Exam 2 Flashcards
Rigor mortis is due to
Lack of ATP in post mortem muscle
Formation of actin myosin cross bridges
Protein denaturation
Occurs when ph declines rapidly while muscle is still warm
Causes change in protein conformation and or function
Resolution of rigor occurs due to
Proteolytic dissolution of the z disks
Dissolution of the myostatin gene
Causes extreme or double muscled cattle
The callipyge gene
Causes higher muscle calpstatin levels
Rendement Napole (RN)
Leads to altered AMPK
Halothane (Hal) gene
encodes for mutated SR calcium change proteins
The calpain enzyme system is
most active at neutral ph
primarily responsible for improvements in tenderness during aging
requires calcium for activity
Feed withdrawal prior to slaughter is important to
reduce transport weight
reduce excreta during transport
reduce risk of gastral intestinal track lacerations
decrease cost of handling digesta
Which of the following affect stress when moving animals
loading ramp design
moving objects
shadow/ lighting
alley way flooring design
Rigor mortis is stiffening of death
true
Myoglobin is the pigment responsible to 80-90% of the color of meat
true
Rigor mortis onset is typically faster in pork than in lamb or beef muscle
true
shorter sarcomeres are correlated with tougher meat
true
The enzyme m-calpain requires millimolar calcium for activity
true
Pyruvate contains 4 carbon atoms
false
Three USDA approved methods of stunning include: physical (captive bolt), CO2, and electrical
true
According to the text, Halal and Kosher ritual slaughters do not allow stunning prior to exsanguination
true
The two largest contributors to postmortem changes are deviation in tissue temp and ph
true
Lactic acid is frequently used as carcass antimicrobial
true
DFD
dark, firm, dry
PSE
pale, soft, exudative
pH
=-log[H+]
ATP
Adenosine triphosphate
ADP
Adenosine diphosphate
PSS
Porcine Stress syndrome
rigor mortis
stiffness of death
glycogen assimilation
glycigenisis
glycogen breakdown
glycogenolysis
glucose storage form in muscle (muscle starch)
glycogen
cellular pathway for glucose lysis
glycolysis
ATP yield from 1 molecule of glucose diffusing into myofiber during aerobic conditions
34
resting place before slaughter
lairage
ambient temperature where animal does not need to alter its basal metabolic rate
thermal neutral zone
ATP yield from 1 molecule of glucose-1-p from glycogen during aerobic conditions
35
weight loss during transport of live animals
shrink
non-ambulatory animals
downers
propels a retractive bolt into the skull
captive bolt stunner
distance at which an animal will move away from the handler
flight zone
esophagus
weasand
maintenance of a relatively narrow range of physiological conditions
homeostasis
hemorrhaging and bruising in meat
blood splashing
ATP yield from 1 molecule of glucose-1-P from glycogen during anaerobic conditions
3
list the organs contained in the thoracic cavity
heart, lungs, esophagus and trachea
List the organs contained in the abdominal cavity
kidneys, reproductive tract, rumen/ stomach, bladder, liver, large and small intestine
***Under aerobic conditions over 30 ATP can be generated from a single glucose molecule. Under anaerobic conditions, however, only 2 ATP are generated. Why?
There is a lack of oxygen under anaerobic conditions which means that it cannot undergo the TCA cycle but instead NADH + H+ —> NAD+—> Lactate + H+
***Why is glycogen branched
more compact
takes less water to hydrate
utilize multiple glucose at once
stored as glycogen in cell
*** Why is glucose stored as glycogen and not free glucose
so it can stay in the cell by being more compact and branched
*** the conditions and muscle physiology which results in cold shortening
muscle is chilled to 15-16 degrees C before rigor onset
toughening
*** why ph of normal beef muscle decreases from about 7.4 in the living muscle tissue to 5.4 in the post rigor muscle/meat
H+ builds
ATP hydrolysis
Pyruvate —> lactate
pH decreases because H+ is released each time ATP is hydrolyzed. Pyruvate is changed to lactate which is necessary to regenerate NAD+, there is not oxygen must go anaerobically
*** why, physiologically, rigor mortis occurs in post- mortem muscle
Due to formation of actin-myosin cross bridges
lack of ATP because calcium is high
*** the following phrase: Muscle tissue does not cease functioning at death
ATP is still being generated and muscle is still trying to contract. It does this until all the ATP is spent and it noes not have enough energy to contract. glycolysis occurs
***Why does lactate accumulate in post mortem muscle instead of pyruvate
it is necessary to regenerate NAD+ which is needed in the glycolytic pathway
***Why is the muscle produced from the fastest ph decline pale in color, soft textured, and exudative
loses the water holding capacity
denatures the muscle proteins
muscle absorbs less light, more light reflected
***Why is the highest pH muscle dark in color, firm, textured, and dry or sticky to the touch
glycogen reserves depleted antemortem
relatively high postmortem muscle pH
less effect on water holding capacity, absorbs more light
In chronological order, list the steps involved in slaughter of livestock
1) Stunning
2) Exsanguation
3) Skinning/ Scalding
4) feet and leg removal
5) head removal
6) Eviseration
7) Splitting
8) antimicrobial treatments
9) chilling
what is the red colored liquid that exudes from a retail meat package in the meat counter
sarcoplasm
During my recent elk hike, I came across a guy butchering Eskimo style. What would you tell him about the quality of his loin meat in regards to tenderness
His back straps are going to shrink size because they don’t have tension pulling on them while they go into rigor. The tenderness of the backstrap will be affected greatly because the sarcomeres will be short which makes meat tough
WHC
water holding capacity
Means favorite steak in retail meat case
beef loin, top loin, boneless aged 40 days
Live animal pH
7.4
dead animal pH
5.7-6.8
3 ways to buffer against ATP loss in muscle
1) phosphagen system
2) glycolysis
3) mitochondrial respiration
3 undesirable characteristics af aging
1) microbial growth
2) increased shrink loss
3) lipid oxidation lowers flavor and freezer time
m-calpain
millimolar calcium
u-caplain
micromolar calcium
Antemortem Effects
“Stress” hormones affect metabolism
Epinephrine aids
glycogen breakdown stored in liver and muscles
fat metabolism
Epinephrineand Norepinephrine
maintain adequate blood flow (vaso-dilation)
increased heart rate
Thyroid hormones
increase metabolic rate
Denaturation
rapid ph decline
carcass temp is high
Pale
muscle absorbs less light, more reflected
soft
myofibers contain less water- softer
Myostatin
gene disruption
double muscled cattle
hyperplasia
Halothane (Hal)
mutated SR Ca++ channel protein
muscle keeps contracting because calcium keeps getting let out
Anaerobic
PSE
Rendement Napole (RN)
altered adenosine monophosphate kinase
greater amounts of glycogen in muscle
lower ultimate postmortem pH
Callipyge
Sheep
beautiful buttocks
very muscular hind leg phenotype
higher calpastatin levels
Thaw rigor
when muscle frozen pre rigor is thawed
extreme toughening
cold shortening
when muscle chilled 15-16 degrees before rigor onset
toughening
Carcass electrical stimulation
Not in pork
improvements in tenderness
improves meat quality
