Cell cycle Flashcards
What are the three phases of Interphase
The G1 phase- cell growth. size of cell increases, more organelles and proteins are made
The S-phase- DNA replication -new DNA synthesized when chromosomes are replicated .by the end of the S-phase the cell contains twice as much DNA as before
The G2 phase- preparing for cell division. many organelles and molecules required for division are produced
What is Interphase
When the nucleus is visible, nuclear membrane is intact, the longest period of the cell cycle
One of the four stages of mitosis
Prophase, metaphase, anaphase, and telophase
Describe prophase
- The genetic material inside the nucleus condenses and the chromatin condenses into chromosomes
- nuclear membrane breaks down
- spindle fibers begin to form
- The duplicated chromosomes are visible
Describe metaphase
- The chromosomes attach to the spindle
- The centromeres of the duplicated chromosomes line up in the center of the cell
Describe Anaphase
Sister chromatids separate and begin to move the opposite ends of the cell
Describe telophase
- The chromosomes reach the end of the cell
- spindles disappear
- nuclear membrane and nucleus reappear
- The chromosomes begin to spread into a tangle of chromatin
Define cytokinesis
During cytokinesis the cytoplasm divides into two sister cells completing the process of cell division
What is the difference between cytokinesis in animal cells and plant cell
Animal- The cell membrane is drawn inward and the cytoplasm is pinched into two equal parts
Plant- The cell membrane is not flexible enough to draw inward so a cell plate forms halfway between the divided nuclei
What happens when cells come in contact with one another
They stop growing and dividing. This is called contact inhibition
What are cyclins
They are proteins that regulate the cell cycle
What happens when a cell becomes cancerous
It stops responding to the signals that regulate the growth and division of the cell
What are the two types of factors that help regulate the cell cycle
Internal regulatory proteins and external regulatory proteins
What is the relationship between mitosis and cytokinesis
Mitosis is what triggers the cytokinesis to begin
Explain how the cell cycle is regulated
Proteins inside and outside the cell regulate cell division. They only allow the cell to proceed into the cycle when certain events have occurred inside the cell. External regulators respond to events outside the cell.
