Chemical Bonds & Buffers Flashcards
What is a lysate?
general term describing the internal parts of a broken apart cell
What is the equation for Gibb’s free energy?
deltaG=deltaH - TdeltaS
What is anabolism vs catabolism? Is energy used or produced?
anabolism is building things up (uses energy) catabolism is breaking things down (releases energy)
What are considered the energy currencies of the cell? Why?
ATP and NADH
carry energy and when broken apart can be used to power the cell
What is the difference between endergonic reactions and exergonic reactions? (in terms of ATP)
endergonic use ATP, exergonic make ATP
What laws do all chemical/biochemical phenomena follow?
thermodynamics
What do enzymes do?
speed up reactions by lowering the activation energy
What are the most common elements in organic molecules?
sulfur, phosphorous, oxygen, nitrogen, carbon, hydrogen (SPONCH)
When carbon has four single bonds what are the bond angles?
tetrahedral, 109.5
When carbon has a double bond what are the bond angles?
planar, 120
Why do some biological interactions occur between molecules not covalently bonded?
allows for continual forming/breaking, allows for reversible association
What are some things that make water important?
most all biological molecules assume their shape in response to water, most biochemical reactions happen in water, it also often participates in reactions, oxidation of water is also important for photosynthesis
Why is water such a good solvent for polar compounds?
asymmetry of the water molecules makes a significant dipole moment
What is the hydrophobic effect?
non polar groups will orient themselves to minimize their contact with water
How do lipids orient themselves when in water? How does this affect entropy?
dispersed, clusters, micelles
entropy is lowest when the lipids on are their own and it increases as they cluster and when they form a spherical micelle entropy is increased even more
Why do micelles have higher entropy than dispersed lipids?
more water molecules are ordered by the fatty acid tails but in micelles the tails are completely seperate from water, therefore they are not being ordered
What does amphiphilic mean? How will they orient themselves?
contains both polar and non polar sections
maximize polar contacts with water and the non polar parts w/other non polar parts
How can hydrogen bonds be broken?
heat or high salt
Are hydrogen bonds stronger than covalent bonds?
no but they still have a big effect (boiling point)
What is proton hopping?
a very small portion of the water is dissociated and a proton is picked up by another water molecule, this proton is passed between water molecules
What is the equation used to describe the ionization of water? What does the 55.5 mean?
K=[H+][OH-]/55.5
55.5 is the molarity of pure water, we susbtitute it because such a small amount of water is ionzied
What is the autoionization of water?
Kw= 1.0 x 10^-14
How can you calculate pH?
pH = -log[H+]
How can you calculate [H+] using pH?
[H+] = 10^-pH
How can you find the pKa?
pKa = -logKa, also the pH where acid is half ionized [A-]=[HA]
What is the buffering capacity of a weak acid with a pKa of 4.76?
3.76 to 5.76 (+- 1 from pKa)
What is the henderson-hesselbach equation?
pH = pKa + log[A-]/[HA]
What are polyprotic acids?
weak acids with more than one ionizable group
How can you find the pH after adding 0.1 mol NaOH to 1 mol acetic acid?
naoh reacts completely cause its a strong base and it makes 0.1 mol acetate leaving 0.9 mol acetic acid, plug these numbers as well as the pKa into HH equation will give you pH
What are examples of some biological buffers?
phosphate, carbonate, protein and peptides
How would you approach a problem using an acid with multiple pKas and you are trying to find the final pH when 10mL of a strong acid is added to the buffer with a given pH?
using the given pH choose the pKa that we will be buffering in (similar), convert everything to mol/L then add the strong acid added to the compound with more H+ and subtract it from the one with less, plug into HH
