Answer:
Instead of a brain, echinoderms have a ring of nerves located around their mouth area that governs their nervous responses. This ring coordinates their motion, their eating, basically anything that requires nerve control.
Explanation:
1) Photosynthesis uses sunlight energy to produce
sugar. Sugar goes from one cell to another until it reaches the cells which don’t
have access to sunlight (or they don’t get enough sunlight), so they can’t make
any photosyntesis or they make very little photosyntesis. That’s how the leaves
of a plant feed the roots of the same plant. When that cell receives the sugar,
it makes cell respiration to convert it back to water and CO2 and release energy.
When an animal eats a plant, animal cells also make this respiration process
with the sugar.
The chemical equation is basically the opposite:
Photosyntesis: water + CO2 -> O2 + sugar
Respiration: sugar + O2 -> CO2 + water
2) The DNA duplication is semiconservative, which means each
new double chain contains 1 original molecule and 1 newly synthesized molecule.
When DNA is duplicated, each one of the molecules (chains) acts
as a template for one of the chains that are being synthesized. Wherever there
is an A in the old molecule, the new molecule will have a T. G goes with C, C
goes with G and T goes with A. The way this happens is related to the number of
hydrogen bonds (C and G have 3, whereas A and T have 2) and the molecular size
(A and G have 2 cycles, whereas T and C have 1 cycle – so it is always a big
one with a small one, total = 3 cycles). You can compare it with a chocolate mold:
if you want a chocolate to be heart-shaped, you have to get a mold which has a
heart-shaped hole and put the warm chocolate inside. So the mold and the
chocolate have the opposite shape – complementary shape. But in this case, once
the duplication process ends, mold and new DNA stay together as a brand new
couple, and the mold never goes back with the other mold.
Answer:
In multicellular organisms, which begin their life with an egg or zygote cell, mitotic cell division is important in the development and maintenance of the various tissues, organs and systems that form it. The new cells caused by mitosis are genetically identical to the stem cell; This is achieved thanks to complex regulatory mechanisms that ensure the integrity of the genomic material and its proper segregation.
Explanation:
Segurine is important because it is responsible for keeping sequestered protease separase; when it is released, thanks to the degradation of segurin, the degradation of the cohesin that holds the sister chromatids together takes place. This cohesin allows chromosomal segregation, while degradation of cyclin results in the inactivation of CDK1 (cyclin dependent kinase).
When the alignment of the chromosomes does not satisfy the SAC (spindle assembly control point), the signal from non-anchored kinetocores induces protein recruitment to the control point. This signal leads to the formation of two independent complexes. The union of the two complexes will lead to the formation of a mitotic control complex. In this way, the segurin will not be marked for degradation and the separase will not be released and the chromosomes will not secrete until the requirements of the SAC are met.
The tectonic plates<span> are made up of </span>Earth's<span> crust and the upper part of the mantle</span>layer<span> underneath. Together the crust and upper mantle are called the lithosphere and they extend about 80 km deep.</span>
