The document summarizes key information about the endoplasmic reticulum (ER):
- ER is a network of membrane-bound tubules, vesicles and sacs found in most cell types that is involved in protein and lipid synthesis.
- It has two forms - rough ER with attached ribosomes that synthesizes proteins, and smooth ER without ribosomes that synthesizes lipids.
- ER was first observed under electron microscopes in the 1940s and was termed the endoplasmic reticulum in 1952. It plays an important role in protein processing and transport within cells.
The endoplasmic reticulum (ER) is an organelle found in eukaryotic cells that transports materials throughout the cell. It is classified into two types: smooth ER and rough ER. Smooth ER synthesizes lipids and transports products, while rough ER synthesizes proteins with attached ribosomes. Both play essential roles in functions like protein production, lipid synthesis, and calcium storage to support cell processes.
This document discusses cell organelles and plasma membrane. It describes that cells contain various organized structures called organelles, which can be separated by disrupting the cell membrane and applying differential centrifugal forces. Some organelles contain marker enzymes that can identify them. The document then discusses the structure and functions of the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria, and plasma membrane. It explains that the plasma membrane regulates transport into and out of the cell using both passive and active transport mechanisms.
The document provides an overview of various cell organelles including the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, mitochondria, peroxisomes and cytoskeleton. It describes the structure and functions of the nucleus, ribosomes and endoplasmic reticulum in detail. The endoplasmic reticulum functions to synthesize proteins and lipids and is involved in detoxification. It has two types - smooth endoplasmic reticulum and rough endoplasmic reticulum which differ in their functions.
This document discusses cell membranes and transport mechanisms. It describes the four main mechanisms of transport through cell membranes: diffusion, facilitated diffusion, osmosis, and active transport. Diffusion is the passive movement of molecules or ions from an area of higher concentration to lower concentration down a concentration gradient. Facilitated diffusion utilizes membrane proteins to transport specific molecules. Osmosis is the passive movement of water across a membrane, moving from an area of lower solute concentration to higher. Active transport requires energy and transports molecules against a concentration gradient using membrane proteins like pumps and channels.
This document provides information on cells at both the prokaryotic and eukaryotic levels. It discusses cell theory and key aspects of prokaryotic cells including their shape, structures like plasmids and mesosomes, and cell envelopes. For eukaryotic cells, it describes the membrane-bound organelles like the nucleus, mitochondria, plastids, Golgi apparatus, endoplasmic reticulum, lysosomes and vacuoles. It also discusses cytoskeletal elements and membrane properties.
The endoplasmic reticulum (ER) is a network of tubules and sacs that extends throughout the cytosol of eukaryotic cells. It was discovered in 1945 and named in 1953. The ER exists in three forms - cisternae, tubules, and vesicles. There are two main types, the rough ER which has ribosomes and is involved in protein synthesis, and the smooth ER which lacks ribosomes and performs functions like lipid synthesis. The ER synthesizes proteins and lipids, transports products between organelles like the Golgi apparatus, and is involved in processes such as calcium regulation and toxin removal.
The document discusses various types of transport through cell membranes. It begins by explaining the four main mechanisms of transport: diffusion, facilitated diffusion, osmosis, and active transport. Diffusion is described as the passive, random movement of molecules from an area of higher concentration to lower concentration down a concentration gradient. Facilitated diffusion utilizes membrane proteins to transport specific molecules. Osmosis involves the diffusion of water across the semi-permeable cell membrane. Active transport transports molecules against a concentration gradient by using energy in the form of ATP.
The document discusses the ultrastructure and functions of the endoplasmic reticulum. It describes the endoplasmic reticulum as a network of membrane-bound channels found in the cytoplasm of eukaryotic cells. The endoplasmic reticulum can be rough or smooth, with rough ER having ribosomes attached. The endoplasmic reticulum functions in protein transport and folding, lipid and steroid synthesis, and forms part of the intracellular transport system.
The endoplasmic reticulum (ER) is an organelle found in eukaryotic cells that transports materials throughout the cell. It is classified into two types: smooth ER and rough ER. Smooth ER synthesizes lipids and transports products, while rough ER synthesizes proteins with attached ribosomes. Both play essential roles in functions like protein production, lipid synthesis, and calcium storage to support cell processes.
This document discusses cell organelles and plasma membrane. It describes that cells contain various organized structures called organelles, which can be separated by disrupting the cell membrane and applying differential centrifugal forces. Some organelles contain marker enzymes that can identify them. The document then discusses the structure and functions of the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria, and plasma membrane. It explains that the plasma membrane regulates transport into and out of the cell using both passive and active transport mechanisms.
The document provides an overview of various cell organelles including the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, mitochondria, peroxisomes and cytoskeleton. It describes the structure and functions of the nucleus, ribosomes and endoplasmic reticulum in detail. The endoplasmic reticulum functions to synthesize proteins and lipids and is involved in detoxification. It has two types - smooth endoplasmic reticulum and rough endoplasmic reticulum which differ in their functions.
This document discusses cell membranes and transport mechanisms. It describes the four main mechanisms of transport through cell membranes: diffusion, facilitated diffusion, osmosis, and active transport. Diffusion is the passive movement of molecules or ions from an area of higher concentration to lower concentration down a concentration gradient. Facilitated diffusion utilizes membrane proteins to transport specific molecules. Osmosis is the passive movement of water across a membrane, moving from an area of lower solute concentration to higher. Active transport requires energy and transports molecules against a concentration gradient using membrane proteins like pumps and channels.
This document provides information on cells at both the prokaryotic and eukaryotic levels. It discusses cell theory and key aspects of prokaryotic cells including their shape, structures like plasmids and mesosomes, and cell envelopes. For eukaryotic cells, it describes the membrane-bound organelles like the nucleus, mitochondria, plastids, Golgi apparatus, endoplasmic reticulum, lysosomes and vacuoles. It also discusses cytoskeletal elements and membrane properties.
The endoplasmic reticulum (ER) is a network of tubules and sacs that extends throughout the cytosol of eukaryotic cells. It was discovered in 1945 and named in 1953. The ER exists in three forms - cisternae, tubules, and vesicles. There are two main types, the rough ER which has ribosomes and is involved in protein synthesis, and the smooth ER which lacks ribosomes and performs functions like lipid synthesis. The ER synthesizes proteins and lipids, transports products between organelles like the Golgi apparatus, and is involved in processes such as calcium regulation and toxin removal.
The document discusses various types of transport through cell membranes. It begins by explaining the four main mechanisms of transport: diffusion, facilitated diffusion, osmosis, and active transport. Diffusion is described as the passive, random movement of molecules from an area of higher concentration to lower concentration down a concentration gradient. Facilitated diffusion utilizes membrane proteins to transport specific molecules. Osmosis involves the diffusion of water across the semi-permeable cell membrane. Active transport transports molecules against a concentration gradient by using energy in the form of ATP.
The document discusses the ultrastructure and functions of the endoplasmic reticulum. It describes the endoplasmic reticulum as a network of membrane-bound channels found in the cytoplasm of eukaryotic cells. The endoplasmic reticulum can be rough or smooth, with rough ER having ribosomes attached. The endoplasmic reticulum functions in protein transport and folding, lipid and steroid synthesis, and forms part of the intracellular transport system.
Introduction
Structure of Plasma Membranes
Functions of Plasma Membranes
Cytoplasm: Cytosol, Organelles
Functions of Cytoplasm
Ribosome, Functions of Ribosomes
2. Endoplasmic reticulum (ER)
a. Rough Endoplasmic Reticulum and its Functions
b. Smooth ER and its Functions
3. Golgi complex and its Functions
4.Lysosomes and its Functions
5. Peroxisomes and its Functions
6. Proteasomes and its Functions
7.Mitochondria and its Functions
8. Cytoskeletal
a. Microfilaments and its Functions
b. Intermediate filaments and its Functions
c. Microtubules and its Functions
9. Centrosome and its Functions
10. Cilia and Flagella and its Functions
11. Nucleus and its Functions
a. Nuclear Membrane and its Functions
b. Nucleoplasm and its Functions
c. Chromosomes and its Functions
d. Nucleolus and its Functions
The document provides information about microscopic anatomy and the cell. It discusses the key differences between prokaryotic and eukaryotic cells, and describes the basic structures and organelles of a typical eukaryotic cell, including the cell membrane, nucleus, cytoplasm, mitochondria, endoplasmic reticulum, Golgi complex, lysosomes, peroxisomes, ribosomes, centrioles, and cytoskeleton. It also covers the functions of these cellular components and structures like the cell membrane, as well as cellular transport mechanisms and intercellular junctions.
1) Physiology is the study of the normal functioning of living organisms and their parts. It includes the mechanical, physical, and biochemical processes within living things.
2) The human body is made up of cells, tissues, organs and organ systems. A typical human cell contains a nucleus, cytoplasm, organelles and a plasma membrane. The plasma membrane separates the cell from its external environment.
3) Cell physiology examines the structures and functions of eukaryotic cells, including the plasma membrane, nucleus, cytoplasm and organelles like mitochondria, endoplasmic reticulum and lysosomes that perform specialized functions.
Cell Structures and Functions In pathology.pptxVictory120660
Cell structure and function are fundamental to understanding biology. Here's a broad overview:
1. **Cell Structure:**
- **Cell Membrane:** Acts as a barrier, controlling the passage of substances in and out of the cell.
- **Cytoplasm:** Gel-like substance within the cell where organelles are suspended.
- **Nucleus:** Contains genetic material (DNA) and controls cell activities.
- **Organelles:** Structures within the cell with specific functions, such as mitochondria (energy production), endoplasmic reticulum (protein synthesis), Golgi apparatus (protein packaging), and lysosomes (digestion).
2. **Cell Function:**
- **Metabolism:** Cells carry out metabolic processes to maintain life, including energy production, nutrient breakdown, and waste removal.
- **Reproduction:** Cells can reproduce through processes like mitosis (cell division) or meiosis (reproductive cell division).
- **Homeostasis:** Cells maintain a stable internal environment by regulating processes like temperature, pH, and nutrient levels.
- **Communication:** Cells communicate with each other through chemical signals, allowing coordination within tissues and organ systems.
- **Differentiation:** Cells specialize into different types with specific functions during development, forming tissues and organs.
- **Response to Stimuli:** Cells can respond to external stimuli, such as light or chemicals, through processes like movement or changes in gene expression.
Understanding cell structure and function is crucial for comprehending biological processes at all levels, from the functioning of individual organisms to the interactions within ecosystems.
Stem cells are cells that have the ability to divide for indefinite periods in culture and to give rise to specialized cells. They are important for growth, development, tissue maintenance and repair. There are two main types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues.
This document provides information about cell biology and the structure and function of eukaryotic cells and their organelles. It focuses on the endoplasmic reticulum and ribosomes. The key points are:
1) Eukaryotic cells contain a nucleus and membrane-bound organelles like the endoplasmic reticulum and ribosomes.
2) The endoplasmic reticulum is a network of membranes involved in protein and lipid synthesis. It exists in two forms - smooth and rough, characterized by the absence or presence of ribosomes.
3) Ribosomes are structures that synthesize proteins and exist freely in the cytoplasm or attached to the endoplasmic reticulum. They facilitate protein production through interactions with mRNA
The document summarizes key aspects of the endoplasmic reticulum (ER), Golgi apparatus, and their discovery. It discusses how the ER was first observed in 1945 and forms an interconnected network involved in protein transport and synthesis. The Golgi apparatus was discovered in 1898 and helps process and package proteins and lipids. It has a stacked structure and modifies proteins as they pass through. Both organelles are essential in the transport and processing of molecules within eukaryotic cells.
The document summarizes key aspects of cell structure and function. It describes cells as the basic unit of life and distinguishes between prokaryotic and eukaryotic cells. The main organelles of eukaryotic cells are then outlined, including the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, cytoskeleton, and cytoplasm. Each organelle is briefly characterized by its structure and main functions in the cell.
Here are the answers to the questions:
- Golgi apparatus serves as a primary packaging area for molecules that will be distributed throughout the cell.
- Ribosomes
- Spindle fibers
- Nerve cells
- Lysosomes
- Cell
- Smooth endoplasmic reticulum
The endoplasmic reticulum (ER) is a network of interconnected membranes found throughout the cytoplasm of eukaryotic cells. It consists of flat sacs and tubules with a single continuous lumen. The ER is involved in protein transport and synthesis, lipid and steroid synthesis, calcium storage, and processing of toxins. It has two types - smooth ER which lacks ribosomes and is involved in lipid synthesis, and rough ER which is studded with ribosomes and is the main site of protein synthesis.
1. The document discusses the structure and function of cells. It states that cells are the basic unit of life and all organisms are made of one or more cells.
2. The cell theory developed by Schleiden and Schwann states that all organisms are composed of cells, cells come from pre-existing cells, and their functions occur within cells.
3. There are two main types of cells - eukaryotic and prokaryotic. Eukaryotic cells have a nucleus and organelles, while prokaryotic cells like bacteria do not have a nucleus or organelles.
4. Key organelles in eukaryotic cells and their functions are discussed in detail, including the nucleus,
The Cell........................................................................mariafermani1
The document summarizes key aspects of cell biology. It begins by outlining cell theory and distinguishing between eukaryotic and prokaryotic cells. It then describes several organelles found in eukaryotic cells including the nucleus, mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus, peroxisomes, and cytoskeleton. It also discusses tissue formation, classification of prokaryotic cells, and the structure and function of bacterial and viral cells.
Cell Anatomy and physiology ( structure and function for NEET asparients, Biology, MBBS, BPT, Allied, nursing , medical and paramedical students. This is the easiest form of slide share to understand the context better.
Biochemistry is the study of chemical processes within living organisms. It emerged in the early 20th century through the combination of chemistry, physiology, and biology. The study of biochemistry involves enzymes, nucleic acids, carbohydrates, proteins, lipids, and their interactions within cells and tissues. Biochemistry is highly significant for nursing as it provides understanding of how the human body functions normally and in disease states. Nurses apply biochemistry knowledge to interventions and understanding how medications work at the cellular level. A solid grasp of biochemistry fundamentals is crucial for nurses to comprehend common medical conditions and preserve patient health.
cell and cell organelles-Nursing. Day 2.pptxUsman Hashmi
The document discusses cell biology and cell organelles. It begins by defining cells and providing examples of different cell types. It then describes the key differences between prokaryotic and eukaryotic cells. The main organelles of eukaryotic cells are then outlined, including their structures and functions. These organelles include the nucleus, mitochondria, endoplasmic reticulum, Golgi complex, lysosomes, peroxisomes, and cytoskeleton. The roles of the cytosol and plasma membrane are also summarized. Finally, the document briefly discusses tissue regeneration and abnormalities in cell division like cancer.
Cell membranes are composed of lipids (45%), proteins (45%), and carbohydrates (10%). Lipids form a bilayer with hydrophilic heads facing out and hydrophobic tails facing inward. Membrane proteins can be peripheral or integral. Peripheral proteins attach to lipid heads while integral proteins span or embed within the membrane. Together, lipids and proteins give cell membranes a fluid mosaic structure and allow them to perform important functions like selectively regulating transport into and out of the cell.
The document provides information on various cell organelles:
1. Cell organelles include the nucleus, plasma membrane, cytoplasm, and specialized structures like the endoplasmic reticulum, Golgi body, lysosomes, mitochondria, plastids, and vacuoles.
2. The chloroplast is a double-membraned plastid that contains chlorophyll and is the site of photosynthesis in plants.
3. The endoplasmic reticulum is a network of tubules connected to the nuclear membrane that helps synthesize lipids, modify proteins, and transport materials within the cell.
eukaryote, any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus, in which the well-defined chromosomes (bodies containing the hereditary material) are located.
The document describes the main organelles found in animal cells including their structures, locations within the cell, and functions. The organelles discussed are the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, mitochondria, lysosomes, and peroxisomes. Each organelle plays an important role such as generating energy, modifying and transporting proteins, breaking down waste, and carrying genetic instructions.
The document discusses the structure and function of cells. It defines the cell as the basic structural and functional unit of life. Human beings contain billions of cells arranged into over 200 types across four basic tissue groups. The document then describes the key components of cells including the cell membrane, cytoplasm, organelles like mitochondria and lysosomes, and inclusions. It provides detailed information on the structure and functions of the cell membrane and various organelles.
The document provides a detailed overview of the history and evolution of chemical use in agriculture. It discusses how the earliest recorded uses of chemicals in agriculture date back to ancient Egypt and the Roman Empire when sulphur was used to control pests in grain stores. It then outlines several important milestones and discoveries that expanded the use of chemicals in agriculture throughout history, such as the Haber-Bosch process in the early 1900s and the rise of the agrochemical industry between 1940-1960. The document also examines the environmental and health implications of modern chemical farming practices.
1. Soil fertility refers to a soil's ability to support plant growth through favorable chemical, physical, and biological conditions, including providing essential nutrients. Regular soil testing can help farmers understand their soil's nutrient levels and needs.
2. Factors that affect soil fertility include organic matter content, soil texture, pH, moisture, aeration, temperature, and biota activity. Management practices like crop rotation, cover cropping, organic fertilization, reduced tillage, and intercropping can improve soil fertility over time.
3. Earthworms, microbes, fungi, and other soil biota play an important role in soil fertility by breaking down organic matter, improving soil structure, and making nutrients available to
Introduction
Structure of Plasma Membranes
Functions of Plasma Membranes
Cytoplasm: Cytosol, Organelles
Functions of Cytoplasm
Ribosome, Functions of Ribosomes
2. Endoplasmic reticulum (ER)
a. Rough Endoplasmic Reticulum and its Functions
b. Smooth ER and its Functions
3. Golgi complex and its Functions
4.Lysosomes and its Functions
5. Peroxisomes and its Functions
6. Proteasomes and its Functions
7.Mitochondria and its Functions
8. Cytoskeletal
a. Microfilaments and its Functions
b. Intermediate filaments and its Functions
c. Microtubules and its Functions
9. Centrosome and its Functions
10. Cilia and Flagella and its Functions
11. Nucleus and its Functions
a. Nuclear Membrane and its Functions
b. Nucleoplasm and its Functions
c. Chromosomes and its Functions
d. Nucleolus and its Functions
The document provides information about microscopic anatomy and the cell. It discusses the key differences between prokaryotic and eukaryotic cells, and describes the basic structures and organelles of a typical eukaryotic cell, including the cell membrane, nucleus, cytoplasm, mitochondria, endoplasmic reticulum, Golgi complex, lysosomes, peroxisomes, ribosomes, centrioles, and cytoskeleton. It also covers the functions of these cellular components and structures like the cell membrane, as well as cellular transport mechanisms and intercellular junctions.
1) Physiology is the study of the normal functioning of living organisms and their parts. It includes the mechanical, physical, and biochemical processes within living things.
2) The human body is made up of cells, tissues, organs and organ systems. A typical human cell contains a nucleus, cytoplasm, organelles and a plasma membrane. The plasma membrane separates the cell from its external environment.
3) Cell physiology examines the structures and functions of eukaryotic cells, including the plasma membrane, nucleus, cytoplasm and organelles like mitochondria, endoplasmic reticulum and lysosomes that perform specialized functions.
Cell Structures and Functions In pathology.pptxVictory120660
Cell structure and function are fundamental to understanding biology. Here's a broad overview:
1. **Cell Structure:**
- **Cell Membrane:** Acts as a barrier, controlling the passage of substances in and out of the cell.
- **Cytoplasm:** Gel-like substance within the cell where organelles are suspended.
- **Nucleus:** Contains genetic material (DNA) and controls cell activities.
- **Organelles:** Structures within the cell with specific functions, such as mitochondria (energy production), endoplasmic reticulum (protein synthesis), Golgi apparatus (protein packaging), and lysosomes (digestion).
2. **Cell Function:**
- **Metabolism:** Cells carry out metabolic processes to maintain life, including energy production, nutrient breakdown, and waste removal.
- **Reproduction:** Cells can reproduce through processes like mitosis (cell division) or meiosis (reproductive cell division).
- **Homeostasis:** Cells maintain a stable internal environment by regulating processes like temperature, pH, and nutrient levels.
- **Communication:** Cells communicate with each other through chemical signals, allowing coordination within tissues and organ systems.
- **Differentiation:** Cells specialize into different types with specific functions during development, forming tissues and organs.
- **Response to Stimuli:** Cells can respond to external stimuli, such as light or chemicals, through processes like movement or changes in gene expression.
Understanding cell structure and function is crucial for comprehending biological processes at all levels, from the functioning of individual organisms to the interactions within ecosystems.
Stem cells are cells that have the ability to divide for indefinite periods in culture and to give rise to specialized cells. They are important for growth, development, tissue maintenance and repair. There are two main types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues.
This document provides information about cell biology and the structure and function of eukaryotic cells and their organelles. It focuses on the endoplasmic reticulum and ribosomes. The key points are:
1) Eukaryotic cells contain a nucleus and membrane-bound organelles like the endoplasmic reticulum and ribosomes.
2) The endoplasmic reticulum is a network of membranes involved in protein and lipid synthesis. It exists in two forms - smooth and rough, characterized by the absence or presence of ribosomes.
3) Ribosomes are structures that synthesize proteins and exist freely in the cytoplasm or attached to the endoplasmic reticulum. They facilitate protein production through interactions with mRNA
The document summarizes key aspects of the endoplasmic reticulum (ER), Golgi apparatus, and their discovery. It discusses how the ER was first observed in 1945 and forms an interconnected network involved in protein transport and synthesis. The Golgi apparatus was discovered in 1898 and helps process and package proteins and lipids. It has a stacked structure and modifies proteins as they pass through. Both organelles are essential in the transport and processing of molecules within eukaryotic cells.
The document summarizes key aspects of cell structure and function. It describes cells as the basic unit of life and distinguishes between prokaryotic and eukaryotic cells. The main organelles of eukaryotic cells are then outlined, including the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, cytoskeleton, and cytoplasm. Each organelle is briefly characterized by its structure and main functions in the cell.
Here are the answers to the questions:
- Golgi apparatus serves as a primary packaging area for molecules that will be distributed throughout the cell.
- Ribosomes
- Spindle fibers
- Nerve cells
- Lysosomes
- Cell
- Smooth endoplasmic reticulum
The endoplasmic reticulum (ER) is a network of interconnected membranes found throughout the cytoplasm of eukaryotic cells. It consists of flat sacs and tubules with a single continuous lumen. The ER is involved in protein transport and synthesis, lipid and steroid synthesis, calcium storage, and processing of toxins. It has two types - smooth ER which lacks ribosomes and is involved in lipid synthesis, and rough ER which is studded with ribosomes and is the main site of protein synthesis.
1. The document discusses the structure and function of cells. It states that cells are the basic unit of life and all organisms are made of one or more cells.
2. The cell theory developed by Schleiden and Schwann states that all organisms are composed of cells, cells come from pre-existing cells, and their functions occur within cells.
3. There are two main types of cells - eukaryotic and prokaryotic. Eukaryotic cells have a nucleus and organelles, while prokaryotic cells like bacteria do not have a nucleus or organelles.
4. Key organelles in eukaryotic cells and their functions are discussed in detail, including the nucleus,
The Cell........................................................................mariafermani1
The document summarizes key aspects of cell biology. It begins by outlining cell theory and distinguishing between eukaryotic and prokaryotic cells. It then describes several organelles found in eukaryotic cells including the nucleus, mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus, peroxisomes, and cytoskeleton. It also discusses tissue formation, classification of prokaryotic cells, and the structure and function of bacterial and viral cells.
Cell Anatomy and physiology ( structure and function for NEET asparients, Biology, MBBS, BPT, Allied, nursing , medical and paramedical students. This is the easiest form of slide share to understand the context better.
Biochemistry is the study of chemical processes within living organisms. It emerged in the early 20th century through the combination of chemistry, physiology, and biology. The study of biochemistry involves enzymes, nucleic acids, carbohydrates, proteins, lipids, and their interactions within cells and tissues. Biochemistry is highly significant for nursing as it provides understanding of how the human body functions normally and in disease states. Nurses apply biochemistry knowledge to interventions and understanding how medications work at the cellular level. A solid grasp of biochemistry fundamentals is crucial for nurses to comprehend common medical conditions and preserve patient health.
cell and cell organelles-Nursing. Day 2.pptxUsman Hashmi
The document discusses cell biology and cell organelles. It begins by defining cells and providing examples of different cell types. It then describes the key differences between prokaryotic and eukaryotic cells. The main organelles of eukaryotic cells are then outlined, including their structures and functions. These organelles include the nucleus, mitochondria, endoplasmic reticulum, Golgi complex, lysosomes, peroxisomes, and cytoskeleton. The roles of the cytosol and plasma membrane are also summarized. Finally, the document briefly discusses tissue regeneration and abnormalities in cell division like cancer.
Cell membranes are composed of lipids (45%), proteins (45%), and carbohydrates (10%). Lipids form a bilayer with hydrophilic heads facing out and hydrophobic tails facing inward. Membrane proteins can be peripheral or integral. Peripheral proteins attach to lipid heads while integral proteins span or embed within the membrane. Together, lipids and proteins give cell membranes a fluid mosaic structure and allow them to perform important functions like selectively regulating transport into and out of the cell.
The document provides information on various cell organelles:
1. Cell organelles include the nucleus, plasma membrane, cytoplasm, and specialized structures like the endoplasmic reticulum, Golgi body, lysosomes, mitochondria, plastids, and vacuoles.
2. The chloroplast is a double-membraned plastid that contains chlorophyll and is the site of photosynthesis in plants.
3. The endoplasmic reticulum is a network of tubules connected to the nuclear membrane that helps synthesize lipids, modify proteins, and transport materials within the cell.
eukaryote, any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus, in which the well-defined chromosomes (bodies containing the hereditary material) are located.
The document describes the main organelles found in animal cells including their structures, locations within the cell, and functions. The organelles discussed are the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, mitochondria, lysosomes, and peroxisomes. Each organelle plays an important role such as generating energy, modifying and transporting proteins, breaking down waste, and carrying genetic instructions.
The document discusses the structure and function of cells. It defines the cell as the basic structural and functional unit of life. Human beings contain billions of cells arranged into over 200 types across four basic tissue groups. The document then describes the key components of cells including the cell membrane, cytoplasm, organelles like mitochondria and lysosomes, and inclusions. It provides detailed information on the structure and functions of the cell membrane and various organelles.
The document provides a detailed overview of the history and evolution of chemical use in agriculture. It discusses how the earliest recorded uses of chemicals in agriculture date back to ancient Egypt and the Roman Empire when sulphur was used to control pests in grain stores. It then outlines several important milestones and discoveries that expanded the use of chemicals in agriculture throughout history, such as the Haber-Bosch process in the early 1900s and the rise of the agrochemical industry between 1940-1960. The document also examines the environmental and health implications of modern chemical farming practices.
1. Soil fertility refers to a soil's ability to support plant growth through favorable chemical, physical, and biological conditions, including providing essential nutrients. Regular soil testing can help farmers understand their soil's nutrient levels and needs.
2. Factors that affect soil fertility include organic matter content, soil texture, pH, moisture, aeration, temperature, and biota activity. Management practices like crop rotation, cover cropping, organic fertilization, reduced tillage, and intercropping can improve soil fertility over time.
3. Earthworms, microbes, fungi, and other soil biota play an important role in soil fertility by breaking down organic matter, improving soil structure, and making nutrients available to
This document discusses solid waste pollution and its management. It defines different types of solid waste such as municipal waste, hazardous waste, and biomedical waste. It describes the sources and impacts of solid waste pollution including various diseases. The major causes of increased solid waste are identified as population growth, urbanization, and increased affluence. Common methods for municipal solid waste disposal include landfilling, recycling, incineration, composting, while hazardous waste requires specialized disposal methods. Proper waste management can reduce pollution and health impacts.
1. Soil fertility refers to a soil's ability to support plant growth through favorable chemical, physical, and biological conditions, including providing essential nutrients. Regular soil testing can help farmers understand their soil's nutrient levels and needs.
2. Factors that affect soil fertility include organic matter content, soil texture, pH, moisture, aeration, temperature, and biota activity. Management practices like crop rotation, cover cropping, no-till farming, and fertilization can help preserve and improve soil fertility over time.
3. Earthworms, green manures, and organic matter additions increase soil fertility by loosening the soil, adding nutrients, and promoting beneficial microbial activity. Mixed cropping and mulching also help
Organic farming is a method that aims to protect the environment and ecology by using natural resources and avoiding synthetic inputs. It focuses on crop rotations, composting, and biological pest control to nourish soils and crops without chemicals. The principles of organic farming are health, ecology, fairness, and care - seeking to sustainably produce nutritious food while safeguarding farmer, consumer, and environmental well-being for current and future generations. Practicing organic techniques like composting and crop rotations can help improve soil health, reduce costs, and strengthen food security in an environmentally-friendly way.
Ecological balance refers to a stable state of dynamic equilibrium within an ecosystem where species and genetic diversity remain stable despite natural disturbances. It ensures the continuous existence of organisms and signifies a sustainable habitat where animals, plants, and microorganisms depend on each other. Maintaining ecological balance is important as it creates stable environments and enhances thriving of organisms.
Climate conditions such as temperature, rainfall, sunlight, soil quality, and growing season length influence the nutritional production of crops. Different crops thrive in different climates. Crop rotation, the practice of planting different crops in sequences, provides benefits like nutrient management, pest and disease control, and soil structure improvement, leading to more nutritionally valuable food. Factors like crop selection, sequence, cover crops, and local conditions should be considered when planning crop rotations.
Plastids are membrane-bound organelles found in plant cells and some protists that are involved in photosynthesis and storing food. There are three main types - chloroplasts contain chlorophyll and carry out photosynthesis, chromoplasts are colored and contain pigments like carotenoids, and leucoplasts are colorless and store food like starch. Chloroplasts have an inner and outer membrane, and contain stacks of thylakoid membranes where photosynthesis takes place. Chlorophyll and accessory pigments like carotenoids are embedded in the thylakoids and absorb light energy for photosynthesis.
Foliose, fruticose, and crustose lichens are the three main growth forms of lichens. Foliose lichens have broad, leaf-like structures, fruticose lichens have branching, shrub-like structures, and crustose lichens form crusts that tightly adhere to the substrate on which they grow. These three categories describe the different morphological forms that lichens can take on rocks, trees, and other surfaces.
Golgi bodies are membrane-bound organelles found in eukaryotic cells that serve as the centers of cellular secretion and processing. They modify, package, and transport proteins and lipids and are made up of stacks of flattened sacs called cisternae. Golgi bodies were first discovered and described in 1898 by Camillo Golgi, who observed them in neurons and termed them the "internal reticular apparatus." They play an important role in synthesizing and packaging molecules for export from the cell.
The electron transport chain (ETC) transports electrons from electron donors like NADH to molecular oxygen. It consists of protein complexes embedded in the inner mitochondrial membrane. Complexes I, III, and IV pump protons out of the matrix, building up an electrochemical gradient used for ATP synthesis. Electrons flow from complex to complex via mobile carriers like coenzyme Q and cytochrome c. This transfers energy from electrons to protons, conserving energy as ATP. Mitochondria contain many copies of the ETC to generate sufficient ATP through oxidative phosphorylation.
Mitochondria are double-membraned organelles found in eukaryotic cells that generate most of the cell's supply of adenosine triphosphate (ATP). They contain their own DNA and ribosomes. The inner membrane forms folds called cristae that increase its surface area and house protein complexes involved in oxidative phosphorylation. This process uses energy released from oxidation of nutrients to produce ATP. Mitochondria were first observed in the 1880s and their role in cellular respiration was established in the mid-20th century through studies of their structure and biochemical properties.
The document discusses three proposed mechanisms for the formation of mitochondria: self-duplication of existing mitochondria, de novo origin from cytoplasmic vesicles, and transformation from non-mitochondrial systems like the plasma membrane or ER. It states that the self-duplication hypothesis through fission of existing mitochondria is now most widely accepted. The endosymbiont hypothesis that mitochondria evolved from prokaryotes engulfed by early eukaryotic cells over a billion years ago is also described. Mitochondria's key functions like ATP production through oxidative phosphorylation are summarized.
Anacardiaceae is a family of trees and shrubs commonly known as the mango or cashew family. Key characteristics include alternate, simple or pinnately compound leaves; pentamerous flowers with 10 stamens inserted on a disc and 1-2 carpels forming a drupe fruit. Many plants in this family produce edible fruits like mango and cashew nut. Resins from some species are used for varnishes while others provide gums or cause skin irritation. The family includes about 80 genera and 600 species mostly found in tropical regions.
Coffee is a crop cultivated primarily in southern India. There are two main species - Arabica and Robusta. Arabica grows at higher elevations between 900-1200 meters and produces higher quality coffee, while Robusta grows at lower elevations and is more resilient. The document provides detailed information on the morphology, varieties, and management of coffee plants. It describes the plant structure including leaves, flowers, fruits, and berries and lists commercially important Arabica and Robusta varieties. It also includes a monthly management time table outlining operations such as harvesting, pruning, pest control, and nursery activities.
Capsicum annuum, commonly known as chilli pepper, is an important crop cultivated worldwide for use as a spice, vegetable, and ornamental. It is rich in vitamins C and A. Chilli peppers show variation in shape, color, size, and pungency depending on variety and region. India is the largest producer of chillies, with the states of Andhra Pradesh, Maharashtra, Karnataka, Odisha, and Tamil Nadu accounting for over 70% of national acreage. Chillies have various economic uses as food flavoring, medicine, and natural colorants.
Production of synthetic seed involves encapsulating somatic embryos, shoot buds, or cell aggregates using tissue culture techniques. This allows for the large-scale, low-cost propagation of plants while maintaining genetic uniformity. Synthetic seeds can be stored longer than traditional seeds and planted directly in fields without the need for transplanting. While synthetic seeds have advantages over traditional micropropagation methods, their production and germination rates can still be limited for some plant species.
Shoot tip culture is a plant tissue culture technique used to produce virus-free plants by culturing the meristematic tissue at the tip of a plant shoot. This allows production of new plants that are genetically identical to the donor plant but free of viruses, as viruses are unable to move between cells in the meristem. The protocol involves surface sterilizing and culturing shoot tip explants less than 1mm on agar media, with stages of culture establishment, shoot proliferation, and root regeneration using cytokinins and auxins. Shoot tip culture has applications in micropropagation, storage of plant genetic resources, quarantining imported plant materials, and eliminating viruses from infected plants.
Somatic embryogenesis is the process where embryos form from somatic (non-reproductive) plant cells in vitro. It is an important biotechnological tool that allows for clonal propagation, genetic transformation, and other applications. The first observation of somatic embryogenesis was in carrot cells in 1958. Somatic embryogenesis occurs through direct or indirect pathways and involves induction, development, and maturation stages. It has advantages over zygotic embryogenesis like a higher propagation rate and applications in synthetic seed production and genetic engineering.
Tissue culture is a method of biological research where plant tissues are grown under sterile conditions. There are several methods of plant tissue culture including seed culture, embryo culture, callus culture, cell culture, bud culture, meristem culture, and protoplast culture. Each method involves explants from various plant tissues being placed on nutrient media to induce cell growth and differentiation. Tissue culture has many applications including rapid clonal propagation, inducing genetic variation, producing transgenic plants, and conserving plant genetic resources.
More from Kottakkal farook arts and science college (20)
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
Digital Artefact 1 - Tiny Home Environmental Design
ER.pptx
1. • Endoplasmic reticulum (ER) is a vast network of membrane-bound,
branching and interconnecting tubules, vesicles and flattend sacs,
irregularly distributed in the cytoplasmic matrix.
• With the exception of prokaryotes and mature mammalian erythrocytes, it is
present in almost all kinds of cells.
• It is only poorly developed in egg cells, sperm cells and undifferentiated and
rapidly dividing embryonic cells and cancer cells.
• Generally, it is very simple in those cells which actively engage in lipid
metabolism (e.g., adipose cells, brown fat cells, adrenocortical cells, etc.),
but complex and extensive in protein synthetically active cells.
3. Discovery
• The first fruitful investigations about ER were made by Garnier (1897).
• He could observe a basophilic fibrillar material in stained cells.
• It was later on termed ergastoplasm.
• With the help of electron microscope, Porter, Thompson, Claude and
Fullam (1945) observed a lace-like network of membranes within the
cytoplasm.
• It was termed endoplasmic reticulum by Porter and Kallman (1952).
4. Morphology
• ER is a complex system of membrane-bound spaces.
• These spaces are filled with a fluid,. rich in enzymes, metabolites and synthetic
products.
• There are two kinds of ER, namely granular or rough -surfaced ER (RER) and
agranular or smooth-surfaced ER (SER).
• RER has attached ribosomes, and SER has no attached ribosomes.
• RER is the major location for the synthesis of secretory or export proteins and
the protein constituents of ER.
• It is mainly concerned with the assembling, storage, processing and export of
secretory proteins.
• So, it is most extensive in cells which are active in the synthesis of secretory
proteins (e.g., enzyme-secreting cells, liver cells, pancreatic acinar cells).
5.
6. • SER is mainly concerned with the synthesis of non-protein substances, mainly
lipids (such as (glycerides, glycolipids, phospholipids, sterols, etc.).
• It is also involved in the chemical modification of low molecular weight
substances (e.g., modification of sterols to steroid hormones), cellular
detoxification mechanisms and the formation of transport vesicles, which
carry proteins and lipids to Golgi bodies for chemical processing and
packaging.
• So, it predominantly occurs in cells, which actively engage in the synthesis of
lipids (e.g., adipose cells, interstitial cells of testis, adrenocortical cells, etc.).
7. • ER exists in three morphologically different forms, namely lamellae, vesicles and
tubules.
• Lamellae are unbranched and flattened sacs, arranged in parallel stacks. Their
internal lumen is called cisterna.
• Vesicles are closed oval or rounded sacs. They are found in large numbers in liver
cells and pancreatic cells.
• Tubules are branching and interconnecting units, much abundant in cells which are
active in the synthesis of steroids.
• Vesicles and tubules are mostly agranular, whereas lamellae are granular.
• The lamellar and tubular units may merge together to form a continuous network.
When cells are homogenized, their ER may get fragmented.
• These fragments soon get reorganized forming small vesicles, called microsomes.
• Quite often, the components of ER perform sweeping movements within the cell.
• This brings about the distribution of substances and the molecular exchanges
between the cytoplasmic matrix and the contents of ER.
8.
9.
10. Chemical make-up and molecular
organization of ER
• The membranes of ER have lipoprotein composition and fluid-mosaic organization.
• They are formed mostly of phospholipids, cholesterol and intrinsic and extrinsic
proteins.
• Phospholipids form a bilayer.
• Cholesterol binds with this bilayer to form a stable complex.
• Intrinsic proteins partially or completely penetrate the lipid bilayer, whereas
extrinsic proteins remain entirely outside the lipid bilayer.
• Intrinsic proteins are mostly structural, and extrinsic proteins are mostly enzymatic.
• There are two characteristic transmembrane structural glycoproteins in the RER,
namely ribophorins I & II (absent in SER).
• They serve as the binding sites for ribosomes, and also mediate the binding of
ribosome with RER.
• Ribophorins interact with each other and form a network within the membrane to
control the distribution of ribosome binding sites.
11.
12. • The protein to lipid ratio is much higher, and the cholesterol content is very low
in the ER membranes than in plasma membrane.
• The high protein content (50-70%) gives the membrane structural stability
(possibly by immobilizing most of the amphipathic lipid molecules), and the low
lipid content makes the membrane less fluid.
• ER membranes do not have lamellar organization every where.
• In some regions they are lamellar, and in some other parts micellar (globular).
• Micellar regions are probably the dynamic regions of fission and fusion.
• The combination of lamellar and micellar organization may permit drastic
changes in the surface area of the membrane.
13. Biogenesis
• The origin of ER is not clearly understood.
• Still, it is believed that a cell receives a full set of membranes from its
parent cell, and also that ER is "budded" off from nuclear envelope by
a process of evagination (the nuclear envelope, in turn, is believed to
take its origin from vesicular ER during telophase).
• RER is believed to appear first, and later it gives rise to SER.
14. • The biogenesis of ER involves two major steps, namely membrane synthesis
and membrane differentiation.
• The former involves the initial synthesis of a basic framework of lipids and
intrinsic proteins, and the latter involves the chemical modification of this
framework by the incorporation of additional constituents.
• Membrane differentiation includes structural and functional modifications.
Structural modification includes the incorporation of structural lipids and
proteins.
• Functional modification includes the introduction of enzymes and other
functional proteins and some specific sugars.
• Evidences suggest that the introduction of each kind of molecule is
independent of the others.
• Most of the ER proteins are synthesised on the ER-bound ribosomes, and a few
on free cytoribosomes.
15. • The budding of ER from nuclear envelope a outer nuclear membrane
gives out finger-shaped off and get into the cytosol and form vesicles
called blebs. This is called blebbing.
• Blebs soon migrate to the periphery of the cell, get arranged in rows
and fuse to form stack of double membrane sheets, called annulate
lamellae.
• These lamellae are similar to the nuclear envelope in having pores,
annuli and annular and central granules.
• They probably represent an intermediate stage in the formation of ER.
• Gradually, they lose their pores, get studded with attached ribosomes,
and then transform to RER.
16.
17.
18. Enzymatic properties
• The fluid that fills the lumen of ER contains a variety of enzymes
which, in general, are concerned with the following functions:
• (i) synthesis of glycerides, fatty acids, phospholipids, glycolipids and
steroids
• (ii) metabolism of plasmalogens (a kind of phospholipids)
• (iii) steroid transformation, aromatisation, hydroxylation,
deamination, thioester oxidation, drug detoxification, etc.
• (iv) dephosphorylation of UDP glucose.
19. Functions
• ER is actively involved in several mechanical and physiological functions
of the cell.
• Its major functions are the following:
• (i) Provides a structural framework and a supplementary mechanical
support to the colloidal cytoplasmic matrix, and also serves as an
intracellular transport system.
• (ii) Segregation, distribution and association of enzyme systems.
• (iii) Collection, storage, chemical processing and intracellular transport
of secretory proteins.
• (iv) Regulation of the intracellular exchange of materials, probably by
serving as diffusion barriers.
20.
21. • (v) Regulation of ionic gradients, membrane potential and intracellular pH.
• (vi) Synthesis of phospholipids, lipoproteins, glycerides, sterols, steroid
hormones, bile acids, etc. (by SER).
• (vii) Chemical processing of nascent polypeptides (by RER)
• (viii) Glycosylation (complexing with oligosaccharides) of nascent proteins to
form glycoproteins, with the help of the enzyme oligosaccharyl transferase.
• (ix) Selective uptake, storage and release of Cat and the intracellular
transmission of impulses in striated muscles (by sarcoplasmic reticulum).
• (x) Secretion of chloride ions in the oxyntic (acid - secreting) parietal cells of
the gastric glands of vertebrate animals.
22. • .(xi) Enzymatic detoxification of harmful exogenous or endogenous substances
(by SER), mainly lipid-soluble poisons, drugs, anaesthetics, insecticides,
petroleum products, carcinogens, etc.
• (xii) Metabolism of vitamin A and the synthesis of visual pigments from it (in
the retinal cells of vertebrate animals).
• (xiii) Transport of RNAs and ribonucleoproteins from nucleus to cytoplasm.
• (xiv) Enzymatic dephosphorylation of glucose-6 phosphate to form free
glucose (glucogenesis), with the help of the enzyme glucose-6 phosphatase.
• (xv) Enzymatic detoxification of toxic metabolic products and drugs and lipid-
soluble poisons (in SER).
23. Sarcoplasmic reticulum(SR)
• SR is the extensive network of specialized SER, found in striated muscles.
• It consists of extensively branched membranous sacs, which enclose spaces
comparable to the cisternae of ER.
• SR surrounds each myofibril.
• At the two ends of each sarcomere (muscle segment), it bears expansions called
terminal cisternae.
• Typically, SR consists of three components, namely transverse, longitudinal and
junctional.
• The transverse component, also called T-system, is connected to the plasma
membrane of the muscle cell.
• The longitudinal component surrounds the muscle cell, and the junctional
component connects together the other two components.
• SR is mainly concerned with the storage of Ca++ ions.
• When the muscle is in the unexcited resting state, its membranes are impermeable to
Cat+ ions.
24.
25.
26. • Then the longitudinal component of the SR takes up Ca ions from the cytosol
by an active transport mechanism, called calcium pump or calcium - ATPase
transport system.
• These Ca ions are stored in the SR with the help of calcium-binding proteins.
• When the muscle fibres get excited by a nerve impulse, the calcium-
permeability of their SR increases and the calcium pump stops functioning.
• As a result, the Ca ions, stored in the cisternae of SR, are quickly released to
the sarcoplasm as a second messenger.
• This triggers muscular contraction. Once the elicitation of the nerve impulse
stops, the membranes of the SR quickly become impermeable to Ca ions.
• Now, calcium pump operates again, resulting in the accumulation of Ca++ ions
in the SR and the relaxation of the muscle.
• One ATP molecule is spent for the active transport of two Ca ions into the SR.