Post on 28-Dec-2015
Chapter 9 – Cellular Reproduction
Section 1- Cellular Growth
Cellular Growth
• Cells grow until they reach their size limit, then they either stop growing or divide.
Cellular ReproductionSection 1
Cell Size Limitations
• The ratio of a cell’s surface area (area covered by plasma membrane) to its volume (space taken up by the inner contents) is the major factor that limits the size of the cell.
• As a cell grows, its volume increases much more rapidly than the surface area.
• When cells get too large they cannot get enough nutrients into and out of the cell.
Cellular ReproductionSection 1 - Cellular Growth
Cell Size Limitations
• Small cells also maintain more efficient transport systems.
• Cell size also affects the ability of a cell to communicate instructions for cellular function.
Cellular ReproductionSection 1 - Cellular Growth
The Cell Cycle
• Cell division prevents the cell from becoming too large.
• Cell division is the way the cell reproduces so that you grow and heal certain injuries.
• Cell division is asexual reproduction, meaning the offspring are clones/identical to the parent.
• Cells reproduce by a cycle of growing and dividing called the cell cycle and become two cells.
Cellular ReproductionSection 1 – Cellular Growth
https://www.youtube.com/watch?v=Wy3N5NCZBHQ
The cell cycle has 3 main stages:1. Interphase - the stage during which the cell grows,
carries out cellular functions, and replicates (makes copies of the DNA).
- G1 (1st growth phase)- S (Synthesis phase)- G2 (2nd growth phase)2. Mitosis – the cell’s nucleus and nuclear material
divide.3. Cytokinesis – the cell’s cytoplasm divides, creating
a new cell.
Cellular ReproductionSection 1 – Cellular Growth
The Cell Cycle
Cellular Reproduction
The Stages of Interphase
• The first stage of interphase, G1
- The cell is growing, carrying out normal cell functions, and preparing to replicate DNA.
Section 1 – Cellular Growth
Cellular Reproduction
The Stages of Interphase• The Second Stage of Interphase, S
- The cell copies its DNA in preparation for cell division.
Section 1 – Cellular Growth
Cellular Reproduction
The Stages of Interphase• The Third Stage of Interphase, G2
- The cell prepares for the division of its nucleus.
Section 1 – Cellular Growth
Cellular Reproduction
Chromosomes – rod-shaped structures that contain the genetic
material that is passed from one generation to the next.
- Visible only during cell division.
Chromatin – relaxed form of DNA in the cell’s nucleus;
loose network of bumpy threads.
Section 1 – Cellular Growth