Cell Cycle Quiz

What two molecules are important in the control of the cell cycle?

CDK and cyclin

What does the M in the "M phase" stand for?

Mitosis; the process in which one cell divides into two

Do all cells divide at the same rate?

No, it depends on the cell type

Describe the process of semi-conservative replication.

Process of DNA synthesis, in which the two original strands of the molecule separate, and each acts as a template on which a new complementary strand is laid down.

What are the 4 parts of Mitosis?

Prophase, Metaphase, Anaphase, and Telophase

What signals a cell to start dividing?

Receptors that detect empty space from cell death

What happens during the life of a cell?

The cell cycle consists of two main phases, interphase and mitosis. Mitosis is the process during which one cell divides into two. (The later stages of mitosis are usually accompanied by the division of the cytoplasm into two daughter cells in a process called cytokinesis.) Interphase comes before mitosis and is the time during which preparations for mitosis are made and when the cell acquires energy and nutrients from the environment and duplicates its chromosomes. Interphase itself is made up of three phases - G1 phase, S phase, and G2 phase - along with a special phase called G0. G1 is the phase that comes after the most recent cell division and before the duplication of chromosomes. (A large percentage of cells usually grow during the G1 stage.) Later in the G1 phase referred to as the restriction point, cells undergo an internal investigation along with their ability to complete the cell cycle and produce two viable daughter cells. If the evaluation is negative, the cell does not go on to the mitosis stage but rather exits the cell cycle to a non-dividing state called the G0 stage. If the evaluation is positive, the cell becomes committed to DNA replication and mitosis. (The restriction point can also be known as a point of cell division.) If a cell is continuing and heading on to mitosis, it begins to produce proteins called histones that are critical to organizing and condensing chromosomes during mitosis. As the production of histones peaks, the S - phase begins. During the S phase, duplicate copies of each chromosome are synthesized. After the chromosomes are duplicated in the S - phase, g2, which is usually the shortest phase of interphase begins. During G2, cells get even more prepared for mitosis by synthesizing various proteins and other molecules that will be required for both mitosis and cytokinesis.

What is a replication fork?

The site of DNA replication

What must occur inside of cell before cell division can occur?

Before the process of cell division can even take place, the cell must be in an environment where it is able to grow and obtain enough energy for the next few stages of the cell cycle. Also, in order for the cell to begin its division into two viable daughter cells, everything must be duplicated.

What can happen if there is a problem regulating the cell cycle?

Cancer - a disease caused from uncontrolled cell division

What is chemotherapy?

Chemotherapy tries to stop cell division in rapidly dividing cells. This includes cancer and some healthy cells within the body.

What happens during metaphase?

Chromosomes begin lining up at the metaphase plate ( an imaginary line dividing the cell into two); the fibers begin pulling the chromosomes towards opposite ends of the cell

What happens during prophase?

Chromosomes condense and appear to be as they are usually are depicted as; four arms that attach to each other at one point. At this time, each chromosome is exactly two identical copies. Each copy is called a chromatid. A spindle begins to form at the end of the centrioles. This spindle is made up of fibers. The centrioles begin to separate. The membrane of the nucleus, or nuclear envelope, fragments and disperses.

What are the three major phases of the cell cycle?

Interphase, mitosis, and cytokinesis

What are the 3 phases of interphase? What happens during each phase?

The 3 phases of interphase are the G1 phase, the S- phase and the G2 phase. G1 cells carry out what is needed for a cell to carry out its daily life and action. The G1 phase is the most variable phase of the cell cycle. The cells grow and increase with size and new proteins and organelles are made during this stage. Some cells exit the cell cycle and become temporarily inactive but others continue to quickly go through the G1 phase over and over again in order to divide. During the G2 phase, proteins that from microtubules used during mitosis have to be synthesized, and membrane materials for the new daughter cells must be packaged in vesicles ready for use. In the S- phase, the cell must produce two similar daughter cells and then the complete DNA instructions in the cell need to be duplicated.

Where do cells come from?

The cell theory states "All living things come from pre-existing cells" and so therefore, new cells come from pre-existing cells. The original cells then undergo the stage of mitosis where the cell divides into two new daughter cells.

What happens during telophase?

The chromatids (now also known as chromosomes) reach opposite ends of the cell and a new nuclear membrane is formed; mitosis (the division of the nucleus) is now completed

Cytokinesis

The division of the cell's cytoplasm into two viable daughter cells

What happens during anaphase?

The fibers begin pulling the chromatids towards opposite ends of the cell.

in non-dividing cells, nuclear DNA exists as.....

chromatin