T1 | Test 1 Chap. 1-5 Flashcards
(110 cards)
1
Q
What is include in the basic structure of an alpha-Amino Acid (4)
A
- 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
2
Q
What is a Zwitter ion
A
Compound with one positively and one negatively charged group
3
Q
Types of Noncovalent (Weak) Interactions in Aqueous Solutions
A
Ionic Bonding, Hydrogen Bonding, Hydrophobic Interaction, Van der Walls: ‘microgravity’
4
Q
What is Ionic Bonding?
A
When a negative and a positive charge are attracted to each other. (Na+ and Cl- or COO- and NH3+)
5
Q
What is Hydrogen Bonding?
A
It involves polar bonds, including H-bonding groups like OH-, SH-, NH2, amido)
6
Q
What is a hydrophobic interaction?
A
Involves Nonpolar bonds, primarily hydrocarbon, ether
7
Q
What is Van der Walls, ‘microgravity’ ?
A
When two masses get close enough to each other, then there is an additional gravitational force created between them
8
Q
How many Standard Amino Acids are there in Proteins
A
20
9
Q
Name the different groups of Standard Amino Acids
A
-Nonpolar (aliphatic), polar (uncharged), aromatic, negatively charged, positively charged
10
Q
Name characteristics of the non-polar/aliphatic (amino acid) R groups
A
- R Group is non-polar (hydrophobic)
- Will interact with other hydrophobic groups through hydrophobic interaction
11
Q
Name the Nonpolar (aliphatic) amino acids
A
Glycine, Alanine, Proline, Valine, Leucine, Isoleucine, Methionine
12
Q
What is the only non-chiral among the 20 standard AAs?
A
Glycine
13
Q
What is the only AA with ring between R and alpha-amino group?
A
Proline
14
Q
What is one of only 2 sulfur-containing AAs? (One in the Nonpolar, aliphatic R group)
A
Methionine
15
Q
Characteristics of Polar, uncharged R groups
A
-Polar groups foster hydrogen bonding
16
Q
Which of the points (A-E) depicted is Kd?
A
C
17
Q
Name group A
A
Alpha Carbon
18
Q
Name Group B
A
Carboxyl Group
19
Q
What is Group C
A
Amino Group
20
Q
A
Glycine
21
Q
A
Alanine
22
Q
A
Proline
23
Q
A
Valine
24
Q
A
Leucine
25
Isoleucine
26
Methionine
27
Name the circled part of the Amino Acid
Thioether
28
Serine
29
Threonine
30
Cysteine
31
Asparagine
32
Glutamine
33
Phenylalanine
34
Tyrosine
35
Tryptophan
36
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
37
Lysine
38
Arginine
39
Histidine
40
Aspartate (aspartic acid)
41
Glutamate (glutamic acid)
42
What role does Carnitine play in the body?
Transport of fatty acids into mitochondria for breakdown
43
What is the purpose of creatine?
To store back up energy in skeletal muscle
44
What is condensation?
H20 Released while covalent bond formed between two molecules & catalyzed by ribosomes
45
Hydrolysis is...
Covalent bond broken that requires H2O and catalyzed by peptidases and prteases.
46
What is a Dipeptide
Dimer of two amino acids
47
What is a Peptide Bond?
Amide (amido group) formed by condensation of two amino acids.
48
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 - ...
49
What is the C-Terminus?
the last amino acid of a polymer.
50
What is the N-terminus of a polymer
The first Amino Acid of a peptide chain.
51
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
52
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
53
Sickle cell Anemia is a:
genetic disorder
54
Carnitine:
Carries fatty acids into the mitochondria
55
In a conjugated protein, a prosthetic group is:
A part of the protein that is not composed of amino acids
(fake leg)
56
The secondary structure of the fibrous proteins consists of:
Beta-sheet only or alpha helix only, but not both.
57
How many water molecules are released when a hexapeptide is synthesized from free amino acids?
9
58
Fe(2+) is protected from ____________ by surrounding nitrogen atoms in the pyrrole ring structure of heme and a nitrogen atom of a histidine
Oxidation
59
The interaction of ligands with proteins:
Is temporary
60
The heme part of protein in myoglobin is the _____________
Prosthetic group
61
In sickle cell anemia, __________ is replaced by ________ in subunit beta
Hydrophilic (glu)/hydrophobic (val)
62
What is the most likely weak interaction between the R groups of valine and alanine in an aqueous solution?
D. Hydrophobic Interaction
63
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
64
The main stabilizing force in alpha-helices is __________.
Hydrogen bonding
65
Two amino acids of the standard 20 contain sulfur atoms. They are _______________.
Methionine and cysteine
66
Changing the shape of a molecule by rotating functional groups around a single bond, without breaking it, leads to ___________________.
A conformation change
67
The formation of a peptide bond is a _____________.
Condensation
68
The chirality of an amino acid results from the fact that its alpha-carbon __________________.
Is bonded to four different chemical groups
69
___________ is/are (a) covalent stabilizing force in the tertiary/quaternary structure of many proteins
Disulfide bonds
70
Oxygen is a(n) _____________ of hemoglobin
Ligand
71
The charge of aspartate at pH 12 is __________
-1
72
Some of the typical symptoms of sickle cell anemia are signs of _________
Lack of oxygen supply to the body
73
Which of the following is NOT a fibrous protein?
A. Alpha-Keratin
B. Collagen
C. Insulin
C. Insulin
74
```
Which of the following involve a double bond?
A.cis/trans isomers
B. Enantiometers
C. Diastereometers
D. Anometers
A. Cis/trans isomers
75
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
76
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
77
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
78
Name the two-covalent (enzyme-catalyzed) modification steps that occur in the rER and briefly explain why these modifications lead to better/stronger collagen
1. Hydroxylation
- Additional -OH for: increased hydrogen bonding and/or increased sites for glucosolation
2. Glucosulation
- Increases -OH for increased hydrogen bonding
79
How does the body adjust to high altitudes in the short term?
Increased BPG—>Lowers O2 affinity of Hb—>Increases O2 available to tissue
80
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)
81
The depicted Formula shows a _______________.
disulfide
82
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
83
What functional groups are present on this molecule?
Hydroxyl and Aldehyde
84
The depicted Molecule is an __________________.
anhydride
85
The functional group between R1 and R2 in the depicted compound is a(n) _________________.
Ester
86
The name of the amino acid #1 in the depicted oligopeptide is _____________________.
Tyrosine
87
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
88
The configuration at the α-carbon of the vast majority of naturally occurring amino acids is _________.
1. L
2. D
L
89
___________ 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
90
Hydrophobic interaction occurs between ___________ R-goups.
a. Nonpolar, aliphatic
b. Polar, uncharged
c. Aromatic
d. Positively charged
e. Negatively charged
a. nonpolar, aliphatic
91
The only uncommon amino acid found in proteins that is modified pre-translation is ___________.
a. selenocysteine
b. hydroxyproline
c. hydroxylysine
d. carboxyglutamate
a. Selenocysteine
92
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
93
The C-terminal amino acid in the depicted tripeptide is:
alenine
94
At pH 4, aspartate has an overall charge of __________.
d. +1
95
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
96
T or F
| Every amide bond is a peptide bond.
False
97
T or F
| Every peptide bond is an amide bond.
True
98
___________ is a prosthetic group of hemoglobin.
a. Histidine
b. CO
c. O2
d. Heme
e. Myoglobin
D. Heme
99
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.
100
The heme prosthetic group of hemoglobin consists of a pyrrole-ring system with _________ bound in its center.
Fe2+ (Iron)
101
_______________ is a ligand of hemoglobin.
O2
102
Fe2+ is protected from ________________ by surrounding nitrogen atoms in the pyrrole ring structure of heme and a nitrogen atom of a histidine.
Oxidation
103
Myoglobin shows a ______________ O2-binding curve.
Hyperbolic
104
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.
105
_____________ 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
106
The mutation behind scale cell anemia leads to the replacement of ________________ by ___________ in subunit β.
hydrophilic GLU
| hydrophobic VAL
107
Carriers of the sickle cell trait have protection from
Malaria
108
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
109
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.
110
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
