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