There are slight differences in the meanings of these terms, but they are often used interchangeably. 1  Independent Variable: It implies causality: the independent variable affects the dependent variable. 2  Used predominantly in ANOVA, but often in regression as well. 3  It can be either continuous or categorical.
Protein Quality. Collagen is not a complete protein because it is lacking in the amino acid tryptophan. A Protein Digestibility Corrected Amino Acid Score (PDCAA) of a complete protein is 1.0.ollagen is a protein found in the muscle and connective tissue of animals. Hydrolyzed collagen protein supplements are typically made from the bones and skin of cows, horses or pigs.
80-90% of collagen in the human body consists of types I, II, and III collagen, although at least 16 different forms of the protein are known. Gram for gram, type I collagen is stronger than steel! Collagen used for medical purposes need not be human collagen. The protein may also be obtained from pigs, cattle, and sheep. Collagen may be applied to wounds to serve as a scaffold on which new cells can form, thus improving healing. Because collagen is such a large protein, it is not absorbed through the skin.