Download BIOLOLGY 2401 CHAPTER 2

BIOLOLGY 2401
DR. WELCH
CHAPTER 2: THE CHEMICAL BASIS OF LIFE
* The chemical level is the simplest level of structural organization, yet it is the most important*
I. Basic Chemistry: Describe the subatomic particles of an atom and explain how they determine atomic number, mass number,
isotopes, and atomic mass.
A. MATTER is anything that has a mass and occupies space; it may be a solid, liquid, or a gas.
1. Cannot be created or destroyed; however, matter can be converted to energy.
2. Weight (F) vs. Mass
B. Elements Table 2.1
1. An ELEMENT is a form of matter that cannot be broken down into simpler substances by normal chemical
reactions.
2. All forms of matter are composed of chemical elements
3. 96% weight of body via O,C,H, & N
4. An element is composed of atoms of only one kind.
C. An ATOM is the smallest particle of an element that contributes the chemical characteristics of that element. Atoms are
electrically neutral.
1. Subatomic particles - N (0), P(+) = nucleus, & E(-) cloud.
2. Atomic # (P) vs. Atomic Mass (Mass Number) = (P+N)
3. Isotopes (^ N = ^ mass) vs. Isomers (change shape)
4. Electron shells, valence & electronegativity (2/8/8)
a. * In a chemical reaction, the electrons are the only particle directly involved. Chemical behavior is
directly related to the electronegativity of the atom.
b. * electrons cannot exist between fixed levels
c. Inert elements
5. A molecule is a substance composed of two or more atoms
6. A compound is a substance composed of two or more elements (i.e. different types of atoms)
II. Types of Chemical Bonds - Chemical Bonds are forces of attraction that hold together the atoms of a molecule. (requires vs.
releases energy)
A. Ionic Bond - ion, cation (+) vs. anion (-)
1. Transfer of electrons (opposites attract = bond)
B. Covalent Bond - sharing of e- by both elements
1. Single bond (H-H)
2. Double bond (O=C=O)
a. Nonpolar (CH4)
b. Polar (H2O)
C. Hydrogen Bonds (intermolecular force) are the weakest bonds; used for quick relay, brain transmission of messages to
receiving cells. In living cells the electronegative partners involved are oxygen (H2O water) and nitrogen (NH3 ammonia)
D. Refer to Table 2.4 Describe the types of chemical bonding and contrast them with intermolecular forces.
III. Solubility & Dissociation
A. SOLUBILTY is the ability of one substance to dissolve in another; substances dissolve in water when they become
surrounded by water molecules creating a hydration shell.
B. DISSOCIATION is the separation of an ionic compound into anions and cations
1. If an ion has the ability to conduct an electric charge ii is referred to as an electrolyte
2. Covalent molecules usually remain intact and do not split
IV. Chemical Reactions List 4 types of reactions. Describe the events that occur in metabolism (include AKAs and energy
placement).
A. A chemical reaction depends on energy as well as particle concentration, speed, and orientation. Products vs. reactants
B. Four Basic types of chemical reactions
1. Synthesis (A+B --> AB + H2O) dehydration; anabolism
2. Decomposition (AB + H2O --> A+B) hydrolysis; catabolism
3. Redox (AB + CD --> AD + BC) Review electron transfer and agents.
4. Reversible (A + B <==> AB) These may require special conditions (heat or light)
5. All anabolic and catabolic reactions (as well as enzymatic activity) in the body are collectively defined as
METABOLISM
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V. Energy A. ENERGY is the capacity to do work
B. Potential (Ep) vs. Kinetic (Ek) (stability & tendency)
C. Mechanical (movement) vs. Chemical (store with in bonds)
D. Thermal Energy - represented be heat which is measured in temperature
1. Heat is always transferred from a hotter object to a cooler one until both reach equal temps
2. Friction converts kinetic energy into heat
E. Activation energy (Ea) - the minimum energy that reactants must have to start a reaction
1. Molecules are constantly in motion
2. With sufficient Ek, molecules can overcome the natural tendency to repel and come together
3. ENZYMES - protein catalysts used to decrease to Ea and accelerate reactions exponentially
a. Rise in temperature (fever) increases collision potential
b. Enzymatic activity is directly proportional to concentration of reactants and environmental
circumstance
III. Water List and explain 4 functions that water performs in living organisms and give an example of each.
A. The body's most abundant substance (approximately 50% YF & 60% YM)
1. Its is also a very versatile solvent due to its polarity
2. Plasma = 92% H2O
B. Hydrophobic vs. Hydrophilic
C. Specific heat - absorbs and releases heat slowly; maintains body temperature/ evaporation
D. Acts as a lubricant against friction
E. Hydrolysis and dehydration
F. Mixing Medium: Review solution, solute, & solvent
1. Solution (glucose)
2. Suspension medium (RBCs)
3. Colloid larger particles (proteins)
IV. Inorganic Acids & Bases
A. Acids vs. Bases
1. HCl
2. NaOH
3. Weak base NH3 + H <==> NH4
B. Salts - undergo ionization (KCl); acid + base (ex. HCl + NaCl --> NaCl + H2O)
C. Review pH scale
1. Give the normal range pH for blood. Identify and describe the conditions if pH level rises or falls below this
range.
2. Buffers - resist changes in of acidity of a solution with the use of conjugate acid-base pair
a. H2CO3 (carbonic acid) <==> [H+] + HCO3- (base)
b. Example: lungs and kidneys
c. Be able to explain and give an example of how a buffer system works with an increase / decrease of
pH.
V. Oxygen (O2) - inorganic molecule used as a final step in which energy is extracted (ATP) - ex. ETC
VI. Carbon Dioxide (CO2) - organic molecule (glucose) consists of energy stored in covalent bonds and CO2 is eliminated through
lungs
VII. Organic Chemistry - use of carbons - 4 types
A. Carbohydrates (C+H2O) - sugar (-ose) - main functions are energy release and energy storage
1. Relatively polar due to oxygen; therefore, soluble in H2O
2. Monosaccharides = monomer = building blocks of CH2O
a. Isomers - glucose, fructose, & galactose
3. Disaccharides - sucrose, maltose, lactose
4. Polysaccharides - (polymer = chain)
a. Glycogen - stored glucose found in live and skeletal muscle
b. Starch - sugar stored in plants
c. Cellulose - structural sugar found in plants (cannot be digested = bulk in feces)
B. Lipids (less polar than carbohydrates due to lack of enough O2 molecules = "hydrocarbons"= hydrophobic)
1. Types of lipids: Fats, Phospholipids, Steroids, Lipoproteins, and Eicosanoids
2. Fats provide padding (retroperitonium) and as an insulator (below the skin)
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a. Triglyceride/ triglycerol: 1 glycerol + 3 fatty acids
i. protects, insulates, provides energy, and stores energy
b. Saturated vs. unsaturated
c. Mono vs. polyunsaturated
3. Phospholipids - head (hydrophilic) and tails (hydrophobic)
a. Lipid bilayer (plasma membrane)
4. Steroids
a. Cholesterol - part of cell membrane & is required to form other steroids
b. Bile salts - emulsify fats & promote the absorption of fat soluble vitamins
c. Male & female sex hormones - reproduction and sexual traits
d. Vitamin D helps regulate the body's Ca+ concentration
5. Lipoproteins - help transport lipids to various parts of the body
6. Eicosanoids
a. Prostaglandins - modify hormone response, promote inflammation, & open airways
b. Leukotrienes - function in inflammation and allergic responses
C. Proteins - polypeptide bonds joining amino acids (C,H,O,N + R group)
1. Functions: Regulation, transport, protection, contraction, structure, energy
a. Denaturation - change in shape of a protein (ex. abnormally high temperature or changes in pH)
b. Sequence of amino acids determine shape and function of protein
2. Enzymes - catalyst used to decrease activation energy to speed reactions (-ase)
a. Define: active site, cofactor (ions), and coenzyme (organic)
b. Saturation, induced-fit, and denatured
D. Nucleic Acids - building blocks are nucleotides
1. DNA and RNA - composed of nitrogenous bases, sugar, and phosphate groups
2. Nitrogenous bases = pyrimidines and purines
3. DNA = double-helix; primary hereditary molecule
a. NB - Adenine, Thymine & Cytosine, Guanine
b. Blue print for genetic material and directs RNA synthesis
4. RNA - Uracil for thymine; single strand; different sugar
VIII. ATP - high energy bond in the covalent bond between 2nd and 3rd Pi
A. Cellular activities require energy
1. Catabolic reaction (break down of nutrients provides ATP for other needs in the body
2. Energy is require to make ATP (anabolic) via ADP + enzymes
(recycled)
B. Mitochondria = is the energy station; oxidizes food (Cellular respiration)
What is the significance of ATP? How does the structure of ATP play a role in energy exchange?
Don’t forget about Clinical Connections, Disorders: Homeostatic Imbalance located in all chapters.
This is only a general outline. There may be material that has been discussed in lecture that is not included in this outline and there may be material
on this outline that has not been discussed in lecture. Any material discussed in lecture or listed in this outline is "fair game" for the test.
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