Week 1: Atoms and Molecules Flashcards
Chemical Element
Pure substance that cannot be broken down any further by chemical means.
What are the four most common chemical elements in the body?
Oxygen (65%), Carbon (18.5%), Hydrogen (9.5%), Nitrogen (3.2%)
What is the importance of Oxygen in the body?
Major component of organic and inorganic molecules.
Ex: water; solvent in all body and cellular fluids and oxygen gas - cellular energy.
All Macromolecules.
What is the importance of Carbon in the body?
Major component of Organic molecules such as: sugars, fats, proteins, nucleic acids.
Ex: Carbon Dioxide, Bicarbonate.
What is the importance of Hydrogen in the body?
Component of all organic molecules and some inorganic molecules (water).
As in ion - influences acidity of bodily fluids.
Carbohydrates, Lipids, Proteins, Nucleic Acids.
What is the importance of Nitrogen in the body?
Component of proteins (structural molecules and enzymes), nucleic acids (genetic material), and other important organic molecules.
Nitrogenous excretion products.
Atom
The smallest unit of an element that still retains its physical and chemical properties of that element.
3 Subatomic Particles: Name, mass, charge, location.
Electron (-) outside cell
Protons (+) nucleus
Neutrons (neutral) nucleus
Electron Shell Amounts
1st: 2
2nd: 8
3rd: 18
Effect of Subatomic Particles
Equal number of electrons and protons (roughly same number of neutrons - can vary); neutral charge.
Molecule
When two or more atoms are joined together by chemical bonds.
Ex: 2 Oxygen = O2
Compound
A molecule consisting of more than one type of element.
Ex: 2 Hydrogen + 1 Oxygen = H2O
Stable Element Condition
Full valence (outer) shell, or containing 8 electrons.
What happens to an unstable element?
Will gain or lose electrons by exchanging them with other elements - results in negative or positive charge
Ion
Charged atoms
Ionic Bond
When two oppositely charged ions are held together by electrostatic attraction for one another.
Common in most inorganic compounds.
Covalent Bond
When electrons are shared between atoms (neither one loses or gains electrons)
Double Covalent Bond
When two electron pairs are shared between two atoms.
Inorganic Molecule
Does not always have Carbon (ex: CO2, HCO3)
Simple and small
Covalent or Ionic
Ex: H2O, NaCl, HCl, NaOH.
Organic Molecule
Carbon
Large, complex
Covalent bonds
New bonds release energy - metabolism.
Body can carry out chemical reactions.
Ex: fats, sugars, proteins.
Inorganic Compounds
Simple structure, usually lack Carbon.
Ex: water, most salts, acids, and bases.
Ex: Carbon Dioxide and Bicarbonate.
Organic Compounds
Always have Carbon (often with Hydrogen).
Always contain covalent bonds.
Ex: carbohydrates, lipids, protein, and nucleic acids.
Composition of Organic Molecules
Made by living organisms with Carbon as the core element.
Not soluble in water.
Primarily covalent bonds.
Importance of Organic Molecules to Living Organisms
(Carbon) Can bond with hundreds of others to form large/complex molecules - allows body to build complex structures and carry out complex processes.
Not soluble in water - building materials (cell membranes)
Primarily covalent bonds - when broken give off energy. Stored energy.
