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.
<u>Sunspots</u> are temporary phenomena on the photosphere of the Sun that appear as dark spots compared to surrounding regions. They are caused by intense magnetic activity.
Answer:
Moist walls - gases dissolve in the moisture helping them to pass across the gas exchange surface. Permeable walls - allow gases to pass through. Extensive blood supply - ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.
Step 1: Glycolysis. In glycolysis, glucose—a six-carbon sugar—undergoes a series of chemical transformations. In the end, it gets converted into two molecules of pyruvate, a three-carbon organic molecule. In these reactions, ATP is made, and \text{NAD}^+NAD + N, A, D, superscript is converted to {NADH}NADHN, A, D, H.
Step 2:Pyruvate oxidation. Each pyruvate from glycolysis goes into the mitochondrial matrix—the innermost compartment of mitochondria. There, it’s converted into a two-carbon molecule bound to Co-enzyme A, known as acetyl CoA. Carbon dioxide is released and NADH is generated.
Step 3:Citric acid cycle. The acetyl CoA made in the last step combines with a four carbon molecule and goes through a cycle or reaction, ultimately regenerating the four carbon starting molecule.
An environmental scientist might study the effect of soil pollution on plant growth. This is true.
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