In complementary base pairing, the G pairs with C, and A pairs with T. Given that this be the rule, the complementary nucleotides for your sequence would be as follows: CGATTAACGTAGGCA.
With regards to proofreading, mutations in cell division occur once in around every 100,000 base pairs. If this happens, the enzyme that pairs the nucleotides to form DNA, called DNA polymerase, detects the error and moves back along the strand, it then cuts the incorrect nucleotide and replaces it with the correct one, fixing the error and continuing with the DNA synthesis.
This process corrects the majority of errors in DNA synthesis, but some errors can still be missed by the DNA polymerase, this is then rectified by a protein complex which binds to the incorrect pairing until anther complex, comes along and cuts that particular section of DNA out, which is then replaced by a new section of correct nucleotides synthesized by the polymerase enzyme, the two sections at either end that were cut is then sealed by ligase, an enzyme which essentially "glues" the DNA stands back together.
My apologies for the long answer, I hope I answered your question and that you understand it well enough.
Answer:
1. Stabilizing Selection
2. Directional Selection
3. Disruptive Selection
Explanation:
Stabilizing Selection
This type of natural selection occurs when there are selective pressures working against two extremes of a trait and therefore the intermediate or “middle” trait is selected for. If we look at a distribution of traits in the population, it is noticeable that a standard distribution is followed:
Example: For a plant, the plants that are very tall are exposed to more wind and are at risk of being blown over. The plants that are very short fail to get enough sunlight to prosper. Therefore, the plants that are a middle height between the two get both enough sunlight and protection from the wind.
Directional Selection
This type of natural selection occurs when selective pressures are working in favour of one extreme of a trait. Therefore when looking at a distribution of traits in a population, a graph tends to lean more to one side:
Example: Giraffes with the longest necks are able to reach more leaves to each. Selective pressures will work in the advantage of the longer neck giraffes and therefore the distribution of the trait within the population will shift towards the longer neck trait.
Disruptive Selection
This type of natural selection occurs when selective pressures are working in favour of the two extremes and against the intermediate trait. This type of selection is not as common. When looking at a trait distribution, there are two higher peaks on both ends with a minimum in the middle as such:
Example: An area that has black, white and grey bunnies contains both black and white rocks. Both the traits for white and black will be favored by natural selection since they both prove useful for camouflage. The intermediate trait of grey does not prove as useful and therefore selective pressures act against the trait.
Flatworms are unsegmented worms. They have a tail and a head end by don't have any body cavity or specialized respiratory and circulatory organs. They are also bilaterally symmetrical which gives them both upper and lower surface. With this accompanying characteristics they typically have a flat shape or appearance.
One problem is they drink all the water
According to the angular size contrast theory of the ........
