Sci 230 Dna

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Associate Program Material

DNA Worksheet

Answer the following in at least 100 words:

1. Describe the structure of DNA?

DNA is composed of two polynucleotide strands wound together into a structure known as a double helix. Each nucleotide consists of a sugar base .Nucleotides form together creating a sugar phosphate backbone to each strand. There are three forms of DNA that differ significantly. The most common, B form, is the structure most people have heard of. It consists of the right handed double helix, with a large major groove and a smaller but accessible minor groove. These grooves are spaces between the backbones which allow access to the bases for interactions with proteins. A form DNA is also a right handed helix, but as yet has not been found in organisms, and only exists in synthetic environments. It has a wider, flatter structure. Z form DNA is found in living organisms, but is a left handed helix, meaning it twists in the opposite direction.

2. How does an organism’s genotype determine its phenotype?

The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration. A phenotype is the composite of an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, phrenology, behavior, and products of behavior. Phenotypes result from the expression of an organism's genes as well as the influence of environmental factors and the interactions between the two. Genotype means all the genes in a species DNA. Phenotype is what you would see in a species. Reactions involve the formation of products that are functioning in the cell for various things such as structural support, fibers, cytoskeleton, channels on membrane, enzymes that metabolize food molecules like glucose, energy production, transport, signal systems, pigmentation, attachment to other cells and various others. When...
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