The accurate statements to the signal transduction pathways are as follows:
1. A receptor changes conformation upon attachment, conducting a signal across the cell membrane.
2. A second messenger may carry a signal from the cell membrane to an organelle.
3. Signal transduction cascades, often involving protein kinases, amplify a signal intracellularly.
4. A receptor may pass on a signal by associating with another protein or by functioning as an enzyme.
5. A ligand, like hormone, combines with a specific cell surface receptor on a target cell.
6. Phosphatase eradicate phosphoryl groups from polypeptides, monitoring the response of the cell.
1 pic : B ; cell divison allows the org to reproduce
2nd : A ; interphase then mitosis and last cytokinesis
Estuaries. Brackish water condition commonly occurs when fresh water meets seawater. In fact, the most extensive brackish water habitats worldwide areestuaries, where a river meets the sea. The River Thames flowing through London is a classic river estuary.
