Macromolecules | Biology library | Science | Khan Academy

Tags

Top Highlights

• For example, amino acids such as valine and leucine are nonpolar and hydrophobic, while amino acids like serine and glutamine have hydrophilic side chains and are polar.

• They come in every size, shape, and type you can imagine, and each one has a unique and specific job.

• Proteins are among the most abundant organic molecules in living systems

• is salivary amylase, which breaks amylose (

• Hormones are long-distance chemical signals released by endocrine cells

• insulin is an important peptide hormone that helps regulate blood glucose levels.

• Myosin Carry out muscle contraction

• while collagen, found in our skin, is a fibrous protein.

• Changes in temperature and pH, as well as the presence of certain chemicals, may disrupt a protein’s shape and cause it to lose functionality, a process known as denaturation.

• Amino acids are the monomers that make up proteins.

• the amino group is typically protonated and bears a positive charge, while the carboxyl group is typically deprotonated and bears a negative charge.

• Some amino acids, such as lysine and arginine, have side chains that are positively charged at physiological pH and are considered basic amino acids.

• Aspartate and glutamate, on the other hand, are negatively charged at physiological pH and are considered acidic.

• The amino acids of a polypeptide are attached to their neighbors by covalent bonds known as a peptide bonds.

• Each bond forms in a dehydration synthesis (condensation) reaction. During protein synthesis, the carboxyl group of the amino acid at the end of the growing polypeptide chain chain reacts with the amino group of an incoming amino acid, releasing a molecule of water.

• amino terminus (or N-terminus). The other end, which has a free carboxyl group, is known as the carboxyl terminus (or C-terminus).