The four levels of protein structure are distinguished from one another by the degree of complexity in the polypeptide chain. A single protein molecule may contain one or more of the protein structure types: primary, secondary, tertiary, and quaternary structure. 1. Primary Structure: describes the unique order in which amino acids are linked together to form a protein.
2. Secondary Structure: refers to the coiling or folding of a polypeptide chain that gives the protein its 3-D shape. There are two types of secondary structures observed in proteins. One type is the alpha (α) helix structure. This structure resembles a coiled spring and is secured by hydrogen bonding in the polypeptide chain. The second type of secondary structure in proteins is the beta (β) pleated sheet. This structure appears to be folded or pleated and is held together by hydrogen bonding between polypeptide units of the folded chain that lie adjacent to one another
3. Tertiary Structure: refers to the comprehensive 3-D structure of the polypeptide chain of a protein.
4. Quaternary Structure: is the structure of a protein macromolecule formed by interactions between multiple polypeptide chains. Each polypeptide chain is referred to as a subunit. Proteins with quaternary structure may consist of more than one of the same type of protein subunit.
En 1990 se inauguró definitivamente el Proyecto Genoma Humano calculándose quince años de trabajo. Sus objetivos principales en una primera etapa eran la elaboración de mapas genéticos y físicos de gran resolución, mientras se ponían a punto nuevas técnicas de secuenciación, para poder abordar todo el genoma.
Dame corazón porfis
Answer:
A) produces offspring genetically identical to the parent
Explanation:
DNA replication is said to be semi-conservative because of this process of replication, where the resulting double helix is composed of both an old strand and a new strand. ... Semiconservative replication would produce two copies that each contained one of the original strands and one new strand.
I believe the answer to this question is a food web.
Food Web definition: "<span>a series of organisms related by predator-prey and consumer-resource interactions; the entirety of interrelated food chains in an ecological community."
Source: </span>http://www.dictionary.com/browse/food-web
