Plant vs Animal Cells & Membranes

• Plant and animal cells qualify as eukaryotic cells, each possessing a nucleus and intricate organelles
• While they share similarities, plant and animal cells exhibit notable distinctions, largely stemming from their distinct functions

Cell Membrane Properties

• The cell membrane, also known as the plasma membrane, constitutes a biological barrier that demarcates the cell's interior from its external milieu across all types of cells
• Selective permeability signifies the cell membrane's ability to permit passage to certain molecules while impeding others, a vital characteristic for maintaining cellular homeostasis
• Phospholipid bilayer is the foundational structure of the cell membrane, incorporating two layers composed of phospholipid molecules
• Hydrophilic heads refer to the polar, water-attracting ends of phospholipids
• Hydrophobic tails denote nonpolar, water-repelling ends of phospholipids
• Within the cell membrane, the hydrophobic tails orient inward, shielded from water, whereas hydrophilic heads interact with water both inside and outside the cell
• Membrane proteins perform varied roles, such as facilitating molecular transport, acting as signal receptors, and lending structural integrity
• Fluid mosaic model is the concept describing the cell membrane as a dynamic entity with diverse proteins embedded within
• Animal cell membranes incorporate cholesterol to aid in modulation of fluidity
• Membrane fluidity is key for cellular function, enabling shape changes and incorporation of proteins and lipids
• Transport occurs as the cell membrane regulates substance movement via diffusion, osmosis, active transport, and vesicular transport
• Cell communication is achieved via membrane proteins that serve as receptors, relaying external cues to the cell
• Protection and support are among the cell membrane's functions, offering a barrier and upholding cell shape

Cell Structure Differences

• Cell wall: Plant cells feature a sturdy wall made of cellulose, providing support and protection, a feature absent in animal cells
• Chloroplasts: Plant cells possess chloroplasts for photosynthesis; animal cells do not
• Vacuoles: Plant cells have a large central vacuole for storing water, nutrients, and waste, unlike animal cells, which have smaller vacuoles, if any
• Shape and size: Plant cells typically have a defined shape due to their cell wall, while animal cells can vary in shape
• Centrioles: Animal cells have centrioles for cell division, whereas plant cells lack them but use other mechanisms for similar functions
• Glyoxysomes: Plant cells use glyoxysomes to convert stored fats into carbohydrates
• Lysosomes: Animal cells utilize lysosomes with enzymes to break down waste, a feature rare in plant cells
• Plasmodesmata: Plant cells communicate and transport substances via plasmodesmata, unlike animal cells, which use gap junctions
• Intercellular junctions: Animal cells use tight junctions, adherens junctions, desmosomes, and gap junctions for cell adhesion and communication

Plant Cell Structures

• Cell Wall: Delivers structural integrity and safeguards the cell
• Cellulose: The cell wall's main component, ensuring firmness
• Plasmodesmata: Channels that facilitate intercellular communication and transport
• Chloroplasts: Locations for photosynthesis, equipped with light-capturing chlorophyll
• Chlorophyll: The green pigment capturing light for photosynthesis
• Thylakoids: The inner membrane system in chloroplasts for the light-dependent reactions of photosynthesis
• Grana: Stacks of thylakoids
• Stroma: The fluid surrounding grana in chloroplasts, where light-independent reactions (Calvin cycle) take place
• Large Central Vacuole: Stores water, nutrients, and waste while upholding turgor pressure
• Turgor Pressure: The force exerted by the cell's contents against its wall, necessary for maintaining rigidity
• Glyoxysomes: Convert stored fats into carbohydrates
• Cell Shape: Consistent and well-defined, thanks to the cell wall

Animal Cell Structures

• Cell Membrane (Plasma Membrane): Surrounds the cell, managing material flow
• Cytoplasm: The gel-like medium that houses organelles
• Nucleus: Holds the cell's genetic material (DNA)
• Nuclear Envelope: The nucleus's double-layered cover
• Nucleolus: Ribosome creation occurs here inside the nucleus
• Chromosomes: DNA-containing structures
• Endoplasmic Reticulum (ER): A membrane network for protein and lipid synthesis
• Rough ER: Ribosome-studded for protein creation
• Smooth ER: Handles lipid synthesis and detoxification
• Golgi Apparatus: Modifies, sorts, and ships proteins and lipids
• Lysosomes: Use enzymes to break down waste
• Mitochondria: Perform cellular respiration, generating ATP (energy)
• Cristae: Inner folds within mitochondria for ATP synthesis
• Cytoskeleton: A protein fiber network for structure and movement
• Microfilaments: Aid in cell movement and muscle activity
• Intermediate Filaments: Supply structural support
• Microtubules: Involved in cell division and transport
• Centrioles: Help in cell division, specifically spindle formation
• Vacuoles: Serve as small storage units
• Cell Shape: Flexible and varied, lacking a rigid wall
• Intercellular junctions: Utilize structures for connection and signaling between cells, including tight junctions, adherens junctions, desmosomes, and gap junctions
• Extracellular matrix: Secreted for support and signaling