Answer: A protein domain is a region of the protein's polypeptide chain that is self-stabilizing and that folds
independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of several domains.
One domain may appear in a variety of different proteins. Molecular evolution uses domains as building blocks and these may be recombined in different arrangements to create proteins with different functions.
In general, domains vary in length from between about 50 amino acids up to 250 amino acids in length.
The shortest domains, such as zinc fingers, are stabilized by metal ions or disulfide bridges. Domains often form functional units, such as the calcium binding EF-hand domain of calmodulin.
Because they are independently stable, domains can be "swapped" by genetic engineering between one protein and another to make chimeric proteins.
The correct answer is option D, that is since genetic drift is random, it does not always favor the better or healthier organisms.
A mechanism of evolution in which the frequencies of alleles of a population change with generations because of sampling error is known as genetic drift. It takes place in all the populations of non-infinite size, however, its influences are strongest in small populations.
Answer:Each and every one of us have several roles. Organisms in a community play other roles too. An organism's role within an ecosystem depends on how it earn its nutrients. Organisms collect their nutrients in very different actions, so they have different roles in an ecosystem.
Explanation:
The food chain describes who eats whom in the wild. Every living thing—from one-celled algae to giant blue whales—needs food to survive. Each food chain is a possible pathway that energy and nutrients can follow through the ecosystem.
For example, grass produces its own food from sunlight. A rabbit eats the grass. A fox eats the rabbit. When the fox dies, bacteria break down its body, returning it to the soil where it provides nutrients for plants like grass.
Of course, many different animals eat grass, and rabbits can eat other plants besides grass. Foxes, in turn, can eat many types of animals and plants. Each of these living things can be a part of multiple food chains. All of the interconnected and overlapping food chains in an ecosystem make up a food web.
Answer:
C: Take infected amphibians and assign them to two populations. Leave one population alone; inoculate the other with Jl. Measure the rate at which infection proceeds in both populations.
Explanation:
In scientific investigations, the best way to determine the effect of certain experimental factor on the population of study is to have a baseline for comparison. This is usually referred to as controlled experiment.
<em>In the case of the observation that chytrid infection in amphibians seems to be inhibited by Janthinobacterium lividum, the best way experimental design is to get a population of amphibians suffering from the disease, divide them into two groups and subject them to the same conditions except the introduction of Janthinobacterium lividum to the skin of one of the groups.</em>
<em>A suitable method can thereafter be employed to measure the rate at which infection proceeds in both population. If indeed, the bacterium has the capacity to inhibit the infection, the rate of infection in the group with the bacterium will be significantly less than that of the group without the bacterium. </em>
The correct option is C.
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