Bio 1201 Gregg Exam 3 Study Questions and Answers Graded A 2024

the units of heredity and are made up of segments of DNA - genes how many chromosomes do humans have in the nucleus of their somatic cells? - 46 chromosomes (23 pairs) the two chromosomes in each pair are called... - homologous chromosomes/homologs each pair of homologous chromosomes includes... - one chromosome from each parent what does meiosis result in - 4 haploid daughter cells what does meiosis 1 do - separates homologous chromosomes when does crossing over and synapsis occur - prophase 1 what does meiosis 2 do - separates sister chromatids mitosis vs meiosis - Mitosis: one division forming 2 identical cells (clones); Meiosis: two divisions forming 4 genetically different cells meiosis 2 is similar to mitosis because... - sister chromatids separate how do different alleles occur - through mutation what 3 things contribute to genetic variation - crossing over, independent assortment, random fertilization when does independent assortment occur? - metaphase I of meiosis random fertilization - any sperm can fertilize any egg the mating of 2 true-breeding varieties - hybridization p generation - true-breeding parents f1 generation - hybrid offspring of the P generation f2 generation - offspring of the F1 generation alternative versions of a gene - alleles the specific spot where a gene resides on a chromosome - locus two alleles for a heritable character separate during gamete formation and end up in different gametes - law of segregation organism with two identical alleles for a character - homozygote organism with two different alleles for a gene - heterozygote to determine the genotype, breed the mystery individual with a homozygous recessive individual - testcross crossing two true-breeding parents differing in two characters produces ______ in the F1 generation, heterozygous for both characters - dihybrids a cross between F1 which can determine whether two characters are transmitted to offspring as a package or independently is called? - a dihybrid cross law of independent assortment - each pair of alleles segregates independently of any other pair of alleles during gamete formation do genes located near each other on the same chromosome tend to be inherited together? - yes occurs when phenotypes of the heterozygote and dominant homozygote are identical - complete dominance the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties - incomplete dominance two dominant alleles affect the phenotype in separate, distinguishable ways - codominance when one gene has multiple phenotypic effects - pleiotropy what hereditary diseases are caused by pleiotropic alleles - cystic fibrosis and sickle-cell disease when expression of a gene at one locus alters the phenotypic expression of a gene at a second locus - epistasis when multiple genes independently affect a single trait - polygenic inheritance example of epistasis - labrador retriever coat color: one gene determines the pigment color and the other gene determines if the pigment is deposited in the hair