Answer:
1 . The stage on the first meiotic division when the homologous chromosomes move to opposite poles but the sister chromatids remain together
: b. Anaphase I
2 . The stage in the second meiotic division where sister chromatids migrate to opposite poles
: c. Anaphase II
3 . A structure on the chromosome that holds a pair of chromatids together during replication
: f. centromere
4 . A double-stranded chromosome following replication attached by a centromere
: d. chromatid
5 . A condition where non-sister chromatid of homologous chromosomes exchange genes
: e. crossing over
6 . The stage in the first meiotic division where the homologous chromosomes line up as a pair
: a. Metaphase I
7 . The stage in the second meiotic division where the chromatid pair lines up at the equator of the cell: g. Metaphase II
Explanation:
DNA replication occurs during the S phase of the interphase of the cell cycle. The replicated DNA molecules are accommodated in two sister chromatids of a chromosome that are held together by a centromere.
During prophase I, the chromatids of a homologous chromosome pair exchange a genetic segment. This process is called crossing over. It generates recombinant chromatids with new combinations of genes.
Metaphase I of meiosis I includes the alignment of homologous pairs of chromosomes at the cell's equator. This is followed by separation and movement of homologous chromosomes to the opposite poles of the cell during anaphase I.
Metaphase II of meiosis II includes the alignment of individual chromosomes, each with two sister chromatids, on the cell's equator. During anaphase II, splitting centromere separates the sister chromatids which then move to the opposite poles of the cell.
A commensal bacterium does not infect its host, which is option D. Details about commensalism can be found below.
<h3>What is commensalism?</h3>
Commensalism is a kind of relationship that involves the sharing of the same environment by two organisms where one species benefits and the other is unaffected.
For example, barnacles on whales is a commensalistic relationship.
According to this question, a commensal bacterium will not affect or harm it's host by infect it neither will it benefit its host.
Learn more about commensalism at: brainly.com/question/14224704
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Answer: when one is lost, one is formed
Answer:
Hormones are controlled by a
(negative)
feedback system between the glands that produce this hormone and the concentration of blood calcium ions. If the level of ions is
(low)
,hormone secretion is increased. This causes resorption by cells called
which releases both calcium and phosphate ions into the blood stream.
Explanation:
Negative Feedback a the process in your body that helps to maintain Homeostasis. If some variable changes a value in your body, like your ion levels, your glands produce a hormone that causes resorption by cells. This releases both calcium and phosphate ions into the blood stream and therefore your ion levels go back to normal.
Hope this helps!
