Diploid nuclei of the ascomycete Neurospora crassa contain 14 chromosomes. A single diploid cell in an ascus will undergo one round of meiosis, followed in each of the daughter cells by one round of mitosis, producing a total of eight ascospores. If a single, diploid G 2 nucleus in an ascus contains 400 nanograms (ng) of DNA, then a single ascospore nucleus of this species should contain how much DNA (ng), carried on how many chromosomes?

The question is incomplete as it does not have the option which are:

A) 100, 7

B) 100, 14

C) 200, 7

D) 200, 14

E) 400, 14

A) 100, 7

Explanation:

The ascomycetes reproduce by the forming ascospores which are formed by the process of meiosis thus from 1 Parent cell, 4 daughter cells are reproduced. The 4 ascospores then undergo the mitosis and 4 daughter ascospores form 8 ascospores.

If the parent cell of an ascospore contains  

1. Ploidy- 2n=14 chromosomes, therefore, Meiosis process will reduce the number to half and will form the n=7 in daughter cells.

2. The DNA amount- in G2 stage will be 400 ng therefore during meiosis I, two cells with 200 ng DNA and then two more cells with 100 ng will be formed after meiosis II.

Thus, A) 100, 7  is correct.

one would be wind another would be water density

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.