IG

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