Answer:
b. DNA replication occurs only during the G1 phase of the cell cycle.
Explanation:
By understanding DNA and gene expression, humans have been able to understand how genetic diseases are caused, therefore they have been able to devise gene therapy and other technologies to treat such disease. Second, the understanding has also allowed humans to devise plants that are resistant to pests and drought hence increasing crop yields.
A negative aspect of this understanding is the issue of bioterrorism. In the wrong hands, this technology can be used against society. The technology can be used to modify organisms to make them deliberately harmful to humans. Second is the issue of bioethics. This technology can be used to enhance humans and result to an ‘arms race’ between human races that can tear down the social fabric.
In biochemistry, aligand is a substance that forms a complex with a biomolecule to serve abiological purpose. In protein-ligandbinding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein.
Receptor mediated endocytosis is an endocytotic mechanism in which specific molecules are ingested into the cell. The specificity results from a receptor-ligand interaction. Receptors on the plasma membrane of the target tissue will specifically bind to ligands on the outside of the cell. An endocytotic process occurs and the ligand is ingested.
A very well studied example of receptor mediated endocytosis involves the metabolism of cholesterol.
Collagen supported cells :)
