Cell Structure and Function

• Cells are the basic building blocks of all living organisms.
• Cells are the smallest units of life that can perform all life processes.
• The cell theory states that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells.

Types of Cells

• There are two main types of cells: prokaryotic and eukaryotic.
• Prokaryotic cells do not have a nucleus or other membrane-bound organelles.
• Bacteria and Archaea are examples of organisms with prokaryotic cells.
• Eukaryotic cells have a nucleus and other membrane-bound organelles.
• Animals, plants, fungi, and protists are examples of organisms with eukaryotic cells.

Cell Structures and Functions

• Cell Membrane: A selectively permeable barrier that encloses the cell and regulates the movement of substances in and out.
• Cytoplasm: The gel-like substance within the cell membrane, containing water, salts, and organic molecules.
• Nucleus: The control center of the cell, containing DNA organized into chromosomes.
• Mitochondria: Powerhouse of the cell, responsible for generating energy through cellular respiration.
• Ribosomes: Sites of protein synthesis, where proteins are assembled.
• Endoplasmic Reticulum (ER): A network of membranes involved in protein and lipid synthesis.
• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for transport within or outside the cell.
• Lysosomes: Contain enzymes for breaking down cellular waste and debris.

Plant Cell Structures

• Cell Wall: A rigid outer layer made of cellulose that provides support and protection to the plant cell.
• Chloroplasts: Organelles responsible for photosynthesis, containing chlorophyll.
• Vacuoles: Large, fluid-filled sacs that store water, nutrients, and waste products; help maintain cell turgor pressure.

Cell Organization

• Cells are organized into tissues, tissues into organs, organs into systems, and systems into organisms.
• Tissues are groups of similar cells performing a specific function.
• Organs are structures composed of different tissues working together.
• Systems are groups of organs that cooperate to perform major bodily functions.

Cell Processes : Diffusion

• Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration.
• Osmosis is the diffusion of water across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.

Cell Processes : Photosynthesis

• Photosynthesis is the process by which plants convert light energy into chemical energy in the form of glucose.
• It occurs in chloroplasts, using chlorophyll to capture sunlight.
  • Carbon dioxide and water are used as reactants, and oxygen is released as a byproduct.

Cell Processes : Respiration

• Cellular respiration is the process by which cells break down glucose to release energy in the form of ATP (adenosine triphosphate).
• It occurs in mitochondria, using oxygen and glucose to produce carbon dioxide, water, and energy.