Download 5.1 The Cell Cycle

5.1 The Cell Cycle
Cell Cycle Overview
5.1 The Cell Cycle
Cells have distinct phases of growth, reproduction,
and normal functions.
5.1 The Cell Cycle
The cell cycle has four main stages.
4. cell divides
1. cell grows
2. DNA is
copied
3. cell
grows more
5.1 The Cell Cycle
Cells divide at different rates.
• The rate of cell division varies with the need for those
types of cells.
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
Biology Notes
The Cell Cycle
and
Mitosis (5.1-2)
5.1 The Cell Cycle
* Cells
– are composed of DNA (deoxyribonucleic acid)
– DNA contains genetic material
– replicate and divide through the cell cycle (is controlled
by proteins)
5.1 The Cell Cycle
* Cell Division
– cells divide at different rates
~ prokaryotic cells (have no membrane-bound
organelles) divide faster than eukaryotic cells (have
membrane-bound organelles)
5.1 The Cell Cycle
~ also depends on the type of cell and how often the
body needs the new cell
~ some cells remain in G0 (no division, but still carry out
normal functions) for long periods, until needed
5.1 The Cell Cycle
– division is important to both single-celled and
multicellular organisms
~ single-celled – is used to reproduce
~ multicellular – is used for growth, development, and
repair
5.1 The Cell Cycle
* Cell Size
– cannot be too small
~ could not contain necessary organelles & molecules
– cannot be too large
~ if ratio of surface area to volume is too small, oxygen,
nutrients, and waste cannot move in and out of the cell
efficiently
– cell division helps the cell to maintain its size when it
grows
5.1 The Cell Cycle
* Cell Cycle
A. Composed of Interphase and the M Phase
5.1 The Cell Cycle
- Interphase
- longest part of the cell cycle
~ includes G1, S, and G2 Phases
- by the end of interphase, the cell will have 2 sets of DNA
and chromosomes, and will be large enough to divide
5.1 The Cell Cycle
B. Cell cycle is continuous
(does not stop), but can be
divided into 4 main phases:
5.1 The Cell Cycle
- also called “gap 1” phase
- longest phase in interphase
G1 Phase
- cell grows & carries out normal
functions
- organelles are replicated/duplicated
- cell must pass checkpoint (be the
right size, have enough nutrition, and
undamaged DNA) before continuing
5.1 The Cell Cycle
- “synthesis” phase
S Phase
- DNA is copied (chromosomes duplicate)
5.1 The Cell Cycle
- also called “gap 2” phase
G2 Phase
- cell grows & carries out normal
functions
- preparation for mitosis
- cell must pass checkpoint before
continuing
5.1 The Cell Cycle
M Phase
- mitosis and cytokinesis
5.1 The Cell Cycle
Cell Cycle
5.1 The Cell Cycle
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