Protein structure is the three-dimensional arrangement of atoms in a protein molecule. Proteins are polymers — specifically polypeptides — formed from sequences of amino acids, the monomers of the polymer. A single amino acid monomer may also be called a residue (chemistry) indicating a repeating unit of a polymer. Proteins form by amino acids undergoing condensation reactions, in which the amino acids lose one water molecule per reaction in order to attach to one another with a peptide bond. By convention, a chain under 30 amino acids is often identified as a peptide, rather than a protein.[1] To be able to perform their biological function, proteins fold into one or more specific spatial conformations driven by a number of non-covalent interactions such as hydrogen bonding, ionic interactions, Van der Waals forces, and hydrophobic packing. To understand the functions of proteins at a molecular level, it is often necessary to determine their three-dimensional structure. This is the topic of the scientific field of structural biology, which employs techniques such as X-ray crystallography, NMR spectroscopy, and dual polarisation interferometry to determine the structure of proteins.
Protein structures range in size from tens to several thousand amino acids.[2] By physical size, proteins are classified as nanoparticles, between 1–100 nm. Very large aggregates can be formed from protein subunits. For example, many thousands of actin molecules assemble into a microfilament.
A protein may undergo reversible structural changes in performing its biological function. The alternative structures of the same protein are referred to as different conformational isomers, or simply, conformations, and transitions between them are called conformational changes.
Answer:
Four (4) cells
Explanation:
Meiosis is the type of cell division in which four daughter cells that are genetically different is produced. The daughter cells are gametes that have undergone a reduction in their chromosome number (by half).
For example, one cell of an oak tree with 14 chromosomes is said to undergo meiosis. This means that, based on the explanation of meiosis above, the oak cell will give rise to four (4) daughter cells containing 7 chromosomes each.
14. compound
15. the concentration cannot be increased.
16. heterogenous mixtures
17. chocolate chip cookies
18. vegetable soup
19. a mixture is a pure substance a compound is not
20. Tastes sour
Answer:
all are true
Explanation:
this is because middle ear start from the ear drum,,,and all those are associated with ear ossicles.
