1. Caenorhabditis elegans (the famous model genetic organism) has 6 different chromosomes: 5 autosomes (called I-V) and 1 sex chromosome (called X). That is, n=6 for hermaprhodites (which are basically XX females that make both sperm and eggs). Hermaphrodites can either self-fertilize or they can be fertilized by males (which only have one X chromosome per diploid cell; i.e. males are hemizygous and designated "XO", where the "O" just represents no chromosome, "nullo").
How many chromatids per nucleus (in a diploid somatic cell) will there be in a hermaphrodite of C. elegans at prophase of mitosis?
A. 6
B. 11
C. 12
D. 22
E. 24
2. How many chromatids per diploid nucleus (in a diploid somatic cell) will there be at telophase of mitosis in C. elegans male cells? (Hint: a cell in telophase contains two separate nuclei.)
A. 6
B. 11
C. 12
D. 22
E. 24
3. During meiosis I of spermatogenesis in C. elegans males, what arrangement will be found at the metaphase plate? (Reminder: a tetrad is a complex of four chromatids; a dyad is a complex of two chromatids.)
A. The autosomes will form tetrads and the X will exist as a dyad.
B. All chromosomes will form tetrads.
C. The autosomes will form tetrads, and the X and O will pair as a tetrad.
D. No tetrads will form in this case because males are hemizygous.
E. The autosomes will form dyads and the X will form a tetrad.