Biochemistry Flashcards
Biochemistry
Branch of science that studies chemical processes, substances (and the atoms/molecules that comprise them) in living things.
Chemistry of living organisms and the MOLECULAR BASIS for the CHANGES occurring in living CELLS.
Life Science + Chemical Science
- proteins, nucleic acids, lipids, vitamins, and hormones
Metabolism
The sum total of all the reactions that occur throughout the body in each cell.
The cell’s TOTAL CHEMICAL ACTIVITY.
Metabolic Pathway
Complex sequence (series) of controlled biochemical reactions
EX: cellular respiration, protein synthesis, transport, cell division, excretion
Most abundant chemicals in the human body
Oxygen - 65%
Carbon - 18.5%
Hydrogen - 9.5%
Nitrogen - 3.2%
Calcium - 1.5% (neuron signals, muscle contractions)
Phosphorus - 1%
Potassium - 0.4%
Sulfur - 0.3%
Elements of Life
CHNOPS - 98% of life
Carbon - backbone
Hydrogen - water, acid-base reactions
Nitrogen - DNA, amine groups
Oxygen - water, breathing
Phosphorus - DNA, ATP, (de)phosphorylation
Sulfur - amino acids
Why are they called “carbon-based” life forms?
Carbon backbone
The Atom
Smallest part of an element
Composed of subatomic particles: protons, neutrons and electrons
Ion
Charged atom
Cation - positive (loss of e-)
Anion - negative (gain of e-)
Isotopes
Atoms of the same element with the same number of protons, but a different number of neutrons
~400 stable isotopes
Isotopes of Hydrogen
1/1 - Protium
2/1 - Deuterium
3/1 - Tritium
Radioisotopes
Unstable, radioactive isotopes that decay to release radiation
Applications of Radioisotopes
Carbon dating with C-14
Radioactive Tagging (Tracer/Label)
A chemical compound in which one or more atoms have been replace by a radionuclide, so by its radioactive decay, it can be used to explore the mechanism of chemical reactions by tracing its path from reactants to products
Valence electrons
Electrons in the outer most shell
Chemical Bonds
Attractive forces that hold atoms/ions together in a compound
Electronegativity
The measure of an atoms ability to attract electrons.
Determines the type of bond atoms form
Ionic Bonds
Bonds formed between cations and anions, involving electrostatic attraction between them
Covalent Bonds
Bonds between non-metal atoms, where electrons are shared
Polar - unequal sharing (0.4<EN diff<1.7)
Nonpolar - equal sharing (EN<0.4)
Intermolecular bonds
van de waals/London
dipole-dipole
hydrogen bond
DETERMINE PHYSICAL PROPERTIES
Applications of Water
- primary inorganic molecule of life (90% of a cell)
- carrier for dissolved molecules in/out of cell
- raw material essential for cell reactions (added to make/break bonds)
- lubricant between organs, tissues, and individual cells
Unique Properties of Water
- Remains a liquid over wide temp range
- Changes temp gradually when heated/cooled
- Only pure substance that expands when becomes solid (H-bonding)
- Dissolves most substances involved in living processes - Universal Solvent
Polarity of Water
Permanent dipole
O - negative
H - positive
Hydrogen Bonding
Hydrogen atom with Nitrogen, Oxigen, or Fluorine
Hydrophobic
Molecules that do not interact well with water
- nonpolar (can’t h-bond)
- insoluble in water
EX: fats (lipids), hydrocarbons
Hydrophilic
Molecules that interact with water
- polar (h-bond)
- soluble in water
EX: alcohols, salts, acids, bases
Amphiphilic (Amphipathic)
Compunds that contain two distinct covalently bonded components with DIFFERENT AFFINITY for the solvent in the same molecule
- one has high affinity for polar solvents
- other for nonpolar solvents
Have both polar (hydrophilic) and nonpolar (hydrophobic) parts
