1. Explain why neither cyclins nor kinases alone can cause a cell to progress through the cell cycle.
As cyclin accumulates, it activates their kinases that turn on the pathway to mitotic spindle formation, and so on.
2. How do controls of the cell cycle protect multi-cellular organisms from accumulating large numbers of damaged or defective cells?
The checkpoint control is responsible for multi-cellular organisms for not accumulating large numbers of damaged or defective cells. Checkpoint controls consist of proteins that detect mistakes and damage and quickly halt the cell cycle until repairs are made. When this occurs, the cell is said to be in cell-cycle <span>arrest.
</span>3. What is the difference between a cancerous tumor and metastasis?
Cancer is cause by mutations in the genes that encode these proteins can lead to uncontrolled growth. Cancer is when there is uncontrolled cell growth and reproduction. Metastasis is caused by tumors when they grow and interfere with the surrounding tissue or cells and break off and spread around the body. Cancerous tumors cause metastasis, and tumors are caused by mutations in genes that lead to uncontrolled growth.
4. What are the functions of tumor-suppressor genes and protoncogenes in noncancerous cells?
The genes that encode the checkpoint proteins are called tumor suppressors because they suppress the development of cells into tumors. If mutations inactivate these genes, the cell-cycle break is removed with or without a signal from the outside. Proto-oncogene’s are involved in promoting cell division, mutations can cause them to become oncogenes, or cancer genes which stimulate cells to leave G0 and divide whether or not it is a signal.
What's the rest of the question so I can answer it
Explanation:
hurry and type the rest out pls
Easy. Answer is oxygen because it says which one was missing before any life was on earth. And in order to have life on earth you need oxygen!
:)
A. Earth's magnetic field reverses over time; the changes show that seafloor spreading has taken place over time.
Explanation:
The pattern of the magnetic minerals in seafloor ridges are aligned in a repeating pattern because the earth's magnetic field reverses overtime.
This provides evidence because the changes shows that the sea floor spreading has taken place over time.
- The concept of sea floor spreading was first suggested by Harry Hess in the early 1960's.
- Using sophisticated tools, he was able to discover stripe patterns of magnetic minerals in rocks.
- The earth can be likened to a giant bar magnet
- The geomagnetic field originates from the core where the movement of molten metals induces magnetism.
- In a fresh cooling magma, the metallic minerals are able to align their domains with the prevailing magnetic field.
- At some point the magnetic field is normal with a very strong intensity. At other times the intensity is low and it reverses.
- The minerals keeps track of the changes.
- This leads to striped pattern that has been used to suggest sea floor spreading.
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The development of adaptive traits is a result of natural selection, one of the main mechanisms underlying evolutionary change.
Understanding natural selection is also becoming more and more important in real-world settings, such as resource management, agriculture, and medicine. Even among people with postsecondary physical education, studies show that natural selection is generally very poorly understood.
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