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Free radical formed by radiation, chemicals, ATP-producing oxidation reactions in mitochondria, and white blood cells use to kill bacteria. Mutations in mitochondrial DNA have been linked with certain genetic diseases including a form of young adults blindness, and different type of muscle degeneration. Mitochondria affect health and aging by leaking electrons. These electrons form free radicals, which are toxic, highly reactive compounds that have unpaired electrons. These electrons bond with other compounds in the cell, interfering with normal function. If DNA in mitochondria repeatedly been damaged it looses ability to fix so over time, damage in DNA causing the organism to age and cell to die. Once the DNA of the cell changed, the mutation of the cell occurs. Free radicals damage many molecule and whole chain reaction. Free radicals damage the cell, enzymes, blood lipoprotein, unsaturated fatty acids in the cell membranes, DNA, RNA, cellular organelles, proteins which leads to development of disease. These types of damage reflecting on the function and health of the cell. The damage leads to some type of cancer, myocardial infarction, aging, death of heart tissue that leads to heart attack/disease, Alzheimer's disease, Parkinson's disease, sterility, muscular dystrophy, and many other disorders. Some severe free radicals (hydroxyl radicals) can damage all types of macromolecules such as lipids that makeup cell walls, amino acids, carbohydrates, and nucleic acids. Antioxidants neutralize free radicals.
A solution may be acid, basic (alkaline), or neutral in its chemical properties. This characteristic of a solution depends on its hydrogen ion (H+) concentration, and is measured by its pH. The pH scale extends from a pH of 0 (strongly acid) to a pH of 14 (strongly alkaline, or basic). A pH of 7 represents a neutral condition (neither acid nor basic). Pure water has a pH of 7. Acids have less than 7. Acid have a pH less than 7. Bases have a pH greater than 7. The solution with pH3 is moderately acidic and solution with pH6 is slightly acidic, the acidity is decreasing toward pH6. An acid is a substance that dissociates in solution to yield hydrogen ions (H+) and an anion. An acid is a proton donor. An acids solution has a hydrogen ion (H+) concentration that is higher than its hydroxide ion concentration.
Hydrogen ion concentration are almost always less than 1mol/L. One gram of hydrogen ions dissolved in 1L of water (a 1M solution).
Dehydration synthesis can link similar units into long chains called polymers. Carbohydrates made of many sugar units joined together into long chains of repeating units of simple sugar are called polysaccharides. Polysaccharides composed of different isomers and the units can be arranged differently, polysaccharides vary in their properties. Polysaccharides consist of many sugar units linked by glycosidic bonds, e.g., glycogen, cellulose. Starches, glycogen and cellulose are polysaccharides. Starches are formed of thousands of glucose units, and they are serving as a storage form for carbohydrates. They are energy storage of plant cells. The cell walls of plants are composed mainly of the polysaccharide cellulose. Carbohydrates are stored in plants as starch and in animals as glycogen.
Starches form of carbohydrate used for energy storage in plants, is a polymer consisting of ï¡-glucose subunits. These monomers are joined by ï¡ 1-4 linkages, which means that carbon 1 of one glucose is linked to carbon 4 of the next glucose in the chain. Starches occurs in two forms: amylose (unbranched) and amylopectin (consists of about 1000 glucose units in a branched chain). Plant cells store starch as granules within specialized organelles called amyloplasts. When energy is needed for cellular work, the plant can hydrolyze the starch, releasing the glucose subunits. Humans and other animals that eat plant foods have enzymes to hydrolyze starch.
Glycogen is the form in which glucose is stored as an energy source in animal tissues. It is branched, more water-soluble and has similar structure to a plant starch. Glycogen is stored mainly in liver and muscle cells.
Cellulose is an insoluble polysaccharide composed of many glucose molecules joined together. The bonds joining these sugar units are different from those in starch. Cellulose contains ï¢-glucose monomers joined by ï¢ 1-4 linkages. These bonds cannot be split by the enzymes that hydrolyze the ï¡ linkages in starch. The ï¢-glucose subunits are joined in a way that allows extensive hydrogen bonding among different cellulose molecules. Humans don't have enzymes that can digest cellulose therefore can't use it as a nutrient. Cellulose helps keep the digestive tract functioning properly. Some microorganisms can digest cellulose to glucose.
The atoms of a compound are held together by forces of attraction (chemical bonds). Each bond represents a certain amount of chemical energy. Bond energy is the energy necessary to break a chemical bond. The valence electrons dictate how many bonds an atom can participate in. Tetrodotoxin molecule consist of covalent bonds. This covalent bonds involve the sharing of electrons between atoms in a way that results in each atom having a filled valence shell. Tetrodotoxin molecule has one double covalent bond between carbon and nitrogen, and the rest of the atoms connected by single covalent bonds. These bonds consist of an electron pair shared between two non-metal atoms. To understand the stability of the electron-pair bond, we plot the energy of interaction between two atoms as a function of distance. A pair of electrons shared between two atoms in the covalent bond. A two atoms (C=N) share two electron pairs creating a double covalent bond, and single electron pair is shared between two bonded atoms (C-C, C-N, N-H, C-O, C-H, O-H) creating a single covalent bond. When one pair of electrons is shared between two atoms, the covalent bond is referred to as a single covalent bond. Single covalent bond is the joining of two carbons. In two bonded atoms such as C-C, carbon atom has four electrons in its valence shell, all of which are available bonding. Two electrons are required to complete its valence shell. The carbon atoms have equal capacities to attract electrons, so neither donates an electron to the other. Two carbons atoms share their single electrons to that each of the two electrons is attracted to the two protons in the two carbon nuclei. In two bonded atoms such as O-H, oxygen atom has six electrons in its valence shell and hydrogen has one. They share their single electrons to form a covalent bond, hydrogen atom covalently bonded to a oxygen atom. In two bonded atoms such as C-H, carbon atom has four electrons in its valence shell, all of which are available bonding and hydrogen has one electron. Two electrons are required to complete its valence shell. They share their single electrons to form a covalent bond, hydrogen atom covalently bonded to a carbon atom. In two bonded atoms such as C-O, carbon atom has four electrons in its valence shell, all of which are available bonding and oxygen has six electrons. Two electrons are required to complete its valence shell. They share their single electrons to form a covalent bond, oxygen atom covalently bonded to a carbon atom. In two bonded atoms such as C-N, carbon atom has four electrons in its valence shell, all of which are available bonding and nitrogen has five electrons. Each orbital can hold a maximum of two electrons. Usually two electrons occupy one orbital, leaving three available for sharing with other atoms. Two electrons are required to complete its valence shell. They share their single electrons to form a covalent bond, nitrogen atom covalently bonded to a carbon atom. In two bonded atoms such as N-H, nitrogen atom has five electrons in its valence shell, all of which are available bonding and hydrogen has one electron. Two electrons are required to complete its valence shell. They share their single electrons to form a covalent bond, hydrogen atom covalently bonded to a nitrogen atom. Two (C=N) atoms may achieve stability by forming covalent bonds with one another. Carbon atom has four electrons in it is outer shell and nitrogen has five electrons. To become stable, the two atoms share two pairs of electrons, forming a double covalent bond.
In covalent bond between two different elements, such as (C-N, N-H, C-O, O-H), the electronegativities of the atoms may be different. Electrons are pulled closer to the atomic nucleus of the element with the greater electron affinity, for example in O-H oxygen has greater electron affinity. A covalent bond between atoms that differ in electronegativity is called a polar bond. This bond has two dissimilar ends, one with a partial positive charge and the other with a partial negative charge. In O-H, partial positive charge at the hydrogen end of the bond and a partial negative charge at the oxygen end, oxygen electronegative and forms covalent bond with hydrogen. When covalently bound atoms have similar electronegativities such as (C-C, C-H), the electrons are shared equally, and the covalent bond is nonpolar. Covalent bonds are known also as a strong bonds because of their strength.
A sodium atom has one electron in its valence shell. It cannot fill its valence shell by obtaining seven electrons from other atoms, for it would then have a large unbalanced negative charge. It gives up its single valence electron to a very electronegative atom, for example a nonmetal which acts as an electron acceptor. When a metal such as sodium (Na) reacts with a nonmetal, sharing one electron with nonmetal in order to make a covalent bond, the product is usually an ionic compound (sodium ion is Na+). Sodium has 11 (atomic number 11) protons and 11 electrons. With a sodium ion, there is one less electron. The Na+ ion has 11 protons and 10 electrons. When sodium reacts with nonmetal, sodium's valence electron is transferred completely to nonmetal. Sodium becomes a cation, with one unit of positive charge (Na+). A sodium ion has one less valence (outer) electron in its valence shell, Na+ means that the sodium atom has lost 1 negative charged electron, therefore it has a positive charge. The electron configuration of sodium ion is 11Na+: 1s22s22p6.