•  
agra,ahmedabad,ajmer,akola,aligarh,ambala,amravati,amritsar,aurangabad,ayodhya,bangalore,bareilly,bathinda,bhagalpur,bhilai,bhiwani,bhopal,bhubaneswar,bikaner,bilaspur,bokaro,chandigarh,chennai,coimbatore,cuttack,dehradun,delhi ncr,dhanbad,dibrugarh,durgapur,faridabad,ferozpur,gandhinagar,gaya,ghaziabad,goa,gorakhpur,greater noida,gurugram,guwahati,gwalior,haldwani,haridwar,hisar,hyderabad,indore,jabalpur,jaipur,jalandhar,jammu,jamshedpur,jhansi,jodhpur,jorhat,kaithal,kanpur,karimnagar,karnal,kashipur,khammam,kharagpur,kochi,kolhapur,kolkata,kota,kottayam,kozhikode,kurnool,kurukshetra,latur,lucknow,ludhiana,madurai,mangaluru,mathura,meerut,moradabad,mumbai,muzaffarpur,mysore,nagpur,nanded,narnaul,nashik,nellore,noida,palwal,panchkula,panipat,pathankot,patiala,patna,prayagraj,puducherry,pune,raipur,rajahmundry,ranchi,rewa,rewari,rohtak,rudrapur,saharanpur,salem,secunderabad,silchar,siliguri,sirsa,solapur,sri-ganganagar,srinagar,surat,thrissur,tinsukia,tiruchirapalli,tirupati,trivandrum,udaipur,udhampur,ujjain,vadodara,vapi,varanasi,vellore,vijayawada,visakhapatnam,warangal,yamuna-nagar
Contractile Proteins

Contractile Proteins

Introduction:

  • In a muscle fibre, there are two types of myofilaments present that are responsible for muscle contraction-
    (a) Thin filaments
    (b) Thick filaments

Explanation

a) Thin filament or Actin filaments

  • It contains two polymeric filamentous (‘F’ actin filaments) that are a polymer of globular or G actin monomers helically wound together.
  • Lengthwise,2 tropomyosin filaments are coiled around the actin filaments.
  • Troponin,a complex protein, is present at regular intervals on the tropomyosin which masks the active binding sites for myosin,at resting state.
  • Troponin and tropomyosin are known as regulatory proteins, as they play an important role in muscle contraction by regulating the binding of actin and myosin filaments.


    troponin

     

b. Thick filament or Myosin filaments

  • The thick filament is a polymeric protein composed of myosin which consists of monomeric units known as meromyosin.
  • Each meromyosin has two important parts
    a) Heavy meromyosin (HMM)- Globular head with a short arm
    b) Light meromyosin (LMM)- Tail
  • Cross arm is formed as the HMM component projects outwards at a regular distance and angle from each other from the surface of a polymerized myosin filament.
  • Globular head is an active ATPase enzyme. It also provides the binding site for ATP and active sites for actin.


    sarcomere

     

Frequently Asked Questions: FAQs

Q1 What are the types of myofilaments present in the muscle fibre?
Ans:

  • In a muscle fibre, there are two types of myofilaments present that are responsible for muscle contraction-
    a) Thin filaments
    b) Thick filaments

Q2 Name the components of the actin filament.
Ans:

a) Troponin
b) Tropomyosin
c) F-actin

Q3 What are the regulatory proteins responsible for? Name them.
Ans:

Troponin and tropomyosin are known as regulatory proteins, as they play an important role in muscle contraction by regulating the binding of actin and myosin filaments.

Q4 Monomeric unit of myosin / thick filament is __________.
Ans:
Meromyosin

NEET Related Links

NEET Exam 

NEET  Exam Dates

NEET  Exam pattern

NEET  Syllabus

NEET  Eligibility Criteria

NEET  Application

NEET UG Counselling

NEET FAQ

NEET UG Result

NEET  Cut Off

JEE MAIN Related Links

JEE Main 

JEE Main Rank Predictor 

JEE Main College Predictor 

JEE Main  Exam Dates

JEE Main  Exam pattern

JEE Main  Application

JEE Main  Eligibility Criteria

JEE Main  Syllabus

JEE Main  Physics Syllabus

JEE Main  Maths Syllabus

JEE Main  Chemistry Syllabus

JEE Main  Admit Card

JEE Main  Counselling

JEE Main marks vs rank vs percentile

JEE Advanced Related Links

JEE Advanced  Exam Dates

JEE Advanced  Application

JEE Advanced  Eligibility Criteria

JEE Advanced  Syllabus

JEE Advanced  Maths Syllabus

JEE Advanced  Physics Syllabus

JEE Advanced  Chemistry Syllabus

JEE Advanced Exam Result

JEE Advanced Exam Dates

JEE Advanced Registration Dates

CUET Related Links

CUET  Eligibility Criteria

CUET  Admit Card

CUET  Exam Pattern

CUET  FAQs

CUET  Counselling

CUET  Syllabus

CUET  Result

CUET  Answer Key

CUET  Preparation

CUET CUTOFF

CUET  Application Form

Important Topics

Talk to our expert
Resend OTP Timer =
By submitting up, I agree to receive all the Whatsapp communication on my registered number and Aakash terms and conditions and privacy policy