MATTER - Solid, Liquid, Gaseous States All Found in the Human Body

Ch 2 - Chemistry Comes Alive

BASIC CHEMISTRY

 MATTER - Solid, liquid, gaseous states – all found in the human body

. ENERGY

. Less tangible, (not mass, fills no space)

. Def: the capacity to do work; or put matter into motion.

. The greater the work done, the more energy used.

Type of Energy:

 Kinetic - Energy in action/motion

. Potential

. Stored energy; inactive energy.

. When potential energy is released it becomes kinetic energy

Forms of Energy

. Chemical energy - ATP (Adenosine triphospate)

. ATP is needed for cellular metabolism in the human body

. Electrical energy

. Results from charged particles (ions).

. Nerve impulses in the nervous system are electrical currents that transmit messages from one part of the body to another.

. Mechanical energy

. Directly involved in moving matter. Like riding a bike or the Stomach’s mechanical digestion

. Radiant energy – electromagnetic - Energy that travels through waves

MOLECULES

. Atoms combined with other atoms

. Compound molecules – 2 or more different6 kinds of atoms bind. Mixtures: solutions, colloids, suspension

. Solution – homogenous mixture of compounds

. Solvent – substance present in greatest amount.

. Solute - the substance present in smallest amount

Colloids – emulsions; a heterogeneous mixture

. Solute particles are larger than those in a solution

. Particles do not settle out. Ex: Cytosol

Suspensions – heterogeneous mixtures with large visible solutes

. Solute particles settle out. Ex: blood & plasma

Chemical Bonds

. Ionic Bonds – form by transferring one or more electrons from one atom to the other.

. Changes the balance of + (cation) or - (anion) charges to form an ion

. Covalent bonds – share the outer electron with the bonded atoms

. Hydrogen bonds – attractions rather than bonds, weakest bond.

. Forms when a H atom (already linked with another atom; N, O2) is attracted by another electron-hungry atom and bridges between Ex: water molecules

Organic compounds - Contain carbon, are covalently bonded, and are often large

Inorganic compounds - Do not contain carbon. Ex: water, salts, and many acids and bases

Properties of Water:

. High heat capacity – absorbs and releases large amounts of heat before changing temperature

. High heat of vaporization – changing from a liquid to a gas requires large amounts of heat

. Polar solvent properties – dissolves ionic substances, forms hydration layers around large charged molecules, and serves as the body’s major transport medium

. Reactivity – important part in hydrolysis and dehydration synthesis reactions

. Cushioning – resilient cushion around certain body organs Characteristics of water polarity

1. Liquid – remains liquid in our bodies

2. Universal solvent – helps facilitate chemical reactions in/out of our bodies

3. Cohesive properties – helps water-base solutions fill blood vessels

Salts: Inorganic compounds

. Contain cations other than H+ and anions other than OH–

. Are electrolytes; they conduct electrical currents

Water and Living Things: Characteristics of water polarity

 Ability to change temperature slowly – prevents drastic changes

 Vaporization – keeping body temperature from overheating

 Ability to freeze – becomes less dense and in weight.

Acid – Base

. Water breaks up (dissociates) equal number of hydrogen (H) and hydroxide (OH) ions

. Acid solutions – release H

. Tomato juice, coffee, vinegar

. Sharp, sour taste associated with indigestion

. Basic solutions – release OH and gain H

. MOM, ammonia, household cleaners & detergents

. Bitter taste, become slippery when wet

. Acid-Base Concentration (pH)

. Necessary to maintain homeostasis

. Acidic solutions have higher H+ concentration and therefore a lower pH

. Alkaline solutions have lower H+ concentration and therefore a higher pH

. Neutral solutions have equal H+ and OH– concentrations

. The pH scale Buffers:

. Are systems that resist abrupt and large swings in the pH of body fluids

. Carbonic acid-bicarbonate system

. Carbonic acid dissociates, reversibly releasing bicarbonate ions and protons

. The chemical equilibrium between carbonic acid and bicarbonate resists pH changes in the blood

. They combine with Hydrogen (H) ions or hydroxide ions (OH) to resist pH changes

. Bicarbonate ions

. Stabilize pH within normal limits

. Take up excess H or OH molecules to resist pH changes

. Ex: Bufferin, shampoos, deodorants

ORGANIC MOLECULES

. Organic Compounds

. Molecules unique to living systems contain carbon and hence are organic compounds

. They include: Carbohydrates; Lipids; Proteins and Nucleic Acids

Organic molecule Structure: The molecules of life always:

. Are important to living organisms

. Always contain carbon and hydrogen

. Macromolecules – a large molecule structure containing many molecules joined together (polymers)

. Simple organic molecule - subunit of a polymer (monomers)

Carbohydrates: functions of carbohydrates

. Principal energy source for cells

. First function for short term energy storage

. Structural components in some cells

. Cell to cell recognition- surface antigens Carbohydrates - Contain carbon, hydrogen, and oxygen

. Their major function is to supply a source of cellular food

. Examples: Monosaccharides or simple sugars; Disaccharides or double sugars; Polysaccharides or polymers of simple sugars

Organic molecules

. Synthesis and degradation reactions in macromolecules

. `Dehydration synthesis

. Links monomers together to form a polymer

. 2 hydrogens and an oxygen removed in the reaction and unite to form water

. Water is also always a byproduct

. Hydrolysis

. Polymer is broken down to monomers

. Water is required to replace 2 hydrogens and the oxygen

Lipids

. Contain C, H, and O, but the proportion of oxygen in lipids is less than in carbohydrates

. Examples:

. Neutral fats or triglycerides

. Phospholipids

. Steroids

. Eicosanoids

. General characteristics of lipids are extremely diverse group of organic molecules:

fats, oils, steroids, waxes, phospholipids

. Common characteristic - nonpolar molecules which are insoluble in water

. Contain more calories of energy per gram so are ideal energy storage molecules

. Also function as structural components, insulation, cushioning of organs, and hormones

. Neutral Fats (Triglycerides) . Composed of three fatty acids bonded to a glycerol molecule

. Other Lipids include: Phospholipids – modified triglycerides with two fatty acid groups and a phosphorus group

. Lipids are broken down by Emulsification. Bile is an emulsifier

Fats are nonpolar; they do not dissolve in water and tend to form “globules” (oil and vinegar dressing)

Emulsifier breaks down the globules of fat into smaller droplets

Emulsifiers have a nonpolar end which attaches to the fat, and a polar end which interacts with water molecules so that the droplets can disperse

Other Lipids:

. Steroids – flat molecules with four interlocking hydrocarbon rings

. Eicosanoids – 20-carbon fatty acids found in cell membranes

. Representative Lipids Found in the Body

. Neutral fats – found in subcutaneous tissue and around organs

. Phospholipids – chief component of cell membranes

. Steroids – cholesterol, bile salts, vitamin D, sex hormones, and adrenal cortical hormones

Representative Lipids Found in the Body

. Fat-soluble vitamins – vitamins A, E, and K

. Eicosanoids – prostaglandins, leukotrienes, and thromboxanes

. Lipoproteins – transport fatty acids and cholesterol in the bloodstream

Amino Acids

. Building blocks of protein, containing an amino group and a carboxyl group

. Amino group (NH2)) and Carboxyl groups COOH

Protein - are Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds

. Structural Levels of Proteins

. Primary – amino acid sequence

. Secondary – alpha helices or beta pleated sheets . Tertiary – superimposed folding of secondary structures

. Quaternary – polypeptide chains linked together in a specific manner

The Structural Levels of Proteins are: Fibrous and Globular Proteins

. Fibrous proteins

. Extended and strand-like proteins

. Examples: keratin, elastin, collagen, and certain contractile fibers

. Globular proteins

. Compact, spherical proteins with tertiary and quaternary structures

. Examples: antibodies, hormones, and enzymes

. Functions of Protein:

. Keratin – builds hair, nails and collagen

. Hormones – cellular metabolism

. Actin & myosin – movement of cells and muscular contractility

. Hemoglobin – transports oxygen in blood

. Antibodies – bind foreign subtances to prevent the destruction of cells

. Enzymes – speed up chemical reactions in the body

Protein Denuaturation

. The final shape of a protein molecule is often critical to its function

. Extreme exposure of heat and pH can change the shape of the protein molecule.

. Denaturation = irreversible change in shape

. Reversible unfolding of proteins due to drops in pH and/or increased temperature

. Irreversibly denatured proteins cannot refold and are formed by extreme pH or temperature change

. Once protein loses its normal shape it become dysfunctional

Characteristics of Enzymes

. Most are globular proteins that act as biological catalysts . Holoenzymes consist of an apoenzyme (protein) and a cofactor (usually an ion)

. Enzymes are chemically specific

. Frequently named for the type of reaction they catalyze

. Enzyme names usually end in -ase

Nucleic Acids

. Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus

. Their structural unit, the nucleotide, is composed of N-containing base, a pentose sugar, and a phosphate group

. Five nitrogen bases contribute to nucleotide structure – adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U)

. Two major classes – DNA and RNA

Deoxyribonucleic Acid (DNA)

. Double-stranded helical molecule found in the nucleus of the cell

. Replicates itself before the cell divides, ensuring genetic continuity

. Provides instructions for protein synthesis

. Structure of DNA

. Ribonucleic Acid (RNA)

. Single-stranded molecule found in both the nucleus and the cytoplasm of a cell

. Uses the nitrogenous base uracil instead of thymine

. Three varieties of RNA: messenger RNA, transfer RNA, and ribosomal RNA

Adenosine Triphosphate (ATP)

. Source of immediately usable energy for the cell

. Adenine - containing RNA nucleotide with three phosphate groups