Describe the effect of calcium ions on tropomyosin and actin in skeletal muscle.

Within the muscle fibre tropomyosin is wrapped around actin filaments and it blocks the binding sites for the myosin-heads.

When calcium ion concentration increases, calcium ions bind to sites on the tropomyosin (troponin-c sites) and this causes a conformational change in shape.

This change in tropomyosin’s shape exposes the myosin-head binding sites on the actin filaments and allows cross-bridge binding to occur.

This then allows the actin and myosin fibres to slide over each other and shorten (contract) the muscle fibre.  This is known as Sliding Filament Theory.  

Aaron H. Mentoring -Medical School Preparation- tutor, Mentoring -Per...

2 years ago

Answered by Aaron, an A Level Human Biology tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist


Rasmus K. A Level Biology tutor, A Level Human Biology tutor, GCSE Hu...
£20 /hr

Rasmus K.

Degree: Medicine (Bachelors) - Nottingham University

Subjects offered:Human Biology, Biology+ 4 more

Human Biology
.BMAT (BioMedical Admissions)
-Personal Statements-
-Medical School Preparation-

“Who am I? Hi, my name is Rasmus. I'm a fourth year medical student at the University of Nottingham. For me, medicine came from an initial love of science and became a dream that I am now fulfilling. I hope to instil the same enthusias...”

£20 /hr

Tashi C.

Degree: Medicine MBCHB (Bachelors) - Manchester University

Subjects offered:Human Biology, Biology+ 1 more

Human Biology
-Medical School Preparation-

“Hi! I'm Tashi, a 2nd-year medical student at the University of Manchester. I offer tuition for Biology and Human Biology at A-level and GCSE. ”

£20 /hr

Zachary B.

Degree: Biochemistry (Masters) - University College London University

Subjects offered:Human Biology, Chemistry+ 1 more

Human Biology

“I have a passion for teaching and continued learning. I am a strong believer in visual learning with discussions around diagrams being the centre of my lessons.”

MyTutor guarantee

About the author

£24 /hr

Aaron H.

Degree: Graduate Entry Medicine (MB ChB) (Bachelors) - Bristol University

Subjects offered:Human Biology, -Personal Statements-+ 1 more

Human Biology
-Personal Statements-
-Medical School Preparation-

“A graduate entry medical student with a wealth of teaching experience who is committed to ensuring each student can achieve their potential.”

You may also like...

Posts by Aaron

Describe the effect of calcium ions on tropomyosin and actin in skeletal muscle.

Describe the roles of DNA and RNA in determining the sequence of amino acids in proteins.

Explain how voltage-gated sodium ion channels on the membranes of neurones generate an action potential.

People with AF often also have narrowing of the valve between the left atrium and the left ventricle. This causes the wall of the left atrium to become thicker. Suggest why.

Other A Level Human Biology questions

What are the major parts of a neuron? What are the three types of nerve cells?

Why should be we careful with using antibiotics?

What is the Role of the Liver during the Metabolism of Food Products?

What is Homeostasis and what are the principles behind it?

View A Level Human Biology tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss