Cell Division: Mitosis and Meiosis

Cell Division

Overview

Cell division is the process by which a cell divides into two daughter cells. It is essential for growth, development, and reproduction.

Types of Cell Division

• Mitosis: occurs in somatic cells (non-reproductive cells) and results in two identical daughter cells.
• Meiosis: occurs in reproductive cells (gametes) and results in four non-identical daughter cells with half the number of chromosomes as the parent cell.

Phases of Mitosis

1. Interphase: cell grows, replicates DNA, and prepares for cell division.
2. Prophase: chromatin condenses, nuclear envelope breaks down, and spindle fibers form.
3. Metaphase: chromosomes line up at the center of the cell.
4. Anaphase: sister chromatids separate and move to opposite poles.
5. Telophase: nuclear envelope reforms, and chromosomes uncoil.
6. Cytokinesis: cytoplasm divides, and the cell splits into two daughter cells.

Photosynthesis

Overview

Photosynthesis is the process by which cells convert light energy into chemical energy.

Light-Dependent Reactions

• Light absorption: light is absorbed by pigments such as chlorophyll.
• Electron transport: light energy is used to generate ATP and NADPH.
• ** ATP synthesis**: ATP is generated from ADP and Pi.

Light-Independent Reactions (Calvin Cycle)

• Carbon fixation: CO2 is fixed into a 3-carbon molecule.
• Reduction reactions: 3-carbon molecules are reduced to form glucose.
• Regeneration: RuBP is regenerated to start the cycle again.

Importance of Photosynthesis

• Produces oxygen as a byproduct.
• Provides energy and organic compounds for cellular processes.
• Supports life on Earth.

Cell Division

• Cell division is essential for growth, development, and reproduction.
• There are two main types of cell division: mitosis and meiosis.

Mitosis

• Occurs in somatic cells (non-reproductive cells).
• Results in two identical daughter cells.
• Consists of six phases: interphase, prophase, metaphase, anaphase, telophase, and cytokinesis.

Phases of Mitosis

• Interphase: cell grows, replicates DNA, and prepares for cell division.
• Prophase: chromatin condenses, nuclear envelope breaks down, and spindle fibers form.
• Metaphase: chromosomes line up at the center of the cell.
• Anaphase: sister chromatids separate and move to opposite poles.
• Telophase: nuclear envelope reforms, and chromosomes uncoil.
• Cytokinesis: cytoplasm divides, and the cell splits into two daughter cells.

Meiosis

• Occurs in reproductive cells (gametes).
• Results in four non-identical daughter cells with half the number of chromosomes as the parent cell.

Photosynthesis

• Photosynthesis is the process by which cells convert light energy into chemical energy.

Light-Dependent Reactions

• Light absorption: light is absorbed by pigments such as chlorophyll.
• Electron transport: light energy is used to generate ATP and NADPH.
• ATP synthesis: ATP is generated from ADP and Pi.

Light-Independent Reactions (Calvin Cycle)

• Carbon fixation: CO2 is fixed into a 3-carbon molecule.
• Reduction reactions: 3-carbon molecules are reduced to form glucose.
• Regeneration: RuBP is regenerated to start the cycle again.

Importance of Photosynthesis

• Produces oxygen as a byproduct.
• Provides energy and organic compounds for cellular processes.
• Supports life on Earth.

Cell division is a crucial process for growth, development, and reproduction, involving two types: mitosis and meiosis. Learn about the phases and differences between these two processes.