3.3 Eukaryotic Cells
4 min read•june 18, 2024
Eukaryotic cells are complex structures with specialized that perform vital functions. Plant and animal cells share similarities but also have unique features that reflect their different roles in nature.
The regulates what enters and exits the cell, while organelles like the , , and carry out specific tasks. The provides structure and facilitates movement within the cell.
Eukaryotic Cell Structure and Function
Structures of plant vs animal cells
Top images from around the web for Structures of plant vs animal cells
Topic 1.2 Ultra-Structure of Cells - AMAZING WORLD OF SCIENCE WITH MR. GREEN View original
Is this image relevant?
Plant and Animal Cell Comparison Activity - ResearchParent.com View original
Is this image relevant?
4.15 Animal vs Plant cells – Mt Hood Community College Biology 101 View original
Is this image relevant?
Topic 1.2 Ultra-Structure of Cells - AMAZING WORLD OF SCIENCE WITH MR. GREEN View original
Is this image relevant?
Plant and Animal Cell Comparison Activity - ResearchParent.com View original
Is this image relevant?
1 of 3
Top images from around the web for Structures of plant vs animal cells
Topic 1.2 Ultra-Structure of Cells - AMAZING WORLD OF SCIENCE WITH MR. GREEN View original
Is this image relevant?
Plant and Animal Cell Comparison Activity - ResearchParent.com View original
Is this image relevant?
4.15 Animal vs Plant cells – Mt Hood Community College Biology 101 View original
Is this image relevant?
Topic 1.2 Ultra-Structure of Cells - AMAZING WORLD OF SCIENCE WITH MR. GREEN View original
Is this image relevant?
Plant and Animal Cell Comparison Activity - ResearchParent.com View original
Is this image relevant?
1 of 3
- Similarities between plant and animal cells
- Both contain plasma membrane enclosing and organelles (nucleus, endoplasmic reticulum, , )
- Both have genetic material () housed within the nucleus
- Differences between plant and animal cells
- Plant cells have additional structures not present in animal cells:
- composed of provides support and protection
- are organelles responsible for photosynthesis (converting light energy into chemical energy)
- Large stores water, nutrients, and waste products
- Animal cells have structures absent in plant cells:
- organize the mitotic spindle during cell division
- contain digestive enzymes that break down cellular waste and foreign particles (bacteria, viruses)
- Plant cells have additional structures not present in animal cells:
Plasma membrane's regulatory role
- Plasma membrane structure consists of a with embedded proteins
- heads of phospholipids face outward while tails face inward creating a semipermeable barrier
- Selective permeability allows some substances to pass through while restricting others
- Small, nonpolar molecules (oxygen, carbon dioxide) can easily diffuse through the membrane
- Larger, polar molecules (glucose, amino acids) require specialized transport proteins to cross the membrane
- Transport proteins facilitate movement of molecules across the membrane
- allow specific ions (potassium, sodium) or water molecules to pass through
- bind to specific molecules and transport them across the membrane
- is passive transport using carrier proteins, moving molecules down their concentration gradient (high to low concentration)
- requires energy () to move molecules against their concentration gradient (low to high concentration)
- bind to specific signaling molecules (hormones, neurotransmitters) on the cell surface
- Binding triggers intracellular responses such as changes in gene expression or enzyme activity (insulin binding to receptors stimulates glucose uptake)
Functions of eukaryotic cell organelles
- Nucleus contains the cell's genetic material (DNA) and controls cellular activities
- Surrounded by a double membrane called the which regulates transport of molecules between nucleus and
- is a network of membranous tubules and sacs
- is studded with and synthesizes, modifies, and transports proteins
- lacks ribosomes and synthesizes lipids (cholesterol), detoxifies harmful compounds (alcohol, drugs)
- Golgi apparatus modifies, packages, and sorts proteins and lipids for transport to other organelles or secretion from the cell
- Mitochondria are the "powerhouses" of the cell, generating ATP through cellular respiration (breaking down glucose in the presence of oxygen)
- Contain their own DNA and ribosomes, reflecting their evolutionary origin as prokaryotic cells ()
- Ribosomes synthesize proteins by translating (mRNA)
- Found free in the cytoplasm or attached to the rough ER
- Lysosomes (in animal cells) contain digestive enzymes that break down cellular waste, damaged organelles, and foreign particles
- (in plant cells) conduct photosynthesis, converting light energy into chemical energy (glucose)
- Contain pigments and their own DNA and ribosomes, similar to mitochondria
Cytoskeleton and extracellular matrix importance
- Cytoskeleton is a network of protein filaments providing structure, support, and movement within the cell
- Three main components:
- () are thin, flexible fibers involved in cell movement (muscle contraction) and changes in cell shape
- provide mechanical strength and resistance to shear stress (keratin in skin cells)
- are hollow tubes that maintain cell shape, organize organelles, and form mitotic spindles during cell division
- Motor proteins (, ) move along microtubules, transporting organelles (mitochondria) and
- Three main components:
- (ECM) is a network of proteins and polysaccharides secreted by cells into the extracellular space
- Provides structural support, anchoring cells together and to the basement membrane
- Components of the ECM:
- is a fibrous protein that provides tensile strength and elasticity (tendons, ligaments)
- are proteins with attached carbohydrate chains () that form a hydrated gel, resisting compressive forces (cartilage)
- is a that binds cells to the ECM, facilitating cell adhesion and migration (wound healing)
- Cell-ECM interactions involve , transmembrane receptors that link the cytoskeleton to the ECM
- Integrins allow cells to sense and respond to their environment, regulating cell behavior (proliferation, differentiation, survival)
Cellular Interactions and Transport
Vesicular transport and cell communication
- are membrane-bound sacs that transport materials within the cell
- is the process of releasing materials from the cell by fusing vesicles with the plasma membrane
- involves the internalization of materials from the cell's environment through membrane-bound vesicles
- The is the liquid component of the cytoplasm in which organelles and other cellular components are suspended
Cell Theory and Prokaryotic Cells
- states that all living organisms are composed of cells, cells are the basic unit of life, and all cells come from pre-existing cells
- Prokaryotic cells are simpler, smaller cells lacking membrane-bound organelles, found in bacteria and archaea
- They have a single circular chromosome, ribosomes, and a cell wall
- Some prokaryotes have additional structures like flagella for movement or pili for attachment
Key Terms to Review (78)
Actin filaments: Actin filaments, also known as microfilaments, are thin protein fibers that are a key component of the cytoskeleton in eukaryotic cells. These filaments play a crucial role in maintaining cell shape, enabling cellular movement, and facilitating various cellular processes like division and intracellular transport. Actin filaments are dynamic structures that can rapidly grow or shrink, allowing cells to adapt to their environment and perform essential functions.
Active transport: Active transport is the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration using energy, typically in the form of ATP. This process is essential for maintaining cellular homeostasis and function.
Active transport: Active transport is the process by which cells move molecules across their membrane against a concentration gradient, using energy in the form of ATP. This process is vital for maintaining cellular homeostasis, allowing cells to uptake essential nutrients and expel waste products even when they are in lower concentrations outside the cell. Active transport plays a crucial role in various cellular functions, especially in eukaryotic cells, where maintaining specific internal environments is necessary for proper cellular activities.
Animal cell: An animal cell is a type of eukaryotic cell that is characterized by the absence of a cell wall and the presence of various membrane-bound organelles. Unlike plant cells, animal cells have flexible shapes and contain structures such as lysosomes and centrioles, which play key roles in cellular processes. This unique structure allows them to perform complex functions necessary for multicellular organisms.
ATP: ATP, or adenosine triphosphate, is the primary energy carrier in all living organisms. It serves as a molecular currency, transporting chemical energy within cells for metabolism and cellular processes, linking various biological activities including movement, biosynthesis, and transport mechanisms.
Carrier proteins: Carrier proteins are specialized membrane proteins that facilitate the transport of specific substances across a cell membrane, often against their concentration gradient. They play a vital role in moving molecules like glucose and ions into and out of eukaryotic cells, ensuring that the cell maintains proper homeostasis and nutrient levels. This transport mechanism is crucial for various cellular processes, including nutrient uptake and waste removal.
Cell membrane: The cell membrane is a biological barrier that surrounds the cell, consisting primarily of a phospholipid bilayer with embedded proteins. It plays a crucial role in maintaining the integrity of the cell by regulating the movement of substances in and out, contributing to cell communication and signaling, and facilitating cellular interactions.
Cell Theory: Cell theory is a fundamental principle in biology that states that all living organisms are composed of cells, that cells are the basic unit of life, and that all cells arise from pre-existing cells. This theory highlights the importance of cells in understanding the structure and function of living organisms, connecting the study of cellular biology with the broader biological concepts of life.
Cell wall: The cell wall is a rigid outer layer that provides structural support and protection to the cells of plants, fungi, and some prokaryotes. It plays a crucial role in maintaining the shape of the cell and regulating the movement of substances in and out, helping to differentiate these cells from those found in animals, which lack a cell wall.
Cellulose: Cellulose is a complex carbohydrate, specifically a polysaccharide, that serves as a primary structural component of plant cell walls. It consists of long chains of glucose units linked by β(1→4) glycosidic bonds, making it resistant to digestion by most animals and providing rigidity and strength to plant cells. This structural role connects cellulose to other biological molecules and the differences between prokaryotic and eukaryotic cells.
Central vacuole: The central vacuole is a large, membrane-bound organelle found in plant cells that stores water, nutrients, and waste products. It also helps maintain cell turgor pressure, which is essential for maintaining the plant's structure.
Centrioles: Centrioles are cylindrical structures made of microtubules that play a crucial role in cell division and the organization of the cytoskeleton in eukaryotic cells. They are typically found in pairs and are located in the centrosome, where they help facilitate the formation of the mitotic spindle during cell division and are important for organizing cilia and flagella.
Channel Proteins: Channel proteins are specialized integral membrane proteins that facilitate the transport of specific ions or molecules across a cell membrane. They create water-filled passages through which substances can move down their concentration gradients, allowing for selective permeability essential for eukaryotic cells to maintain homeostasis and respond to environmental changes.
Chlorophyll: Chlorophyll is a green pigment found in plants, algae, and some bacteria that is essential for photosynthesis. It absorbs light most efficiently in the blue-violet and red parts of the electromagnetic spectrum, allowing plants to convert light energy into chemical energy. This process is fundamental to life on Earth, as it provides the energy that sustains the majority of ecosystems.
Chloroplasts: Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. They convert light energy into chemical energy stored in glucose through the process of photosynthesis.
Chloroplasts: Chloroplasts are organelles found in the cells of plants and some protists that are responsible for photosynthesis, converting light energy into chemical energy stored in glucose. They play a critical role in the energy transformation processes of living organisms and are essential for life on Earth, linking together various biological concepts from cellular structure to metabolic functions.
Cilia: Cilia are small, hair-like structures on the surface of eukaryotic cells. They play roles in movement and sensory functions.
Collagen: Collagen is a structural protein that plays a critical role in maintaining the integrity and strength of various tissues in the body, including skin, bones, tendons, and ligaments. It is the most abundant protein in mammals and provides support to cells and tissues, helping them withstand stretching and pressure. Collagen's unique triple-helix structure gives it exceptional tensile strength, making it essential for the proper function of connective tissues.
Compartmentalization: Compartmentalization refers to the organization of cellular structures into distinct, membrane-bound compartments that allow for specialized functions within a cell. This organization is crucial in eukaryotic cells, as it enables various biochemical processes to occur simultaneously without interference, promoting efficiency and regulatory control over metabolic pathways.
Cytoplasm: Cytoplasm is the jelly-like substance within the cell membrane that contains all organelles and cell parts. It plays a crucial role in maintaining cell structure and facilitating cellular processes.
Cytoplasm: Cytoplasm is the jelly-like substance found within the cell membrane, surrounding the organelles and providing a medium for biochemical reactions. It plays a crucial role in maintaining cell structure, supporting organelles, and facilitating communication between various cellular components.
Cytoskeleton: The cytoskeleton is a dynamic network of protein filaments and microtubules that provides structural support, shape, and organization to eukaryotic cells. It plays a crucial role in various cellular processes including cell division, intracellular transport, and maintaining cell shape, making it essential for the overall function and integrity of eukaryotic cells and their evolutionary origins.
Cytosol: Cytosol is the fluid component of the cytoplasm, consisting mostly of water, salts, and organic molecules. It serves as a medium where various cellular processes occur, facilitating the movement of materials around the cell and acting as a site for metabolic reactions. The cytosol plays a crucial role in maintaining cellular structure and function by providing a space for organelles and supporting essential biochemical pathways.
Deoxyribonucleic acid (DNA): Deoxyribonucleic acid (DNA) is the molecule that carries genetic information in all living organisms and many viruses. It is composed of two strands that coil around each other to form a double helix.
Desmosomes: Desmosomes are specialized structures within the plasma membrane that function to anchor adjacent cells together. They provide mechanical strength to tissues by linking the cytoskeletons of neighboring cells.
DNA: DNA, or deoxyribonucleic acid, is the hereditary material in almost all living organisms, encoding the genetic instructions used in growth, development, functioning, and reproduction. This molecule serves as the blueprint for all biological structures and processes, connecting various themes like the unity of life and the complexity of biological systems.
Dynein: Dynein is a complex motor protein found in eukaryotic cells that moves along microtubules, transporting cellular cargo toward the minus end of the microtubule. This protein is essential for various cellular processes, including vesicle transport, mitosis, and maintaining the structure of cilia and flagella. Dynein works in conjunction with other motor proteins, such as kinesin, to ensure the proper movement and distribution of organelles and molecules within the cell.
Endocytosis: Endocytosis is a cellular process where the cell membrane engulfs external substances, forming a vesicle to bring them into the cell. It is a form of active transport requiring energy.
Endocytosis: Endocytosis is a cellular process where substances are brought into the cell by engulfing them in a section of the cell membrane, which then pinches off to form a vesicle. This mechanism allows eukaryotic cells to take in large molecules, nutrients, and even other cells, playing a crucial role in maintaining cellular functions. By using this method, cells can also regulate their internal environment and communicate with their surroundings more effectively.
Endomembrane system: The endomembrane system is a collection of membrane-bound organelles within eukaryotic cells that work together to modify, package, and transport lipids and proteins. This system includes structures such as the endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles, all of which play crucial roles in cellular processes such as protein synthesis and degradation, lipid metabolism, and intracellular transport.
Endoplasmic Reticulum: The endoplasmic reticulum (ER) is an extensive network of membranes within eukaryotic cells that plays a critical role in the synthesis, folding, modification, and transport of proteins and lipids. It consists of two main types: rough ER, which is studded with ribosomes for protein synthesis, and smooth ER, which is involved in lipid synthesis and detoxification processes.
Endoplasmic reticulum (ER): The endoplasmic reticulum (ER) is a network of membranous tubules and sacs found within eukaryotic cells. It plays a crucial role in the synthesis, folding, modification, and transport of proteins and lipids.
Endosymbiosis: Endosymbiosis is a biological theory that explains how eukaryotic cells evolved through a symbiotic relationship between early prokaryotic cells and engulfed bacteria. This process suggests that certain organelles, like mitochondria and chloroplasts, originated from free-living prokaryotes that entered into a mutualistic relationship with host cells, eventually becoming integral parts of eukaryotic cells. This connection reveals the evolutionary transition from prokaryotic to eukaryotic life forms and showcases the complexity of cellular development.
Eukaryotic cell: A eukaryotic cell is a type of cell that contains a nucleus and other membrane-bound organelles, making it more complex than prokaryotic cells. Eukaryotic cells are found in organisms such as plants, animals, fungi, and protists, showcasing a diverse range of functions and structures. This complexity allows eukaryotic cells to perform specialized tasks and contribute to the overall functioning of multicellular organisms.
Exocytosis: Exocytosis is the process by which cells transport molecules out of the cell by enclosing them in vesicles that fuse with the plasma membrane. This mechanism is vital for various cellular functions, including the release of hormones, neurotransmitters, and other important substances. It involves a series of steps that ensure the contents of the vesicle are expelled into the extracellular space, playing a crucial role in communication and transport within eukaryotic cells.
Extracellular matrix: The extracellular matrix (ECM) is a complex network of proteins and carbohydrates that provides structural and biochemical support to surrounding cells in tissues. It plays a crucial role in cell adhesion, communication, and regulation of various cellular functions, making it vital for the overall integrity and functionality of eukaryotic cells.
Facilitated diffusion: Facilitated diffusion is a passive transport mechanism that allows specific molecules or ions to cross a biological membrane with the assistance of specialized proteins. This process occurs down the concentration gradient, meaning substances move from areas of higher concentration to lower concentration, without the use of cellular energy. It plays a crucial role in maintaining cellular homeostasis, especially in eukaryotic cells where the lipid bilayer can be selectively permeable.
Fibronectin: Fibronectin is a high-molecular-weight glycoprotein of the extracellular matrix that plays a critical role in cell adhesion, growth, migration, and differentiation. It connects cells to the surrounding matrix and influences various biological processes, such as wound healing and embryonic development, highlighting its importance in maintaining tissue integrity and function.
Gap junctions: Gap junctions are specialized intercellular connections that directly connect the cytoplasm of two cells, allowing for the transfer of ions, molecules, and electrical impulses. They play a crucial role in cell communication and coordination within tissues.
Glycoprotein: A glycoprotein is a molecule composed of a protein backbone with carbohydrate chains covalently attached to it. These molecules are essential in eukaryotic cells as they play crucial roles in cell-cell recognition, signaling, and immune responses. The presence of sugar groups on proteins often determines their function and interaction with other cellular components.
Glycosaminoglycans: Glycosaminoglycans (GAGs) are long unbranched polysaccharides composed of repeating disaccharide units that typically consist of an amino sugar and a uronic sugar. They play crucial roles in the extracellular matrix of eukaryotic cells, providing structural support and regulating cellular functions such as cell proliferation, migration, and signaling. GAGs are highly hydrophilic and can retain water, which contributes to the hydration and resilience of tissues.
Golgi apparatus: The Golgi apparatus is a membrane-bound organelle found in eukaryotic cells that is essential for modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles. This organelle plays a vital role in the post-translational modification of proteins, ensuring that they are properly processed and directed to their intended locations within or outside the cell.
Hydrophilic: Hydrophilic refers to substances that have an affinity for water, meaning they are able to interact and form hydrogen bonds with water molecules. This property is crucial for biological processes, as it influences how molecules interact with each other in aqueous environments, affecting solubility, transport, and cellular functions.
Hydrophobic: Hydrophobic refers to the property of molecules that repel water, meaning they do not easily dissolve in or mix with water. This characteristic is vital in biology as it influences the structure and function of cells, especially in the formation of cell membranes and the behavior of proteins. Hydrophobic interactions are critical in maintaining the integrity of cellular structures and contribute to various processes like passive transport across membranes.
Integrins: Integrins are transmembrane proteins that play a crucial role in cell adhesion and communication between cells and the extracellular matrix (ECM). They act as receptors that link the intracellular cytoskeleton to the ECM, facilitating important cellular processes such as migration, proliferation, and differentiation. Integrins are vital for maintaining tissue integrity and are involved in various biological functions like wound healing and immune response.
Intermediate filaments: Intermediate filaments are a type of cytoskeletal component in eukaryotic cells, providing structural support and mechanical strength. They play a key role in maintaining the cell's shape and anchoring organelles, ensuring the cell can withstand mechanical stress and maintain its integrity. Unlike microtubules and microfilaments, intermediate filaments have a more stable structure and are less dynamic, making them crucial for cellular stability.
Kinesin: Kinesin is a type of motor protein found in eukaryotic cells that is responsible for transporting cellular cargo along microtubules, which are part of the cytoskeleton. These proteins play a crucial role in various cellular processes, including cell division, intracellular transport, and maintaining cell shape. Kinesins move toward the plus end of microtubules, helping to facilitate the movement of organelles, vesicles, and other materials within the cell.
Lysosomes: Lysosomes are membrane-bound organelles found in eukaryotic cells that contain enzymes responsible for breaking down waste materials and cellular debris. They play a crucial role in the cell's recycling system, ensuring that cellular components are properly degraded and recycled, which is essential for maintaining cellular health and function.
Messenger RNA: Messenger RNA (mRNA) is a type of RNA that carries genetic information from DNA to the ribosome, where proteins are synthesized. It serves as a template for translating the genetic code into functional proteins, playing a crucial role in gene expression and regulation within eukaryotic cells. The processing and modification of mRNA are essential for its stability and functionality, influencing protein production in various cellular contexts.
Microfilaments: Microfilaments are thin, thread-like protein fibers made of actin that play a crucial role in maintaining the structural integrity of eukaryotic cells. These components are part of the cytoskeleton, providing support and shape while also participating in cellular movement and division. Microfilaments interact with other proteins to facilitate processes such as muscle contraction, cell motility, and the transport of organelles within the cell.
Microtubules: Microtubules are cylindrical structures made of tubulin proteins that play critical roles in the structure, transport, and division of eukaryotic cells. They are a component of the cytoskeleton, helping to maintain cell shape and facilitating intracellular transport, as well as organizing the mitotic spindle during cell division.
Mitochondria: Mitochondria are membrane-bound organelles found in eukaryotic cells, responsible for producing energy through cellular respiration. They are often referred to as the 'powerhouses' of the cell due to their role in ATP production.
Mitochondria: Mitochondria are membrane-bound organelles found in eukaryotic cells, often referred to as the 'powerhouses' of the cell because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. These organelles play a crucial role in energy metabolism and are involved in various biochemical processes, including the citric acid cycle and oxidative phosphorylation.
Nuclear envelope: The nuclear envelope is a double membrane structure that surrounds the nucleus of eukaryotic cells, separating the contents of the nucleus from the cytoplasm. It consists of an inner and outer membrane, with the space between them known as the perinuclear space. This structure plays a critical role in maintaining the integrity of genetic material and regulating the passage of molecules in and out of the nucleus.
Nucleus: The nucleus is a membrane-bound organelle found in eukaryotic cells that contains the genetic material (DNA) and controls cellular activities. It serves as the command center of the cell, regulating gene expression and mediating the replication of DNA during the cell cycle, linking it to various fundamental biological concepts and processes.
Organelles: Organelles are specialized structures within cells that perform distinct functions necessary for the cell's life processes. These structures enable cells to maintain homeostasis, process energy, and synthesize materials, playing a crucial role in overall cellular function and organization.
Peroxisomes: Peroxisomes are small, membrane-bound organelles in eukaryotic cells that contain enzymes to break down fatty acids and detoxify harmful substances. They play a crucial role in cellular metabolism and the maintenance of cellular health.
Phagocytosis: Phagocytosis is a type of active transport where a cell engulfs large particles or other cells. This process involves the cell membrane wrapping around the particle to form a phagosome that is then internalized and digested by the cell.
Phagocytosis: Phagocytosis is a cellular process in which certain cells, known as phagocytes, engulf and digest large particles, such as bacteria and dead or dying cells. This process is crucial for immune defense and tissue maintenance, helping to protect the body from pathogens and clear away debris. It involves the membrane of the phagocyte extending around the target particle, eventually enclosing it in a vesicle for breakdown and digestion.
Phospholipid: A phospholipid is a type of lipid molecule that is a major component of all cell membranes, forming the lipid bilayer. This structure consists of two fatty acid tails that are hydrophobic (water-repelling) and a phosphate group that is hydrophilic (water-attracting), allowing phospholipids to create a barrier between the inside and outside of the cell. Their unique properties enable them to play crucial roles in membrane fluidity, signaling, and the overall function of eukaryotic cells.
Phospholipid bilayer: The phospholipid bilayer is a fundamental structure of cell membranes, consisting of two layers of phospholipids with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward. This arrangement creates a semi-permeable membrane that separates the interior of the cell from the external environment, playing a crucial role in maintaining cellular integrity and function.
Plant cell: A plant cell is a type of eukaryotic cell that is characterized by its unique structures and functions, distinguishing it from animal cells. Plant cells contain chloroplasts for photosynthesis, a rigid cell wall for structural support, and large central vacuoles that store nutrients and waste products. These features enable plants to thrive in various environments and perform essential processes like energy production and nutrient storage.
Plasma membrane: The plasma membrane is a selectively permeable barrier that surrounds the cell, composed primarily of a phospholipid bilayer with embedded proteins. This structure is crucial for maintaining the cell's internal environment, allowing for the transport of materials in and out while protecting the integrity of the cell. Its characteristics differ between prokaryotic and eukaryotic cells, influencing cellular function and interaction with the environment.
Plasmodesmata: Plasmodesmata are microscopic channels that traverse the cell walls of plant cells, enabling transport and communication between them. They facilitate the movement of ions, molecules, and sometimes organelles.
Prokaryotic Cell: A prokaryotic cell is a simple, unicellular organism that lacks a membrane-bound nucleus and other organelles. These cells are typically smaller than eukaryotic cells and include bacteria and archaea, which are vital to many ecological processes and human health. Understanding prokaryotic cells is essential because they represent the most ancient form of life on Earth and provide insights into the evolution of more complex organisms.
Proteoglycans: Proteoglycans are large, complex macromolecules found in the extracellular matrix of eukaryotic cells, consisting of a core protein with one or more glycosaminoglycan (GAG) chains attached. They play crucial roles in providing structural support, regulating cell behavior, and facilitating cell signaling within tissues. Their unique composition allows them to bind water and ions, contributing to the hydration and resilience of connective tissues.
Receptor proteins: Receptor proteins are specialized proteins located on the cell membrane or within cells that bind to specific molecules, known as ligands, and initiate a cellular response. These proteins play a crucial role in cell communication and signal transduction, allowing cells to respond to their environment and coordinate various biological processes.
Ribosomes: Ribosomes are complex molecular machines found within all living cells that facilitate the synthesis of proteins by translating messenger RNA (mRNA) into polypeptide chains. They play a crucial role in the expression of genetic information and are composed of ribosomal RNA (rRNA) and proteins, forming two subunits that come together during protein synthesis. This process is essential for cellular functions and organismal development.
Rough endoplasmic reticulum (RER): The rough endoplasmic reticulum (RER) is a membrane-bound organelle covered with ribosomes, giving it a 'rough' appearance. It is involved in the synthesis and initial folding of proteins destined for secretion or membrane insertion.
Rough ER: Rough endoplasmic reticulum (rough ER) is a type of organelle in eukaryotic cells characterized by its studded appearance due to ribosomes attached to its cytoplasmic surface. This structure plays a crucial role in the synthesis and processing of proteins, particularly those that are destined for secretion, incorporation into the cell membrane, or for use within lysosomes. The rough ER's connection to the nucleus allows for efficient translation and folding of proteins as they are synthesized.
Smooth endoplasmic reticulum (SER): The smooth endoplasmic reticulum (SER) is an organelle in eukaryotic cells responsible for lipid synthesis and detoxification. Unlike the rough ER, it lacks ribosomes on its surface, giving it a smooth appearance.
Smooth ER: Smooth endoplasmic reticulum (smooth ER) is a type of organelle in eukaryotic cells that is involved in the synthesis of lipids, metabolism of carbohydrates, and detoxification of drugs and poisons. Unlike rough ER, it lacks ribosomes on its surface, giving it a smooth appearance. It plays essential roles in cellular functions such as lipid production and maintaining cellular homeostasis.
Tight junction: Tight junctions are specialized connections between adjacent cells that create a selective barrier to molecules. They help maintain the polarity of cells by preventing the passage of substances through the space between them.
Unified cell theory: Unified cell theory states that all living organisms are composed of one or more cells, and the cell is the basic unit of life. Additionally, all cells arise from pre-existing cells.
Vacuole: A vacuole is a membrane-bound organelle found in eukaryotic cells, primarily responsible for storing substances such as nutrients, waste products, and other materials. Vacuoles play a crucial role in maintaining cellular homeostasis and can also contribute to turgor pressure in plant cells, which is essential for maintaining their structure and integrity.
Vacuoles: Vacuoles are membrane-bound organelles found in eukaryotic cells that store nutrients, waste products, and help maintain turgor pressure. They play a crucial role in cell homeostasis and can vary greatly in size depending on the cell's needs.
Vesicles: Vesicles are small membrane-bound sacs within eukaryotic cells that transport, store, or digest cellular products and waste. They play a crucial role in processes such as metabolism, transport, buoyancy control, and enzyme storage.
Vesicles: Vesicles are small, membrane-bound sacs that transport and store substances within eukaryotic cells. They play a vital role in cellular processes such as metabolism, communication, and the transport of materials like proteins and lipids between different organelles or to the cell membrane for secretion.