Answer:
Power stroke (myosin head bends) coupled with the release of ADP and phosphate
Explanation:
Muscle contraction results from myosin heads adhering to actin and attracting it inwards. It uses ATP. Myosin adhers to actin at a binding site of its globular actin protein and adheres at another binding site for ATP (hydrolyzed ATP to ADP, Pi and energy)
ATP binding prompts myosin to detach from actin, ATP is changed to ADP and inorganic phosphate, Pi by ATPase. The energy formed at this process orientates myosin head to a “cocked” direction.
The myosin head goes in the direction of the M line, holding the actin with it in the process causing the filaments to orientate nearly 10 nm in the direction of the M line--- power stroke (force is produced), the sarcomere reduces in length and the muscle contracts.
Note: The power stroke is seen when ADP and phosphate disattaches itself from the myosin head.
At the terminal point of the power stroke, the myosin head as low-energy, followed by ADP release.
The attached image shows the cross-bridge muscle contraction cycle, which is activated by Ca2+ sticking to the actin active site. And how actin moves in relation to myosin.
Answer:
The answer is B.
Explanation:
Regarding the situation explained in the question that "African Americans are not affected by the malaria disease because of a specific genetic trait that they possess and that trait provides them with protection" can be explained by the answer given in option B.
Being heterozygous, meaning possessing a dominant and a recessive allele regarding that genetic trait, in terms of sickle cell trait which is a gene that causes the individual's blood cells to be sickle shaped and balanced polymorphism which means carrying two different versions of a gene is an argument that is enough to prove that the above statement is incorrect because it means they have blood cells that can be affected by the malaria disease.
I hope this answer helps.
Answer: Sexual reproduction is advantageous over asexual reproduction because it reduces the rate of mutation accumulation.
New Zealand mud snails reproduce through asexual and sexual modes of reproduction. Asexual reproduction allows these organisms to reproduce more number of offsprings. Asexual reproduction advantageous as these organisms faces natural disaster conditions like tide, drought results in the decrease in the population. Therefore, does not get mate to undergo sexual reproduction. Sexual reproduction in these snails results in genetic variation in offsprings. Sexual reproduction results in increase in mutation rate in the genetic material being passed to offsprings because of resorting of genetic material being distributed from parent to offspring. This will result in genetic variations. Hence, parent will be different from offsprings. In asexual reproduction offsprings are the clones of parents as there is no resorting of genetic material takes place.
Answer:
Thymine and uracil or adenine have two hydrogen bonds between them, whereas guanine and cytosine have three.
