BIO 141 UMBC exam 3 Study Guide With Correct Answers Graded A+

Compare and contrast meiosis and mitosis. - Number of times DNA is replicated 1 Number of cell divisions 1 mitosis, 2 meiosis Number of daughter cells produced 2 mitosis, 4 meiosis "Ploidy" of daughter cells stays the same in mitosis, cut in half in meiosis Type of cells in which the process occurs somatic cells mitosis, germ cells meiosis Number and genetic make-up of chromosomes in parent cell compared to daughter cells What is the difference between diploid and haploid? - Diploid organisms have two alleles of the same gene, each allele carried on a homologous chromosome while haploid organisms only have one allele What cells in the body are diploid and which are haploid? - Gametes are haploid while almost all other body cells are diploid What kind of diploid cells can become haploid cells? - Germ cells are diploid and go on to form haploid gametes If a particular species of plant is made up of cells that each have 30 separate chromosomes, 15 of which appear to be paired in terms of size and shape, what is the "ploidy" of this plant? What is the term for these similar chromosomes? - The cell is 2n and n is 15 therefore ploidy is 30 These similar chromosomes are homologous chromosomesWhat is the ploidy of a different plant species in which the cells also have 30 separate chromosomes, but there seem to be 10 triplets of similar size and shape? How many different alleles can the same gene of a tetraploid plant have? - The cell is 10n and n is 30 therefore ploidy is 300 It can have 3 different alleles Draw cells in metaphase of mitosis, metaphase I of meiosis, and metaphase II of meiosis. What is different between the chromosomes in your three drawing? - During metaphase of mitosis, individual chromosomes line up at metaphase plate During metaphase I of meiosis, homologous pair of chromosomes line up During metaphase II of meiosis, individual chromosomes line up Metaphase I of meiosis consists of homologous chromosomes that are paired together while metaphase of mitosis and metaphase II consist of individual chromosomes Explain what takes place immediately after metaphase in mitosis, meiosis I, and meiosis II. (Don't just name the phases; describe specifically what happens.) What happens if the steps you just described do not occur correctly during meiosis? State the term for this sort of meiotic error and the term that describes the resulting daughter cells. - During anaphase, either sister chromatids or homologous chromosomes begin to separate and in telophase, they finish moving to opposite poles and the nuclear envelope reforms If both homologs during meiosis I or both sister chromatids during meiosis II move to the same pole of the parent cell, nondisjunction will occur because the homologs or sister chromatids failed to separate. The resulting daughter cells will be aneuploid (too few or too many chromosomes of a particular type). What happens during crossing over? - During crossing over, the non-sister chromatids from each homolog have been broken at the chiasmata and reciprocal changes occur between different homologs. As a result, non-sister chromatids that have both maternal and paternal segments are formed.