Exam 2 Flashcards by Mikayla Wilson

Rigor mortis is due to

Lack of ATP in post mortem muscle

Formation of actin myosin cross bridges

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Protein denaturation

Occurs when ph declines rapidly while muscle is still warm

Causes change in protein conformation and or function

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Resolution of rigor occurs due to

Proteolytic dissolution of the z disks

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Dissolution of the myostatin gene

Causes extreme or double muscled cattle

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The callipyge gene

Causes higher muscle calpstatin levels

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Rendement Napole (RN)

Leads to altered AMPK

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Halothane (Hal) gene

encodes for mutated SR calcium change proteins

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The calpain enzyme system is

most active at neutral ph
primarily responsible for improvements in tenderness during aging
requires calcium for activity

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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

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Which of the following affect stress when moving animals

loading ramp design
moving objects
shadow/ lighting
alley way flooring design

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Rigor mortis is stiffening of death

true

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Myoglobin is the pigment responsible to 80-90% of the color of meat

true

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Rigor mortis onset is typically faster in pork than in lamb or beef muscle

true

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shorter sarcomeres are correlated with tougher meat

true

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The enzyme m-calpain requires millimolar calcium for activity

true

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Pyruvate contains 4 carbon atoms

false

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Three USDA approved methods of stunning include: physical (captive bolt), CO2, and electrical

true

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According to the text, Halal and Kosher ritual slaughters do not allow stunning prior to exsanguination

true

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The two largest contributors to postmortem changes are deviation in tissue temp and ph

true

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Lactic acid is frequently used as carcass antimicrobial

true

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DFD

dark, firm, dry

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PSE

pale, soft, exudative

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=-log[H+]

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ATP

Adenosine triphosphate

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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

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

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

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