Answer/Explanation:
DNA polymerase is the enzyme responsible for replicating DNA. It is hugely important that is performs its functions accurately, as if incorrect bases are incorporated this can lead to mutations that disrupt the structure and function of genes. It adds nucleotides in a 5' - 3' direction only.
DNA polymerase III also has high processivity, which means that for every time it binds DNA, it is able to add many bases before it becomes dissociated.
A. DNA polymerase avoids the incorporation of improperly paired nucleotides in two ways:
- The first way depends on the structure of the enzyme. If the nucleotide that the enzyme is in the process of adding is not complementary to the template, then the nucleotide will not align with the template, and thus it is more inefficient to add. This inefficiency means the nucleotide is more likely to leave the active site before it is added, and DNA polymerase can replace it with the correct nucleotide.
- It also has proofreading capabilities. This means, when an incorrect base is added, it recognises the error and can fix this. It can do this because it possesses 3'-5' exonuclease activity. That means, it can chop out incorrectly added bases.
B. Ribonucleotides are the nucleotides that are incorporated into a growing RNA molecule. They are different from deoxyribonucleotides because of the differences in the sugar backbone (ribose vs deoxyribose). Their incorporation would disrupt the structure and function of the DNA, leading to problems with transcription and replication.
DNA polymerase avoids incorporating these nucleotides primarily because of the structure of the enzyme. Ribonucleotides cannot fit into the active site of DNA polymerase due to what is called a "steric filter" or "steric gate". This gate/filter function is performed by specific amino acid residues which usually have a bulky side chain and thus block the incorporation of the 2'OH of the ribose sugar (which is lacking in the deoxyribose sugar)
Answer:
Immunity to Small Pox
Explanation:
Over the years, Europeans had built up an immunity to smallpox because many had contracted the disease and still survived. As the population grew children were born with some immunity to the disease. When the Europeans arrived in the Americas, and smallpox spread around the native peoples, the Europeans did not contract the disease because they were immune. However, since the natives were not immune, they slowly died of due just to the disease as well as some parts of the war between the europeans.
Answer:
d. Fire ants spread by winged members and by hitching rides so a single colony can cause infestation.
Explanation:
An invasive fire ant colony can be very disastrous to the population of organisms in a locality. They cause massive competition with the native species thereby infesting them and destroying the native population.
Fire ants spread by winged members which makes a single colony to cause severe damage to the native specie. Often times, as they become endemic, they manifest as the dominant specie in a particular location.
Answer:
depending on conditions !
Explanation:
e.g a peat bog or somewhere like the north pole vs a humid jungle or hot desert
things to consider
air composition in the environment to feed microbes
temperature to speed up reactions
any natural catalysts
PH of your environment
Natural selection<span> acts upon two major sources of genetic variation: </span>mutations<span> and</span>recombination<span> of </span>genes<span> through sexual </span>reproduction<span>. Most </span>mutations<span> do not affect the reproductive fitness of individuals -- some may be beneficial, some may be harmful, and </span>many<span> may be neutral. </span>Mutation rates<span> per gene are generally low</span>
