Transcript Introduction – Inorganic Chemistry

Introduction – Inorganic
Chemistry
Biology 2121
What we need to stay alive – Necessary Life Functions
1.
Movement
2.
Response to Stimuli
– Nervous system
3.
Digestion
– Break down foodstuffs -------- absorb in blood --- tissues and cells
4.
Metabolism
– Catabolic process vs. anabolic processes
5.
Excretion
– Digestive system (solid waste); urinary (liquid waste)
6.
Reproduction
– Asexual vs. sexual
– Fertilization via gametes
7.
Growth
8.
Maintain Boundaries
To survive you must have the following
9. Nutrients to digest and absorb
10. Oxygen
– Cellular Respiration in cells – produce ATP
11. Water
– 60-80% of body weight; allows for chemical reactions; cell
balance; solvent
12. Must maintain normal body temperature
– 37 C or 98.6 F
Necessary Life Functions – Homeostasis
Homeostasis: state of body equilibrium or to maintain a
stable internal environment.
– “Dynamic” process
How it works
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–
–
–
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Variable
Stimulus
Receptor
Control center
Effector
Examples of Homeostatic Mechanisms
1. Negative Feedback Systems
– Most prevalent
– Variable relationship – inverse
• Original stimuli is lowered or shut down
– Examples: Glucose control; Body Temperature
2. Positive Feedback Systems
– Original stimuli is enhanced
– Examples: Blood Clotting; oxytocin
Introduction – Inorganic Chemistry
Organization of the Human Body – Levels of Structural
Organization
Basics of Chemistry – Atomic Structure
Atomic Structure
– Nucleus
• Protons (+) and Neutrons (0)
– Both weight 1.0 amu
– Energy Levels
• Electrons (-)
– <1 amu (1/2000)
Atoms make up Elements
– Same types of atoms (Fe, Cu, etc.)
– Elements form compounds and molecules
Not all atoms of the same kind are alike
– Isotopes
Electrons Interact to form Chemical Bonds
Valence Electrons – Atomic Number
– Atomic number: number of protons = number of electrons
– Valence: most outer shell electrons that react with other atoms
• Identifying valence electrons: Group Number
Ions: when an atom gains or loses an electron
Metals and Nonmetals
– Location on the periodic table
– Formation of Ions
– Metals: tend to lose electrons
• Positive ions or cations
– Nonmetals: gain electrons
• Form negative ions or anions
Ion Attraction
– Electrostatic attraction
– Forms Ionic Bonds
Ionic and Covalent Bonds
1. Ionic Bonds
– Formed via electrostatic attraction
• Metals (cations) and Nonmetal
(anions)
• Electronegativity
– Crystalline solids
– Salts: NaCl; MgCl2 (Electrolytes)
– Importance of ions/electrolytes
2. Covalent Bonds
– Similar electronegativity
– Nonmetals
– Forms molecules
• Importance of molecules and covalent
compounds
Covalent Compounds – Polarity
Covalent compounds
– Slight charges are formed during the
sharing of electrons
– Equal Sharing “nonpolar”
• No slight charges formed
– Unequal Sharing “polar”
• Slight differences in EN – charges
• Forms two poles or “dipole”
• Water – Polar Covalent Compound
– Universal Solvent
– Chemical reactions
Hydrogen Bonding
• Covalent polar compounds
form a ‘weak’ bond.
• Attraction between dipoles
• Intramolecular bond
– Holds a molecule to a molecule
• Significance of Hydrogen
bonding
– DNA: holds double strand together
– Proteins
Chemical Reactions – Human Body
• Chemical Reactions produce new substances
• Chemical Reactions in the Human Body
– Anabolic – “Build up”
– Catabolic – “Break down”
– Metabolic pathways (Glycolysis, Kreb’s Cycle, etc.)
• Chemical Reactions are mediated by Enzymes
– Biological Catalysts – Speed up chemical reactions
• Types of Chemical Reactions
– Synthesis
• amino acids combine to make proteins
– Decomposition
• Starch(glycogen) broken down to produce glucose
– Exchange or displacement
Chemical Reactions
Synthesis Reaction –
Energy consuming or
absorbing
“Endergonic”
“Anabolic”
Decomposition Reaction –
Energy Releasing
“Exergonic”
“Catabolic”
EA – Energy of
Activation
Factors that Affect Chemical Reactions
1. Temperature
– >Temperature faster the reaction speed
– Increase in KE
2. Concentration
– >Concentration the faster the reaction speed
– Greater chances of collisions
3. Size of Particles
– Smaller the particles faster the reaction speed
– Collides more often
4. Catalysts
– Lowers the activation energy; reaction takes place with less
energy.
Mixtures and Solutions
Human body is made of many mixtures
Mixture vs. Chemical Reaction
Types of Mixtures
– 1. Solution
– 2. Colloids
– 3. Suspensions
Solutions
– “Homogeneous” – same composition throughout
– Solvent vs. Solute
– Water is solvent “aqueous” solution
• Water dissolves gases, liquids and solids
– Example: Blood Plasma
– Concentration: % or Molarity
Mixtures and Solutions
Colloids or “emulsions”
– “Heterogeneous”
– “Sol-Gel” transformation
– Example: Cytosol in
cytoplasm of cells
Suspensions
– “Heterogeneous”
– Example: Blood
Electrolytes in the Body
Salts, Acids and Bases are “electrolytes”
1. Salts
– Ionic compound that contains a cation other than a H+ and an
anion other than a hydroxyl ion (OH-): NaCl
– Common salts in the body: NaCl; CaCO3; KCl
2. Acids
– Releases H+ in solution
– “Proton donor”
– Lowers pH
3. Bases
– Releases OH- in solution
– “Proton acceptors”
– Raises pH
HCl releases H +
Acids and Bases in the Body
Acids
– Hydrochloric Acid (HCl) –
digestion
Bases
– Act as buffers – “acid-base
homeostasis”
– Bicarbonate ion
pH = “Power of Hydrogen”
pH Scale
• Concentration of hydrogen ions
• Expressed in terms of moles/L or
Molarity
pH scale Animation
• Logarithmic
– One pH unit represents a 10-fold
change in ion concentration
– pH of a solution is the negative log of
the concentration of hydrogen ions
– Scale: 0-14
• pH = - log
+
[H ]
pH Scale