Answer:
In a diploid organism there are two copies of most genes.
The versions of the genes are called alleles.
Explanation:
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The genetic servants of a population are all variants of each of the genes present. These variables are possible thanks to the mutations that occur in the formation of the zygote (before or after fertilization).
When part of the DNA of an organism undergoes a point mutation (on one or a few nitrogenous bases) the body activates a series of responses to reverse it, however sometimes the mutation is maintained and can give rise to a change in a protein.
Sometimes and under certain circumstances (the change should not cause death or significant disadvantages in the body that is born) the mutation is maintained in the population giving rise to different alleles of the same gene.
In an organism there are two copies of each gene (genotype) but only one of them (phenotype) is expressed.
The allele of the gene that is expressed may depend on various factors but the dominant allele is usually expressed.
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Answer:
d. all endothelial cells would be venous
Explanation:
The Notch signaling pathway is a cell signaling system which consist basically of 4 NOTCH genes ( NOTCH1, NOTCH2, NOTCH3, and NOTCH4) each of them having the information to build a particular cell membrane receptor protein.
It has been demonstrated in zebrafish embryos that Notch signaling are highly determinant factors during vascular development, and a key function of these genes was specifically to regulate the differentiation of arterial fate in endothelial cells.
Notch signaling-deficient embryos showed a loss of expression of arterial markers such as ephrinB2 from arterial vessels with an accompanying expansion of venous markers into normally arterial domains. In contrast, embryos in which Notch signaling had been ectopically activated, meaning an activation out of "proper" place (where not expected, e.g. venous endothelial), exhibited the contrary phenotype, this is a suppression of vein-specific markers with ectopic expression of arterial markers in venous vessels.
To summarize, when Notch is supressed (in this case inhibited with a specific Notch inhibitor) arterial fate of endothelium is not followed, and venous fate is stablished. Thus, endothelial cells (those expected to form venous tissues but also arterial ones) would specified as venous.
Answer:
mitosis
Explanation:
because mitosis is a continuous cell division process which occur in the somatic cell
This is all i know about caves: Caves are large, natural holes beneath the surface of the earth. Underground passages and caves are found in rocky landscapes across the world. They are found in areas with a lot of limestone, a common type of rock. They can be created in various ways, but most caves are hollowed out of rock by water.
