Term | Definition |
messenger RNA (mRNA) | carries the genetic message from the DNA in the nucleus to the ribosome |
transfer RNA (tRNA) | carries amino acids to the ribosome for protein synthesis (from floating in the cytoplasm to the ribosome) |
ribosomal RNA (rRNA) | the RNA material that forms the two subunits that make up the ribosome |
crossing over | when homologous chromosomes that are bundled together so closely they exchange segments |
gene | segment of DNA that controls an organism’s traits |
hybrid | offspring of parents with DIFFERENT traits; heterozygous |
alleles | the different possible forms of a gene |
genotype | the genetic makeup of an organism; which alleles they possess |
phenotype | appearance, or physical characteristics; what you can see; physical trait |
codominance | 2 alleles are fully expressed |
incomplete dominance | 2 alleles that share expression; neither is completely dominant |
polygenic inheritance | controlled by several genes at once |
sex-linked inheritance | determined by a gene located on the sex chromosome(the X or Y chromosome) |
multiple alleles | trait is determined from many possible alleles, although the individual only gets 2 alleles |
autosomal chromosomes | all chromosomes except the sex chromosomes |
trisomy | chromosomes do not seperate equally resulting in an extra homologous chromosome; (3 of chromosome #23) |
monosomy | chromosomes do not seperate equally resulting in a missing homologous chromosome; (only 1 chromosome #23) |
non-disjunction | chromosomes are not properly sorted during meiosis leading to incorrect numbers of chromosomes in each gamete |