T1 | Test 1 Chap. 1-5 Flashcards
What is include in the basic structure of an alpha-Amino Acid (4)
- Amino group: protonated at the physiological pH (H3N+)
- Carboxyl group (organic acid): deprotonated at the physiological pH (COO-)
- Hydrogen group
- Variable Group: R = Residue/Rest
What is a Zwitter ion
Compound with one positively and one negatively charged group
Types of Noncovalent (Weak) Interactions in Aqueous Solutions
Ionic Bonding, Hydrogen Bonding, Hydrophobic Interaction, Van der Walls: ‘microgravity’
What is Ionic Bonding?
When a negative and a positive charge are attracted to each other. (Na+ and Cl- or COO- and NH3+)
What is Hydrogen Bonding?
It involves polar bonds, including H-bonding groups like OH-, SH-, NH2, amido)
What is a hydrophobic interaction?
Involves Nonpolar bonds, primarily hydrocarbon, ether
What is Van der Walls, ‘microgravity’ ?
When two masses get close enough to each other, then there is an additional gravitational force created between them
How many Standard Amino Acids are there in Proteins
20
Name the different groups of Standard Amino Acids
-Nonpolar (aliphatic), polar (uncharged), aromatic, negatively charged, positively charged
Name characteristics of the non-polar/aliphatic (amino acid) R groups
- R Group is non-polar (hydrophobic)
- Will interact with other hydrophobic groups through hydrophobic interaction
Name the Nonpolar (aliphatic) amino acids
Glycine, Alanine, Proline, Valine, Leucine, Isoleucine, Methionine
What is the only non-chiral among the 20 standard AAs?
Glycine
What is the only AA with ring between R and alpha-amino group?
Proline
What is one of only 2 sulfur-containing AAs? (One in the Nonpolar, aliphatic R group)
Methionine
Characteristics of Polar, uncharged R groups
-Polar groups foster hydrogen bonding
Which of the points (A-E) depicted is Kd?
C
Name group A
Alpha Carbon
Name Group B
Carboxyl Group
What is Group C
Amino Group
Glycine
Alanine
Proline
Valine
Leucine
Isoleucine
Methionine
Name the circled part of the Amino Acid
Thioether
Serine
Threonine
Cysteine
Asparagine
Glutamine
Phenylalanine
Tyrosine
Tryptophan
The three Amino Acids that are Aromatic and the two features they share:
Phenylalanine, Tyrosine, Tryptophan
Alternating double bounds in ring structure (aromatic)
Absorb UV light around 280 nm
Lysine
Arginine
Histidine
Aspartate (aspartic acid)
Glutamate (glutamic acid)
What role does Carnitine play in the body?
Transport of fatty acids into mitochondria for breakdown
What is the purpose of creatine?
To store back up energy in skeletal muscle
What is condensation?
H20 Released while covalent bond formed between two molecules & catalyzed by ribosomes
Hydrolysis is…
Covalent bond broken that requires H2O and catalyzed by peptidases and prteases.
What is a Dipeptide
Dimer of two amino acids
What is a Peptide Bond?
Amide (amido group) formed by condensation of two amino acids.
What is the nature of the backbone of a polymer?
Repetitive. From Left to Right, repeats a three component pattern.
Ca - CO - NH - - Ca - CO - NH - …
What is the C-Terminus?
the last amino acid of a polymer.
What is the N-terminus of a polymer
The first Amino Acid of a peptide chain.
The first Protein sequenced in 1953 was?
Insulin
- Took 10 years
- 2 different polypeptides
- 2 disulfide bonds between the polypeptides and one disulfide bond within one of the polypeptides
What are the symptoms of sickle cell anemia?
- Muscle pain
- Weakness
- Dizziness
- Shortness of Breath
- Heart Murmur
- Death often occurs by age 15, triggered by: physical exertion and infections
Sickle cell Anemia is a:
genetic disorder
Carnitine:
Carries fatty acids into the mitochondria
In a conjugated protein, a prosthetic group is:
A part of the protein that is not composed of amino acids
(fake leg)
The secondary structure of the fibrous proteins consists of:
Beta-sheet only or alpha helix only, but not both.
How many water molecules are released when a hexapeptide is synthesized from free amino acids?
9
Fe(2+) is protected from ____________ by surrounding nitrogen atoms in the pyrrole ring structure of heme and a nitrogen atom of a histidine
Oxidation
The interaction of ligands with proteins:
Is temporary
The heme part of protein in myoglobin is the _____________
Prosthetic group
In sickle cell anemia, __________ is replaced by ________ in subunit beta
Hydrophilic (glu)/hydrophobic (val)
What is the most likely weak interaction between the R groups of valine and alanine in an aqueous solution?
D. Hydrophobic Interaction
Which of the following statements is false?
A. Myoglobin has one oxygen-binding site, whereas hemoglobin has four
B. Myoglobin is a monomer and hemoglobin is an oligometer
C. Myoglobin’s oxygen binding curve is sigmoid while the one of hemoglobin is hyperbolic
D. Myoglobin’s is smaller than hemoglobin
E. Myoglobin and hemoglobin have the function of binding oxygen
C. Myoglobin’s oxygen binding curve is sigmoid while the one of hemoglobin is hyperbolic
The main stabilizing force in alpha-helices is __________.
Hydrogen bonding
Two amino acids of the standard 20 contain sulfur atoms. They are _______________.
Methionine and cysteine
Changing the shape of a molecule by rotating functional groups around a single bond, without breaking it, leads to ___________________.
A conformation change
The formation of a peptide bond is a _____________.
Condensation
The chirality of an amino acid results from the fact that its alpha-carbon __________________.
Is bonded to four different chemical groups
___________ is/are (a) covalent stabilizing force in the tertiary/quaternary structure of many proteins
Disulfide bonds
Oxygen is a(n) _____________ of hemoglobin
Ligand
The charge of aspartate at pH 12 is __________
-1
Some of the typical symptoms of sickle cell anemia are signs of _________
Lack of oxygen supply to the body
Which of the following is NOT a fibrous protein?
A. Alpha-Keratin
B. Collagen
C. Insulin
C. Insulin
~~~
Which of the following involve a double bond?
A.cis/trans isomers
B. Enantiometers
C. Diastereometers
D. Anometers
A. Cis/trans isomers
Which modification step of tropocollagen synthesis is dependent on vitamin C?
A. Hydroxylation
B. Glycosylation
C. Disulfide bond formation
D. Removal of C- and N-termini
A. Hydroxylation
Which of the following are considered ligands and have an allosteric effect on hemoglobin, which leads to a change in affinity for O2?
1) O2
2) BPG
3) CO
4) Heme
A. 1 only
B. 2 only
C. 1,2,3
D. 1,2,3, and 4
C. 1,2,3
In titration curves pKa values are determined by finding the pH values that correspond with __________ and the label of the y-axis is ________
A. Endpoints; pH
B. Endpoints; equivalents (or mL) OH-
C. Midpoints; pH
D. Midpoints; equivalents (or mL) OH-
C. Midpoints, pH
Name the two-covalent (enzyme-catalyzed) modification steps that occur in the rER and briefly explain why these modifications lead to better/stronger collagen
- Hydroxylation
- Additional -OH for: increased hydrogen bonding and/or increased sites for glucosolation - Glucosulation
- Increases -OH for increased hydrogen bonding
How does the body adjust to high altitudes in the short term?
Increased BPG—>Lowers O2 affinity of Hb—>Increases O2 available to tissue
How does the body adjust to high altitudes in the long term (few weeks)?
Increased RBCs (Increased Hb)—> Increased # of O2-binding sites—>Delivery of needed amount of O2 (Despite lower saturation in lungs)
The depicted Formula shows a _______________.
disulfide
The Pka values of the depicted amino acid are: pK1 = 2.17, pK2 = 9.04, pKr = 12.48. The pI of this amino acid is:
10.76
What functional groups are present on this molecule?
Hydroxyl and Aldehyde
The depicted Molecule is an __________________.
anhydride
The functional group between R1 and R2 in the depicted compound is a(n) _________________.
Ester
The name of the amino acid #1 in the depicted oligopeptide is _____________________.
Tyrosine
The depicted amino acid has a(n) _______________ R-Group.
A. positively charged (basic)
B. Non-polar (aliphatic)
C Uncharged Polar
D. Negatively charged (acidic)
C. Uncharged Polar
The configuration at the α-carbon of the vast majority of naturally occurring amino acids is _________.
- L
- D
L
___________ has a pKr that is close to 7 and hence is commonly found at the active site of enzymes.
a. Proline
b. Cysteine
c. Glycine
d. Lysine
e. Histidine
e. Histidine
Hydrophobic interaction occurs between ___________ R-goups.
a. Nonpolar, aliphatic
b. Polar, uncharged
c. Aromatic
d. Positively charged
e. Negatively charged
a. nonpolar, aliphatic
The only uncommon amino acid found in proteins that is modified pre-translation is ___________.
a. selenocysteine
b. hydroxyproline
c. hydroxylysine
d. carboxyglutamate
a. Selenocysteine
Carnitine (an uncommon amino acid…
a. transports fatty acids into the mitochondria
b. is an intermediate of bile biochemistry
c. is an intermediate of the urea cycle
d. stores phosphate in muscle tissue
a. transports fatty acids into the mitochondria
The C-terminal amino acid in the depicted tripeptide is:
alenine
At pH 4, aspartate has an overall charge of __________.
d. +1
The pI of aspartate is _____________.
(pK1 = 1.88, pK2 = 9.60, pKr = 3.65)
a. 1.88
b. 2.77
c. 3.65
d. 5.77
e. 6.63
f. 9.60
b. 2.77
T or F
Every amide bond is a peptide bond.
False
T or F
Every peptide bond is an amide bond.
True
___________ is a prosthetic group of hemoglobin.
a. Histidine
b. CO
c. O2
d. Heme
e. Myoglobin
D. Heme
A ligand is______________________…
a. Bound non specifically by its protein.
b. a chemical species that is reversibly bound to its protein.
c. always covalently bound to its protein.
d. Always a polypeptide.
e. Always a complex molecular structure
B. A chemical species that is reversibly bound to its protein.
The heme prosthetic group of hemoglobin consists of a pyrrole-ring system with _________ bound in its center.
Fe2+ (Iron)
_______________ is a ligand of hemoglobin.
O2
Fe2+ is protected from ________________ by surrounding nitrogen atoms in the pyrrole ring structure of heme and a nitrogen atom of a histidine.
Oxidation
Myoglobin shows a ______________ O2-binding curve.
Hyperbolic
BPG (2, 3-bisphosphoglycerate) plays a role in adaptation of the human body to lower pO2 at higher altitudes by…..
binding to an allosteric binding site on the hemoglobin and lowering hemoglobin’s affinity for O2.
_____________ Can be a trigger of an episode of sickle cell anemia.
a. Exercise
b. Hard physical labor
c. An infection
d. All of the above
D. All of the above
The mutation behind scale cell anemia leads to the replacement of ________________ by ___________ in subunit β.
hydrophilic GLU
hydrophobic VAL
Carriers of the sickle cell trait have protection from
Malaria
They typical symptoms of sickle cell anemia are signs of _____________.
a. reaction by the immune system to the condition
b. lack of oxygen supply to the body
c. an autoimmune reaction
d. a genetic disorder
B. lack of oxygen supply to the body
The chiral it’s of an amino acid results in the fact that it’s alpha carbon
A. Is symmetric
B. Has no net charge
C. Bonded to 4 different chemical groups
D. Is in the l-absolute
E. Is the l-absolute configuration
C. Bonded to 4 different chemical groups.
Which modification step of troop collagen synthesis is dependent on Vitamin C.
A. Hydroxylation
B. Glycosylation
C. Disulfide bond formation
D. Removal of the C and N termini
A. Hydroxylation
