Select the correct answer. Tay-Sachs disease is caused by a mutation in the HEXA gene located on chromosome 15. Tay-Sachs follows an autosomal recessive pattern of inheritance. With the help of the diagram, identify which of the offspring will be an unaffected carrier.

a diagram showing the genes of parents who are carriers of Tay-Sachs disease

A.
A, B, and C
B.
B and C
C.
A and D
D.
A
E.
D

the answer is: the „power stroke“ step.

muscle contraction can be divided into a few steps:

1. the release of ach (acetylcholine) in the synaptic cleft, binding of ach for its receptor and consequently opening of the ca channels.

2. the release of ca, binding of ca for the troponin

3. troponin shifting the tropomyosin, which was blocking the active site on the actin

4. myosin heads attaching to actin by breaking down atp to adp+ pi

5.   formation of the ‘cross-bridge’ on the active site of the actin filament by myosin head

6. “power stroke” -the cross bridge pulls actin, which slides over the myosin

9.     7. the release of adp completes the cross-bridge movement and atp attaches to myosin, breaking the actin-myosin cross bridge.