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Genetics
Genetics middle school
Term | Definition |
---|---|
genetics | the study of heredity |
heredity | the passing of traits from parents to offspring |
Gregor Mendel | Father of Genetics, a monk who studied heredity of pea plants and how traits are passed from one generation to another |
traits | physical characteristics of an organism |
genes | factors that control traits-found on chromosomes, inherited in pairs from parents |
alleles | different forms of a gene Ex: brown eyes/blue eyes |
dominant traits | stronger traits represented by a capitol letter- always show up when the the allele is present in a gene pair |
recessive traits | weaker traits represented by a lower case letter-is masked or hidden when paired with a dominant allele in a gene pair |
homozygous/purebred | an organism that has genes that alike for a particular trait ex: 2 genes for tall (TT) or 2 genes for short (tt) |
heterozygous/hybrid | an organism that has 2 different genes for a particular trait ex: Tt-one gene for tall (T) and one for short (t) |
Punnett Square | chart used to show probability of possible gene combinations in a cross between 2 organisms |
phenotype | physical characteristics of an organism ex: brown eyes, purple flowers |
genotype | the gene makeup or allele combination ex: BB homozygous dominant Bb hybrid BB homozygous recessive |
meiosis | cell process that produces sex cells (sperm and egg) sex cells have half the number of chromosomes as the original cell |
chromosomes | rod shaped structures found in the nucleus/contain genes |
sex chromosomes | specialized chromosomes that determine the gender of offspring EX: XX=female XY=male |
gametes | sex cells (sperm and egg) |
zygote | fertilized egg cell |
sexual reproduction | reproduction that requires 2 parents, offspring gets half of their genes from each parent, offspring are genetically different, creates greatest genetic diversity |
asexual reproduction | reproduction that requires 1 parent, offspring are genetically identical to the parent, no genetic diversity Ex: binary fission, budding, cuttings from plants |
mitosis | cell division that forms 2 new identical cells with the same number of chromosomes |