3 Which statement best describes a cause and its effect that occurs during the process of muscle contraction? A. The release of
calcium ions causes myosin and actin to attach to each other. B. The pull of myosin on actin causes the motor neuron to send a nerve impulse. C. The presence of calcium ions within nerve cells causes the sarcomere to shorten. D. The shortening of the sarcomere causes the release of calcium around the myofibrils.
Answer:A. The release of calcium ions causes myosin and actin to attach to each other.
The contraction of skeletal muscles takes place by induction of a nerve impulse, which produces a movement and the interaction of the filaments containing proteins named as actin and myosin. This interaction of filaments is regulated by proteins called tropomyosin and troponin present on the actin filaments. The motor nerve causes the depolarization of the muscle membrane sarcolemma. This triggers the sarcoplasmic reticulum to release calcium ions. This calcium binds to troponin and thus allows the tropomyosine strand on the actin filament to displace so that the part of the actin where myosine head needs to be attached remain uncovered. Binding of the actin myosine filament results in contraction.
Hence, the release of calcium ions causes myosin and actin to attach to each other causes muscle contraction.
The endosymbiotic incorporation of a cyanobacterium into a eukaryotic host cell offered to ascend to the basic progenitor of the Archaeplastida that along these lines split into the three essential plastid genealogies, Glaucophyta, Viridiplantae, and Rhodophyta
Endosymbionts and their hosts frequently speak to the distinct domains of life. As an outcome, their amalgamation can create totally new blends of biochemical capacities and permit the two, interweaved species to flourish in conditions that would be aloof to either alone
The examination of the total chromatographic genome sequence of P. chromatophore strain CCAC 0185 uncovered a principal genome decrease. The single, round chromosome of 1.02 Mb encodes just 867 protein-coding genes and is, therewith, the littlest cyanobacterial genome reported to date
In spite of the fact that the chromatophore genome contains a practically complete arrangement of photosynthesis genes, it needs not just genes thought to be nonessential for an intracellular way of life yet additionally genes of fundamental pathways for amino corrosive and cofactor biosynthesis
Hence, the right answer is "P. Chromatophore is a result of evolutionarily recent endosymbiosis"
