| A | B |
|---|
| meiosis | Number of chromosomes per cell is cut in half by seperating homologous chromosomes. |
| mRNA | takes DNA instructions for making proteins to the cytoplasm |
| variation | A difference between members of the same population. |
| genetics | Scientific study of heredity. |
| trait | Specific characteristic that varies from one individual to another. |
| purebred | Allowed to self-pollinate, produce offspring identical to themselves. |
| hybrid | The offspring of crosses between parents with different traits. |
| genes | Chemical factors that determine traits. |
| allele | The different forms of a gene. |
| dominant | Particular form of a trait that is always expressed. |
| recessive | Form of a trait only expressed when paired with the same form. |
| genotype | Genetic makeup |
| phenotype | Physical makeup |
| homozygous | Organisms that have two identical alleles for a particular trait |
| heterozygous | Organisms that have two different alleles for the same trait |
| Punnett square | Diagram often used to determine genetic combinations that might result form a genetic cross. |
| pedigree | Chart which shows the relationships within a family. |
| carrier | An individual who possesses a particualr recessive trait but doesn't express it. |
| incomplete dominance | Situation where one allele is not completely dominant over another. |
| codominance | Situation where both alleles contribute to the phenotype. |
| multiple alleles | Genes that have more than two alleles |
| polygenic trait | Traits controlled by two or more genes. |
| pleiotropy | Single gene that affects more than one trait. |
| linked genes | Genes located on the same chromosome. |
| crossing over | Process where homologous chromosomes exchange portions of their chromatids during meiosis. |
| sex-linked genes | Gene located on a sex chromosome. |
| sex-limited traits | An autosomal gene expressed in only one sex. |
| sex-influenced traits | An autosomal gene expressed differently in different sexes. |
| polyploidy | Condition in which an organism has extra sets of chromosomes. |
| trisomy | A genetic condition in which the zygote receives three copies of a particular chromosome instead of two. |
| monosomy | A genetic condition in which the zygot receives only one copy of a particular chromosome instead of two. |
| nondisjunction | Error in meiosis in which homologous chromosomes fail to seperate. |
| autosome | Chromosome that is not a sex chromosome. |
| sex chromosomes | One of two chromosomes that determine an individual's sex. |
| karyotype | Set of photographs of chromosomes grouped in order in pairs. |
| genome | The base sequence for all of the DNA in an organism |
| introns | Sections of DNA or RNA in eukaryotic cells that do not code for proteins. |
| exons | Sections of DNA or RNA in eukaryotic cells that code for proteins. |
| mutation | Change in DNA sequence that affects genetic information |
| oncogene | A gene that has the ability to cause cancer. |
| carcinogen | Chemical compound known to cause cancer. |
| transcription | Process in which part of the nucleotide sequence of DNA is copied into complementary sequence in RNA. |
| translation | Decoding of a mRNA messge into a polypeptide chain. |
| codon | Three-nucleotide sequence on messenger RNA that codes for an amino acid. |
| anticodon | Group of three bases on a tRNA molecule that are complimentary to an mRNA codon. |
| homologous pair | Chromosomes that have a corresponding chromosome from the opposite-sex parent. |
| tRNA | transfers amino acids to ribosomes during protein synthesis |
| rRNA | type of RNA that makes up the major part of ribosomes |
| promoter | a section of DNA that serves as the binding site for RNA polymerase |
| repressor | a protein that binds to DNA, turning genes "off" or halting gene expression |
| protein synthesis | made up of two processes called transcription and translation |
| fertilization | process in sexual fertilization in which male and female reproductive cell form a new cell |
| segregation | separation of alleles during gamete formation |
