Review of Chemical Principles in Mol Bio Flashcards
What are biological molecules comprised of?
atoms
What do atoms contain?
subatomic particles
What is the structure of atoms?
neutrons and protons are at the atomic nucleus, with electrons surrounding the nucleus
What charge are protons?
positively charged
What charge are neutrons?
neutral
What charge are electrons?
negatively charged
What is the atomic number?
the number of protons
What is the atomic mass?
the number of protons + the number of neutrons
What determines the interactions with other atoms?
arrangement of electrons
Where are electrons found?
in separate “shells” surrounding the nucleus
How many electrons fill each shell?
the innermost shell contains up to 2 electrons, the second and third shells contain 8 electrons
What shell is most stable and chemically unreactive?
the outermost shell filled
What makes atoms more stable?
if an outer electron shell is unfilled, atoms can share electrons to complete their outer shells
What forms covalent bonds?
sharing of electrons forms covalent bonds
What is a single bond?
where one electron from each atom is shared
When do multiple bonds form?
when more than one electron is shared
T or F: covalent bonds are very stable
true
What do covalent bonds form?
strict geometrical configurations characteristic of the atoms involved
What shape is formed from a carbon with four single bonds?
they are equally spaced from one another in a tetrahedron, as in methane
T or F: atoms cannot rotate freely about a single bond
true
T or F: atoms can rotate freely about a double bond
false; rotation of atoms around the bond is restricted, so other bonds are in a single plane, as in ethene
What are peptide bonds?
covalent bonds that form between amino acids to form polypeptides( chains of amino acids) and proteins
What atoms are in peptide bonds?
three covalent bonds are shared between the O, C, and N atoms of the bond
What are the bonds between C, O, C, and N in peptide bonds?
both have partial double bond character
How do partial double bonds affect rotation in peptide bonds?
restricts rotation at the bond and is crucial for protein structure and function
What is electronegative?
the atom with the greater share of the electron is partially negatively charged
What is electropositive?
the atom with the lesser share
What is a dipole?
separation of charge between electrons shared unequally within a covalent bond
What are polar bonds?
covalent bonds with a dipole
What are non-polar bonds?
covalent bonds that do not have any charge separation
T or F: polar molecules interact favorably with water
true
T or F: non-polar molecules interact favorably with water
false
What is the polarity of water?
O has a partial negative charge and the H atoms are partially positive
What are anions?
negative charged ions
What are cations?
positive charged ions
What are ionic bonds?
charged ions interact very strongly with one another, such as sodium chloride
T or F: charged chemical groups do not have ionic interactions
false
What does ionized water become?
hydroxide and hydronium ions
What is the concentration of pure water?
OH- and H3O is 10^-7 each M, 10^-14 in product
What are acids?
molecules that release H+
What are bases?
molecules that accept H+
What affects biological reactions?
the concentration of H+
What is the pH of lyzosomes?
~5
What are non-covalent bonds?
mostly weaker than covalent bonds but have important roles in molecular structure and stabilization
What allows molecules to be flexible for function?
weaker bonds can be formed and broken
T or F: non-covalent reactions are fundamentally electrostatic interactions
true
What are salt bridges
ionic interactions between charged atoms plus an H-bond
What are hydrogen bonds?
interactions between polar atoms with partial charges, mediated by one hydrogen atom
What are van der Waals interactions?
weak attractions between atoms at a certain distance
T or F: ionic bonds are very stable and strong in the absence of water
true
What weakens ionic bonds?
polar water molecules which interact with the charges
What are hydrophobic molecules?
non-polar molecules that do not interact favorably with water
How do hydrophobic interactions drive molecular folding?
- hydrophobic regions associated with one another and exclude water
- hydrophilic regions tend to located on outer surfaces of molecules where the interact with water
T or F: multiple weak bonds combine to produce stable yet potentially dynamic associations between macromolecules
true
