The <span>dermis is the layer of skin below the epidermis. </span>
Answer:
a.The phenotypic proportions obtained after having the genotypes are 50% marbled seeds, 25% spotted and dotted seeds since they are codominant, 25% spotted seeds.
b. Taking into account the F1 genotypes in the previous point, the expected phenotypes for the first crossing are 100% marbled seeds and for the second crossing 100% dotted seeds.
Explanation:
Let's suppose:
Marbled allele: M
Spotted allele: S
Dotted allele: D
Allele for Clear: C
a. Because both crosses were between homozygous parents, the entire F1 genotype is the same.
For the first crossing the descendants have the MS genotype, and for the second crossing the descendants have the DC genotype. It is enough to make a Punnett square to obtain the different combinations of genotypes between the crossing of MS and DC.
Answer:
The correct answer is ''METAPHASE I.''
Explanation:
Metaphase I is the stage in which chromosomal studies are generally performed, because its morphology is very clear. The chromosomes, moved by the mitotic spindle, are placed in the center, between the two asters and form the so-called metaphase plate, in which the chromosomes are positioned in such a way that the kinetochore of each sister chromatid are oriented towards the opposite poles. Keeping chromosomes on the cell equator implies a balance between the forces of the microtubules that tend to move the kinetochores toward opposite poles, so positioning them in the center involves a great deal of energy.In each kinetochore, between 20-30 microtubules can be anchored, which exert traction force towards the pole from which they come, so the metaphase plate is maintained by the balance between the opposite forces of the poles on the chromosomes, which hold their sister chromatids by centromeric cohesin.
Answer and Explanation:
In rest, attraction strengths between myosin and actin filaments are inhibited by the tropomyosin. When the muscle fiber membrane depolarizes, the action potential caused by this depolarization enters the t-tubules depolarizing the inner portion of the muscle fiber. This activates calcium channels in the T tubules membrane and releases calcium into the sarcolemma. At this point, tropomyosin is obstructing binding sites for myosin on the thin filament. When calcium binds to the troponin C, the troponin T alters the tropomyosin by moving it and then unblocks the binding sites. Myosin heads bind to the uncovered actin-binding sites forming cross-bridges, and while doing it ATP is transformed into ADP and inorganic phosphate which is released. Myofilaments slide impulsed by chemical energy collected in myosin heads, producing a power stroke. The power stroke initiates when the myosin cross-bridge binds to actin. As they slide, ADP molecules are released. A new ATP links to myosin heads and breaks the bindings to the actin filament. Then ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, which starts a new binding cycle to actin. Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
