Question

Question 1: This question may be completed independently or as a group exercise. You have learned that humans have 46 total chromosomes, and chimpanzees have 48 total chromosomes. Use other textbooks in biological anthropology and biology (or reputable online resources) to find the number of chromosomes in other organisms. Give an organism with considerably more chromosomes than humans. Give an organism with considerably fewer chromosomes than humans. Did your findings surprise you? What did your research suggest about the relationship between chromosome number and organism complexity?

Question 2: This question may be completed independently or as a group discussion. What do you think might happen if a person had two X chromosomes and one Y chromosome? Would this person be male or female? What would they look like?

Question 3: Why is it important that meiosis results in daughter cells that have half of the original cell’s chromosomes?

Question 4:How are RNA and DNA similar? How are they different?

Answer 1

1. Animal chromosome numbers range from 254 in hermit crabs to 2 in a species of roundworm. Yes, the findings surprised me. The chromosome number is not correlated to the complexity of an organism.in humans, for example, the diploid number is 2n = 46 (that is, 23 pairs), compared with 2n = 78, or 39 pairs, in the dog and 2n = 36 (18) in the common earthworm.

2. Presence of Y chromosomes will make it a male but an incomplete one as this male will have two sets of X chromosomes which means there would be two sets of genes present in X chromosome working. This would be a chromosomal aberration resulting in a non-working male phenotype with having certain female characters.

3. Meiosis occurs prior to the formation of zygote. If the number of the chromosome would have not been reduced to half then every generation would have double the chromosomes of the previous generation and chromosome number would have increased in every generation. This is not possible as chromosome number remains constant in every generation.

4. DNA and RNA have the same monomers i.e nucleotides. One of the most significant similarities between DNA and RNA is that they both have a phosphate backbone to which the bases attach. Both DNA and RNA have four nitrogenous bases each—three of which they share (Cytosine, Adenine, and Guanine) and one that differs between the two (RNA has Uracil while DNA has Thymine) also sugar in DNA is deoxyribose and sugar in RNA is ribose.