BIOPART2

• covalent bonds - the electrons of an atom are shared. This is the characteristic of most chemicals in living things. During this bond, the smallest particle or the molecule is formed.
• the electrons are shared equally because the two atoms have the same electronegativity—the tug-of-war is at a standoff. Such a bond is called a nonpolar covalent bond
• when an atom is bonded to a more electronegative atom, the electrons of the bond are not shared equally. This type of bond is called a polar covalent bond
• The two resulting oppositely charged atoms (or molecules) are called ions.
• A positively charged ion is called a cation
• while a negatively charged ion is called an anion.
• Because of their opposite charges, cations and anions attract each other; this attraction is called an ionic bond.
• hydrogen bonds are so central to the chemistry of life that they deserve special attention
• Organic molecules are the molecules that always contain carbon and hydrogen and their atoms are usually held together by covalent bonds. These molecules are usually composed of long chains
• There are four major classes of biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids), and each is an important component of the cell and performs a wide array of functions. Combined, these molecules make up the majority of a cell’s mass. In addition, they may contain hydrogen, oxygen, nitrogen, phosphorus, sulfur, and additional minor elements.
• Carbohydrates are the main source of energy in the body. To lose weight, some individuals adhere to “low-carb” diets. Athletes, in contrast, often “carb-load” before important competitions to ensure that they have sufficient energy to compete at a high level.
• Monosaccharides are simple sugars, the most common of which is glucose. In monosaccharides, the number of carbon atoms usually ranges from three to six.
• Glucose – blood sugar or dextrose; the chemical formula for glucose is C6H12O6. In most living species, glucose is an important source of energy
• Fructose – fruit sugar
• Galactose – double sugar
• Galactose – double sugar
• Disaccharides form when two monosaccharides undergo a dehydration reaction (a reaction in which the removal of a water molecule occurs).'
• Lactose – milk sugar: glucose + galactose - Maltose – malt sugar: glucose + glucose - Sucrose – table sugar: glucose + fructose
• Polysaccharides- is also known as the complex sugar. It is A long chain of monosaccharides linked by covalent bonds. The chain may be branched or unbranched, and it may contain different types of monosaccharides. Polysaccharides may be very large molecules
• Starch- stored form of sugars in plants and is made up of amylose and amylopectin (both polymers of glucose).
• Glycogen- is the storage form of glucose in humans and other vertebrates, and is made up of monomers of glucose.
• Cellulose- is one of the most abundant natural biopolymers.
• Lipids are composed of carbon, hydrogen, and oxygen with no definite ratio, the number of oxygen atoms is very much less compared to hydrogen atoms.
• A fat molecule, such as a triglyceride, consists of two main components—glycerol and fatty acids. Glycerol is an organic compound with three carbon atoms, five hydrogen atoms, and three hydroxyl (–OH) groups. Fatty acids have a long chain of hydrocarbons to which an acidic carboxyl group is attached, hence the name “fatty acid.” Fatty acids may be saturated or unsaturated.
• Most unsaturated fats are liquid at room temperature and are called oils
• Phospholipids are the major constituent of the plasma membrane
• steroids have a ring structure. Although they do not resemble other lipids, they are grouped with them because they are also hydrophobic
• Waxes are made up of a hydrocarbon chain with an alcohol (–OH) group and a fatty acid. Examples of animal waxes include beeswax and lanolin
• Proteins are composed of carbon, hydrogen, oxygen, and nitrogen plus other elements such as sulfur, iron, iodine, etc. Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules
• Fibrous Protein - the polypeptides of fibrous protein are arranged parallel along a single axis to produce long fibers or sheets.
• Collagen – the most abundant protein in vertebrates found in bones, cartilage, and skin.
• Keratin – helical protein, principal component of hair, skin and nails
• Fibrinogen – blood plasma responsible for blood clotting
• Muscle proteins – actin and myosin, responsible for muscle contraction
• Silk – pleated sheet protein produced by silk moths and spider
• Globular Protein- the polypeptide of these proteins is tightly folded into spherical or globular shapes
• Albumins and globulins – soluble proteins abundant in animal cells, blood serum, milk, and eggs
• Hemoglobin – the component of vertebrate blood used to transport oxygen.
• Enzymes, antibodies, and hormones
• Conjugated Protein- It is a simple protein in union with other substances. Here are some examples of conjugated protein: - Nucleoprotein – with nucleic acids (ex. histone) - Glycoprotein – with carbohydrates (ex. mucin) - Lipoprotein – with fatty acids (ex. serum and brain tissue) - Chromoprotein – with pigments (ex. cytochrome)