STD 11 - 15. Body fluids and criculations — NEET STD 11 Science — Question

Marine teleost fishes excrete

Statement I: The first cellular form of life could have originated 3 billion years ago.
Statement II: According to theory of special creation, earth is about 4000 years old.

Which of the following respires by gills

What will happen if a sponge is cut into maximum possible pieces

Select the correct statement regarding the specific disorder of muscular or skeletal system.

Location of hepatic caeca in cockroach.

Mechanism of muscle contraction is best explained by the sliding filament theory which states that contraction of a muscle fibre takes place by the sliding of the thin filaments over the thick filaments. Organise sequence of contraction and choose correct option :
(i) Action potential spreads through the muscle fibre and causes the release of calcium ions into the sarcoplasm.
(ii) This pulls the attached actin filaments towards the centre of A-band.
(iii) Utilising the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge.
(iv) Increase in Ca⁺⁺ level leads to the binding of calcium with a subunit of troponin on actin filaments and thereby remove the masking of active sites for myosin.
(v) Signal sent by the central nervous system (CNS) via a motor neuron.
(vi) The Z-line attached to these actins are also pulled inwards thereby causing a shortening of the sarcomere, i.e., contraction.
(vii) A neural signal reaching neuromuscular junction releases a neurotransmitter (Acetyl choline) which generates an action potential in the sarcolemma.

Who first realized the use of yeast in fermentation