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raegans bio review
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| Term | Definition |
|---|---|
| inheritance | passing of traits from one generation to the next |
| genetics | study of inheritance |
| alleles | different forms of genes (ex: tall plant or short plant) |
| Gregor mendel | used pea plants to study inheritance patterns |
| what did Mendel determine | some alleles are dominant : some alleles are recessive : dominant alleles are always expressed and mask other traits : recessive alleles are only expressed if dominant alleles are not present |
| sex-linked | traits that are carried on the X chromosome and not the Y males only receive one copy of an allele |
| autosomes | Any chromosome not considered as a sex chromosome |
| genotype phenotype heterozygous homozygous | (genotype) genes an organism has (BB bb Bb) (phenotype) physical appearance (homo) same alleles (hetero) diffrent alleles |
| genotype ratio vs phenotype ratio | genotype ratio: 1LL : 2Ll : 1ll phenotype ratio: 3 tall : 1 short |
| pedigree | used to show inheritance of traits thru generations |
| incomplete dominance | one allele is NOT completly Dominant over another ( they blend ) |
| codominance | both alleles are expressed |
| multiple alleles | 3 or more alleles of same gene that code for a single trait (ex: blood type-3 alleles A,B,O) |
| polygenic traits | traits that are carried on more than 1 pair of chromosomes (ex: eye color) |
| chromosomal mutation | change in entire genes or chromosomes TYPES: deletion insertion translocation inversion non-disjunction |
| nondisjunction | meiosis mistake, failure of chromosome pairs to separate |
| monosomy | loss of a single chromosome (daughter cell will have one missing chromosome) |
| trisomy | gaining a single chromosome |
| down syndrome : turners syndrome : klinefelters syndrom | (down) trisomy 21- extra chromosome (turners) missing sex chromosome X (klinefelters) extra sex chromosome X |
| karyotype : human genome project | (karyotype) picture of an individuals chromosomes (human genome project) project to understand order of bases for all human genes found in our DNA |
| during meiosis... | parent cell divides twice, making 4 haploid cells |
| what does meiosis produce | sex cells or gametes (ex: sperm and egg) |
| haploid | sex cells (contains only one copy of each chromosome) (ex: human sex cells=23 chromosomes) |
| when does crossing over occur | during meiosis when chromosome pairs exchange pieces |
| what results in variation | sexual reproduction, crossing over during meiosis, mutations |