Cell Cycle
What is the main purpose of the cell cycle?
The cell cycle allows cells to grow, copy their DNA, and divide to produce new cells.
What is the name of the first stage of mitosis?
Prophase
Why can't cells continue growing larger forever?
Cells cannot continue growing indefinitely because as they become larger, they become less efficient at moving materials into and out of the cell.
What structures contain the cell's genetic information that must be separated during mitosis?
Chromosomes
What is a checkpoint in the cell cycle?
A checkpoint is a control point where the cell checks whether conditions are appropriate for continuing through the cell cycle.
What is a stem cell?
A stem cell is a cell that can divide and can develop into different specialized cell types.
During which part of the cell cycle does a cell copy its DNA?
DNA replication occurs during interphase, before mitosis.
During which stage do chromosomes line up across the middle of the cell?
Metaphase
What happens to a cell's surface-area-to-volume ratio as the cell gets larger?
The surface-area-to-volume ratio decreases as a cell gets larger.
What structures help move chromosomes during mitosis?
Spindle fibers
Why does a cell need to check its DNA before dividing?
The cell checks its DNA to make sure it is correct and not damaged before the cell divides.
What is one ability that makes stem cells different from many specialized cells?
Stem cells can divide repeatedly and/or differentiate into specialized cells.
Put these events in the correct order:
Cytokinesis, Cell growth, DNA replication and Mitosis
Cell growth → DNA replication → Mitosis → Cytokinesis
What happens to sister chromatids during anaphase?
During anaphase, sister chromatids separate and move toward opposite poles of the cell.
Why does a low surface-area-to-volume ratio make it harder for a cell to survive?
A lower surface-area-to-volume ratio makes it more difficult for the cell to exchange materials efficiently with its surroundings.
What is the job of spindle fibers during cell division?
Spindle fibers move/separate chromosomes or sister chromatids toward opposite poles of the cell.
What could happen if a cell continues dividing even when its DNA is damaged?
The damaged cell could continue dividing and potentially produce abnormal cells.
What does it mean when a stem cell differentiates?
Differentiation means a cell develops into a specialized type of cell with a specific function.
Why must DNA be copied before a cell divides?
DNA must be copied so that each daughter cell receives a complete set of genetic information.
Describe two important events that happen during telophase.
During telophase:
- Chromosomes reach opposite ends of the cell.
- Nuclear membranes reform around the chromosomes.
- Chromosomes begin to uncoil into chromatin.
Two cells have the same DNA, but one is much larger. Which cell is more likely to divide soon? Why?
The larger cell is more likely to divide because larger cells become less efficient at transporting materials.
Why is it important for sister chromatids to move to opposite sides of the cell?
Sister chromatids must move to opposite sides so that each daughter cell receives the correct genetic information.
How can problems with checkpoint proteins contribute to cancer?
If checkpoint proteins fail, cells with problems such as damaged DNA may continue dividing, which can contribute to uncontrolled cell division and cancer.
Why are stem cells useful for producing different types of cells in an organism?
Stem cells can produce different specialized cells needed for growth, development, and tissue repair.
A cell has finished copying its DNA but has not started separating its chromosomes. What major stage of the cell cycle comes next?
Mitosis
A cell's chromosomes have reached opposite ends of the cell, and two new nuclei are beginning to form. Which stage is occurring? Explain your answer.
Telophase. The chromosomes have reached opposite poles and new nuclear membranes are forming.
Explain how cell division helps a growing organism maintain cells that can efficiently exchange materials with their surroundings.
Cell division produces smaller cells with a higher surface-area-to-volume ratio, allowing materials to move more efficiently into and out of the cells.
Predict what could happen if the structures responsible for moving chromosomes did not work correctly during mitosis.
The chromosomes could be distributed incorrectly, causing daughter cells to receive unequal or incorrect genetic material.
A cell has severe DNA damage, but its checkpoint system fails to stop the cell from dividing. Explain how this could eventually lead to uncontrolled cell growth.
If damaged cells are allowed to keep dividing, the abnormal cells can continue reproducing. Over time, this can lead to uncontrolled cell growth and cancer.
Explain how the ability of stem cells to divide and differentiate can help an organism grow and repair damaged tissues.
Stem cells can divide repeatedly to produce new cells and those cells can differentiate into specialized cells, helping an organism grow and repair damaged tissues.