CHEMISTRY

@@Atoms:@@

==Matter== is made up of ==atoms==

Atoms join together to from chemicals

==Proton=== positive charge, 1 mass unit

==Neutron=== neutral, 1 mass unit

==Electron=== negative charge, low mass

Atomic Structure

• Atomic number= number of protons

• Mass number= number of protons plus neutrons

• Nucleus contains protons and neutrons

• Electron cloud contains protons

  neutrons= atomic mass - atomic

==Elements==- determined by atomic number of atoms

• Atomic number= number of protons

==Isotopes==- a version of an element based on its mass number

• Mass number= number of protons plus the number of neutrons
• Only neutrons are different because number of protons determines the element

Atomic Weights= Average of the mass numbers of the isotopes

Electrons and Energy Levels

Electrons determine the ==reactivity== of an atom

The electron cloud contains ==shells==, or energy levels that hold a maximum number of electrons

• Lower shells first
• Outermost shell is the valence ==shell==, and it determines bonding
• The number of electrons per shell corresponds to the number of atoms in that row of the ==periodic table==

@@Bonds:@@

Ionic Bonds

• One atom loses one or more electrons and becomes a cation, with a positive charge
• Another atom gains those same electron and becomes an anion, with a negative charge
• Attraction between the opposite charges then draws the two ions together

Covalent Bonds- the sharing of pairs of electrons between atoms

One electron is donated by each atom to make the pair of electrons

Sharing one pair of electrons is a single covalent bond

• sharing two pairs= double covalent bond
• sharing three pairs= triple covalent bond

==Nonpolar covalent bonds==- equal sharing of electrons because of equal pull for the electrons

==Polar covalent bonds==- unequal sharing of electrons because one atom has a disproportionately strong pull on the electrons forming ==polar molecules==- like water

Hydrogen Bonds are bonds between adjacent molecules, not atoms

Involve slightly positive and slightly negative portions of polar molecules being attracted to one another

==Hydrogen bonds== between H2O molecules cause surface tension

@@Importance of Water:@@

water- two-thirds of total body weight

==solubility==- water’s ability to dissolve a ==solute== in a ==solvent== to make a ==solution==

==reactivity==- most body chemistry occurs in water

==high heat capacity==- water’s ability to absorb and retain heat

==lubrication==- to moisten and reduce friction

==pH==- concentration of hydrogen ion (H+) in a solution

==Neutral pH== is a balance of H+ and OH-

• pure water=7.0

==pH of human blood== ranges from 7.35 to 7.45

==Acidic==- pH lower than 7.0

==basic== (or alkaline)- pH higher than 7.0

==pH Scale==- more than H+ ions mean lower pH, less H+ ions mean higher pH

@@Organic Molecules:@@

Contain H, C, and usually O

Covalently bonded

Carbohydrates

Carbohydrates contain carbon, hydrogen, and oxygen ina 1:2:1 ratio

==Monosaccharides==

Simple sugars with 3 to 7 carbon atoms

Glucose, fructose, galactose= C6H12O6

• glucose= sugar in blood
• fructose= fruits
• galactose= milk

==Disaccharides==

Two simple sugars condensed by dehydration synthesis

Sucrose, maltose, lactose= C12H22O11

Sucrose- table sugar (sugar cane)

• glucose + fructose= sucrose

maltose- malt sugar (from grains)

• glucose + glucose= maltose

lactose- milk

==Polysaccharides==

Glucose molecules condensed by dehydration synthesis

Glycogen, starch, cellulose

• glycogen- stored animal starch in liver + muscles
• starch- food for embryonic seed or to store glucose
• cellulose- plant cell walls + provides fiber

@@Lipids:@@

Mainly hydrophobic molecules such as fats, oils, and waxes

Made mostly of carbon and hydrogen atoms

==Fatty Acids==

Long chains of a carbon and hydrogen with a carboxylic acid group (COOH) at one one end

Fatty acids may be

• ==Saturated== with hydrogen (no double covalent bonds)
• ==Unsaturated== (one or more double bonds):

1. monounsaturated= one double bond
2. polyunsaturated= two or more double bond

==Prostaglandins==- local hormones, short- chain fatty acids

==Triglycerides==- three fatty-acid tails attached to a glycerol molecule

• Functions: energy source, insulation, protection

==Steroids==

• Four rings of carbon and hydrogen with an assortment of functional groups
• Types of steroids:

1. Cholesterol is a component of plasma (cell) membrane
2. Estrogens and testosterone are sex hormones
3. Corticosteroids and calcitriol function in metabolic regulation
4. Bile salts are derived from steroids

==Phospholipids==

• a fatty acid, a phosphate group & a glycerol molecules
• components of plasma (cell) membranes

==Proteins== most abundant and important organic molecules

Contain basic elements CHON

Basic building blocks are 20 amino acids

List seven major protein functions:

• Coordination + Control
  • hormones ex. adrenaline
• Defense
  • antibodies
  • identify bacteria/ viruses then alert white blood cells
• Support
  • structural proteins
  • keratin(hair/nails) + collagen(nail)
• Movement
  • contractile proteins
  • actin(act thin) + myosin(me me me)
• Transport
  • transport(carrier) proteins
  • hemoglobin
• Buffering
  • regulation of pH
• Metabolic Regulation
  • enzymes ex. sucrase, lactase

Lipids provide 2x more energy than protein

Anything w/ nitrogen is probably protein

Protein structure= long chains of amino acids

Amino Acid Structure-

• central carbon atom
• hydrogen atom
• amino group(-NH2)
• carboxylic acid group(-COOH)
• variable side chain or “R” group

Enzymes=catalysts

• Proteins lower the activation energy of a chemical reaction, are not changed or used up in the reaction, and are specific- will only work on limited types of substrates

Denaturation= change in shape due to heat or pH

Nucleic acids store + process information at the molecular level

• Deoxyribonucleic Acid (DNA) determines inherited characteristics, directs protein synthesis, controls enzyme production, and controls metabolism
• Ribonucleic Acid (RNA) controls intermediate steps in protein synthesis

Structure of Nucleotides:

• a sugar(deoxyribose or ribose)
• phosphate group
• nitrogenous base (A,G, T, C, or U)

DNA= double stranded, and the bases form hydrogen bonds to hold the DNA together

RNA usually a single strand

DNA forms a twisting double helix

Purines pair with pyrimidines

• DNA:
  • adenine(A) and thymine(T)
  • cytosine(C) and guanine(G)
• RNA:
  • uracil(U) replaces thymine(T)

Types of RNA:

• messenger RNA (mRNA)
• transfer RNA (tRNA)
• ribosomal RNA (rRNA)

Nucleotides can store energy

• Adenosine diphosphate (ADP) di-=2
• Adenosine triphosphate (ATP) tri-=3

Adding a phosphate group to ADP with a high-energy bond to form a high-energy compound

Red blood cells don’t have a nucleusc