Answer:
The birds are oviparous in nature and produces eggs that are hatched later by the parent. the egg hatching require proper heat and protection from the external enemy.
The egg shell is the hard covering of the egg of the bird that is made of the calcium. The egg shell protect the egg from the external environment. The calcium layer for the egg shell formation is obtained by the oseteoclast property of the cells.
Answer;
-Inactivation; limited
Differentiation requires inactivation of particular genes to produce populations with limited capabilities that form tissues.
Explanation;
-Cell differentiation is how generic embryonic cells become specialized cells. This occurs through a process called gene expression.
-Gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a cell functions.
-Gene expression plays a critical role in the morphological changes that take place in a developing embryo and fetus and in the differentiation of stem cells to form specialized cells.
Answer:
The correct insulin pathway is described as under:
2. Binding of insulin to the alpha subunit of the insulin receptor
8. Activation of insulin receptor tyrosine kinase
3. Phosphorylation of IRS proteins
6. Phosphorylation of phosphinositide 3-kinase (PI-3K)
4. Conversion of PIP2 to PIP3
7. Activation of PIP3-dependent protein kinase B (PDK1)
5. Glut4 receptors transported to the cell membrane
Explanation:
The insulin signaling pathway is described as under:
RTK (receptor tyrosine kinases) which is a receptor for insulin is an extracellular receptor but in contrast to other cell surface receptors it is catalytic in nature. In the absence of insulin (ligand), it is monomeric but as soon as it gets activated (activation occurs upon ligand binding), it undergo dimerization. It leads to auto-phosphorylation in it's tyrosine residue which subsequently leads to phosphorylation of tyrosine residue of other receptors. Such hyper-phosphorylated receptor have high affinity with enzyme/molecule like IRS protein which have SH2 domain . IRS down stream activates phosphinositide 3-kinase (PI-3K). This enzyme converts component of animal cell membrane PIP2 into PIP3. PIP3 also remains membrane bound but it has the potential to phosphorylate another enzyme named as PIP3-dependent protein kinase B (PDK1). Further, PDK1 leads to the activation of Akt or PK-B. Akt is a serine-threonine kinase which ultimately leads to the recruitment of Glut4 receptors on cell membrane for uptake of more and more glucose into the cell.
Note: Apart from this Akt also phosphorylates another protein named as FOXO which ultimately causes cell growth, Akt can also phosphorylate BAD protein so as to restrict cell apoptosis or we can say it leads to cell survival, Akt also leads to translation in a cell with the help of mTOR raptor etc.
Answer: Genetic variation within a species can result from a few different sources. Mutations, the changes in the sequences of genes in DNA, are one source of genetic variation. ... As a result, the tree-colored moths are more likely to survive, reproduce, and pass on their genes.
Explanation:
