Proteins - Summary I Flashcards
(160 cards)
1
Q
______ serves as a template upon which myosin molecules form the thick filament during muscle cell differentiation and development.
A
Titin
2
Q
Quaternary structures do not have ___________, unlike tertiary structure
A
NO covalent bonds (disulfide crosslinks)
3
Q
The _____ are more polar than the acid forms, and hence make proteins (more/less) water-soluble
A
amides more
4
Q
The _______ serves as an anchoring point for the protein titan
A
M-line
5
Q
Casein is a ____________ with the phosphate attached to _______
A
phosphoprotein serine
6
Q
Proteinases break down particular proteins of the myofibril, such as ____, ____, and _____ during postmortem conversion of muscle to meat
A
titin nebulin troponin-T
7
Q
____-casein contains 2 cysteine residues, and is only accessible under reducing conditions
A
K
8
Q
The a-helix is stabilized by _______ bonding due to the repetitive proximity of the peptide ___________ (electron-rich) and the _________ from the nitrogen ___ residues away
A
hydrogen carbonyl oxygen hydrogen 4
9
Q
All the variations of ___________________ contain 8 phosphoserine residues, 7 of which are localized between 43 and 80
A
as1-casein
10
Q
___________ binds the troponin complex to tropomyosin
A
Troponin-T
11
Q
___________ are produced by the enzymatic treatment of WPI to break the proteins into peptides that are more easily digested, while the nutritional quality of the protein remains high
A
Whey protein hydrolysates
12
Q
Between pH 3.1 and 5.1, at low temperatures and high concentration, B-lactoglobulin associates to form an _______
A
B-lactoglobulin octomer
13
Q
________ make up 30% of total muscle protein, and is soluble
A
Sarcoplasmic proteins
14
Q
The suprahelix is held together by _______ bonds supplied by ________
A
hydrogen glycine
15
Q
Amino acids with a ____________ group can also undergo reactions with reducing sugars at high temperatures
A
secondary amine
16
Q
Lactose can be recrystallized to yield a _________, which is used as a ________
A
raffinate filler in tablets
17
Q
When _______-casein precipitates with Ca2+, at temperatures of < 1oC, the calcium salt is quite soluble
A
B
18
Q
Groups of myofibers are organized into primary and secondary bundles of _______ that are segregated by another layer of connective tissue called the ________.
A
fascicles perimysium
19
Q
10% of the total casein fraction is present in milk as _________, usually designated as _______ caseins
A
monomers serum
20
Q
The fundamental structural unit of the myofibrils is the _________.
A
sarcomere
21
Q
Casein and the enzyme renin are examples of _________
A
phosphoproteins
22
Q
Upon binding to actin, _________ swivel to approximately a 45oC, pulling the _____ filaments past the _____ filaments toward the _________
A
myosin heads thin thick M-line
23
Q
________ make up 10-20% of total muscle protein; insoluble
A
Stromal proteins
24
Q
Soy sauce is a _____________ produced by the fermentation of soybeans
A
protein hydrolysate
25
The T-tubules are in physical contact at periodic intervals with the \_\_\_\_\_\_\_\_\_\_\_\_\_, which is the muscle equivalent of an endoplasmic reticulum
sarcoplasmic reticulum
26
\_\_\_\_\_\_ is a large skeletal protein associated with thin filaments
Nebulin
27
\_\_\_\_\_\_\_\_\_ contain great amounts of ______ organelles and fuels, such as mitochondria, myoglobin, and lipids
Slow-contracting (red) oxidative
28
The ______ consists of thin filaments only
I-band
29
The peptide bond is an ______ bond
amide
30
Decarboxylase enzymes are inhibited by \_\_\_\_\_\_
DMFO
31
However, at physiological ionic strength, G-actin monomers are polymerized “head-to-tail” in \_\_\_\_\_\_\_\_
F-actin
32
Strongly alkaline environments can lead to ___________ of amino acids
racemization
33
\_\_\_\_\_ contains 2 disulfide bonds, 1 free sulfhydryl group, and no phosphorus
B-lactoglobulin
34
In the case of casein micelles, _______________ are minimal at temperatures below 5oC
hydrophobic interactions
35
\_\_\_\_\_\_\_\_\_ are proteins that are soluble in 50-90% ethanol and insoluble in water
Prolamines
36
Gliadin from wheat is an example of \_\_\_\_\_\_\_\_\_\_\_
prolamines
37
\_\_\_\_\_\_\_\_ linkages play an important role in the 3D structure of a protein, and make it less susceptible to denaturation
Diester
38
All proteins are synthesized from __ amino acids
L
39
Whey protein concentrates are produced by \_\_\_\_\_\_\_\_\_\_\_\_
ultrafiltration
40
At the ________ end of the myosin chain, the protein exhibits a globular structure called the \_\_\_\_\_\_
amino myosin head
41
\_\_\_\_\_\_\_\_\_\_ is activated by micromolar concentrations of Ca2+
u-calpain
42
\_\_\_\_\_\_\_ is a globular monomer
G-actin
43
The initial Maillard reaction forms \_\_\_\_\_\_\_\_\_
Glycosylamine
44
The _______ amino group is the most reactive amino group in Lysine.
epsilon
45
In the horse and rider model of \_\_-casein, the \_\_\_-terminal makes up the horse, the \_\_\_\_-terminal makes up the rider, and the two legs of the horse are made of \_\_\_\_\_\_\_
K N C B-structures
46
A very high pH is needed to suppress the _____ charges on the _____ side chains (i.e. to convert _____ to \_\_\_\_)
positive basic NH3+ to NH2
47
\_\_\_\_\_\_\_ is considered to be somewhat basic, and is capable of ionizing beyond pH 10
Tryptophan
48
Chymosin cleaves K-casein into ___________ and a \_\_\_\_\_\_\_\_\_\_\_
para-K-casein glycomacropeptide
49
filaments on opposite sides of the _____ are directed toward each other within a given sarcomere.
M-line
50
The _______ consists of overlapping thin and thick filaments
A-band
51
The AMP formed by adenylate kinase is _______ to \_\_\_\_\_\_\_\_\_\_, which is catalyzed by ________ (sarcoplasmic protein fraction)
deaminated IMP AMP deaminase
52
A very low pH is needed to suppress the _____ charges on the _____ side chains (i.e. to convert _____ to \_\_\_\_)
negative acidic COO- to COOH
53
The ____________ AA provide flavor due to their breakdown when being cooked, mainly due to the release of \_\_\_\_\_\_
sulfur-containing H2S
54
Due to the ____________ form of AA and \_\_\_\_\_\_\_\_\_\_, protein polymers tend to twist upon itself
L-chiral steric hindrance
55
40% of the residues of the AA sequences of \_\_\_\_\_\_\_\_\_\_\_\_\_and _____________ are the same, including the cysteine residues, and 20% of the residues are similar
a-lactalbumin lysozyme
56
\_\_\_\_\_\_\_\_ has 4 disulfide linkages and no phosphate groups
a-Lactalbumin
57
There might be ___________ during freezing, but there is little browning due to \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
denaturation low temperature of sublimation
58
What is PER's equation?
Weight gained/Weight of protein consumed
59
\_\_\_\_\_\_\_\_\_\_\_\_\_ is one of the best methods of drying in terms of maintaining protein functionality, nutritional quality, and enzyme activity (expensive)
Freeze drying
60
\_\_\_\_\_\_\_ is the most abundant muscle protein, constituting 43% of the muscle myofibril.
Myosin
61
Arginine, Tryptophan, Histidine, Glutamine, and Asparagine all have a ___________ group
secondary amine
62
\_\_\_\_\_\_\_\_\_\_\_ contains 5 phosphoserine residues that are localized between 1 and 40, which contains practically all the __________ sites of the molecule
B-casein ionizable
63
The C-CO-NH-C unit is planar with the ___________ and ___________ of the peptide bond always trans to each other
carboxyl oxygen amino hydrogen
64
The center of the A-band appears brighter than the distal zones (less dense), and is termed the \_\_\_-zone.
H
65
The _________ trigger the release of Ca2+ from the lumen of the \_\_\_\_\_\_\_\_\_\_, which rises at least \_\_\_\_-fold
T-tubules sarcoplasm 100
66
Which milk protein has a dynamic disulfide bond?
B-lactoglobulin
67
This structure, called the \_\_\_\_\_\_, consists of proteins that maintain the structural arrangement of the thick filament proteins
M-line
68
Below pH 3.0 and above pH 8.0, \_\_\_\_\_\_\_\_\_\_exists as a \_\_\_\_\_\_
B-lactoglobulin monomer
69
At the pH of milk, _________ tends to form a \_\_\_\_\_\_
B-lactoglobulin dimer
70
\_\_\_\_\_\_\_\_ and ________ are used in the manufacture of paper for coating to improve the adhesion of ink to the surface, in waterproof glue, to make fabrics water-repellent, etc.
Caseins caseinates
71
What are the 3 types of myofibers?
1) Slow-red 2A) Fast-red 2B) Fast-white
72
\_\_\_\_\_-casein is a monomer
K
73
The side chains of the amides of _____________ and _____________ play a role in non-enzymatic browning reactions
aspartic acid glutamic acid
74
\_\_\_\_\_\_\_\_\_\_ modifies the activity of galactosyl transferase
a-lactalbumin
75
\_\_\_\_\_\_\_\_ are proteins that are soluble in water and precipitated by ammonia
Histones
76
The _________ are anchored at the Z-disc
thin filaments
77
Proteins are separated on the basis of \_\_\_\_\_\_\_\_\_\_
solubility
78
Classify the troponin subunits from largest to smallest.
Troponin-C \< Troponin-I \< Troponin-T
79
\_\_\_\_\_ is the largest single polypeptide chain known
Titin
80
\_\_\_\_\_\_\_\_\_ are basic proteins, which contain large amounts lysines and arginines
Histones
81
\_\_\_\_\_\_\_\_\_\_\_\_ causes extensive denaturation and browning if sugars are present
Drum drying
82
Each myofiber is encased in a layer of connective tissue called the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
endomysium
83
\_\_\_\_\_\_\_\_ contains a portion with 12 carboxyl groups from _____________ and _____________ residues, making it extremely \_\_\_\_\_\_
as1-casein glutamic acid aspartic acid polar
84
In \_\_\_-casein, varying amounts of carbohydrate are bound to the peptide chain through Threonine residues at positions 131, 133, 135, or 136 (A variant)
K
85
To produce a casein product that is soluble or readily dispersible, the casein is dispersed in ______ and treated with ______ at 90oC and pH 6.2-6.7
water alkali
86
The electrostatic interactions in casein micelles are mostly between ________ and ________ that form bridges between __________ and ________ residues
calcium calcium phosphate phosphoserine glutamic acid
87
\_\_\_\_\_\_\_\_\_ serve as a major reservoir for a family of proteolytic enzymes known as \_\_\_\_\_\_\_
Lysosomes cathepsins
88
When myosin heads form cross-bridges between the thick and thin filaments, they are placed ________ to the thick filament axis
perpendicular
89
The narrow, dark, electron-dense center of the I-band is termed the \_\_\_\_\_\_\_\_\_\_
Z-disc
90
The plasma membrane of myofibers is called the \_\_\_\_\_\_\_\_\_\_
sarcolemma
91
In \_\_\_\_\_\_\_, AA 100-199 are _______ and responsible for the self-association tendencies of the protein despite the repulsive forces between the _________ groups, and the lack of ___________ residues
as1-casein apolar phosphate cysteine
92
\_\_\_\_\_\_\_\_ precipitates with Ca2+ more easily than as1-casein
as2-casein
93
What are the three classes of proteins?
Sarcoplasmic Myofibrillar Stromal
94
B-lactoglobulin is effective at binding \_\_\_\_\_\_\_\_\_\_
retinol
95
\_\_\_\_\_\_\_\_\_\_ is found both in the sarcoplasm and as a component of the ______ of the myofibril
Creatine kinase M-line
96
\_\_\_\_\_\_\_\_ binds Ca2+ ions
Troponin-C
97
The protein _____ spans the sarcomere from the _____ to the \_\_\_\_\_\_\_
titin M-line Z-disc
98
Unlike \_\_\_\_\_-casein, \_\_\_\_\_\_-casein does not self-associate spontaneously
as1 B
99
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ adds UDP-galactose to glucose and produces _______ and UDP, which is faster when __________ is attached
galactosyl transferase lactose a-lactalbumin
100
a-lactalbumin uses calcium to form _________________ bonds that tend to make the molecule resistant to thermal unfolding
intramolecular ionic
101
At very low ionic strength, actin exists primarily as \_\_\_\_\_\_\_\_\_\_
G-actin
102
\_\_\_\_\_\_\_\_ make up 50-60% of total muscle protein; solubilized in concentrated salt solutions (e.g., 0.3M NaC1)
Myofibrillar proteins
103
The ___ variant of B-lactoglobulin forms more readily than the ___ variant since it has an extra ______ group
A B carboxyl
104
\_\_\_\_\_\_\_\_\_ runs the entire length of the thin filament, spanning seven actin monomers
Tropomyosin
105
Certain proteins can reduce surface tension, resulting in the formation of a \_\_\_\_
foam
106
\_\_\_\_\_\_\_\_\_\_ are proteins that are soluble in neutral, dilute salt solution, but not in distilled water
Globulins
107
The ___________ and the _________ combine to provide the necessary framework for maintaining the structural integrity of these tissues within the muscle.
perimysium endomysium
108
\_\_\_\_\_\_\_\_\_\_\_\_ are less likely to trigger allergic reactions than \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_; they are used often in infant formulas
Whey protein hydrolysates non-hydrolyzed whey protein
109
Stretching results from an increase in _____ separation, accomplished by sliding of thin filaments of a sarcomere from each other as they move along the \_\_\_\_\_\_\_\_
Z-disc A-band
110
\_\_\_\_\_\_\_\_\_ proteins form the fibrous connective tissues that strengthen and protect muscles
Stromal
111
The _________ functions as a reservoir of calcium ions that serve as the trigger for muscle contraction
sarcoplasmic reticulum
112
The _______ penetrate into the myofiber, and form a network of \_\_\_\_\_\_\_\_\_\_\_\_, distributed along the length of the myofiber, and conduct the stimulus for contraction into the interior of the myofiber
sarcolemma transverse tubules (T-tubules)
113
\_\_\_\_\_\_\_ aromatic AA is reactive due to its OH group; forms _____ linkages with phosphate
Tyrosine ester
114
Proteins with significant quantities of \_\_\_\_\_\_\_\_\_\_\_, \_\_\_\_\_\_\_\_\_\_\_, and ___________ are especially susceptible to changes in pH
aspartic acid, glutamic acid, and lysine
115
\_\_\_\_\_\_\_\_\_ are proteins that are soluble in dilute acid or base, but not in neutral solutions
Glutelins
116
One _______ molecule extends from the Z-line to the distal end of a thin filament
nebulin
117
\_\_\_\_\_\_\_\_ inhibits the actomyosin ATPase
Troponin-I
118
The ______ consists only of thick filaments with no overlapping thin filaments
H-zone
119
At the center of the _____ is a dark zone analogous to the \_\_\_\_\_\_.
H-zone Z-disc
120
Which milk protein associates to form a barrel with _______ and a lid with \_\_\_\_\_\_\_?
B-lactoglobulin B-structures a-helix
121
\_\_\_\_\_\_\_ is used to remove headspace oxygen from food packages
Glucose oxidase
122
\_\_\_\_\_\_\_\_\_ are proteins that are soluble in neutral distilled water
Albumins
123
The red to reddish pink color of red meat is due to \_\_\_\_\_\_
myoglobin
124
The changes from freezing are exemplified by the loss of __________________ (manifested by the development of freezer drip) and often result in a loss of desirable texture
water-binding capacity
125
\_\_\_\_\_\_\_\_\_\_\_\_ is unusual since the molecule is more stable to heat in the presence of calcium
a-lactalbumin
126
\_\_\_\_\_\_\_ and _______ can disrupt H-bonds by _______________ of a protein
Alcohol acetone partial dehydration
127
\_\_\_\_\_\_\_\_\_\_ are proteins that are insoluble in water and neutral salts
Scleroproteins
128
Upon stimulation of a muscle fiber by the nerve, the neurochemical impulse is transmitted into the fiber by the \_\_\_\_\_\_\_.
T-tubules
129
Myoglobin is present in greater abundance in _______ myofibers because they derive a greater share of their energy from \_\_\_\_\_\_\_\_\_\_\_\_
slow-red oxidative metabolism
130
IMP is further degraded to \_\_\_\_\_\_\_\_, which imparts a _____ flavor to meat
hypoxanthine bitter
131
Sugars and carbohydrate are often attached to the amide group of asparagine by an \_\_\_-glycosidic linkage
N
132
\_\_\_\_\_\_\_\_\_\_\_\_ may also be found embedded in the __________ and is visible in red meats as while flecks of fat (marbling) in contrast to the red background of myofibers.
Adipose tissue perimysium
133
In putrefaction, at lower pHs, ________ are the most active, while at higher pHs, the _________ are the most active
decarboxylases deaminases
134
Which method is highly detrimental to whey?
- Steam injection - Precipitation of the denatured proteins - Sedimentation centrifuge - Drying
135
A final layer of heavy connective tissue sheaths, called the \_\_\_\_\_\_\_\_\_\_, surrounds the whole muscle
epimysium
136
Putrefactive odors and flavors are due to compounds produced by the _____________________________ by \_\_\_\_\_\_\_\_\_
enzymatic deamination or decarboxylation of free AA microbial enzymes
137
The portion of ______ located in the gap between the ______ filament and the ______ is elastic
titin thick filament Z-line
138
\_\_\_\_\_\_ contains 11 phosphoserine and 2 cysteine residues
as2-casein
139
Enzymatic action of cross-linked amide bonds will stop at ___ amino acid on either side of the cross-linked amino acids, leaving an indigestible \_\_\_\_\_\_\_\_\_\_\_
one hexapeptide
140
Denaturation of a protein generally results in a reduction in \_\_\_\_\_\_\_\_\_
solubility
141
\_\_\_\_\_ may be involved in restoring resting sarcomere length when the muscle relaxes
Titin
142
\_\_\_\_\_\_\_\_\_\_\_\_\_ are used to make meaty flavours
Protein hydrolysates
143
How is whey usually dried? What is a technique that can reduce the cost?
- Spray drying - Reverse osmosis
144
The thick filaments of the sarcomere are primarily composed of \_\_\_\_\_\_\_\_, and _____ is also associated with thick filaments
myosin titin
145
\_\_\_\_\_\_\_\_\_ AA are very reactive and play an important role in protein structure
Carboxylic
146
When ____ binds to Ca2+, this causes a change in the binding of ____ to \_\_\_\_, which in turns alters the binding between _______ and _______ in the thin filaments, which allows _____ to bind to \_\_\_\_\_
Troponin-C Troponin-T tropomyosin tropomyosin actin actin myosin
147
\_\_\_\_\_\_\_\_\_ is associated with microbial spoilage of high-protein foods
Putrefaction
148
Electron micrographs indicate that a thick filament is surrounded by an array of ___ thin filaments
six
149
\_\_\_\_\_\_ is the most hydrophobic casein
B-casein
150
\_\_\_\_\_\_\_\_\_\_\_\_ converts ADP to ATP and AMP, and is an enzyme present in the sarcoplasmic protein fraction
Adenylate kinase
151
Which casein acts like soap?
B-casein Polar head and an apolar tail
152
Like \_\_\_\_\_\_\_-casein, \_\_\_\_\_\_\_-casein contains no cysteine residues
as1 B
153
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ can make enzymes work in opposite ways
Organic solvents
154
Why aren't proline and hydroxyproline considered to be amino acids?
They do not contain a true amino group (NH2) - Instead they contain an imino group (NH)
155
The R group in Histidine is the _________ group
imidazole
156
Phosphorylase B is more abundant in _______ myofibers because these myofibers rely heavily on ______ for energy requirements
fast-white glycolysis
157
Classify the types of casein in order of most present to least present.
as1 \> B \> K \> as2 \> γ
158
What are the four proteins that consist of the thin filaments of the sarcomere?
- Actin - Tropomyosin and troponin - Nebulin
159
Normally, \_\_-casein occurs as a trimer or as higher oligomers by the formation of \_\_\_\_\_\_\_\_bonds
K disulfide
160
\_\_\_\_\_\_\_\_\_ are degradation products of B-casein formed by milk proteases
gamma-casein
