● An actin filament is made of 2 filamentous actins which form double helix.
● F-actin is a polymer of monomeric Globular actins.
● Actin contains 2 other proteins. Two filaments of tropomyosin run along the grooves of the F-actin double helix.
● Troponin are having 3 subunits which is seen at regular intervals on tropomyosin. In the resting state a subunit of troponin masks the binding sites for myosin on the actin filaments.
● Each myosin filament is a polymer of many monomeric proteins called Meromyosins.
● A meromyosin has 2 parts:-
→ Heavy meromyosin or HMM or cross arm.
→ The globular head is an active ATPase enzyme and has binding sites for ATP and active sites for actin.
( b ) Meromyosins ; meromyosin, globular head , short arm and a tail, light meromyosin, heavy meromyosin
( c ) Monomyosins ; monomyosin, globular head , body and a tail, light meromyosin, heavy meromyosin
( d ) Meromyosins ; meromyosin, globular head , body and a tail, light meromyosin, heavy meromyosin
▶ Paramecium have most complex contractile vacuoles. it is surrounded by several canals, which absorb water by osmosis from the cytoplasm. water is pumped into the vacuole.
After the canals fill with water.
The excess water is collected into a contractile vacuole which swells and finally expels waterthrough an opening in the cellmembrane.
In Paramecium, which has one of the most complex contractile vacuoles, the vacuole is surrounded by several canals, which absorb water by osmosis from the cytoplasm. ... In Amoeba contractile vacuoles collect excretory waste, such as ammonia, from the intracellular fluid by both diffusion and active transport.
Actin and Myosin are the two Contractile Proteins:
Actin consists of three components - F-actin, tropomyosin and troponin.
F- Actin has myosin binding site where myosin head attaches itself during muscle contraction.
In relaxed muscle tropomyosin covers myosin binding sites on actin and thus blocks attachment of myosin heads to actin.
During muscle contraction troponin removes tropomyosin from myosin binding sites on actin.
It consists of a globular head with a short cross arm and a tail.
The globular head is an active ATPase enzyme that has binding sites for actin and active sites for ATP.
Visit our website for purchasing XI & XII Complete Syllabus Video Lectures
Actin and myosin filaments
.. Form bands
One dark one light
By contractile proteins, we mean actin (thin filament) and myosin (thick filament). Each actin filament is composed of two helical “F” actin (filamentous actin) and each 'F' actin is made up of multiple units of 'G' actin. ... During muscle relaxation, troponin covers the binding sites for myosin on actin filaments.
F’actins ; ‘F’ actin, ‘G’actins; tropomyosin, ‘F’ actins; troponin
Structure of Contractile Proteins (Actin) : Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein Troponin is distributed at regular intervals on the tropomyosin. In the resting state a subunit of troponin masks the active binding sites for myosin on the actin filaments
Hope it will help u.
Here is ur answer..!!
Ans :‘F’actins ; ‘F’ actin, ‘G’actins; Tropomyosin, ‘F’ actins; Troponin
I Hope this may helpful to u...!!
And Keep smiling..!!:)
tum sab mehnati baccho thodha aaram karlo ☺☺
kya fitness hai yaar✊✊✊❤
no one will inbox
and no one is interested
don't post type of questions
u will not get only u will loss