Biology Chapter on Cellular Organization and Plant Structures

Cellular Organization

• Cells are the basic units of life, organized into tissues, organs, and organ systems.
• Organisms are collections of organ systems.
• Specialized cells (like nerve, muscle, or blood cells) have specific functions related to their structure.
• Plant cells have cell walls and chloroplasts, while animal cells don't.
• Cellular structures like cell membranes, cytoplasm, nucleus, mitochondria and vacuoles perform important cellular functions.

Plant Structures

• Plants have roots, stems, leaves, and flowers, all playing vital roles in the plant's life cycle.
• Roots absorb water and nutrients.
• Stem supports the plant and transports materials.
• Leaves facilitate photosynthesis—producing food.
• Flowers are involved in reproduction.

Organ Systems in Humans

• Humans have systems like the digestive, breathing, circulatory (blood), and excretory systems in which organs work together to keep the organism alive.

Tissues

• Tissues are similar cells grouped together to perform specific functions.
• Plant tissues (including epidermal, mesophyll, and vascular tissues) are specialized for various functions.
• Similar cells form tissues, and organized tissues form organs.

Animal Cells & Tissues

• Epithelial tissue forms layers that cover surfaces and line body cavities.
• Connective tissue supports and connects other tissues (e.g. blood).
• Muscle tissue enables movement due to the contractile muscle cells.
• Nervous tissue transmits electrical impulses for communication.