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Terms in this set (77)

1~ a hereditary trait is governed by a gene
2~ genes reside on chromosomes and are specific sequences of DNA in all cells, but they are RNA in some viruses
3~ a gene for each trait can exist in two or more alternative forms called alleles. an individuals alleles, interacting w/ the environment, determine its external appearance, biochemical functioning, and behavior
4~ most higher organisms have two copies of each gene in body cells (they are diploid) gametes (eggs or sperm), however, have only one copy of each gene (they are haploid).
5~ homologous chromosomes are two chromosomes that are similar in size, shape, and genetic content
6~ a homozygote has two identical alleles of a gene; a heterozygote has two different alleles of a gene
7~ an individuals physical makeup (the way it looks and functions)is its phenotype; an organism's genetic makeup is its genotype
8~ in a heterozygote, generally only one of the two alleles shows in the phenotype, while the other allele is hidden. The allele that shows is the dominant allele, and the hidden allele is the recessive allele
9~ pairs of alleles separate, or segregate, before egg and sperm formation, so each gamete has a single copy of each gene. At fertilization, sperm and egg combine randomly w/ respect to the alleles they contain, and the resulting zygote in general has two copies of all genes
10~ genes on different chromosomes assort independently of each other into gametes
11~ linked genes lie on the same chromosome and tend to be packaged into gametes together