ATOMS • Smallest particles unique to each element • Consists of: • Protons • = Atomic Number • Neutrons • = Atomic # - Atomic Mass • Electrons • = Protons
Isotopes • Variant forms of Atoms • Atoms that vary in neutron numbers • Example: • Carbon has 3 • Our body’s cells can use any isotope for metabolic activities • Radioisotopes • Have an unstable nucleus and become more stabilized by spontaneously emitting energy and particles.
Radioisotopes and Cancer • Are used for PET scans to track abnormal cells and their metabolic activity. • Also used in radiation therapy.
Chemical Bonds • Ionic Bonds • Covalent Bonds • Hydrogen Bonds
Ionic Bonds • A bond of 2 or more ions that have opposing charges. • Example: NaCl
Covalent Bonds • Atoms that share a pair of electrons • Can be polar or nonpolar • Example: H2, O2, N2
Hydrogen Bonding • A weak covalent bond between an electronegative atom and a Hydrogen Atom • Example: H20, DNA
Properties of H2O • Hydrogen bond in H20 gives it life-sustaining properties. • Important part of life: • Temperature-stabilizing effects • Cohesion • Capillary Action
pH Scale • Acid = 0-6.9 • Base = 7.1-14 • Neutral = 7 • Based on the concentrations of Hydrogen Ions (H+) & Hydroxide Ions (OH-) • The greater the H+ concentration, the lower the pH
Spicy Food Anyone? • How does an antacid work when we eat spicy food and develop an upset stomach?
Tonight’s Homework • The pH of our blood is between 7.3-7.5. If it declines to 7 it can lead to a coma or if there is an increase in pH (to 7.8) it can lead to tetany.What are different factors that can cause a shift (increase or decrease) in pH in our blood?