General structure and function of biological molecules
Biological Molecules Overview
- Biological molecules are all the substances that are present in living organisms.
- They are formed from simple molecules by chemical reactions, which are controlled by enzymes.
- These molecules make up the structure of cells and perform many of the functions necessary for life.
Proteins
- Proteins are constructed from small building blocks called amino acids.
- There are 20 different types of amino acids, and their sequence is specific to each protein.
- Some proteins are structural, forming part of cells or tissues. Various proteins have a functional role, such as enzymes and hormones.
- The shape of a protein is critical to its function, and changes to the shape can inactivate the protein.
Carbohydrates
- Carbohydrates are made from carbon, hydrogen, and oxygen atoms.
- They come in different forms, including simple sugars (monosaccharides) like glucose, double sugars (disaccharides) like sucrose, and complex sugars (polysaccharides) like starch and cellulose.
- Carbohydrates function as the primary energy source for cellular functions, help in storage and transport of energy, and provide structural support in cells.
Lipids
- Lipids are large molecules made mostly from carbon and hydrogen atoms.
- They include fats, oils, and waxes. Triglycerides, cholesterol, and phospholipids are the most common types of lipids in biology.
- Lipids function as a long-term energy store, provide insulation, protection, and are essential for forming cell membranes.
Nucleic Acids
- Nucleic acids are made up of nucleotides, which are composed of a sugar, a phosphate, and a nitrogenous base.
- Nucleic acids include DNA and RNA, which carry genetic information and are responsible for protein synthesis.
- DNA is a double helix structure and stores and transfers genetic information during cell division, while RNA is typically a single strand that codes, decodes, regulates, and expresses genes.
Water and Inorganic Ions
- Water H2O, an inorganic molecule, is necessary for life, helping in transport, temperature regulation, and chemical reactions.
- Inorganic ions like Na+, K+, Ca2+ and Cl-, are involved in various cellular functions including pH buffering, enzyme activity, water balance, nerve and muscle function.