BMB 200 Exam 1 Questions and
Answers
Titration experiment - ANSWER-measured amount of base is added to a known
amount of acid, pH changes
the pH at the inflection point equals... - ANSWER-the pKa
if the pH is less than the pKa of an acid, what form of the element dominates? -
ANSWER-The protonated form
What is the Henderson-Hasselbach equation? - ANSWER-pH = pKa + log (A-/HA)
What is in a buffer solution? - ANSWER-a weak acid (HA) and it's conjugate base
(A-)
[Ka] = -log [A-*H+/HA]; what does whole equation stand for? - ANSWER-the point at
where the solution is good for a buffer
[Ka] = -log [A-*H+/HA]; what does [A-*H+/HA] stand for? - ANSWER-Buffer region
capacity
What is a buffering capacity? - ANSWER-the amount of acid and base that can be
absorbed by a buffer
Where does the buffering region ("stability of the acid") capacity occur? - ANSWER-
around the pKa of the acid
Why are buffers needed? - ANSWER-to stabilize the pH of cells and preserve the
structure and function of biomolecules
Since blood cells do not contain sufficient phosphate, what buffers them? -
ANSWER-carbonic acid
What are zwitterions? - ANSWER-compounds that have positive and negative
charge
- they're considered less likely to interfere with biochemical reactions
if an extra hydrogen source is added to a buffer solution, what will be formed? -
ANSWER-a WEAK ACID from reacting with the conjugate base
if OH- is added to a buffer solution, it will react with what and form what? -
ANSWER-react with a WEAK ACID and water + conjugate base will be formed
, What are 2 naturally occurring buffers that help maintain physiological pH near 7 -
ANSWER-phosphate and carbonate buffers
What does our body recognize D + L stereoisomers as? - ANSWER-distinct
molecules
The 5 groups of amino acid side chains are: - ANSWER-1. Nonpolar alipathic
2. Aromatic
3. Polar, uncharged
4. Acidic
5. Basic
the amino and carboxyl groups in zwitterions have at least ( ) that can dissociate -
ANSWER-1 or 2 protons
Non polar side chains - ANSWER-Leucine, Proline, Glycine, Alanine, Isoleucine
Aromatic side chains - ANSWER-Phenylalanine, Tyrosine, Tryptophan
Polar/uncharged side chains - ANSWER-serine, aparagine, glutamine, cystine
Acidic side chains - ANSWER-Aspartic Acid (Asp)
Glutamic acid (Glu)
Basic side chains - ANSWER-Arginine, Histidine, Lysine
Where can you get complete proteins that will contain essential amino acids? -
ANSWER-Animal sources that contain all 20 amino acids
isoelectric point (pI) - ANSWER-pH at which it is not charged average between 2
pKas
Glycine - - ANSWER-- no chiral center
- gives extra flexibility in protein
- water soluble
Cysteine - ANSWER-- thiol group can be either oxidized or reduced
Tyrosine - ANSWER-important hormone that regulates our metabolism
what are two naturally occurring peptides and their functions? - ANSWER--
carnosine - antiaging and muscle building
- glutathione - scavenger for oxidizing agents
What is the danger in Amanita? - ANSWER-- toxins present in high concentrations
- survive through cooking and digestive tract
- transported into liver cells
- after a few days, a liver transplant is the only cure
Answers
Titration experiment - ANSWER-measured amount of base is added to a known
amount of acid, pH changes
the pH at the inflection point equals... - ANSWER-the pKa
if the pH is less than the pKa of an acid, what form of the element dominates? -
ANSWER-The protonated form
What is the Henderson-Hasselbach equation? - ANSWER-pH = pKa + log (A-/HA)
What is in a buffer solution? - ANSWER-a weak acid (HA) and it's conjugate base
(A-)
[Ka] = -log [A-*H+/HA]; what does whole equation stand for? - ANSWER-the point at
where the solution is good for a buffer
[Ka] = -log [A-*H+/HA]; what does [A-*H+/HA] stand for? - ANSWER-Buffer region
capacity
What is a buffering capacity? - ANSWER-the amount of acid and base that can be
absorbed by a buffer
Where does the buffering region ("stability of the acid") capacity occur? - ANSWER-
around the pKa of the acid
Why are buffers needed? - ANSWER-to stabilize the pH of cells and preserve the
structure and function of biomolecules
Since blood cells do not contain sufficient phosphate, what buffers them? -
ANSWER-carbonic acid
What are zwitterions? - ANSWER-compounds that have positive and negative
charge
- they're considered less likely to interfere with biochemical reactions
if an extra hydrogen source is added to a buffer solution, what will be formed? -
ANSWER-a WEAK ACID from reacting with the conjugate base
if OH- is added to a buffer solution, it will react with what and form what? -
ANSWER-react with a WEAK ACID and water + conjugate base will be formed
, What are 2 naturally occurring buffers that help maintain physiological pH near 7 -
ANSWER-phosphate and carbonate buffers
What does our body recognize D + L stereoisomers as? - ANSWER-distinct
molecules
The 5 groups of amino acid side chains are: - ANSWER-1. Nonpolar alipathic
2. Aromatic
3. Polar, uncharged
4. Acidic
5. Basic
the amino and carboxyl groups in zwitterions have at least ( ) that can dissociate -
ANSWER-1 or 2 protons
Non polar side chains - ANSWER-Leucine, Proline, Glycine, Alanine, Isoleucine
Aromatic side chains - ANSWER-Phenylalanine, Tyrosine, Tryptophan
Polar/uncharged side chains - ANSWER-serine, aparagine, glutamine, cystine
Acidic side chains - ANSWER-Aspartic Acid (Asp)
Glutamic acid (Glu)
Basic side chains - ANSWER-Arginine, Histidine, Lysine
Where can you get complete proteins that will contain essential amino acids? -
ANSWER-Animal sources that contain all 20 amino acids
isoelectric point (pI) - ANSWER-pH at which it is not charged average between 2
pKas
Glycine - - ANSWER-- no chiral center
- gives extra flexibility in protein
- water soluble
Cysteine - ANSWER-- thiol group can be either oxidized or reduced
Tyrosine - ANSWER-important hormone that regulates our metabolism
what are two naturally occurring peptides and their functions? - ANSWER--
carnosine - antiaging and muscle building
- glutathione - scavenger for oxidizing agents
What is the danger in Amanita? - ANSWER-- toxins present in high concentrations
- survive through cooking and digestive tract
- transported into liver cells
- after a few days, a liver transplant is the only cure
