Answer: C. Homologous chromosomes are separated in meiosis but not in mitosis.
Explanation: There are two main types of division that take place in eukaryotic cells, mitosis, and meiosis. Mitosis is the type of division that is used for growth, repair, and replacement of tissues. Therefore it is not necessary that the cells have different chromosome numbers or are varied genetically in the daughter cells in the case of mitosis.
Meiosis is the division that takes place to form the gametes for sexual reproduction. It is important in the first stages of meiosis I, to introduce variation and to halve the chromosome number.
Chromosomes numbers are halved (from 46 to 23) during meiosis I because the gametes (sperm and egg) come together and fuse during fertilization to form a zygote. When this fusion occurs (23 from the zygote and 23 from the egg), the chromosome number needs to be returned to that of the parent cell (46).
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Genetic variation is introduced during synapsis which only occurs in meiosis, not mitosis. Homologs exchange genetic information during crossing over of synapsis. Entire chromosomes also separate during meiosis I.
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At the end of meiosis, four genetically unique cells are produced with half the number of chromosomes as the parent cell (23 cromosomes) . After the process of mitosis is completed, two cells genetically identical to each pther are produced and have the same number of chromosomes as the parent cell (46 cromosomes).
Genetic variation is actually important because of changing environmental conditions.
Answer:
362 nucleosomes
Explanation:
A nucleosome repeat is made up of the DNA (146 bp) wrapped around the core nucleosome particle and the linker DNA (110 bp as in this situation). We can conclude that, every repeat stands for 256 (146 + 110) base pairs of DNA.
We are given the length of the entire region to be 92,672 bp long,
To determine the number of nucleosomes to organize the region into the 10nm fiber structure
Let,
Number of nucleosomes =
the length of the entire region
------------------- -----
base pairs of DNA.
= 92,672
-------
256
= 362 nucleosomes
Therefore, 362 nucleosomes is needed to structure the region into the 10nm fiber structure.
Answer:
Jupiter, Saturn, Uranus, Neptune
Explanation:
Jupiter, Saturn, Uranus, Neptune
