Answer:
PFFT this might help? sorry if not mate
Explanation:
Cell cycle checkpoint controls play a major role in preventing the development of cancer [see Sherr, 1994, for a more detailed discussion]. Major checkpoints occur at the G1 to S phase transition and at the G2 to M phase transitions. Cancer is a genetic disease that arises from defects in growth-promoting oncogenes and growth-suppressing tumor suppressor genes. The p53 tumor suppressor protein plays a role in both the G1/S phase and G2/M phase checkpoints. The mechanism for this activity at the G1/S phase checkpoint is well understood, but its mechanism of action at the G2/M phase checkpoint remains to be elucidated. The p53 protein is thought to prevent chromosomal replication specifically during the cell cycle if DNA damage is present. In addition, p53 can induce a type of programmed cell death, or apoptosis, under certain circumstances. The general goal of p53 appears to be the prevention of cell propagation if mutations are present. The p53 protein acts as a transcription factor by binding to certain specific genes and regulating their expression. One of these, WAF1 or Cip1, is activated by p53 and is an essential downstream mediator of p53-dependent G1/S phase checkpoint control. The function of p53 can be suppressed by another gene, MDM2, which is overexpressed in certain tumorigenic mouse cells and binds to p53 protein, thus inhibiting its transcriptional activation function. Other cellular proteins have been found to bind to p53, but the significance of the associations is not completely understood in all cases. The large number of human cancers in which the p53 gene is altered makes this gene a good candidate for cancer screening approaches.
Answer:
Yes
Explanation:
No matter what age, trees still give out oxygen. It may not be the same amount as an older tree, but it still has the same effect.
Answer:
4. B cells become activated by interacting with helper T cells.
1. B cells display antigens in MHC class II receptors on the cell surface.
2. Antibodies released by plasma cells bind to the antigen so they will be destroyed by other cells of the immune system.
3.B cells rearrange their DNA to create a unique B-cell receptor.
5. B cells undergo clonal expansion.
6. B cells digest antigens that bind to the antibodies on their surface.
Explanation:
B-cells get activated by interacting with helper T cells when they bind to the antigen to receptors i.e (MHC class II receptors on the cell surface) on the surface of the cell. Series of activities such as release by plasma cells which cause rearrangement of B cells causes the cell to divide and proliferate. The process through which daughter cells arise from a parent cell called clonal expansion.
Y=-(x^2-20x+64)
----find two numbers that multiply to 64 and add to -20. They are -16 and -4--
y=-(x-16)(x-4)
ROOTS : 16, 4
