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98% of the body consists of:
Hydrogen (63%), Oxygen (25.5%), and Carbon (9.5%)
What determines whether molecules are inorganic/organic or animate/inanimate?
The organization of hydrogen, oxygen, and carbon atoms
Homeostasis
Claude Bernard/Cannon 1926 Organ systems integrated by automatic adjustments to keep interior environment within narrow limits despite external changes
Negative feedback
Correction back to "center"
Positive feedback
Amplification, away from center
Evidence is based on:
Verifiable and quantifiable observations
Theory of Vitalism
The theory that organic substances can only be produced by living organisms. Disproved by Friedrich Wohler in 1828 when he synthesized urea (NH2-CO-NH2) from inorganic compounds.
3 major structures of the cytoskeleton, their proteins, and diameters:
Microtubules- tubulins, 250A Intermediate filaments- three proteins, 120A Microfilaments- actin, 70A
Lysosomes
Digestive enzymes in vesicles
Apoptosis vs Necrosis
Apoptosis: fragmentation of nucleus and cytoplasm induced by cellular damage or specific signaling pathways. Result of cell mechanism. Necrosis: the nucleus stays intact longer than the cytoplasmic structures. Result of injury.
Slow entry of Ca++ vs fast entry
Slow- apoptosis Fast- necrosis
Apoptosis results in:
1. condensation of the nucleus 2. cell shrinkage 3. chromosomal fragmentation due to the controlled digestion of DNA by apoptosis DNAses 4. cytoplasmic blebbing and apoptosis bodies are also seen 5. cell death without inflammation of the surrounding tissue
Atom
Smallest particle of an element that still retains the properties of that element
Elements
Substance composed of atoms of one particular kind
Compound
Substance composed by chemical union of two or more elements
Mixture
Combination of compounds or elements that are not chemically combined
Valence
Number of bonds an atom can form
Electrolyte
Any substance that ionizes in water
Radioisotopes
Unstable isotopes
Unit for atomic weight
Daltons
Charge distributions and their effects
Neutral: equal number of charges Charged: unequal number of charges Dipole: equal number of charges but unequally distributed
Linus Pauling's electronegativity principle:
Partial charges are produced by oxygen's tendency to pull valence electrons closer to the nucleus. Forms an electric dipole. Dipole/dipole interactions are responsible for hydrogen bonds
Hydration
Water around ions or at dipoles
Hydrophilic
Able to form hydrogen bonds with water (ions, amino acids, ATPs, sugars)
Hydrophobic
Unable to form hydrogen bonds with water (fats, oils, hydrocarbons)
Amphipathic
Molecules with both hydrophobic an hydrophilic regions (oleate, phospholipids, detergents). Important for self-assembly of unique structures (micelles and membranes)
__ play a vital role in the self assembly of membranes
Phospholipids
Colligative properties
Those that depend on the total number of solute particles in a given volume 1. depress freezing point (salt water) 2. elevate boiling point 3. depress water vapor pressure 4. osmotic pressure (membrane)
Ion
an atom or molecule bearing a net charge due to loss or gain of electrons
ionization
the dissociation into ions of a compound in solution
Atomic mass unit before and after 1960:
before: based on oxygen-16 after: 1/12 of the mass of a neutral atom of most abundant isotope of carbon (carbon-12)
List the molecular bonds in order of increasing strength.
london dispersion forces, van de Waals forces, hydrogen bonds, electrostatic ionic bonds, and covalent bonds
Activity
"effective" free concentration of an electrolyte
mole
the relative molecular weight in grams
hydronium ion
H3O+
Hydroxyl ion
OH-
acid
any substance which releases H+
base
any substance which captures H+
What is normal blood pH?
7.4 (+/-) 0.1
What blood pH causes a coma or death?
7
What blood pH causes alkalosis?
7.5
What blood pH causes convulsion and death?
7.8
3 major mechanisms of controlling acid or alkaline load:
1. pulmonary ventilation (CO2 removal) 2. kidney acid or alkaline urine (H+ removal) 3. buffer system in blood
Buffer system in blood: definition and components
an acid-base buffer system is a solution of two or more chemical compounds that react in a manner so as to prevent changes in the H+ concentration 1. proteins 2. phosphate buffer 3. bicarbonate buffer system
current
flow of charge
voltage
electromotive force or electric potential expressed in volts
resistivity
the resistance of a conductor 1 cm in length and 1 cm2 in cross-sectional area
resistance
property that hinders the flow of current measured in ohms (Ω)
conductance
the reciprocal of resistance. unit is siemen (S)
conductivity
the reciprocal of resistivity
Ohm's law
current is proportional to voltage and inversely proportional to resistance (V=IR)
capacitance
a measure of the ability of a nonconductor to store electric charge (C=q/v)
affinity/selectivity sequence
an order of binding preference among cation species, ranging from those that bind most strongly to those that bind most weakly
cation
positive ion
anion
negative ion
carbonyl structure
C=O
silicate structure
Si-O
carboxyl structure
O=C=OH
ether structure
R-O-R
Types of lipids
fats, phospholipids, sterols, sphingolipids, glycolipids, waxes
characteristics of lipids
1. solubility in organic solvents (chloroform ether, benzene) 2. insoluble in water (most)
characteristics of saturated fats:
no double bonds, low melting points
characteristics of unsaturated fats
some double bonds between carbons, form solids at room temperatures
what determines the physical properties of a fat molecule?
degree of saturation and length of carbon chain
Where do triglycerides accumulate? What is the significance of this?
in fat vacuoles in adipose tissue cells. can be stored in high concentrations without water
structure of triglycerides
glycerol + 3 fatty acids
structure of phospholipids
phosphate group and two fatty acid chains.
structure of sterols
structure of sterols membrane components, precursors for steroid hormones
structure of sphingolipids
fatty acid + amino alcohol sphingosine
structure of glycolipids
lipids with one or more sugar molecules
structure of waxes
esters of higher fatty acids
general functions of lipids
1. structural components of membranes-self assembly 2. storage depots of metabolic fuel (intracellular) 3. protective component of skin
three types of carbohydrates
monosaccharides, oligosaccharides, and polysaccharides
glycogen
a polysaccharide. large, covalently-linked macromolecule consisting of glucose subunits
primary protein structure
amino acid sequence
secondary protein structure
regional structure conformation (α helix, β sheet, random coil)
tertiary protein structure
detailed folding of entire molecule (S-S bonds)
quarternary protein structure
protein complexes
DNA is composed of:
guanine, cytosine, adenine, and thymine
RNA is composed of:
guanine, adenine, cytosine, and uracil
ribosomal RNA
forms much of ribosome
messenger RNA
information for protein assembly
transfer RNA
attach to amino acids
replication
old DNA → new DNA
transcription
DNA → mRNA
translation
mRNA → protein
potential vs kinetic energy
potential- stored energy kinetic- energy of motion
1st law of thermodynamics
energy is neither created nor destroyed in the universe
2nd law of thermodynamics
the entropy of a closed system will always increase with time
Free energy
biological systems can utilize only that component of the total available energy capable of doing work under isothermal conditions

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