Answer:
C) Reflects the light from the sun
Explanation:
Moon does not emit its own light. The moonlight is primarily the sunlight that is being reflected form the surface of moon. The moon is actually quite black so only a little amount of sunlight is reflected back.
We see colour due to the presence of cones in our retina. When we look at the moon, the light coming from moon does not have enough intensity to excite or cone cells and thus only rod cell are get excited. As the rods can't sense colours so the moon appears white.
Answer: d. none of the other answers
Explanation:
Enzymes that turn chemical energy into mechanical work are molecular motors.
There are three main components of cytoskeleton including microtubules, actin filaments and Intermediate filaments. Only actin filaments and microtubules carry the motor-driven transport on the cytoskeleton.
The most important feature of intermediate filaments is to provide the plasma membrane with mechanical support where it comes into contact with the extracellular matrix and other cells.
Unlike microtubules and microfilament , intermediate filaments are not involved in motility of the cells, hence do not associat with molecular motors.
Hence, the correct option is d.
NADPH is a reduced form of NADP+. The latter features an extra hydrogen ion in its chemical structure. When NADP+ transforms into NADPH, the other hydrogen ion is released as part of the reaction while the other hydrogen ion becomes a part of the NADPH structure.
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.
