Explain the role of chromosomes, DNA and genes in the formation of phenotypes in an organism. hel quicklll ill give brainliest HURRYY

Mitosis occurs in somatic cells; this means that it takes place in all types of cells that are not involved in the production of gametes. Prior to each mitotic division, a copy of every chromosome is created; thus, following division, a complete set of chromosomes is found in the nucleus of each new cell. Indeed, apart from random mutations, each successive duplicate cell will have the same genetic composition as its parent, due to the inheritance of the same chromosome set and similar biological environment. This works well for replacing damaged tissue or for growth and expansion from an embryonic state.

Because the genes contained in the duplicate chromosomes are transferred to each successive cellular generation, all mitotic progeny are genetically similar. However, there are exceptions. For example, there are genetic variations that arise in clonal species, such as bacteria, due to spontaneous mutations during mitotic division. Furthermore, chromosomes are sometimes replicated multiple times without any accompanying cell division. This occurs in the cells of Drosophila larvae salivary glands, for example, where there is a high metabolic demand. The chromosomes there are called polytene chromosomes, and they are extremely large compared to chromosomes in other Drosophila cells. These chromosomes replicate by undergoing the initial phases of mitosis without any cytokinesis (Figure 2). Therefore, the same cell contains thick arrangements of duplicate chromosomes side by side, which look like strands of very thick rope. Scientists believe that these chromosomes are hyper-replicated to allow for the rapid and copious production of certain proteins that help larval growth and metamorphosis (Gilbert, 2008).

Gene Transmission in Meiosis

Three photomicrographs show polytene chromosomes. The chromosomes look like horizontal tubes composed of white, grey, and black bands against a black background. They look like thick, striated lengths of rope.

Figure 2: Examples of polytene chromosomes

Pairing of homologous chromatids results in hundreds to thousands of individual chromatid copies aligned tightly in parallel to produce giant, "polytene" chromosomes.

© 2007 Nature Publishing Group Novikov, D. et al. High-pressure treatment of polytene chromosomes improves structural resolution. Nature Methods 4, 483 (2007). All rights reserved. View Terms of Use

Although he did not know it, Walther Flemming actually observed spermatozoa undergoing meiosis in 1882, but he mistook this process for mitosis. Nonetheless, Flemming did notice that, unlike during regular cell division, chromosomes occurred in pairs during spermatozoan development. This observation, followed in 1902 by Sutton's meticulous measurement of chromosomes in grasshopper sperm cell development, provided definitive clues that cell division in gametes was not just regular mitosis. Sutton demonstrated that the number of chromosomes was reduced in spermatozoan cell division, a process referred to as reductive division. As a result of this process, each gamete that Sutton observed had one-half the genetic information of the original cell. A few years later, researchers J. B. Farmer and J. E. S. Moore reported that this process—otherwise known as meiosis—is the fundamental means by which animals and plants produce gametes (Farmer & Moore, 1905).

The greatest impact of Sutton's work has far more to do with providing evidence for Mendel's principle of independent assortment than anything else. Specifically, Sutton saw that the position of each chromosome at the midline during metaphase was random, and that there was never a consistent maternal or paternal side of the cell division. Therefore, each chromosome was independent of the other. Thus, when the parent cell separated into gametes, the set of chromosomes in each daughter cell could contain a mixture of the parental traits, but not necessarily the same mixture as in other daughter cells.

To illustrate this concept, consider the variety derived from just three hypothetical chromosome pairs, as shown in the following example (Hirsch, 1963). Each pair consists of two homologues: one maternal and one paternal. Here, capital letters represent the maternal chromosome, and lowercase letters represent the paternal chromosome:

Pair 1: A and a

Pair 2: B and b

Pair 3: C and c

When these chromosome pairs are reshuffled through independent assortment, they can produce eight possible combinations in the resulting gametes:

A B C

A B c

A b c

A b C

a B C

a B c

a b C

a b c

Hope This Helps!!!

on a cabin, which was on a boat, (that looked like a paper cruise), we were all on a trip and an example of one word to describe it was 'amazing' as we all had a party (almost like the one i had previously had at a house of my friend's) and we played games with a bag, a box and a letter!

sorry, i could only think of one sentence, check it before you use the sentence because it is important that it is up to your standards.

the illustration   that would give a reader a clear understanding of the text is a picture of men constructing the frame of a building.the frame is made of iron bars. the text describes the job of blacksmiths'. these were very organised and they had different names: "the driver" and "the heater". the text describes the way in which these men worked ; they worked iron pieces as if they were playing a sport. in fact, the text wants to show the men's skills. the text also puts some emphasis on the use of '' rivets'' in construction. this kind of nails were not always used in the construction of manhattan.

some examples:

"and with an underhand toss he hurled the smoking rivet straight at the catcher, who caught it in mid-air in his catching can." men's skills

"when the driver was ready for a new " the emphasis on the rivet ( special nail used in construction).

" it against a beam to remove any cinders, and jammed it into the waiting hole. " the emphasis on the rivet.