I think it is the 3rd one because health problems at older age.
<span>enable humans to live forever.
Hope this helps!
-Payshence xoxo</span>
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.
Answer:
a) the oxidizing agent.
Explanation:
In the citric acid cycle, malate is dehydrogenated into oxaloacetate and the reaction is catalyzed by malate dehydrogenase. The released electrons are accepted by NAD+. So, NAD+ is reduced into NADH. The substances that accept electrons during chemical reactions and are reduced to oxidize the other substances are called oxidizing agents. NAD+ serves as an oxidizing agent as it accepts electrons to oxidize malate into oxaloacetate.
Carbon atoms got 4 surface electrons which makes them in the middle regarding the electrical surface charge and they can make a maximum relations of 4
