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 following9. 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– 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 BondsValence 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 ReactionTypes 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 BodySalts, 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 BodyAcids– Hydrochloric Acid (HCl) –

digestion

Bases– Act as buffers – “acid-base

homeostasis” – Bicarbonate ion

pH Scale pH = “Power of Hydrogen”

•Concentration of hydrogen ions

•Expressed in terms of moles/L or Molarity

•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 Animation

pH Scale