biochemistry unit chapter 2: chemical foundations for cells you can be a chemist without knowing...
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Biochemistry Unit
Chapter 2: Chemical Foundations for Cells
You can be a chemist without knowing biology, but you can’t be a biologist
without knowing chemistry.
I. Basic ChemistryA. Subatomic Particles
Charge Mass
(AMU)
Location
Neutron
Proton
Electron Nearly 0
I. Basic ChemistryB. Atoms
• The smallest unit of matter that still retain the properties of a given element.
• Too small to be seen by nearly all microscopes/imaging technology.
• Each element is represented by a capital letter, possibly followed by a lower case letter. (e.g. H, O, C, Ag, Au)
Basic ChemistryB. Atoms
• Structure: Nucleus (no membrane or surrounding core) and electron clouds.
• Just know first three clouds hold:
>2 electrons, cloud 1
>8 electrons, cloud 2
>8 electrons, cloud 3
Outer cloud call valence cloud (it reacts with other atoms)
Basic ChemistryC. The Periodic Table
3. Reading the Details:
Atomic Number - # of
Protons
Atomic Mass - # of
Protons + # of
Neutrons
Atomic Symbol – Only 1
upper case letter
Basic ChemistryC. The Periodic Table
4. Rush Limbaugh Rule (Boint’s favorite part of chemistry): All electrons what to be like those on the FAR RIGHT (Noble gases).
A full outer cloud is known as a stable octet (having 8 electrons).
Basic ChemistryC. The Periodic Table
5. Left side of table
are metals
Right side are
nonmetals
Along stair are the
metalloids
Basic ChemistryD. Molecules
1. Two or more atoms chemically combined.
2. Mixtures (salt and water) are simply physically mixed, not chemically combined.
3. Molecules are written with no space between atomic symbols (e.g. H2O or NH4)
II. Key Concepts in Chemistry
A. Ions: Atoms with net electric charge.
Balanced atom/molecule: # of electrons and protons equal.
Ion: Unequal # electrons and protons.
Polyatomic Ion: Two or more atoms combined, with the molecule/compound having a overall negative charge. (NO3-)
II. Key Concepts in Chemistry
B. Isotopes: Atoms of the same element with different numbers of neutrons, thus different atomic masses.
Number of protons is ALWAYS constant
for an element.
Number of neutrons can vary.
II. Key Concepts in Chemistry
C. Radioactivity: An atom with an unstable nucleus that undergoes decay (lost of subatomic particles) as it transitions to a stable state.
Decay of trilium: 3H1 => 3He2 + 0e-1
III. Electrons
• Negligible mass
• Exist in clouds of probability, not defined ‘shells’! (ignore the book when they use this term)
• Basis of Bonds
III. Electrons
A. Ionic Bonds: Strong bonds between a metal and nonmetal
• Two ions joined together
• Electrons ‘donated’ not ‘shared’
• The strongest of the bonds
• Ionic compounds have high melting points and crystal structures
III. Electrons
B. Covalent Bonds: Bond between nonmetals in which electron pairs are ‘shared.’
• Not as strong as ionic bonds
• Compounds form discrete molecules
• Molecular formula (H2O)
III. Electrons
B.1. Polar Covalent: A covalent bond in which electrons are unevenly shared, resulting in a electrically balanced molecule (equal number of protons and electrons) but with charged ends.
• Involves (mainly) F, Cl, O due to their highly electronegative properties