Biochemistry Flashcards
Chemical Fundamentals
Living things are composed of matter
Definition: Matter is anything that has mass and occupies space
Atom
Smallest unit of matter composed of:
- protons
- neutrons
- electrons
Isotopes
elements of an atom with the same number of protons but different number of neutrons
ex. carbon, a major constituent of living organisms has 3 isotopes ie. C12, C13, C14
C12=most abundant
C14=least abundant
Radioisotopes
isotope that decays or decomposes into smaller atoms, subatomic particles of energy.
ex. C14 is radioactive breaks down to N14
Definition: Half-life is the time it takes for one half of the nuclei in a radioactive sample to decay
Uses of Radioisotopes
Radiometric dating
nuclear medicine for diagnosis and treatment
Two main types of chemical bonding
Intra-molecular forces (forces WITHIN the molecules)
Inter-molecular forces (forces BETWEEN molecules)
Intra-molecular forces
Two types:
Ionic bonds, and covalent bonds
Ionic bond
bond between atoms that have lost or gained electrons and have become charged
Ions
Charged atoms
Cation
Ion that is negatively charge
Anion
ion that is negatively charged
Covalent bond
bonds formed when atoms share one or more pairs of valance electrons
They can be either polar or non-polar
Electronegatively
measure of an atom’s ability to attract a shared electron pair when it is participating in a covalent bond
ex. En for noble gases is 0
Symmetrical molecules
Bonds are all polar are nonpolar
Asymmetrical molecule
are non polar if all the bonds are non polar, and they are polar if at least one bond is polar
Inter-molecular bonds
chemical bonds between molecules weaker then intramolecular bonds THREE TYPES: London dispersion forces Dipole-dipole forces Hydrogen bonds
London dispersion forces
weakest bond, they exist between all molecules. Only forces between noble gases and non polar molecules
Dipole-dipole forces
hold polar molecules together
Hydrogen bonds
forms between a partial positive charged H atom with a partially negative charged O,N and F atom in another molecule
This bond is the strongest and most biologically significant, and responsible for many unique properties of water
Water
Very important to life. Without we wouldn’t exist
All organisms have water
Ex. control body temp, keep eyeballs moist, lubricate joints
Water properties
- colourless, odourless, and tasteless
- can exist as a solid, liquid, and gas in temp range found on earth
- chemical composition H2O
- It’s polar due to - polar bond & asymmetrical shape
Water the versatile solvent
- more substances dissolve in it
- Most chemicals of biological interest dissolve in water
ex. NaCl dissolve in water
NaCl is an ionic compound, it dissociates in water i.e breaking of the ionic bond
Polar molecules = dissolve in water
Hydrophobic molecules
non-polar molecules that are not strongly attached to water
Hydrophilic molecules
polar or charged molecules that are strongly attracted to water
