Living and nonliving things are all made of elements. It is the way that atoms combine that give every element a different characteristic. 98% of the body is made of only 6 elements
The 6 elements are: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and Sulfur (CHNOPS) Elements are made of atoms. Atoms are the building blocks of all matter..
ATOMIC STRUCTURE The center of an atom is called the nucleus. Inside the nucleus are positively charged particles called protons. There are also particles with no charge, called neutrons. Outside the nucleus are negatively charged particles called electrons.
Each atom has equal number of protons & electrons. No net charge. ISOTOPES Atoms of the same element can have different numbers of neutrons. These atoms are called isotopes. Isotopes are useful to scientists because they break down & their radiation is detectable, and can be used as a diagnostic tools. Ex. Iodine is used to measure the thyroid's activity.
Molecules and compounds A compound is a substance composed of 2 or more different elements combined. When elements combine they do so to gain stability. They can share electrons with another element or compound and give away electrons
Ionic Bonds When atoms gain or lose electrons it becomes an ion. The attractive force between 2 ions of opposite charge is called an ionic bond. Ex. NaCl: Sodium Chloride, too much causes Hypertension Ca +2, K +1, Mg +1, P, Fe +2 are other ions you'll hear about
Covalent Bonds When 2 atoms share electrons. Most compounds in organisms covalent bonds. A molecule is a group of atoms held together by covalent bonds. Water is the most important Inorganic Molecule
Water is most abundant molecule 60-70% of the body weight Water is polar, has + - ends like a magnet.
Characteristics of water Cohesive, fills vessels Absorbs heat for cooling Since water is polar, it is a good solvent- helps facilitate reactions in the cells. NaCl, acids and bases dissociate in water (break apart) These are called
Acids, Bases, and ph Equal numbers of positive and negative ions are produced which makes water neutral. The ph scale indicates the concentration of H+ ions. The scale ranges from 0-14. Pure water has a ph of 7.
ph scale
Each step on the ph scale is a factor of 10. 1.5 Stomach acid; 2.5 lemon juice; 4.5 Acid rain. 6 normal rainfall; 8.5 sea water; 10 Soap; 12.5 bleach Solutions with a ph below 7 on the scale are acids. They have higher concentrations of H+ ions in solution. Solutions with a ph above 7 are called bases because they have more OH- ions that H+
Blood has a ph of 7.4 Buffer: is a weak acid or base that can react to sudden changes in ph. Acidosis:Blood ph below 7.35 Alkalosis: Blood ph above 7.45 A person usually cannot survive if the ph drops to 6.9 or rises to 7.8 for more than a few hours.
Part 2: Organic molecules All contain carbon which create the skeleton for biomolecules (carbs, lipids, proteins and nucleic acids) Carbon can also bond with other carbon atoms to form long chains. These carbon-carbon bonds can be single, double, or triple covalent bonds.
CARBOHYDRATES Sugars & Starches Energy Rich Also used for storage purposes Contains C, H, O 1:2:1 ratio of C:H:O End in ose Ex. Glucose C6H12O6 Simple sugars are monosaccharides like glucose, galactose, and fructose.
Condensation vs Hydrolysis Water is taken away to build larger molecules-->condensation synthesis Water is added to break apart large molecules---> Hydrolysis.
The large carbs formed from monosaccharides are either disaccharides (2 monosaccharides) like maltose or polysaccharides (glycogen, starch and cellulose) Glycogen is stored formed of glucose in the liver of humans. The liver releases glucose so that the blood levels are.1%. If the blood contains more glucose it spills over into the urine indicating diabetes may exist. Starch and cellulose are in plants
LIPIDS Contain mostly C, H, O H ratio is larger than 2:1 3 Fatty Acids & 1 Glycerol Saturated: No double bonds Unsaturated: Double bonds, found in veg. oil Stored energy Phospholipids are found in cell membranes. Polar head and tails Steroids are also lipids
PROTEINS Hair, nails, muscles, some act as enzymes Contain C, H, O, N, and possibly S. Composed of Amino Acids by condensation synthesis 4 shapes
ENZYMES The energy that is needed to get a reaction started is called activation energy. Enzymes decrease activation energy. Complex proteins Increase the rates (speed) of reactions. Biological catalyst. End in -ase
Proteins can have up to 4 levels or organization 1. The sequence of amino acids in a protein chain (primary) 2. The amino acids in a chain twist like a helix or bend like a pleat (Secondary) 3. The chain itself is folded (Tertiary) van der waals and H bonds help to form globular proteins. 4. A protein that is assembled from 2 or more separate chain (Quaternary)
NUCLEIC ACIDS Contain H,O,N,C,P Compose of strands of nucleotides Store and transmit genetic information. 2 kinds:(dna) and (RNA) RNA contains the sugar ribose DNA contains the sugar deoxyribose.
ATP Has high energy phosphate bonds. Used for synthetic reactions, nerve impulses, muscle contractions. The energy needed to rebuild ATP comes from glucose metabolism.
Chemical Reactions Take place when bonds are formed and broken. REMEMBER: All the chemical reactions that occur within an organism are called metabolism.
Enzyme movie clip