Answer AND Explanation:
In spite being called the resting phase, many cellular processes take place during this phase. One of the most important of these is chromosomal replication in which each chromosome produces an exact copy of itself. The chromosomes are not visible as discrete structures but instead they appear as diffuse tangle of threads called chromatin.
Another important event is the formation of new organelles like mitochondria. There is also a build up of energy stores which is necessary to drive the mitotic process.
Answer:
The correct answer is option d.
Explanation:
Based on the given question, the genotype of the male parent is aa, the genotype of the female parent is Aa, and the genotype of the offspring is AAa, showing trisomy characteristics. In the given case, the existence of two A chromosomes shows that the chromosomes non-disjunction at the time of gametogenesis have taken place in the female as she is the only one possessing A allele. Hence, it can be concluded that the disjunction is maternal in characteristic.
The duplication of chromosomes takes place at the time of the S-phase of meiosis. Thus, after going through S-phase, the karyotype of the cell will be AAaa (maternal gametogenesis), this set of the chromosome is termed as homologous pair, and the pair of AA or aa is termed as sister chromatids.
The meiotic disjunction takes place in two phases. First, in meiosis I disjunction, in this separation of homologous chromosomes takes place, that is, the maternal cell AAaa get differentiated into aa and AA daughter cells. Secondly, in meiosis II disjunction, the separation of sister chromatids takes place into two independent chromosomes, that is, the formation of two cells each comprising chromosome A from the AA cell and the formation of two cells each with chromosome a from the aa cell.
Thus, the phenomenon of non-disjunction would have taken place at the time of meiosis II in the case of a female gamete to exhibit two A chromosomes. Hence, the correct answer is option d.
Answer:
A
Explanation:
At the start of a drought, groundwater may not be noticeably lower (not B). Only aquifers near the ocean may become contaminated with salt water (not C). And it is definitely not D.
Answer:
- <u>Medullary hormones</u>: the epineprhin and the norepineprhin. <u>Five different effects that these hormones produce are:</u> increase heart rate, produce cardiac muscle contraction, elevate blood preasure, increase breathing, dicrease digestive activity, increase metabolic rate.
- <u>The most important mineralocorticoid secreted by the adrenal cortex: </u>aldosterone.
- <u>Actions of the aldosterone: 1. </u>Conserves sodioum ions and water in kidneys. 2. Excrete potasium ions 3. Conserves H2O.
Explanation:
The epineprhin and norepineprhin are the most important medullary hormons. They are so important because of the functions that they have. They are responsable for the increase of heart rate and if it´s movement, along with digestive and metabolic activity.
Thanks to the aldosterone which is the most important secreted minaralocoricoid, kidneys conserve water and sodium and eliminate posatium.
Cells can not function properly at high temperatures
