Nondisjunction that leads to problems in offspring can occur in:
a. Mitosis
b. Meiosis I only
c. Meiosis I and II
d. Mitosis, meiosis I, and meiosis II
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Nondisjunction that leads to problems in offspring can occur in:
a. Mitosis
b. Meiosis I only
c. Meiosis I and II
d. Mitosis, meiosis I, and meiosis II
Norway rats have 42 chromosomes in their diploid cells. If such a cell enters meiosis, how many chromosomes and double-helical molecules of DNA will be present in each daughter cell at the end of meiosis II?
a. 21 chromosomes and 21 double-helical DNA molecules
b. 21 chromosomes and 42 double-helical DNA molecules
c. 42 chromosomes and 42 double-helical DNA molecules
d. 42 chromosomes and 84 double-helical DNA molecules
Triploid (3n) watermelons, which are seedless, are produced by crossing a tetraploid (4n) strain with a diploid (2n) plant. Explain why this mating produces a triploid individual.
Select True or False for each statement.
Sister chromatids are homologous chromosomes.
Non-sister chromatids are found on two different homologs.
Crossing over occurs between sister chromatids.
A chiasma forms between two of the four molecules of double-stranded DNA on duplicated homologous chromosomes.
What proportion of chromosomes in a man's skin cell are maternal chromosomes?
Meiosis results in independent assortment of egg-derived and sperm-derived chromosomes. If 2𝑛=4 for a given organism, and there is no crossing over, what is the chance that a gamete produced by this diploid organism will receive only sperm-derived chromosomes? In domestic cats, 2𝑛=38. What is the chance that a cat gamete contains only egg-derived chromosomes?