Questions: What cell cycle regulatory protein is a tumorsuppressor protein? E2F EGF p53 HER2 Question 52 1 pts During which stage of mitosis do replicated chromosomes condense and the nuclear envelope disappears? Interphase Prophase Telophase Metaphase Anaphase

The answer to the first question is: p53.

Explanation for each option:

• E2F: This is a group of genes that codes for a family of transcription factors in higher eukaryotes. They are involved in the control of the cell cycle and the action of tumor suppressor proteins, but E2F itself is not a tumor suppressor protein.
• EGF: Epidermal Growth Factor is a growth factor that stimulates cell growth, proliferation, and differentiation by binding to its receptor EGFR. It is not a tumor suppressor protein.
• p53: This is a well-known tumor suppressor protein that plays a crucial role in preventing cancer formation. It regulates the cell cycle and can induce apoptosis if DNA damage is irreparable.
• HER2: Human Epidermal growth factor Receptor 2 is a protein that can promote the growth of cancer cells. It is not a tumor suppressor protein.

The answer to the second question is: Prophase.

Explanation for each option:

• Interphase: This is the phase of the cell cycle in which the cell prepares for mitosis, but it is not a stage of mitosis itself. Chromosomes are not condensed during interphase.
• Prophase: During this stage of mitosis, the replicated chromosomes condense, and the nuclear envelope begins to disappear, marking the start of mitosis.
• Telophase: This is the stage where the chromosomes arrive at opposite poles, and the nuclear envelope re-forms around each set of chromosomes.
• Metaphase: During this stage, chromosomes line up at the metaphase plate, but they are already condensed by this point.
• Anaphase: This is the stage where sister chromatids are pulled apart to opposite poles of the cell.

In summary, p53 is the tumor suppressor protein, and the stage of mitosis where replicated chromosomes condense and the nuclear envelope disappears is Prophase.