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.
Examples of Organic Molecules
Macromolecules: glycogen, starch, lipids, proteins, nucleic acids, carbohydrates,
Chemical Properties of Water
Inorganic compound consisting of one partially negatively charged oxygen atom covalently bonded to two partially positive charged hydrogen atoms.
How do water molecules interact with each other?
Through weak hydrogen bonds between hydrogen of one atom to oxygen of another.
Atomic Number
Number of protons in the nucleus of the atom.
Mass Number
Sum of protons and neutrons in nucleus of an atom.
Valence Shell
Outermost shell of an electron.
Cation
A positively charged ion.
Anion
A negatively charged ion.
Compounds
Substance composed of two or more different elements joined by chemical bonds.
Nonpolar
Molecule with electrons that are relatively equally shared in covalent bonds.
Polar
Molecule with regions that have opposite charges; uneven number of protons in nuclei of atoms participating.
Ex: water.
Dipole
Molecule with negatively charged portion separated from a positively charged portion. Forms a tent.
Explain ionic bond between Sodium and Chlorine
Sodium - 11 electrons - one in valence shell
Chlorine - 17 electrons
Sodium readily gives up solo electron - now positively charged and vice versa.
Emergent Properties
Function that was not present before and is a result of interactions.
What is essential for all aerobic breakdown of glucose into ATP?
Oxygen.
Isotopes
Atoms with same number of protons, but differing number of neutrons.
Different forms of a single element.
Which bond is stronger: Covalent or Ionic?
Covalent.
Release energy when formed, require energy to break.
Hydrogen Bond
When a polar molecule weakly bonds with another polar molecule.
Ex: water.
