Proteins - after midterm Flashcards
which meat is the most important. That has played a significant role?
pork and beef
Is poultry included in the “meat”?
no
why almost all meat is consumed from young animals
because strenghthening of the muscles with time leads to tougher meat
The color of the meat is red to reddish pink why it is that
Myoglobin
red meat is mainly composed of what
skeletal muscle
What are other tissues that are associated with muscle’s physiological function?
bone, connective tissue, adipose tissue, nerves and blood
Meat composition will dependent on what
on the relative proportion of each type of tissue
what are the factots that affect the gross composition of re meat?
species, breed, sex, age, nutrition of the animal and the muscle condition
What are other factors that can be additioned when cuting meat?
anatomical location of the retail cut
extent of retail trim
methods of processing and cooking
In beef, pork and lamb what are the composition that composes most of their tissue. And in second, third, and 4th place
water
protein
lipid
ash
true or false
does meat has a lot of water
true
true or false
does meat has a lot of lipid
false
how is water found in the composition of the meat
they are either bound to proteins or free - trapped within muscle cells
how is protein analysed in meat
they are analyzed by the % of nitrogen content in the meat by doing a method called Kjeldahl analysis.
The % of nitrogen in the tissue is multiplied by 6.25 a factor that is based on the average of nitrogen amount
what is the method that we can do to calculate the amount of nitrogen in the meat
Kjeldahl analysis
true or false
the protein content of red meat is lower than usually reported
true
The values of the lipid that are stored in meat means what
The larger values indicated the prensence of variable amounts of neutral storage lipids
Wht there is a large variability in the % of lipid content
because the variability of lipid content is accounted by the variablity in water content
what is ash and what it does represent
it is the inorganic residue that remains after a muscle sample is incinerated at extremely high temperatures and it represent the mineral component of muscle
what is the main carbohydrate in meat
lactate
why the main carbs of meat is lactate
because it is in the muscle where it occurs the conversion of glycogen to lactate by anaerobic glycolysis
complete the sentence
However, the main carbohydrate in meat is …
because during conversion of muscle to meat the glycogen is
largely converted to lactate by … glycolysis.
lactate
anaerobic
Proteins in skeletal msucke can be separated based on their solubility into 3 classes, which are they?
- sarcoplasmic
- myofibrillar
- stromal
Which one of the classes (sarcoplasmic, myofibrillar, stromal) is
- Soluble
- insoluble
- concentrated in salt solution
- sarcoplasmic is soluble and 30% of total muscle
- stromal is insoluble and 10-20% of total muscle protein
- myofibrillar is concentrated in salt solution. 50-60% of total muscle proteins
Where is sarcoplasmic protein dissolved
cytoplasm (sarcoplasm ) inside the muscle cell
What are the proteins of the sarcoplasmic class and what are their function?
myoglobi and glycolytic enzymes. They regulate the cell and energy homeostasis
The colors f meat is associated with what
the oxidation state of the iron which is associated with myoglobin
Which animal as a paler color: young veal or an adult beef
young veal- they have less myoglobin
true or false
myofibrillar proteins constiture the largest fraction
true
Myofibrillar proeins can be concentarted in what
salt solutions
how is myofibrillar comports itself in the muscle tissue
because the muscle tissue has a high concentration of salt the myofibrillar is assembled into a compelx quternary structural filaments
what does a quaternary structural filaments do
it regulated, support perform the mechanical work of contraction
In the myofibrillar which protein is contractile
myosin and actin
what is the function of myosin and actin
myosin: muscle contraction in association with actin
actin: muscle contraction in association with myosin
what are the regulatory protein in myofibrillar proteins
troponin C, troponin I, troponin T and tropomyosin
what is the function of the TROPONIN COMPLEX (troponin C, troponin I, troponin T)
tromponin C: binds calcium
tromponin I :inhibits actin/myosin interaction
troponin T: binds the troponin complez to tropomyosin
what is the function of tropomyosin
binds actin and troponin
myosin anc actin together make for .. % of the total protein in skeletal muscle
40
Why the behavior of myofibrillar proteins is important in fresh meat?
because of the contraction and rigor mortis can be critical in the successful conversion of muscle to meat
What stromal proteins do
they form the fibrious connevtive tissues that strengthen and protect muscle - these insoluble proteins contribute to meat toughness
Complete the sentence:
… the most abundant protein in the animal body, is also the
most prevalent of the stromal proteins in muscle
collagen
what processing and cooking methods for meat do to collagen fibers?
theu are disrupt and partially solubilized
non protein nitrogen is made of what
creatine, amino acids, nucleic acids and nucleotides
What are the 2 sources of non-protien nutrogen that are key to the devlopment of rigor mortis
creatine and nucleotide ATP
complete the sentece
each myofiber is encased in a layer of connective tissue called
endomysium
groups of myofibers are organized into primary and secondary bundles of fascicles that are segregated by another layer of connective tissue called
perimysium
final layer is … it surround the whole muscle
epimysium
the 3 layers of the muscle are
endomysium, perimysium and epimysium
the perimysium and the endmysium combine to form what
to provide the necessary framework for maintaining the structural integrity of these tissues within the msucle
What is embedded in the perimysium layer
adipose tissue
if we see an aidpose tissue embedded in the perimysium in red meat what is the name
marbling
how does muscle cells function
by translation of electrochemical impulses - triggered by neural simulation
An increase in what ion will trigger muscle concentration?
calcium
Myofibers are bound by what
plasma membrane
what conducts the stimulus for contraction into the interior of the myofiber
T tubules
T tubules are in contact with what? and what are their function?
they are in contact with SR (Sarcoplasmic Reticulum) which encircle the contractile organelles and function as a reservoir of calcium. They serve as a trigger of muscle contraction
lysosome serve asa reservoir for a family of proteolytic enzymes known as
cathepsins
what cathepsin do
play a catabolic function in protein turnover
myofibers are typlically
a. 1 nucleous
b. 0 nucleus
c. multinucleated
c. multinucleated
the sarcoplasm has 2 elements that will vary depending on the muscle fiber, nutrion and exercise. What are those 2 elements
glycogen and lipid
1) complete:
the … storage protein myoglobin is found to varying
degrees within the sarcoplasm
2) what are also examples that can vary
1) oxygen
2) A.A, nucleotides, enzymes, etc
what are the 3 types of myofibers?
type 1: slow red
type 2a: fast red
type 2b: fast white
slow contracting red myofibers contains what
conain a lot of oxidative organelles and fuels like mitochondria, myoglobin and lipid
fast contracting myofibers are more equipped for what
anaerobic metabolism fueled by carbs
myofibrilis is what of the organelles of a muscle and what its his volume
it is the contractile organalle and constitute of 80-90% of the volume of the cell
myofibrilis is composed of what
protein filaments in a highly specific structural organization
wat is the fundamental structural unit of the myofribrils
sarcomere
when you put a muscle under the microscope what do you see
A-bans and I-bans. They are anisotropic and isotropic
what the A band constis of? and the I band ?
A-band consist of overlapping thin and thick fiaments while the I bands consist of thin filaments only
The center of the A-band is brighter than the rest. What is the name of this part? and what this zone consist of
H zone it consists only of thick filaments with no overlapping thin filaments.
Define sarcomere lengths and what is depend on?
definition: distance between adjacent Z-diss
dependent: on the satte of contraction of the myofiber on the stretch force applied to it
during a contraction and resting state does both thin and thick filaments remain constant?
yes
explain the shortening of the sarcomere lenght
thin filaments and thick
filaments interdigitate, allowing for sliding of filaments past each other. Thus, when contraction takes place, the thin and thick filaments
slide past each other such that the thin filaments at opposite
ends of a sarcomere move toward each other
myofibrils is madeup of myofilament which is composed of what
myosin and actin
what is the 2 functions of actin?
binds to myosin and binds to the regulatory proteins tropomyosin and troponin
what is the function of tropomyosin?
exists in the myofiber as a head-to-tail
polymer
what is the 3 subunits of troponin
troponin T
troponin C
troponin I
What is nebulin
a large cytoskeletal protein associated with thin filaments
what is the most abundant msucle protein
myosin
what hapens during muscle at rest
When the muscle cell is at rest, tropomyosin sterically blocks
myosin heads from binding to the myosin-binding sites of the actin
filament.
sarcoplasmic proteis include enzymes associated with glycolysis and glucogenolysis. What is the most abundant glycolytic enzyme?
glyceraldehyde phosphate dehydrogenase - over 20% of the total sarcoplasmic protein fraction
what are the 5 most abundant sarcoplasmic proteins in muscle?
phosphoglucose isomerase
phosphofructokinase
glyceraldehyde phosphate
creatine kinase
adenylate kianse
phosphorylase B is more abundant in ….. because these myofibers rely hevily on glycolysis for energy requirements
type II b myfibers
myoglobin is present in greater abundance in … because they derive a greater share of their energy from oxidative metabolism.
type I myofibers
How is AMP formed? and what is produced
AMP is formed by 2ADP-> ATP+ AMP
this happens after the animal dies. AMP will after form IMP and NH3
IMP is further degraded to …, which imparts a bitter flavor to meat
hypoxanthine
complete the sentence
Among the proteinases in muscle sarcoplasm, the calcium dependent proteinases known as … are of particular
interest in relation to the conversion of muscle to meat
calpain
what is the role of calpain
convert muscle to meat. they breaj down particular proteins of the muofibril such as titin, nebulin and TnT during postmorde,
what are the 3 types of calpain? and how they are activated
u calpain activated by micromolar concentration of calcium
m calpain activated by milimolar concentration of calcium
calpain 3 activated by submicromolar conc of ca
which protein consist in stromal proteins
collagen (90%) and elastin (10%)
where is collagen found
in connective tissues such a bone, tendons
what is the basic unit of collagen
tropocollagen - constis of 3 polypeptide alpha chains
type 1 collagen and type 3 collagen are made of what
type 1: 2 alpha chains of alpha 1 and 1 chain of alpha 2
type 3 collagen: 3 identical chains of alpha 1
which amino acid is absent in collagen
tryptophan
what is a common repeating sequence of A.A in collagen
glycine-proline,- hydroxyproline
Glycine is the amino acid with the smallest possible “side chain”
(i.e., H) and thus is the only amino acid that could be
accommodated in the … of such a structure
interior
… Fish sarcoplasmic proteins are mostly
enzymes. These enzymes correspond to those of mammalian
muscle tissue.
sarcoplasmic proteins
connective tissue is lower in mammalian muscle or in fish
fish
During bacterial decay of the flesh, a large
amount of … is formed from histidine
histamine
ovalbumin
The major globular protein in albumen is ovalbumin. It
is a phosphoglycoprotein, with a molecular weight of about 44.5
kD
… is the most easily heat-denatured egg protein but it
is less susceptible to surface denaturation than ovalbumin
ovotransferrin
ovomocoid
is a glycoprotein consisting of three
tandem homologous domains, each cross-linked by three disulfide
bonds, with a total molecular weight of 28 kDa
lysozyme
It is a bacteriolytic enzyme commonly found in nature that
catalyzes the hydrolysis of the glycosidic linkage between Nacetylmuraminic acid and N-acetylglucosamine in the
polysaccharides of certain bacterial cellwalls
True or false. As the acidity increase the solubility decreased in soy protein
True
What are the principle components of 2S, 7S, 11S and 15S
2S : alpha conglycinin
7S: beta conglycinin
11S: glycinin
15S: dimer of glycinin
Which enzyme is responsible for rancidity in soybean oil and that leads to a bad smell
Lipoxygenase
What is the 2 types of trypsin inhibitor
Kunitz and bowman-birk
What is the function of hemagglutenins
Produce red blood cells
What so the functional properties of soy protein
Emulsify, form gels, foams, thickens
…. 65% to 85% protein content. Usually manufactured by using alcohol to remove the soluble carbohydrates from the oiled soy flakes.
… are produced using minimum heat and homogenization followed by spray drying or by water wash process at an acid ph
…protein content higher than 85%. It produces a bland flavour, light in colour and have a number of functional properties such as gelatin, emulsification, water holding, etc
Soy proteins concentrate
Functional soy concentrate
Soy protein isolate
What is the major component of cereal protein
Starch
What are the 2 major groups of gluten
Gluten in and gliadin
Which bond glutenin has
Intermolecular disulphide bonds
Which bonds gliadin has
Intramolecular disulphide bonds and SH groups
When glutenin and gliadin are bound together, what happens
They form a dough/ elastic. The elasticity is due to the interaction of glutenin and gliadin and the S-S bonds and the S-H bonds. When you are kneading this reactions are formed and broken
