AnSci 171 M3

Question 1

Three types of muscle tissue

Answer 1

• skeletal muscle
• smooth muscle
• cardiac muscle

Question 2

providing elasticity elasticity to the walls of arteries, linings of the gastrointestinal, reproductive, urinary and respiratory tracts and lymphatic system.

Answer 2

smooth muscle

Question 3

is located only in the heart where it provides rhythmic contractions throughout an animal’s life.

Answer 3

cardiac muscle tissue

Question 4

cardiac muscle tissue is controlled involuntarily by the ____ nervous system.

Answer 4

autonomic

Question 5

skeletal muscle contraction is directly stimulated by ____ efferent nerves

Answer 5

somatic

Question 6

Comprised of the thin Actin filaments. Outer edge of the xadjacent sarcomeres.

Answer 6

I band (light bands)

Question 7

Marks the junction of actin filaments in adjacent sarcomeres. Also anchors the actin filaments.

Answer 7

Z line

Question 8

Thick myosin filaments, which overlap thin actin filaments.

Answer 8

A band (thick bands)

Question 9

Centrl region zone. Consists of thick filaments

Answer 9

H band

Question 10

In the center of A band

Answer 10

M band

Question 11

it is the functional unit of skeletal muscle.

Answer 11

sarcomere

Question 12

thick filaments are also known as

Answer 12

myosin

Question 13

thin filaments are also known as

Answer 13

actin

Question 14

is a fibrous protein chain that lies in the groove between the two strands of actin

Answer 14

tropomyosin

Question 15

covers the myosin binding site, preventing cross-bridges forming between actin and myosin

Answer 15

tropomyosin

Question 16

is the protein complex located at regularly spaced intervals along the tropomyosin protein chain. The troponin complex is made up of three subunits.

Answer 16

troponin

Question 17

binds the troponin complex to tropomyosin (hence ‘T’).

Answer 17

troponin T

Question 18

has an uncertain role

Answer 18

troponin I

Question 19

contains the Ca2+ binding site (hence ‘C ’for Ca2+). Binding of Ca2+ to troponin C causes tropomyosin to roll deeper into the actin groove, which uncovers the myosin binding site, allowing cross- bridges to form between actin and myosin

Answer 19

troponin C

Question 20

bind to troponin (on actin) and cause tropomyosin to move, exposing
binding sites for the myosin heads

Answer 20

calcium ions

Question 21

causes the myosin heads to swivel and change orientation

Answer 21

ATP hydrolosis

Question 22

sliding of actin along myosin therefore (shortens/elongates) the sarcomere, causing muscle contraction

Answer 22

shortens

Question 23

bind to the actin filament before returning to their original conformation (releasing ADP + Pi)

Answer 23

Swivelled myosin heads

Question 24

Distinctive connective tissue layers

Answer 24

• epimysium
• primysium
• endomysium

Question 25

Highest mass fractions or most abundant proteins in the Intramuscular Connective Tissue (IMCT)

Answer 25

Collagens

Question 26

Protein molecules made up of amino acids. It provides structural support to the extracellular space of connective tissues.

Answer 26

Collagens

Question 27

comprised of the protein elastin and associated microfilaments.

Answer 27

Elastic fibers

Question 28

minor component of IMCT and typically represents much less than 1% of the fatfree dry weight of muscle.

Answer 28

Elastin

Question 29

These molecules contain both protein and carbohydrate units.

Answer 29

Glycoproteins and Proteoglycans

Question 30

have more protein and short glycan chains with no repeating unit.

Answer 30

Glycoproteins

Question 31

confer stability to the proteins.

Answer 31

Glycans

Question 32

are commonly transmembrane proteins that take part in cell communication and signaling.

Answer 32

Glycoproteins

Question 33

have much more carbohydrate units attached to the central protein backbone.

Answer 33

Proteoglycans

Question 34

stored in the form of triglycerides in adipose cells

Answer 34

Lipids

Question 35

consists of adipocytes bound together by thin collagenous networks

Answer 35

Adipose tissue

Question 36

white fat is aggregated in meat animals into four main sections:

Answer 36

* subcutaneous fat * visceral fat * intermuscular fat * intramuscular fat (marbling)

Question 37

chemical composition of meat:

Answer 37

* water * protein * lipid * carbohydate * miscellanous soluble nonprotein substances * vitamins

Question 38

Muscle becomes inextensible: this is the stiffening reffered to as

Answer 38

Rigor Mortis

Question 39

what is called a postmortem rigidity is a definite sign of death.

Answer 39

rigor mortis

Question 40

Two of the major quality defects facing the meat industry

Answer 40

Pale, Soft, Exudative (PSE) Dark Firm and Dry (DFD)

Question 41

predisposing factors contributing to pse and dfd in meats

Answer 41

* breed * sex * species * pre-slaughter handling and post handling of animals

Question 42

pH of PSE meat is ____ at ____ minutes after slaugter

Answer 42

<6; 45 minutes

Question 43

pH of DFD meat is ____ at ____ hours after slaugter

Answer 43

≥6; 12-48 hours

Question 44

causes of PSE meat

Answer 44

* stress in ante-mortem * acute stress

Question 45

causes of DFD meat

Answer 45

* chronic or long-term stress