Chemistry of Living Things Chapter 2 Chemistry of Living Things

Terms Chemistry Matter Energy

Atoms Atom Subatomic particles Isotopes and radioactive isotopes Smallest piece of an element Subatomic particles Protons Neutrons Electrons Isotopes and radioactive isotopes

Figure 2-1 Structure of an atom Figure 2-1 Structure of an atom. Eight protons and eight neutrons are tightly bound in the central nucleus, around which the eight electrons revolve.

Scans CAT scan or CT scan MRI PET scan Bone, liver, brain, and spleen scans Sonography or ultrasound Mammograms (Chapter 21)

Watch “How an MRI works” on you tube

Terms Elements Compounds Molecules

Chemical Bonds Ionic bond Covalent bond Hydrogen bond One atom gives up an electron to another atom Covalent bond The atoms share electrons Hydrogen bond Helps hold water molecules together Weak bonds

Figure 2-2 Ionic bond. In this figure the Na+ atom gives up an electron to the Cl- atom to form an ionic bond.

Electrolytes Electrically charged particles that help determine fluid and acid-base balance Can conduct an electrical charge Make it possible for materials to be broken down, altered and recombined to from new substances or compounds

Types of Compounds Inorganic compounds Organic compounds Normally do not contain carbon Water is 55–65% of their weight ● universal solvent Organic compounds Found in living things Always have carbon Four main groups are carbohydrates, lipids, proteins and nucleic acids

Inorganic http://study.com/academy/lesson/what-are-inorganic-compounds-definition-characteristics-examples.html

Organic Compounds Carbohydrates Lipids Proteins Nucleic acids

Table 25.1.1: General Contrasting Properties and Examples of Organic and Inorganic Compounds Hexane    Inorganic NaCl low melting points −95°C high melting points 801°C low boiling points 69°C high boiling points 1,413°C low solubility in water; high solubility in nonpolar solvents insoluble in water; soluble in gasoline greater solubility in water; low solubility in nonpolar solvents soluble in water; insoluble in gasoline flammable highly flammable nonflammable aqueous solutions do not conduct electricity nonconductive aqueous solutions conduct electricity conductive in aqueous solution exhibit covalent bonding covalent bonds exhibit ionic bonding ionic bonds

Carbohydrates (CHO) Elements Monosaccharides Disaccharides Carbon, hydrogen, and oxygen Monosaccharides Simple sugars, e.g., glucose Disaccharides Two monosaccharide molecules, e.g., sucrose Polysaccharides Complex molecules e.g., starch

Lipids Elements Fats Phospholipids Steroids Carbon, hydrogen, and oxygen, contain much less oxygen than CHO Fats Phospholipids Steroids

Proteins Elements Most diverse and essential organic compounds Carbon, hydrogen, oxygen, and nitrogen; and often, phosphorus and sulfur Most diverse and essential organic compounds Found in every living part of a living cell Amino acids Essential and non-essential

Enzymes Specialized protein molecules Found in all living cells Help control chemical reactions Provide energy for cellular functions Organic catalysts Highly specific in their actions

Nucleic Acids Organic compounds containing carbon, oxygen, hydrogen, nitrogen, and phosphorus Structure of nucleic acids Largest known organic molecules Made up of smaller subunits called nucleotides DNA Deoxyribonucleic acid RNA Ribonucleic acid

Figure 2-5 Schematic of DNA

Acids Sour taste When dissolved in water, will ionize into positively charged hydrogen ions (H+) and negatively charged ions of some other element or more simply … Yields hydrogen ions (H+) in solution Litmus paper testing

Bases Bitter taste Also called alkali When dissolved in water, will ionize into negatively charged hydroxide (OH-) and positively charged ions of a metal Litmus paper testing

Neutralization and Salts Exchange reaction Acid + base = salt + water HCL + NaOH = NaCL + H2O

pH Scale Measure of acidity or alkalinity (basicity) Ranges from 0 to 14 pH of 7.0 = neutral pH 0-6.9 = acid pH 7.1-14 = alkaline (basic)

Homeostasis Homeostasis is essential for living cells to function optimally Maintenance of a balanced pH Through a compound called a buffer (NaHCO3) pH of blood is 7.35–7.45 Intracellular and extracellular fluids