Answer:
<u>Once the myosin-binding sites are exposed, and if sufficient ATP is present, myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens and the muscle contracts. In the absence of calcium, this binding does not occur, so the presence of free calcium is an important regulator of muscle contraction.</u>
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Answer:
In the traditional phylogeny platyhelminthes is depicted as a lophotrochozoan phylum. What probably led to this change?
The removal of the acoel flatworms (Acoela) from the Platyhelminthes allowed the remaining flatworms to be clearly tied to the Lophotrochozoa.
Explanation:
The modern taxonomists classified organisms on the general basis of evolutionary, morphological, and genetic traits
Explanation:
- Evolutionary relationships provides the phylogeny of evolutionary ancestors and descendants
- Homologous structures are structures which look the same but perform different functions
, like bones of a human leg compared to bones on a bird's wing
- Analogous structures have different structure but same function like an insect’s and a bird’s wing
- Embryo developmental pattern and similar relationships
- Similarities in DNA and protein sequencing in related organisms
The above basis provided modern taxonomists to classify organisms according to the various disciplines like Genetics, Cytology, Embryology, Physiology, Anatomy and many more.
Attached is an example of a mRNA wheel.
The codon UAA codes a stop codon. The mRNA wheel is read by starting to choose from the four letters at the centre the one that is the first in the codon. Then, on that quarter of the circle, choose from the four letters, the second in the codon. Repeat again the process for the 1/16 part you chose previously choosing now the last letter in the codon. You are now able to identify what is coded by the mRNA codon.