Transcript 5.1 The Cell Cycle

5.1 The Cell Cycle
KEY CONCEPT
Cells have distinct phases of growth, reproduction,
and normal functions.
5.1 The Cell Cycle
• I can describe the stages of the cell cycle.
• I can compare rates of division in different cell types.
• I can identify factors that limit cell size.
5.1 The Cell Cycle
The cell cycle has four main stages.
• The cell cycle is a regular pattern of growth, DNA
replication, and cell division.
5.1 The Cell Cycle
• The 4 main stages of the cell cycle are gap 1, synthesis,
gap 2, and mitosis.
– Gap 1 (G1): cell growth and
normal functions
– DNA synthesis (S): copies
DNA
– Gap 2 (G2): additional
growth
– Mitosis (M): includes
division of the cell nucleus
(mitosis) and division of the
cell cytoplasm (cytokinesis)
• Mitosis occurs only if the cell is large enough and the DNA
undamaged.
5.1 The Cell Cycle
Cells divide at different rates.
• The rate of cell division varies with the need for those
types of cells.
• Some cells are unlikely to divide (G0).
5.1 The Cell Cycle
Cell size is limited.
• Volume increases faster than surface area.
5.1 The Cell Cycle
• Surface area must allow for adequate
exchange of materials.
– Cell growth is coordinated with
division.
– Cells that must be large have
unique shapes.
5.1 The Cell Cycle
In which stage of the cell cycle do the nucleus and its
contents divide?
• A. synthesis
• B. gap 1
• C. mitosis
• D. gap 2
5.1 The Cell Cycle
5.1 The Cell Cycle
During the gap 1 stage of the cell cycle, a cell
• a. splits into two new cells.
• b. carries out its normal functions.
• c. duplicates its DNA.
• d. divides its cytoplasm.
5.1 The Cell Cycle
Which of the following phrases best describes cytokinesis?
• a. division of the cytoplasm
• b. division of the nucleus
• c. division of DNA
• d. division of surface area
5.1 The Cell Cycle
Which statement is true about the rates of cell division in
eukaryotes?
• A. They remain the same for the life of the organism.
• b. They are faster than that of prokaryotes.
• c. They increase with the age of the organism.
• d. They vary greatly within an organism.
5.1 The Cell Cycle
Which of the following limits the maximum size of a cell?
• a. the stage of the cell cycle
• b. the ratio of cell surface area to volume
• c. the number of mitochondria in the cell
• d. the size of the organism