring |
genetics | the study of how traits are passed from parent to offspring |
Mendel | considered the father of genetics |
dominant trait | a genetic factor that blocks another factor |
recessive trait | a genetic factor that is blocked by the presence of a dominant factor |
gene | a section on a chromosome that has genetic information for one trait |
alleles | the different forms of a gene |
phenotype | how a trait appears or is expressed |
genotype | the two alleles that control the phenotype of a trait |
homozygous | when the two alleles of a gene are the same |
heterozygous | when the two alleles of a gene are different |
Punnett Square | a model used to predict possible phenotypes and genotypes of offspring |
pedigree | a chart that shows phenotypes of genetically related family members |
incomplete dominance | when an offspring's phenotype is a combination of the parents' phenotype (like pink flowers from red and white) |
codominance | when both alleles can be observed in a phenotype (like roan coat color in cattle, a blend of red and white hairs, inherited from each parent) |
multiple alleles | genes that have more than two alleles to be selected from , like blood type |
polygenic inheritance | when multiple genes determine the phenotype of a trait, like hair and eye color |
DNA | an organism's genetic material |
nucleotide | a molecule made of a nitrogen base, a sugar, and a phosphate group |
adenine, guanine, cytosine, thymine | the 4 nitrogen bases that make up DNA |
replication | the process of copying a DNA molecule to make another DNA molecule |
junk DNA | segments of DNA that do not form genes |
RNA | a type of nucleic acid that helps to make proteins (3 kinds) |
mutation | a change in the sequence of a gene |