Spectrum biology

24 .Consider the given diagram of a muscle and read
the statements describing it.

Statements

I.In the centre of each I-band is an elastic fibre

(Z-line) which bisects it.

II.Thin filament are firmly attached to the Z-line.

III.M-line is a fibrous membrane in the middle of

A-band.

IV.A sarcomere comprises one full A-band and two

half I-bands.

Choose the incorrect statements from the given

options.

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

(c) Only II (d) None of these

25 .Consider the diagram of thin myofilament.

Now, read carefully the statements about molecular

arrangement of actin and myosin in the filament.

I.Each actin (thin filament) is made up of 2F

(filamentous) actins.

II.F-actin is the polymer of G (globular) actin.

III.2F actins are twisted into a helix.

IV.Two strands of tropomyosin protein lies in the

grooves of F-actin.

Choose the correct set of statements from the codes

given bolow.

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

(c) I and IV (d) All except IV

26 .Consider the statements given below with reference
to the diagram of typical vertebrum.

Statements

I.It has a acoelous centrum

II.It possess two transverse processes, a neural

arch with neural canal for spinal cord

III.It possess pre-zygapophysis and

post-zygapophysis on anterior and posterior

side respectively.

IV.The central part of intervertebral disc is called

nucleus pulposus.

Choose the correct set of statements from option

given below.

(a) I and IV (b) II and III (c) Only I (d) I, II, III and IV

27 .Consider the diagram showing muscle structure

below.

Identify the events that occur during skeletal

muscle contraction:

I.I band shortens

II.A-band shortens

III.H-zone shortens

IV.Sarcomere contract

V.ATP changes to ADP and Pi.

Choose the option with incorrect events.

(a) Only I (b) Only III (c) IV and V (d) Only II

28 .Consider the diagram of human pelvic girdle and

read the statements describing it.

Tropomyosin

Actin

Neural

spine

Transverse

process

Neural

canal

Centrum

Articulating

surface

I-band I-band

H-zone Z-line

Z-line

A-band

M-zone

Myofibril

A-band I-band H-zone I-band A-band

Z-line Z-line

Sarcomere

Cross

bridges

Thick

myofilament

Thin

myofilament

Thick

filament

Thin

filament

Sarcomere Z-band or

Krause

membrane

M-Band

H-Band

A-Band

I-Band I-Band

A

Coccyx

B D

Femur

Sacral

canal