Question

reading
hmh science dimensions biology, unit 5, lesson 1, pages 225 - 227

1. what would happen if there is not enough surface area for materials to cross into and out of the cell?

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1. what two factors regulate cell division?

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1. explain what occurs during apoptosis.

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1. how do tumors form from cancer cells?

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Explanation:

1. If there is not enough surface area for materials to cross into and out of the cell, the cell would not be able to obtain sufficient nutrients and oxygen, and waste products would accumulate inside the cell. This would disrupt normal cellular functions and could lead to cell death.
2. The two factors that regulate cell division are internal factors (such as cyclins and cyclin - dependent kinases) and external factors (such as growth factors).
3. During apoptosis, the cell undergoes a programmed death. The cell shrinks, its nucleus fragments, and it is eventually phagocytosed by other cells. This process is important for removing damaged or unnecessary cells.
4. Tumors form from cancer cells when cancer cells divide uncontrollably. They do not respond to the normal signals that regulate cell growth and division. As a result, they accumulate and form a mass of abnormal cells.

Answer:

1. The cell would not be able to obtain sufficient nutrients and oxygen, and waste products would accumulate inside the cell, disrupting normal cellular functions and potentially leading to cell death.
2. Internal factors (such as cyclins and cyclin - dependent kinases) and external factors (such as growth factors).
3. The cell undergoes a programmed death: it shrinks, its nucleus fragments, and it is eventually phagocytosed by other cells.
4. Cancer cells divide uncontrollably (not responding to normal growth - regulating signals), accumulate, and form a mass of abnormal cells.