Spectrum biology

(a)A–Fascicle, B–Muscle fibre, C–Sarcolemma, D–Blood

capillary

(b)A–Muscle fibre, B–Fascicle, C–Sarcolemma, D–Blood

capillary

(c)A–Muscle fibre, B–Fascicle, C–Sarcoplasm, D–Blood

capillary

(d)A–Muscle fibre, B–Endoplasmic reticulum, C–Sarcoplasm,

D–Blood capillary

20 .With reference to the structure of muscle, consider
the diagram of thick filament

Given below are few statements regarding the

structure of thick myofilaments.

I.Each myosin is a polymerised protein.

II.Many meromyosin constitutes one thick

filament (myosin)

III.Each meromyosin’s tail is called heavy

meromyosin (HMM) and head is called light

meromyosin (LMM).

IV.The globular head is an active ATPase enzyme

and has binding sites for ATP and active sites

for actin.

Choose the option with correct set of statements.

(a) I, III and IV (b) II and III

(c) I, II and IV (d) I, II, III and IV

21 .Carefully observe the given diagram with reference
to series of events during muscular contraction.

Consider the given statements describing the steps

during the above mentioned process.

I.Myosin head binds to the exposed active site on

actin to form a cross bridge.

II.The Z-line attached to these actin are also

pulled inwards thereby causing shortening of

sarcomere, also called contraction.

III.This pulls the attached actin filaments towards

the centre of A-band.

Arrange the given steps in sequence from first

to last and choose the correct option depicting

it.

(a) I → II → III (b) III → II → I

(c) I → III → II (d) III → I →II

22 .Consider the given diagram and identify the labels

A, B and C.

A B C

(a) Clavicle Costal cartilages Xiphoid process

(b) Costal cartilages Body of sternum Manubrium

(c) Xiphoid process Clavicle Costal cartilages

(d) Manubrium Body of sternum Xiphoid process

23 .Consider the given diagrams in column I and

choose the correct type for each of them from

column II.

Column I Column II

A. (i) Pivot

B. (ii) Saddle

C. (iii) Gliding

D. (iv) Hinge

Choose the correct codes.

A B C D

(a)(i) (iii) (ii) (iv)

(b)(iii) (iv) (i) (ii)

(c)(ii) (iii) (i) (iv)

(d)(iii) (i) (iv) (ii)

Myosin molecules Myosin head

Half I-band One A-band Myosin filament

Z-band

Z-band

Actin

filament

Z M Z

H

T12

L1

A

B

C

RIB 12

RIB 11

Sternum