Lysosomes and peroxisomes are membrane-bound organelles that play important roles in cellular processes. Lysosomes contain digestive enzymes and function in intracellular digestion, breaking down materials through phagocytosis, autophagy, and programmed cell death. Peroxisomes contain enzymes involved in breaking down hydrogen peroxide and performing beta-oxidation of fatty acids. Both are formed by budding from the Golgi apparatus. Defects in the enzymes of lysosomes or peroxisomes can lead to metabolic storage disorders.
This document summarizes key information about the enzyme lysozyme. It begins by providing background on lysozyme, including that it is a 129 amino acid enzyme that catalyzes the breakdown of bacterial cell walls. It then discusses the historical discovery of lysozyme by Fleming in 1922 from nasal mucus and its natural occurrence in egg whites, tears, and saliva. The document concludes by summarizing lysozyme's role in disease defense and its importance as one of the first enzyme structures to be solved using X-ray crystallography.
Lysosomes and peroxisomes are organelles found in eukaryotic cells that help break down molecules. Lysosomes are located in the cytoplasm and contain digestive enzymes that break down lipids, carbohydrates, and proteins. They also digest old or damaged organelles. Peroxisomes contain enzymes that break down fatty acids and produce metabolic energy. Both organelles break down molecules, though lysosomes digest larger components while peroxisomes focus on fatty acid breakdown. They are created and function differently, with lysosomes formed in the ER and Golgi while peroxisomes bud directly from the cytosol.
Mitochondria and lysosomes are intracellular organelles that play important roles in cellular functions. Mitochondria have an outer and inner membrane, with cristae folds in the inner membrane containing oxidative enzymes involved in respiration and ATP synthesis. The respiratory chain includes enzymes like succinate dehydrogenase and cytochrome oxidase that are involved in energy production. Mitochondria are also involved in apoptosis. Lysosomes contain hydrolytic enzymes and function to digest foreign bodies, with lysosomal enzymes produced in the endoplasmic reticulum and Golgi apparatus. Lysosomes aid in cellular waste removal and have bactericidal functions. Peroxisomes also contain oxidative enzymes and functions include detoxification and breaking down excess fatty acids.
Peroxisomes are organelles found in the cytoplasm of plant and animal cells that contain enzymes for oxidizing fatty acids and other organic substances. They produce hydrogen peroxide as a byproduct which is immediately broken down by the enzyme catalase. Peroxisomes play important roles in processes like fatty acid breakdown, bile acid and cholesterol synthesis, and the breakdown of toxic peroxides. Defects in peroxisome function can lead to genetic disorders affecting the nervous system, liver, and other organs.
Lysosomes are spherical organelles that contain digestive enzymes called hydrolases. They are produced in the Golgi apparatus and contain hydrolytic enzymes that help break down macromolecules through processes like phagocytosis, endocytosis, and autophagy. Lysosomes function to digest cellular waste and debris and are sometimes referred to as the cell's "garbage disposal" or "recycling unit." Diseases can occur if lysosomal enzymes do not function properly or reach the lysosome, preventing the breakdown of cellular components and leading to their accumulation.
This document discusses lysosomes, which are spherical organelles found in animal cells that contain digestive enzymes. Lysosomes break down food particles, bacteria, and worn out organelles. They were discovered in 1960 and maintain an acidic pH of 4.5-5.0. Lysosomes contain around 40 types of hydrolytic enzymes and vary in size from 0.2-0.8 nm. Their membrane allows enzymes to be released into vacuoles to digest their contents. Plant and fungal vacuoles are similar to lysosomes. Lysosomes function to digest materials through membrane fusion and release of enzymes, acting as the cell's waste disposal and recycling system.
Basics only
Ultrastructure, Chemical composition and Functions
• Lysosome was discovered by a Belgian biologist, Christian de Duve, and was awarded a Nobel Prize in Medicine or Physiology in the year 1974.
• The word “lysosome” is made up of two words “lysis” meaning breakdown and “soma” meaning body.
• Lysosomes are membrane-bound specialized vesicles, dense granular structures containing hydrolytic enzymes responsible mainly for intracellular and extracellular digestion.
• Lysosomes are formed by budding off of the Golgi apparatus, and the hydrolytic enzymes within them are formed in the endoplasmic reticulum. Lysosomes have an acidic interior pH level of about 5 and carry a high content of digestive enzymes.
• All of the digestive enzymes found in the lysosome require an acidic environment to function properly and are called acid hydrolases.
• Lysosomes cannot digest themselves - Most of the proteins present in its membrane contain high amounts of carbohydrate-sugar groups. Because of the present of these groups, digestive enzymes are unable to digest the proteins present on the membrane.
• Lysosomal Storage Diseases: Some inherited metabolic disorders can cause defects in the proper functioning of lysosomes. These disorders are called lysosomal storage diseases, or LSDs. There are around 40 different LSDs.
Lysosomes and peroxisomes are membrane-bound organelles that play important roles in cellular processes. Lysosomes contain digestive enzymes and function in intracellular digestion, breaking down materials through phagocytosis, autophagy, and programmed cell death. Peroxisomes contain enzymes involved in breaking down hydrogen peroxide and performing beta-oxidation of fatty acids. Both are formed by budding from the Golgi apparatus. Defects in the enzymes of lysosomes or peroxisomes can lead to metabolic storage disorders.
This document summarizes key information about the enzyme lysozyme. It begins by providing background on lysozyme, including that it is a 129 amino acid enzyme that catalyzes the breakdown of bacterial cell walls. It then discusses the historical discovery of lysozyme by Fleming in 1922 from nasal mucus and its natural occurrence in egg whites, tears, and saliva. The document concludes by summarizing lysozyme's role in disease defense and its importance as one of the first enzyme structures to be solved using X-ray crystallography.
Lysosomes and peroxisomes are organelles found in eukaryotic cells that help break down molecules. Lysosomes are located in the cytoplasm and contain digestive enzymes that break down lipids, carbohydrates, and proteins. They also digest old or damaged organelles. Peroxisomes contain enzymes that break down fatty acids and produce metabolic energy. Both organelles break down molecules, though lysosomes digest larger components while peroxisomes focus on fatty acid breakdown. They are created and function differently, with lysosomes formed in the ER and Golgi while peroxisomes bud directly from the cytosol.
Mitochondria and lysosomes are intracellular organelles that play important roles in cellular functions. Mitochondria have an outer and inner membrane, with cristae folds in the inner membrane containing oxidative enzymes involved in respiration and ATP synthesis. The respiratory chain includes enzymes like succinate dehydrogenase and cytochrome oxidase that are involved in energy production. Mitochondria are also involved in apoptosis. Lysosomes contain hydrolytic enzymes and function to digest foreign bodies, with lysosomal enzymes produced in the endoplasmic reticulum and Golgi apparatus. Lysosomes aid in cellular waste removal and have bactericidal functions. Peroxisomes also contain oxidative enzymes and functions include detoxification and breaking down excess fatty acids.
Peroxisomes are organelles found in the cytoplasm of plant and animal cells that contain enzymes for oxidizing fatty acids and other organic substances. They produce hydrogen peroxide as a byproduct which is immediately broken down by the enzyme catalase. Peroxisomes play important roles in processes like fatty acid breakdown, bile acid and cholesterol synthesis, and the breakdown of toxic peroxides. Defects in peroxisome function can lead to genetic disorders affecting the nervous system, liver, and other organs.
Lysosomes are spherical organelles that contain digestive enzymes called hydrolases. They are produced in the Golgi apparatus and contain hydrolytic enzymes that help break down macromolecules through processes like phagocytosis, endocytosis, and autophagy. Lysosomes function to digest cellular waste and debris and are sometimes referred to as the cell's "garbage disposal" or "recycling unit." Diseases can occur if lysosomal enzymes do not function properly or reach the lysosome, preventing the breakdown of cellular components and leading to their accumulation.
This document discusses lysosomes, which are spherical organelles found in animal cells that contain digestive enzymes. Lysosomes break down food particles, bacteria, and worn out organelles. They were discovered in 1960 and maintain an acidic pH of 4.5-5.0. Lysosomes contain around 40 types of hydrolytic enzymes and vary in size from 0.2-0.8 nm. Their membrane allows enzymes to be released into vacuoles to digest their contents. Plant and fungal vacuoles are similar to lysosomes. Lysosomes function to digest materials through membrane fusion and release of enzymes, acting as the cell's waste disposal and recycling system.
Basics only
Ultrastructure, Chemical composition and Functions
• Lysosome was discovered by a Belgian biologist, Christian de Duve, and was awarded a Nobel Prize in Medicine or Physiology in the year 1974.
• The word “lysosome” is made up of two words “lysis” meaning breakdown and “soma” meaning body.
• Lysosomes are membrane-bound specialized vesicles, dense granular structures containing hydrolytic enzymes responsible mainly for intracellular and extracellular digestion.
• Lysosomes are formed by budding off of the Golgi apparatus, and the hydrolytic enzymes within them are formed in the endoplasmic reticulum. Lysosomes have an acidic interior pH level of about 5 and carry a high content of digestive enzymes.
• All of the digestive enzymes found in the lysosome require an acidic environment to function properly and are called acid hydrolases.
• Lysosomes cannot digest themselves - Most of the proteins present in its membrane contain high amounts of carbohydrate-sugar groups. Because of the present of these groups, digestive enzymes are unable to digest the proteins present on the membrane.
• Lysosomal Storage Diseases: Some inherited metabolic disorders can cause defects in the proper functioning of lysosomes. These disorders are called lysosomal storage diseases, or LSDs. There are around 40 different LSDs.
Mitochondria are membrane-bound organelles found in eukaryotic cells that produce energy through respiration. They were first observed by Richard Altmann and named by Benda. Mitochondria have an outer and inner membrane, with cristae extending inward from the inner membrane. They contain their own DNA and ribosomes. Mitochondria play key roles in cellular metabolism and energy production.
Christian de Duve observed in 1955 that cells released the enzyme acid phosphatase in larger amounts when frozen and thawed before centrifugation. To explain this, de Duve suggested the enzyme must be enclosed in a membrane-bound organelle. After estimating the organelle's probable size, he was able to identify it as lysosomes in electron microscope images. Lysosomes are membrane-bound sacs containing digestive enzymes that can break down macromolecules and are involved in intracellular digestion, defense against pathogens, and cellular waste disposal. De Duve's discovery of lysosomes established them as an important cellular organelle.
This presentation summarizes key information about peroxisomes. Peroxisomes are membrane-bound organelles found in the cytoplasm of eukaryotic cells that contain oxidase enzymes and help breakdown hydrogen peroxide. They have a dense matrix and participate in important functions like fatty acid breakdown, alcohol detoxification, and bile acid/cholesterol synthesis. Disorders can arise if single peroxisomal enzymes are abnormal, affecting the nervous system, liver, and other organs. Two examples given are adrenoleukodystrophy, which involves VLCFA metabolism, and Zellweger's syndrome, caused by a lack of functional peroxisomes due to mutations affecting transport of enzymes.
Lysosomes are membrane-bound organelles found in eukaryotic cells that contain digestive enzymes. They were discovered in 1955 by Christian de Duve and function to digest materials through hydrolytic enzymes. Lysosomes are produced in the Golgi apparatus and contain around 40 varieties of hydrolase enzymes that function in an acidic environment. The main functions of lysosomes include digesting extracellular and intracellular material through processes like heterophagy, programmed cell death, autophagy, autolysis, and roles in fertilization and causing chromosomal damage.
Peroxisomes are microbody organelles found in the cytoplasm of eukaryotic cells that perform important metabolic functions. They contain enzymes for oxidation reactions that produce hydrogen peroxide as a byproduct, and also contain the enzyme catalase to break down hydrogen peroxide. Peroxisomes are involved in lipid biosynthesis and fatty acid oxidation. Related organelles like glyoxysomes in plants and glycosomes in kinetoplastids also carry out metabolic functions tailored to their cellular environments.
Peroxisomes are single-membrane organelles found in the cytoplasm of human cells that contain enzymes for oxidizing molecules like fatty acids. They are 0.1-1 micrometers in diameter and cells contain up to 100 peroxisomes. Peroxisomes are formed through self-replication since they lack DNA and ribosomes. Their functions include producing hydrogen peroxide during fatty acid breakdown, synthesizing phospholipids and bile acids, and detoxifying alcohol. Disorders can occur if peroxisomal enzymes are absent or nonfunctional, leading to issues like oral ulcers, impaired brain development, or hearing loss.
Lysosomes play an important role in the cell by consuming worn-out structures, attacking bacteria, and containing enzymes to digest materials. A lack of lysosomes can lead to lysosomal storage diseases where waste builds up and disrupts cell function. Lysosomes contain hydrolases and transport proteins and would ally with vacuoles to help digest food particles. They view the cytoskeleton as dispensable since it mainly provides structure and transport within the cell.
The document discusses the molecular mechanism of autophagy and its role in plants. It begins with an introduction to autophagy and discusses landmarks in the discovery of autophagy. It then covers the different classes of autophagy, genes and proteins involved, and the molecular mechanism. This includes discussion of the induction, expansion, and maturation steps. It also discusses selective autophagy and techniques to study autophagy. The document concludes by covering the physiological roles of autophagy in plants, including roles in nutrient starvation, oxidative stress response, development, pathogen response, and programmed cell death.
Lysosomes are organelles found in cells that function as the "garbage disposals" by digesting and recycling materials the cell no longer needs or wants to get rid of using around 40 digestive enzymes. They take on various shapes and sizes depending on what materials they are digesting. Lysosomes are membrane-bound sacs that perform two main functions - digesting ingested materials through releasing enzymes into vacuoles, and autophagy and cell death by breaking down the cell's own unwanted components like organelles.
Peroxisomes are single-membrane organelles that contain oxidative enzymes. They play important roles in breaking down fatty acids and toxic metabolites. Peroxisomal disorders can result from defects in peroxisome biogenesis or metabolism. Two examples are X-linked adrenoleukodystrophy, which causes a buildup of very long chain fatty acids, and Zellweger syndrome, the most severe peroxisome biogenesis disorder characterized by defects in development and metabolism.
P4-ATPases, also known as flippases, are lipid transporters that are essential for maintaining membrane lipid asymmetry and regulating membrane protein activity. They function as homodimers and heterodimers with a beta subunit. Flippases transport phospholipids from the outer to inner leaflet of membranes and are involved in key processes like vesicular trafficking. They evolved from cation pumps and their transport cycle shares similarities to sodium-potassium pumps. Experimental procedures to study flippases in fungi include gene deletion, complementation mutants, microscopy, and assays of growth, stress response, and virulence.
Lysosomes are membrane-bound organelles found in most animal and plant cells that contain hydrolytic enzymes. They function in intracellular digestion, breaking down molecules like proteins, lipids, carbohydrates, and nucleic acids. The hydrolytic enzymes in lysosomes work optimally at an acidic pH, which is maintained by a proton pump in the lysosomal membrane. Lysosomes digest excess or worn-out cellular components and can also degrade invading pathogens. They exhibit polymorphism with four main types - primary lysosomes, heterophagosomes, autophagosomes, and residual bodies.
Peroxisomes are small organelles found in the cytoplasm of cells. They contain enzymes that break down fatty acids and reactive oxygen species. Specifically, peroxisomes contain catalase which breaks down hydrogen peroxide into water and oxygen. They also play roles in photosynthesis, beta-oxidation of fatty acids, and producing bile acids. Certain genetic diseases can result from defects in peroxisome function, such as Zellweger syndrome.
Lysosomes are spherical organelles found in animal cells that contain hydrolytic enzymes. They function to break down and digest macromolecules from phagocytosis, endocytosis, and autophagy. Lysosomes are produced in the Golgi apparatus and contain enzymes that function only in low pH environments. Lysosomal storage diseases occur due to mutations in lysosomal enzymes, preventing the breakdown of materials and leading to their accumulation.
The document discusses autophagy, which is a normal physiological process in the body that deals with the destruction and recycling of cellular components. It was first observed in 1962 and involves several conserved autophagy-related proteins and multiple stages. There are three main types of autophagy: microautophagy, macroautophagy, and chaperone-mediated autophagy. Microautophagy involves direct engulfment into lysosomes, macroautophagy uses double-membrane vesicles called autophagosomes, and chaperone-mediated autophagy selectively transports proteins across lysosome membranes. Autophagy is regulated by various factors and plays important roles in cellular
Lysosomes have several key functions: they release enzymes to destroy worn out organelles, digest material brought into cells through phagocytosis such as bacteria engulfed by white blood cells, and release enzymes outside of cells to digest other cells through exocytosis. They can also cause autolysis and self-destruction of cells by breaking down and releasing their enzymes.
Peroxisomes are organelles found in the cytoplasm of animal and plant cells. They are bounded by a single membrane and contain many enzymes. Christian deDuve first isolated peroxisomes from liver cells in 1965. Peroxisomes oxidize organic substances like fatty acids and produce hydrogen peroxide as a byproduct, which is then broken down by the enzyme catalase. They are most abundant in liver cells, where they are involved in functions like breaking down fatty acids, synthesizing cholesterol and bile acids, and breaking down excess purines.
Peroxisomes are spherical organelles found in eukaryotic cells that are bounded by a single membrane. They contain enzymes that produce and break down hydrogen peroxide as well as enzymes involved in lipid metabolism. Peroxisomes help degrade toxic compounds produced during metabolism and also play roles in photorespiration and breaking down fatty acids. They grow in size by incorporating proteins and lipids from the cytosol and can multiply by dividing.
Microbodies are derived from smooth endoplasmic reticulum and replicate via fission. They are prominent in leukocytes and platelets, have a granular matrix, and contain peroxidase, catalase, and oxidase enzymes. Peroxisomes break down very long chain fatty acids, are involved in myelin production and bile acid production, and help destroy unwanted peroxides and free radicals in the body. They contain catalase and other oxidative enzymes to protect cells from hydrogen peroxide. Lysosomes contain hydrolases and are responsible for cellular digestion. Diseases associated with peroxisomal deficiencies include adrenoleukodystrophy, Zellweger syndrome, and primary hyperoxaluria.
This document provides an overview of peroxisome metabolism. Key points include:
- Peroxisomes are organelles that contain enzymes for metabolic processes like fatty acid oxidation and production of hydrogen peroxide.
- They are involved in lipid metabolism, reactive oxygen species reduction, and biosynthesis of plasmalogens and bile acids.
- Disorders associated with impaired peroxisome function include peroxisome biogenesis disorders and single enzyme defects, which can result in accumulation of toxic metabolites.
- Important diseases include Zellweger syndrome, Refsum disease, and adrenoleukodystrophy.
The document discusses cellular structure and function. It describes that cells are the basic living units of the body, with each organ composed of many different cell types. The two main types of fluid in the body are intracellular fluid within cells and extracellular fluid outside cells, which provides nutrients to cells. A normal cell maintains homeostasis through adaptations like atrophy, hypertrophy, hyperplasia, metaplasia, and dysplasia in response to stress or increased demand. The main mechanisms of cellular injury are free radical injury, which damages lipids, proteins and DNA, and hypoxic injury caused by lack of oxygen leading to energy depletion and calcium overload within cells.
Radiation. Plant Toxicity. Inhibitors of radiation toxicity.Dmitri Popov
This document discusses cysteine proteases and their role in programmed cell death (PCD) in plants. It notes that vacuolar processing enzyme (VPE), a cysteine protease, has been identified as a key executor of PCD in plants, playing a role similar to caspases in animal apoptosis. VPE is involved in plant responses to stresses like radiation and pathogens by degrading vacuolar membranes and releasing hydrolytic enzymes to break down cellular components. The document examines the mechanisms and pathways of PCD in both animals and plants.
Mitochondria are membrane-bound organelles found in eukaryotic cells that produce energy through respiration. They were first observed by Richard Altmann and named by Benda. Mitochondria have an outer and inner membrane, with cristae extending inward from the inner membrane. They contain their own DNA and ribosomes. Mitochondria play key roles in cellular metabolism and energy production.
Christian de Duve observed in 1955 that cells released the enzyme acid phosphatase in larger amounts when frozen and thawed before centrifugation. To explain this, de Duve suggested the enzyme must be enclosed in a membrane-bound organelle. After estimating the organelle's probable size, he was able to identify it as lysosomes in electron microscope images. Lysosomes are membrane-bound sacs containing digestive enzymes that can break down macromolecules and are involved in intracellular digestion, defense against pathogens, and cellular waste disposal. De Duve's discovery of lysosomes established them as an important cellular organelle.
This presentation summarizes key information about peroxisomes. Peroxisomes are membrane-bound organelles found in the cytoplasm of eukaryotic cells that contain oxidase enzymes and help breakdown hydrogen peroxide. They have a dense matrix and participate in important functions like fatty acid breakdown, alcohol detoxification, and bile acid/cholesterol synthesis. Disorders can arise if single peroxisomal enzymes are abnormal, affecting the nervous system, liver, and other organs. Two examples given are adrenoleukodystrophy, which involves VLCFA metabolism, and Zellweger's syndrome, caused by a lack of functional peroxisomes due to mutations affecting transport of enzymes.
Lysosomes are membrane-bound organelles found in eukaryotic cells that contain digestive enzymes. They were discovered in 1955 by Christian de Duve and function to digest materials through hydrolytic enzymes. Lysosomes are produced in the Golgi apparatus and contain around 40 varieties of hydrolase enzymes that function in an acidic environment. The main functions of lysosomes include digesting extracellular and intracellular material through processes like heterophagy, programmed cell death, autophagy, autolysis, and roles in fertilization and causing chromosomal damage.
Peroxisomes are microbody organelles found in the cytoplasm of eukaryotic cells that perform important metabolic functions. They contain enzymes for oxidation reactions that produce hydrogen peroxide as a byproduct, and also contain the enzyme catalase to break down hydrogen peroxide. Peroxisomes are involved in lipid biosynthesis and fatty acid oxidation. Related organelles like glyoxysomes in plants and glycosomes in kinetoplastids also carry out metabolic functions tailored to their cellular environments.
Peroxisomes are single-membrane organelles found in the cytoplasm of human cells that contain enzymes for oxidizing molecules like fatty acids. They are 0.1-1 micrometers in diameter and cells contain up to 100 peroxisomes. Peroxisomes are formed through self-replication since they lack DNA and ribosomes. Their functions include producing hydrogen peroxide during fatty acid breakdown, synthesizing phospholipids and bile acids, and detoxifying alcohol. Disorders can occur if peroxisomal enzymes are absent or nonfunctional, leading to issues like oral ulcers, impaired brain development, or hearing loss.
Lysosomes play an important role in the cell by consuming worn-out structures, attacking bacteria, and containing enzymes to digest materials. A lack of lysosomes can lead to lysosomal storage diseases where waste builds up and disrupts cell function. Lysosomes contain hydrolases and transport proteins and would ally with vacuoles to help digest food particles. They view the cytoskeleton as dispensable since it mainly provides structure and transport within the cell.
The document discusses the molecular mechanism of autophagy and its role in plants. It begins with an introduction to autophagy and discusses landmarks in the discovery of autophagy. It then covers the different classes of autophagy, genes and proteins involved, and the molecular mechanism. This includes discussion of the induction, expansion, and maturation steps. It also discusses selective autophagy and techniques to study autophagy. The document concludes by covering the physiological roles of autophagy in plants, including roles in nutrient starvation, oxidative stress response, development, pathogen response, and programmed cell death.
Lysosomes are organelles found in cells that function as the "garbage disposals" by digesting and recycling materials the cell no longer needs or wants to get rid of using around 40 digestive enzymes. They take on various shapes and sizes depending on what materials they are digesting. Lysosomes are membrane-bound sacs that perform two main functions - digesting ingested materials through releasing enzymes into vacuoles, and autophagy and cell death by breaking down the cell's own unwanted components like organelles.
Peroxisomes are single-membrane organelles that contain oxidative enzymes. They play important roles in breaking down fatty acids and toxic metabolites. Peroxisomal disorders can result from defects in peroxisome biogenesis or metabolism. Two examples are X-linked adrenoleukodystrophy, which causes a buildup of very long chain fatty acids, and Zellweger syndrome, the most severe peroxisome biogenesis disorder characterized by defects in development and metabolism.
P4-ATPases, also known as flippases, are lipid transporters that are essential for maintaining membrane lipid asymmetry and regulating membrane protein activity. They function as homodimers and heterodimers with a beta subunit. Flippases transport phospholipids from the outer to inner leaflet of membranes and are involved in key processes like vesicular trafficking. They evolved from cation pumps and their transport cycle shares similarities to sodium-potassium pumps. Experimental procedures to study flippases in fungi include gene deletion, complementation mutants, microscopy, and assays of growth, stress response, and virulence.
Lysosomes are membrane-bound organelles found in most animal and plant cells that contain hydrolytic enzymes. They function in intracellular digestion, breaking down molecules like proteins, lipids, carbohydrates, and nucleic acids. The hydrolytic enzymes in lysosomes work optimally at an acidic pH, which is maintained by a proton pump in the lysosomal membrane. Lysosomes digest excess or worn-out cellular components and can also degrade invading pathogens. They exhibit polymorphism with four main types - primary lysosomes, heterophagosomes, autophagosomes, and residual bodies.
Peroxisomes are small organelles found in the cytoplasm of cells. They contain enzymes that break down fatty acids and reactive oxygen species. Specifically, peroxisomes contain catalase which breaks down hydrogen peroxide into water and oxygen. They also play roles in photosynthesis, beta-oxidation of fatty acids, and producing bile acids. Certain genetic diseases can result from defects in peroxisome function, such as Zellweger syndrome.
Lysosomes are spherical organelles found in animal cells that contain hydrolytic enzymes. They function to break down and digest macromolecules from phagocytosis, endocytosis, and autophagy. Lysosomes are produced in the Golgi apparatus and contain enzymes that function only in low pH environments. Lysosomal storage diseases occur due to mutations in lysosomal enzymes, preventing the breakdown of materials and leading to their accumulation.
The document discusses autophagy, which is a normal physiological process in the body that deals with the destruction and recycling of cellular components. It was first observed in 1962 and involves several conserved autophagy-related proteins and multiple stages. There are three main types of autophagy: microautophagy, macroautophagy, and chaperone-mediated autophagy. Microautophagy involves direct engulfment into lysosomes, macroautophagy uses double-membrane vesicles called autophagosomes, and chaperone-mediated autophagy selectively transports proteins across lysosome membranes. Autophagy is regulated by various factors and plays important roles in cellular
Lysosomes have several key functions: they release enzymes to destroy worn out organelles, digest material brought into cells through phagocytosis such as bacteria engulfed by white blood cells, and release enzymes outside of cells to digest other cells through exocytosis. They can also cause autolysis and self-destruction of cells by breaking down and releasing their enzymes.
Peroxisomes are organelles found in the cytoplasm of animal and plant cells. They are bounded by a single membrane and contain many enzymes. Christian deDuve first isolated peroxisomes from liver cells in 1965. Peroxisomes oxidize organic substances like fatty acids and produce hydrogen peroxide as a byproduct, which is then broken down by the enzyme catalase. They are most abundant in liver cells, where they are involved in functions like breaking down fatty acids, synthesizing cholesterol and bile acids, and breaking down excess purines.
Peroxisomes are spherical organelles found in eukaryotic cells that are bounded by a single membrane. They contain enzymes that produce and break down hydrogen peroxide as well as enzymes involved in lipid metabolism. Peroxisomes help degrade toxic compounds produced during metabolism and also play roles in photorespiration and breaking down fatty acids. They grow in size by incorporating proteins and lipids from the cytosol and can multiply by dividing.
Microbodies are derived from smooth endoplasmic reticulum and replicate via fission. They are prominent in leukocytes and platelets, have a granular matrix, and contain peroxidase, catalase, and oxidase enzymes. Peroxisomes break down very long chain fatty acids, are involved in myelin production and bile acid production, and help destroy unwanted peroxides and free radicals in the body. They contain catalase and other oxidative enzymes to protect cells from hydrogen peroxide. Lysosomes contain hydrolases and are responsible for cellular digestion. Diseases associated with peroxisomal deficiencies include adrenoleukodystrophy, Zellweger syndrome, and primary hyperoxaluria.
This document provides an overview of peroxisome metabolism. Key points include:
- Peroxisomes are organelles that contain enzymes for metabolic processes like fatty acid oxidation and production of hydrogen peroxide.
- They are involved in lipid metabolism, reactive oxygen species reduction, and biosynthesis of plasmalogens and bile acids.
- Disorders associated with impaired peroxisome function include peroxisome biogenesis disorders and single enzyme defects, which can result in accumulation of toxic metabolites.
- Important diseases include Zellweger syndrome, Refsum disease, and adrenoleukodystrophy.
The document discusses cellular structure and function. It describes that cells are the basic living units of the body, with each organ composed of many different cell types. The two main types of fluid in the body are intracellular fluid within cells and extracellular fluid outside cells, which provides nutrients to cells. A normal cell maintains homeostasis through adaptations like atrophy, hypertrophy, hyperplasia, metaplasia, and dysplasia in response to stress or increased demand. The main mechanisms of cellular injury are free radical injury, which damages lipids, proteins and DNA, and hypoxic injury caused by lack of oxygen leading to energy depletion and calcium overload within cells.
Radiation. Plant Toxicity. Inhibitors of radiation toxicity.Dmitri Popov
This document discusses cysteine proteases and their role in programmed cell death (PCD) in plants. It notes that vacuolar processing enzyme (VPE), a cysteine protease, has been identified as a key executor of PCD in plants, playing a role similar to caspases in animal apoptosis. VPE is involved in plant responses to stresses like radiation and pathogens by degrading vacuolar membranes and releasing hydrolytic enzymes to break down cellular components. The document examines the mechanisms and pathways of PCD in both animals and plants.
This document discusses using protease inhibitors to treat Guillain-Barre syndrome. It provides background on proteases, describing what they are and how they are classified. It then discusses how protease inhibitors work and can be used to inhibit various classes of proteases. The document proposes that inhibiting proteases may help treat Guillain-Barre syndrome by preventing damage to the peripheral nervous system. It provides examples of protease inhibitors and cells/tissues they have successfully inhibited proteases in.
This document provides information on various cell organelles and their functions. It discusses the key organelles found in eukaryotic cells including the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, plastids, vacuoles, and centrosomes. For each organelle, it provides details on their structure, role, and working within the cell. The nucleus controls all cell activity, mitochondria generate energy, the endoplasmic reticulum modifies and transports proteins, the Golgi apparatus packages molecules for secretion, lysosomes digest waste, peroxisomes break down fatty acids, plastids perform photosynthesis and store food, vacuoles isolate waste and
Proteases can be classified into four main types - serine, cysteine, aspartic, and metallo proteases. Serine proteases contain a catalytic serine residue and include subtilisins. Cysteine proteases contain a catalytic cysteine-histidine dyad and include papain. Metalloproteases require a divalent metal ion like zinc and include thermolysin. The document discusses the classification, sources, and applications of various protease enzymes.
Chemical conversion of a substance mediated by living organisms or enzymes
Can result in DETOXIFICATION and BIOACTIVATION
Vital to survive
Key in defense mechanism
Plastids are organelles found in plant and algal cells that are involved in photosynthesis, food synthesis and storage. There are different types of plastids that serve specialized functions - chloroplasts contain chlorophyll and carry out photosynthesis, while chromoplasts and leucoplasts are involved in food storage and synthesis. Plastids have a double membrane and internal membrane structures called thylakoids that are the site of the light-dependent reactions of photosynthesis. Plastids are thought to have originated from endosymbiotic cyanobacteria and now play essential roles in plant growth, development and metabolism.
The document discusses the fundamental unit of life - the cell. It describes the key components of cells including the plasma membrane, cytoplasm, organelles like mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and cytoskeleton. It also discusses the nucleus. The main functions of these components are to transport ions and molecules, carry out metabolism of carbohydrates, lipids and amino acids, produce energy, synthesize proteins and lipids, modify and sort proteins, aid in cellular digestion, utilize hydrogen peroxide, maintain cell morphology and enable cell motility, and facilitate DNA synthesis and repair.
This Power Point Presentation (PPT) entitled “ Structure and Function of Lysosome”includes 43 slides with following sub- heads.
DEFINITION
INTRODUCTION/ STRUCTURE OF LYSOSOME
DISCOVERY OF LYSOSOME
DISTRIBUTION/LOCATION OF LYSOSOME
ORIGIN/ SYNTHESIS OF LYSOSOME
SHAPE AND SIZE OF LYSOSOME
CHEMICAL COMPOSITION OF LYSOSOME
LYSOSOMES ARE KNOWN AS SUICIDE BAGS
HOW THE CELL IS PROTECTED FROM LYSOSOME RUPTURE
COMMON FUNCTION OF LYSOSOME
TYPES OF LYSOSOME
DISORDERS IN HUMAN RELATED WITH LYSOSOME
SUMMARY
QUESTIONS
BOOKS CONSULTED
REFERENCES
This document discusses proteases, which are enzymes that catalyze the breakdown of proteins. It describes the seven main classes of proteases based on their catalytic residue: serine, cysteine, threonine, aspartic, glutamic, metallo, and asparagine peptide lyases. Each class is explained along with examples. The document also covers protease structure, classification based on pH, mechanisms of action, and various industrial and medical uses of proteases.
This document discusses tracing the evolution of the human body through analyzing the chemical evolution of proteins and other molecules in the body over time. It notes that tracking changes in conserved proteins that control fundamental processes, like the Pax6 gene which regulates eye development, can reveal how closely related different organisms are. It recommends using the human arrestin protein sequence as an example, performing BLAST searches to find the arrestin sequence in the human genome and other organism genomes, then aligning the protein sequences to compare percentages and determine evolutionary relationships.
The document discusses various biology topics including cell organelles, osmosis, photosynthesis, respiration, the immune system, reproduction and development in animals, evolution, and ecology. It provides information on the structures and functions of organelles like the mitochondria and nucleus. It explains concepts such as osmosis, diffusion, active transport and homeostasis. Key processes like cellular respiration and photosynthesis are defined. Immune system cells and their roles are outlined. Stages of animal development from fertilization to gastrulation are named. Principles of evolution, reproduction and ecology are touched on.
This document summarizes different classes of proteolytic enzymes and their mechanisms of action. There are several classes of proteases including serine, aspartate, cysteine, and metalloproteases. Serine proteases like trypsin and chymotrypsin cleave peptides using a catalytic triad of serine, histidine, and aspartate residues. Aspartate proteases also use acid/base catalysis, while cysteine and metalloproteases employ cysteine and zinc residues respectively in their catalytic mechanisms. Proteases are regulated by activation, localization, and inhibition by endogenous protease inhibitors. Lysosomes contain many hydrolytic enzymes including proteases that degrade macromolecules through autophagy and other
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Radiation toxicity : Hydrolytic enzymes.
1. RADIATION TOXICITY:
HYDROLYTIC ENZYMES –
CYSTEINE_PROTEASES.
Dmitri Popov. PhD, Radiobiology. MD (Russia)
Advanced Medical Technology and Systems Inc.
Canada.
2. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
A lysosome (derived from the Greek words lysis,
meaning "to loosen", and soma, "body") is
a membrane-bound cell organelle found in most
animal cells (they are absent in red blood cells).
Structurally and chemically, they are spherical
vesicles containing hydrolytic enzymes capable of
breaking down virtually all kinds of biomolecules,
including proteins, nucleic acids,
carbohydrates, lipids, and cellular debris. They are
known to contain more than 50 different enzymes,
which are all optimally active at an acidic
environment of about pH 5.
http://en.wikipedia.org/wiki/Lysosome
3. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
Thus lysosomes act as the waste disposal
system of the cell by digesting unwanted
materials in the cytoplasm, both from outside
of the cell and obsolete components inside the
cell. For this function they are popularly
referred to as "suicide bags" or "suicide sacs"
of the cell.
http://en.wikipedia.org/wiki/Lysosome
4. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
Cysteine proteases, also known as thiol
proteases, are enzymes that
degrade proteins. These proteases share a
common catalytic mechanism that involves
a nucleophilic cysteine thiol in a catalytic
triad or dyad. The first step in the reaction
mechanism by which cysteine proteases
catalyze the hydrolysis of peptide bonds is de
protonation of a thiol in the enzyme's active
site by an adjacent amino acid with a
basic side chain, usually a histidineresidue.
5. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
The next step is nucleophilic attack by
the deprotonated cysteine's anionic sulfur on
the substrate carbonyl carbon. In this step, a
fragment of the substrate is released with
an amine terminus, the histidine residue in
the protease is restored to its deprotonated
form, and a thioester intermediate linking the
new carboxy-terminus of the substrate to the
cysteine thiol is formed.
http://en.wikipedia.org/wiki/Cysteine_protease
6. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
Therefore they are also sometimes referred to
as thiol proteases. The thioester bond is
subsequently hydrolyzed to generate
a carboxylic acid moiety on the remaining
substrate fragment, while regenerating the free
enzyme.
http://en.wikipedia.org/wiki/Cysteine_protease
7. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
Cysteine proteases play multi-faceted roles,
virtually in every aspect of physiology and
development. In plants they are important in
growth and development and in accumulation
and mobilization of storage proteins such as in
seeds. In addition, they are involved
in signalling pathways and in the response
to biotic and abiotic stresses.
http://en.wikipedia.org/wiki/Cysteine_protease
8. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
In humans and other animals, they are
responsible
for senescence and apoptosis (programmed
cell death), MHC class II immune
responses, prohormone processing,
and extracellular matrix remodeling important
to bone development.
http://en.wikipedia.org/wiki/Cysteine_protease
9. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
The ability of macrophages and other cells to
mobilize elastolytic cysteine proteases to their
surfaces under specialized conditions may
also lead to accelerated collagen
and elastin degradation at sites
of inflammation in diseases such
as atherosclerosis and emphysema.
http://en.wikipedia.org/wiki/Cysteine_protease
11. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
Proteases are usually synthesized as large precursor
proteins called zymogens.
Activation occurs once the protease is delivered to a
specific intracellular compartment (e.g. lysosome) or
extracellular environment.
Protease inhibitors are usually proteins
with domains that enter or block a protease active
site to prevent substrate access. In competitive
inhibition, the inhibitor binds to the active site, thus
preventing enzyme-substrate interaction. In non-
competitive inhibition, the inhibitor binds to
an allosteric site, which alters the active site and
makes it inaccessible to the substrate.
12. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
. Cysteine proteases (CPs) are proteins with
molecular mass about 21–30 kDa. They show
the highest hydrolytic activity at pH 4–6.5.
Because of the high tendency of the thiol
group to oxidation, the environment of the
enzyme should contain a reducing component.
Glutathione serves as an activating agent in
cells, whereas addition of mercaptoethanol or
dithiothreitol is required for in vitro
experiments.
http://www.actabp.pl/pdf/1_2001/1-20.pdf
13. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
Structural studies of cysteine proteases and
their inhibitors. Grzonka et al.
Mammalian cysteine proteases have been
implicated in the development and progression
of many diseases that involve abnormal
protein turnover.
14. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
Caspases, or cysteine-aspartic
proteases or cysteine-dependent aspartate-
directed proteases are a family of cysteine
proteases that play essential roles
in apoptosis (programmed cell
death), necrosis, and inflammation.
http://en.wikipedia.org/wiki/Caspase
15. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
There are two types of apoptotic
caspases: initiator (apical)
caspases and effector (executioner) caspases.
Initiator caspases (e.g., CASP2, CASP8, CASP9,
and CASP10) cleave inactive pro-forms of effector
caspases, thereby activating them. Effector
caspases (e.g., CASP3, CASP6, CASP7) in turn
cleave other protein substrates within the cell, to
trigger the apoptotic process. The initiation of this
cascade reaction is regulated by caspase
inhibitors.
http://en.wikipedia.org/wiki/Caspase
16. RADIATION TOXICITY:
HYDROLYTIC ENZYMES.
The caspase cascade can be activated by:
granzyme B (released by cytotoxic T
lymphocytes and NK cells), which is known to
activate caspase-3 and -7
death receptors (like Fas, TRAIL receptors
and TNF receptor), which can activate caspase-8
and -10
the apoptosome (regulated by cytochrome c and
the Bcl-2 family), which activates caspase-9.
http://en.wikipedia.org/wiki/Caspase