Muscle

Question 1

cilia and flagella are outgrowths of

Answer 1

cell membrane

Question 2

flagellar movement helps in

Answer 2

swimming of spermatozoa
maintenance of water current in canal system of sponges
locomotion of protozoans like Euglena

Question 3

embryonical origin of muscle

Answer 3

mesoderm

Question 4

how much percent of our body weight is muscles

Answer 4

40-50

Question 5

special properties of muscles

Answer 5

excitability
contractility
extensibility
elasticity

Question 6

three types of muscles

Answer 6

skeletal
smooth / visceral
cardiac

Question 7

a skeletal muscle is made up of bundles of

Answer 7

fascicles

Question 8

fascicles are held together by

Answer 8

fascia (collagenous connective tissue)

Question 9

plasma membrane of a muscle fibre

Answer 9

sarcolemma

Question 10

cytoplasm of muscle fibre

Answer 10

sarcoplasm

Question 11

sarcoplasm contains many nuclei
hence, state of muscle fibre

Answer 11

syncytium

Question 12

endoplasmic reticulum of muscle fibre

Answer 12

sarcoplasmic reticulum

Question 13

sarcoplasmic reticulum is the store hous of which ions

Answer 13

calcium

Question 14

band that contains actin

Answer 14

I band (isotropic)

Question 15

band that contains myosin

Answer 15

A band (anisotropic)

Question 16

thick filament

Answer 16

myosin

Question 17

thin filament

Answer 17

actin

Question 18

elastic fibre which bisects the I band

Answer 18

Z line

Question 19

fibrous membrane which bisects the A band

Answer 19

M line

Question 20

portion of myofibril between two successive Z lines

Answer 20

sarcomere

Question 21

in resting state, non overlapping zone is of thick filaments is called

Answer 21

H zone

Question 22

each ____ actin is a polymer of monomeric ____ actins

Answer 22

F (filamentous)
G (globular)

Question 23

two filaments of another protein _______________ run close to F actins throughout its length

Answer 23

tropomyosin

Question 24

a complex protein ___________ is distributed at regular intervals on tropomyosin

Answer 24

troponin

Question 25

in resting state, a subunit of troponin masks __________________________ on actin filament

Answer 25

myosin binding site

Question 26

monomer of myosin is called

Answer 26

meromyosin

Question 27

parts of a meromyosin

Answer 27

globular head with a short arm tail

Question 28

globular head and short arm are called

Answer 28

heavy meromyosin (HMM)

Question 29

tail is called

Answer 29

light meromyosin (LMM)

Question 30

heavy meromyosin has binding sites for ____________ and ____________ therefore, it is called ___________ enzyme

Answer 30

actin atp atpase

Question 31

mechanism of muscle contraction is best explained by which theory

Answer 31

sliding filament

Question 32

what does sliding filament theory state

Answer 32

that contraction of a muscle fibre takes place by sliding of the thin filaments over the thick filaments

Question 33

muscle contraction is initiated by a signal sent by _______ via _________

Answer 33

CNS motor neuron

Question 34

a motor neuron along with muscle fibres connected to it constitute

Answer 34

motor unit

Question 35

junction between a motor neuron and sarcolemma of muscle fibre

Answer 35

neuromuscular junction / motor-end plate

Question 36

a neural signal reaching the neuromuscular junction releases ________________________ which generates ________________________ in sarcolemma

Answer 36

neurotransmitter - acetyl choline action potential

Question 37

action potential spreads through the muscle fibre and causes

Answer 37

release of calcium ions in the sarcoplasm

Question 38

increase in calcium ion levels leads to

Answer 38

binding of calcium ion with a subunit of troponin and thereby remove masking of myosin binding site

Question 39

utilising energy from ___________________, myosin head now binds to exposed sites on action to form _______________

Answer 39

atp hydrolysis cross bridge

Question 40

during contraction of sarcomere, _______ retains the length and _____________ gets reduced

Answer 40

A band I band

Question 41

myosin, releasing ____________ goes back to relaxed state

Answer 41

adp and ip

Question 42

how is cross bridge broken

Answer 42

a new atp binds to myosin

Question 43

till when does this cycle continue

Answer 43

till calcium ions are pumped back to the sarcoplasmic reticulum which results in the masking of actin filaments

Question 44

repeated activation of muscles can lead to accumulation of ______________ due to anaerobic breakdown of glycogen, causing ___________

Answer 44

lactic acid fatigue

Question 45

red coloured oxygen storing pigment

Answer 45

myoglobin

Question 46

reddish appearance in some muscles is due to

Answer 46

high content of myoglobin

Question 47

reddish muscles are called

Answer 47

red muscle fibres

Question 48

amount of mitochondria in red muscles and why

Answer 48

high amount to form more atp using stored oxygen aerobically

Question 49

why do some muscles appear pale or whitish

Answer 49

less content of myoglobin

Question 50

amount of mitochondria in white muscles and why

Answer 50

less amount depend on anaerobic processes for energy

Question 51

amount of sarcoplasmic reticulum in white fibres

Answer 51

high