Chapter 2 - Chemistry Comes Alive

1
Chapter 2 - Chemistry Comes Alive

• Part 1 Basic Chemistry
• I. Matter and Energy
• A. Matter
• 1. Definition anything that has mass and takes
  up space (mass amount of matter). Occupies
  space, has mass, composed of elements.
• 2. States of matter
• a. Solid
• b. Liquid
• c. Gas

2

• B. Energy
• 1. Kinetic energy energy in action moves
  objects
• 2. Potential energy stored or inactive has
  capability to do work dammed water, a battery,
  you being a couch potato
• 3. Forms of Energy
• a. Chemical stored in bonds ATP is cellular
  energy, when bonds are broken, energy is
  released(potential--gt kinetic) for cellular work
• b. Electrical movement of charged particles
  ions moving across cell membranes generate
  electrical currents in your body nerve impulses
  transmit messages, etc.
• c. Mechanical directly involved in moving
  matter legs when you walk
• d. Radiant or electromagnetic travels in
  waves visible light, ultraviolet and infrared
  waves, radio waves, X rays
• 4. Energy can be converted from one form to
  another but not destroyed conversions are
  inefficient (e.g. 40 of cellular energy
  converted to heat)

3
(No Transcript)
4
II. Composition of Matter Atoms and Elements

• A. Terminology
• 1. Elements The simplest kind of matter.
  Elements are the building blocks of matter that
  cannot be broken down into simpler substances.
  112 elements
• a. C, H, O2,N, make up 96 of body weight 20
  others in trace amts.
• b. Periodic table complete list of the
  elements
• c. These elements bind to form molecules. To
  understand one element from another and how they
  combine to form molecules, we must look at atoms.
• 2. Atoms All elements are composed of atoms,
  the smallest particles of matter.
• 3. Atomic symbol see periodic table in
  Appendix D, p.1171

5

• B. Atomic Structure
• 1. Nucleus protons and neutrons
• a. Protons positive charge
• b. Neutrons neutral charge
• c. Each has a mass of 1 atomic mass unit
• 2. Electrons negative charge mass of 0
• 3. Hydrogen has 1 proton and 1 electron,

6

• C. Elements and Atoms
• 1. Atomic number number of protons in the
  nucleus subscript to left (e.g. 1H, 2He) note
  that an atom usually has an equal number of
  protons and electrons giving it an overall
  electrical charge of zero.
• 2. Atomic mass number add protons and neutrons
  (mass of electrons ignored because it is so
  small)
• 3. Isotopes atoms of an element with
  different numbers of neutrons. (2H) isotope of
  hydrogen. An atom that gains or loses neutrons
  becomes an isotope of the same element

7
OK

• 1. Which element has 30 protons?
• 2. How many electrons does one atom of sodium
  have?
• 3. What is the atomic mass of nitrogen?

8

• 1. Zink
• 2. Na has 11 electrons
• 3. Atomic Mass 14

9
H
Atomic number ----------- number of protons
1
Hydrogen
-----Name
Symbol----------
1.0
-----Atomic mass mass Of protons and neutrons
10

• D. Radioisotopes
• 1. Isotopes are important in biology because
  some are unstable and emit energy. These
  unstable isotopes are called radioisotopes and
  the energy they emit is called radiation.
• 2. Both artificial and natural radioisotopes
  have medical uses such as diagnosis imaging, and
  treatment of cancer called nuclear medicine.
• 3. Types of radiation emissions
• a. Alpha radiation lowest penetrating power
  (ie radon)
• b. Beta radiation electron-like particles
• c. Gamma rays high energy waves rather than
  particles. X-rays are similar to gamma radiation
  penetrate more deeply.

11
II. How Matter is Combined

• A. Molecules and Compounds most atoms are
  combined
• Molecules two or more atoms of the same element
  held by chemical bonds Examples include H2, S8
• Compound two or more different atoms bind in a
  definite ratio by chemical bonds
• H20

12
B. Solutions

• a. Solvent present in greatest quantity
  Example is water the bodys solvent
• b. Solutes substances that dissolve in liquid
• c Concentration of Solutions described as the
  percent (parts per 100parts) of the solute in
  solution or molarity - (moles per liter, M)
• d. Molarity a mole (M) is equal to the sum of
  the atomic weights one-molar solution weighs
  this number of grams and dissolves in one liter
  of water (moles per liter).
• e. Solubility ability to dissolve in water

13

• C. Mixtures vs. Compounds
• No chemical bonds in mixtures
• Mixtures can be separated by physical means
  (strain, filter, evaporate)
• Compounds are homogeneous, mixtures are not
  united in definite ratios. A cake mixture for
  example. Separated by chemical means.

14
IV. Chemical Bonds

• A. Electrons Chemical Bonding
• 1. Electron shells - cloud around the nucleus
• a. 1 - 7 shells
• b. Each shell represents a different energy
  level with electrons farthest from the nucleus
  having the most potential energy and are most
  likely to interact with other atoms

15

• 2. Filling of Shells
• a. Valence outermost energy level containing
  chemically reactive electrons
• b. Rule of eights atoms like to have 8
  electrons in valence shell
• c. Chemically inert substances are not reactive
  because valence shell has 8 electrons. Paired
  electrons are stable.
• d. Chemically active elements have an
  incompletely filled valence shell

16

• B. Types of Chemical Bonds
• 1. Ionic Bonds
• a. Ions atoms are electrically neutral. An
  atom that gains or loses electrons becomes an ion
  of the same element
• 1) Anions gains one or more electrons and is
  negatively charged
• 2) Cations loses electrons and has a positive
  charge
• b. Ionic bond due to attraction of positive to
  negative as a magnet (NaCl-, KCl-, etc.) most
  are salts

17

• 2. Covalent Bonds
• a. Sharing electrons
• b. Single, double and triple bonds denoted by -
  or

single
double
18
(No Transcript)
19

• 3. Polar and Nonpolar Covalent Bonds
• a. Nonpolar electrons are balanced or equally
  shared.
• b. Polar
• Unequal electron pair sharing the nucleus of one
  atom has a stronger attraction for the shared
  electrons. Water ( H20) is a polar molecule
• . Polar molecules dissolve easily

nonpolar
polar
20

• 4. Hydrogen Bonds
• a. Weak interaction between Hydrogen (H)
  regions and - oxygen regions is the hydrogen
  bond.
• b. The polar regions of adjacent water molecules
  form weak hydrogen bonds.
• c. Common between water molecules
• d. Result in folding back of molecules or a 3-D
  shape

21
V. Chemical Reactions
Synthesis

• Chemical bonds are formed, rearranged, and or
  broken
• A. Written as Equations
• 1. Reactants -------gt products
• H H ------gt H2
• 2. Molecular formula C6H12O6
• B. Types
• 1. Synthesis anabolism
• A B ---gt AB
• 2. Decomposition catabolism processes like
  digestion reverse of above

Decomposition
22

• 3. Exchange reaction
• involve synthesis decomposition

23
4. Oxidation-reduction reactions

• a. Decomposition reactions food fuels are
  catabolized for energy (ATP is produced)
• b. Removal of oxygen reduced
• c. A molecule that gains oxygen oxidized
• C6H12O6 6O2 -gt 6CO2 6 H2O ATP

24

• C. Factors Affecting Rate of Chemical Reactions
• 1. Temperature proceed quicker at high
  temperature
• 2. Particle size smaller particles move faster
  and therefore react faster
• 3. Concentration higher concentration reacts
  faster
• 4. Catalysts needed to keep reactions going at
  rates to maintain life enzymes are biological
  ones

25
Part II - Biochemistry

• Definitions
• Organic compounds contain CARBON all
  covalently bonded.
• Inorganic compounds NO CARBON (with a few
  exceptions like CO2)
• water, salts, acids, bases

26
I. Inorganic Compounds

• A. Water - the most abundant and important
  60-80of the volume of most living cells.
• 1. Heat capacity absorbs and releases heat
• 2. High heat of vaporization heat removed from
  body with sweating
• Universal solvent because almost all chemical
  reactions in the body rely on water as a solvent
• Reactivity water is an important reactant in
  chemical reactions hydrolysis reactions like
  digestion add water to bonds to break them
  dehydration synthesis removes water for every
  bond formed (carbohydrates proteins)
• 5. Cushioning around brain, synovial fluids,
  etc.

27

• B. Salts
• Ionic compound with a cation other than H and
  anions other that OH-
• When salts are dissolved in water,
• they dissociate into their component ions.

Dissociation of salt in water. The slightly
negative ends of H20 are attracted to Na, the
slightly positive ends orient to Cl-, causing
the ions to be pulled off the crystal
28
C. Acids and Bases -like salts theyare
electrolytes.

• Acid releases hydrogen ions in solution proton
  donor
• HCl
• Base release hydroxyl ions proton acceptor
  taking up H (hydrogen) ions
• NaOH, NH3

29

• pH
• a. One of the most important ionic solutes in
  the body is the hydrogen ion (H).
• b. pH scale (pH 7 has H of 10-7) each change
  of 1 in pH represents a 10-fold change in
  hydrogen ion concentration

30
4. Buffers

• a. Resist changes in pH of body fluids by
  releasing hydrogen ions when pH rises and binding
  hydrogen ions when pH drops maintains blood
  pH Response to rise in pH H2CO3
  ltgt HCO3- H acid
  Response to drop in pH H acceptor proton

31
II. Organic Compounds

• A. Carbohydrates (carbons with water (CH20)
• 1. Contain C, H and O 1-2 of cell mass
• 2. Include Monosaccharides glucose, fructose,
  galactose, deoxyribose
• 3. Glucose is primary source of energy in cells.

32

• 3. Disaccharides
• a. Double sugars formed by dehydration synthesis
  of two monosaccharides
• b. Sucrose glucose fructose
• c. Lactose glucose galactose
• d. Maltose 2 glucose

33

• 4. Polysaccharides
• a. Long chains of simple sugars that are
  Insoluble and therefore good for storage as
  glycogen
• b. Cellulose is many glucose units that we
  cannot digest
• 5. Functions of Carbohydrates
• a. Cellular fuel
• b. Structural purposes such as in DNA and RNA
• c. Cell membrane

34

• B. Lipids (CH0)
• 1. Not soluble in water
• 2. Contain C, H and O
• 3. Neutral Fats (Triglycerides 31 ratio of
  fatty acid to glycerol)
• a. Fats when solid and oils when liquid
• b. Concentrated energy source
• c. Saturated H atoms attached to every
  attachment point, no double bonds between the
  carbons but a single covalent bond. Solid at room
  emperature
• d. Unsaturated, polyunsaturated,
  monounsaturated one or more double bonds

35
Fatty acids link to glycerol to form a
triglyceride - the most important form of
lipid more than 90 of our lipids are in this
form
36

• 4. Phospholipids modified triglycerides
• a. Two fatty acid chains and a phosphorus
  containing group
• b. Compose cell membranes
• 5. Steroids
• a. A lipid-related molecule that is derived from
  cholesterol
• b. Cholesterol is found in cell membranes, raw
  material for vitamin D, and found in steroid
  hormones such as sex steroids.

37
2 fatty acid chains, glycerol, phosphorus
containing group
Cholesterol is the basis for all steroids formed
in the body
38

• C. Proteins
• Large molecules made of the building blocks
  called amino acids.
• a. 10-30 of cell mass
• b. The basic structural material of body
• c. Enzymes, Hgb, contractile proteins of muscle
• d. Contain C, O, H and N, many have sulfur and
  phosphorus
• e. 20 different amino acids occur and may be
  assembled in an almost infinite number of
  combinations.

39

• 2. Amino Acids
• a. All amino acids are identical except for a
  single group of atoms called the R group making
  each amino acid unique. These building blocks can
  be assembled in an almost infinite number of
  combinations.
• b. Human body can synthesize all but 9 of 20
  those must come from the diet and are essential
  amino acids

40
Peptide bonds formed by dehydration synthesis
between AA's forms dipeptides, tripeptides,
polypeptides (gt10 AA's) and proteins (gt50
AA's) Peptide bond amine group to carboxyl
group
41

• 3. 4 structural levels of amino acids
• a. Primary level linear sequence of AA's in a
  chain. It is genetically determined
• b. Secondary structure As the amino acid chain
  forms, it takes on its spatial arrangement or
  secondary structure by the folding and twisting
  of the chain alpha helix spiral is the most
  common
• c. Tertiary the three-dimensional shape of the
  chain into a ball shape
• d. Quaternary structure Hgb

42

• 5. Denaturation
• a. Globular proteins are unstable
• b. Denaturation temperature and pH changes
  cause proteins to unfold and lose 3-D shapes.
  Can be reversed unless conditions are extreme,
  causing it to be irreversibly denatured and
  unable to perform its function.

43
Protein function and shape are dependent

• 4. Proteins - classified according to shape
• a. Fibrous
• Collagen, keratin, elastin, actin and myosin -
  strength
• b. Globular
• Water soluble, mobile, chemically active
• Antibodies, hormones, enzymes

44

• 6. Enzymes - globular proteins that act as
  catalysts
• Catalysts that increase the rate of a
  biochemical reactions without changing

45

• D. Nucleic Acids storage and transfer of
  genetic information
• 1. DNA and RNA Characteristics
• a. C, O, H, N and P
• b. Largest molecules in the body
• c. Nucleotides are structural units composed of
  a base, pentose sugar and phosphate group
• d. Nitrogen-containing bases include adenine,
  guanine, cytosine, thymine and uracil

46

• E. ATP
• 1. Energy released from glucose breakdown
• 2. High-energy phosphate bonds. Provide a form
  of energy immediately usable by all body cells.