Cell Biology: Prokaryotic, Eukaryotic, Plant, and Animal

Why We Study Cells

• Cells form the fundamental building blocks of life
• Understanding cell components leads to a grasp of how organisms function microscopically
• Interactions and interdependence between cell structures ensure proper biological processes

Prokaryotic vs. Eukaryotic Cells

• Both cell types share fundamental processes like responding to stimuli, reproduction, and energy production
• Eukaryotic cells possess greater complexity with membrane-bound organelles which allow advanced regulation and energy processes
• Prokaryotic cells are smaller and streamlined and perform similar processes in a more primitive form
• Prokaryotes directly interact with the environment due to the absence of membrane-bound organelles
• Eukaryotes depend on complex intracellular systems, like the endomembrane system

Plant vs. Animal Cells

• Plant and animal cells are both eukaryotic, sharing structures like the nucleus, endoplasmic reticulum, and mitochondria
• Chloroplasts in plant cells facilitate photosynthesis with a rigid cell wall that supports physical structure
• Animal cells lack a cell wall, making them flexible and dependent on food intake rather than photosynthesis
• Vacuoles in plant cells store nutrients and help maintain pressure
• Vacuoles in animal cells are smaller focusing more on movement and flexibility
• The plasma membrane is present in both, ensuring the control of substances entering or leaving the cell

Eukaryotic Cell as Four Interacting Systems

• The nucleus sends genetic instructions for protein synthesis to the cytosol
• The endomembrane system collaborates with the nucleus, using genetic instructions to create proteins via the rough ER
• The Golgi apparatus packages proteins for transport
• Semiautonomous organelles like mitochondria and chloroplasts help maintain cellular metabolism
• These systems work together to produce energy, proteins, and other cell products, which ensures cell function

Major Cell Parts

• Nucleus directs mRNA synthesis, and ribosomes translate it to form proteins
• Proteins are used throughout the cell like in the mitochondria
• The endomembrane system exports proteins
• The rough ER produces proteins, which are then processed and modified in the Golgi apparatus
• Mitochondria use products from the cytosol like glucose to produce ATP, which powers cellular functions
• The plasma membrane controls entry and exit, while the cytoskeleton maintains cell shape, structure, and response to the environment

Maintaining a Functional Cell

• The nucleus, endomembrane system, cytosol, and semiautonomous organelles interact
• Nucleus provides genetic instructions used by ribosomes in the cytosol to create proteins
• The endomembrane system transports proteins where needed
• The cytoskeleton supports activities by ensuring the proper organization of cell components
• The plasma membrane controls the flow of molecules for metabolic processes while maintaining internal homeostasis

Multicellularity of Plants and Animals

• Plants and animals rely on cell specialization into tissues and organs
• Multicellularity is an essential adaptation for complexity

Extracellular Matrix in Animals

• The extracellular matrix (ECM) provides structural support to cells, which maintains tissue integrity
• The ECM works in tandem with the cytoskeleton, contributing to cellular shape
• It communicates with the plasma membrane, helping cells adhere to each other

Major Structural Components of ECM

• ECM is composed of proteins (e.g., collagen, elastin) and polysaccharides (e.g., glycosaminoglycans)
• Integrins, membrane proteins, connect the ECM to the cytoskeleton, allowing cells to sense the environment

Plant Cell Walls

• The cell wall provides physical support to the plant, helping it maintain its shape
• It works with the vacuole (in plant cells) to maintain turgor pressure
• The cell wall protects the plant from pathogens, working alongside the plasma membrane

Six Basic Cell Processes

• Cell division aka mitosis creates new cells, contributing to tissue growth
• Cell differentiation allows cells to specialize, forming the tissues needed for organ function
• Cell signaling ensures that cells communicate with each other, coordinating actions like tissue growth
• Apoptosis removes damaged cells to maintain tissue health
• Cell adhesion allows cells to stick together forming stable tissues
• Extracellular matrix components support the organization of cells into functional tissues

Four Types of Animal Tissues

• Epithelial tissue protects body surfaces and cavities by providing a barrier and facilitating absorption or secretion
• Connective tissue (e.g., bone, blood) connects and supports other tissues
• ECM in connective tissue supports tissue with internal links to the cytoskeleton inside cells
• Nervous tissue transmits electrical signals, coordinating responses across the body
• Muscle tissue allows for movement, using contraction powered by nervous signals

Types of Plant Tissues

• Dermal tissue provides a protective outer layer which works with the cell wall to prevent water loss
• Ground tissue is involved in photosynthesis and stores nutrients
• Vascular tissue (xylem and phloem) moves water and nutrients, for nutrient storage and water retention

Explore the fundamental building blocks of life, from prokaryotic to eukaryotic cells. Understand the distinctions between plant and animal cells, focusing on structural differences and functions. Learn how cell components interact to ensure proper biological processes.