The document provides information about the basic structures and functions of plant and animal cells. It describes the key components of the cell and their roles, including the cell membrane, cell wall, nucleus, mitochondria, endoplasmic reticulum, ribosomes, Golgi apparatus, plastids, vacuoles, and centrioles. It also compares the structures of plant and animal cells and explains various processes involved in cell transport, such as diffusion, osmosis, and active transport.
The document discusses cell membrane structure and function. It describes the cell membrane as a semi-permeable barrier made of lipids and proteins that surrounds the cell cytoplasm. The membrane regulates what enters and exits the cell and helps maintain its shape. Substances can pass through the membrane through diffusion, osmosis, facilitated transport, active transport, endocytosis, and exocytosis. The membrane plays a key role in cellular processes and transport.
This document provides an overview of the structure and functions of human cells. It begins with an introduction to cell theory and the basic components of the cell, including the nucleus, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, and lysosomes. It then discusses cell membrane structure and transport of substances across the membrane via passive and active transport. The document concludes with explanations of the cell's functions and the process of cell division through mitosis and cytokinesis.
The document summarizes key aspects of cell structure and function. It describes cells as the basic unit of life and outlines several organelles and their functions, including the cell membrane, nucleus, mitochondria and lysosomes. It also explains the process of cell division through mitosis, where a parent cell replicates its DNA and other components before dividing into two identical daughter cells through the phases of interphase, prophase, metaphase, anaphase and telophase.
The document provides an overview of cell structure and function. It discusses the key discoveries and principles of cell theory. The main components of cells are then described, including the plasma membrane, cytoplasm, cytoskeleton, organelles, and cell walls. Specific organelles like the nucleus, mitochondria, chloroplasts, and Golgi apparatus are explained. The processes of passive transport, active transport, endocytosis, and exocytosis are also summarized.
The document provides information about cell membranes and transport across cell membranes. It defines that cell membranes are made of a lipid bilayer and contain embedded proteins. The key functions of the cell membrane are to regulate what enters and leaves the cell. There are two main types of transport - passive transport, which doesn't require energy and includes diffusion, osmosis, and facilitated diffusion, and active transport, which requires energy and includes endocytosis, exocytosis, and pumps. Passive transport moves molecules down a concentration gradient, while active transport moves molecules against a concentration gradient using cellular energy.
The document provides information about cell membranes and transport across cell membranes. It defines that cell membranes are made of a lipid bilayer and contain embedded proteins. The key functions of the cell membrane are to regulate what enters and leaves the cell. There are two main types of transport - passive transport, which doesn't require energy and includes diffusion, osmosis, and facilitated diffusion, and active transport, which requires energy and includes endocytosis, exocytosis, and molecular transport via pumps. Osmosis is the diffusion of water across the membrane, and can result in cells becoming turgid, plasmolyzed, or bursting depending on the solution concentration.
The cell membrane is composed of phospholipids and proteins that give it a selective permeability. It regulates the flow of substances into and out of the cell. Passive transport uses diffusion and requires no energy, while active transport moves substances against a concentration gradient using ATP. The endomembrane system includes the ER, Golgi apparatus and lysosomes to modify and transport cellular products. Mitochondria produce energy in the form of ATP through cellular respiration. The cytoskeleton, made of microtubules, microfilaments and intermediate filaments, maintains the cell's structure and transports materials within the cell. The nucleus contains the cell's DNA and controls its activities.
STEM General Biology 1: The Cells
Cell Theory
Cell Structures and Functions
Prokaryotes vs. Eukaryotes
Animal vs. Plant Cells
Cell Modification
Movement of Molecules in Cells
The document discusses cell membrane structure and function. It describes the cell membrane as a semi-permeable barrier made of lipids and proteins that surrounds the cell cytoplasm. The membrane regulates what enters and exits the cell and helps maintain its shape. Substances can pass through the membrane through diffusion, osmosis, facilitated transport, active transport, endocytosis, and exocytosis. The membrane plays a key role in cellular processes and transport.
This document provides an overview of the structure and functions of human cells. It begins with an introduction to cell theory and the basic components of the cell, including the nucleus, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, and lysosomes. It then discusses cell membrane structure and transport of substances across the membrane via passive and active transport. The document concludes with explanations of the cell's functions and the process of cell division through mitosis and cytokinesis.
The document summarizes key aspects of cell structure and function. It describes cells as the basic unit of life and outlines several organelles and their functions, including the cell membrane, nucleus, mitochondria and lysosomes. It also explains the process of cell division through mitosis, where a parent cell replicates its DNA and other components before dividing into two identical daughter cells through the phases of interphase, prophase, metaphase, anaphase and telophase.
The document provides an overview of cell structure and function. It discusses the key discoveries and principles of cell theory. The main components of cells are then described, including the plasma membrane, cytoplasm, cytoskeleton, organelles, and cell walls. Specific organelles like the nucleus, mitochondria, chloroplasts, and Golgi apparatus are explained. The processes of passive transport, active transport, endocytosis, and exocytosis are also summarized.
The document provides information about cell membranes and transport across cell membranes. It defines that cell membranes are made of a lipid bilayer and contain embedded proteins. The key functions of the cell membrane are to regulate what enters and leaves the cell. There are two main types of transport - passive transport, which doesn't require energy and includes diffusion, osmosis, and facilitated diffusion, and active transport, which requires energy and includes endocytosis, exocytosis, and pumps. Passive transport moves molecules down a concentration gradient, while active transport moves molecules against a concentration gradient using cellular energy.
The document provides information about cell membranes and transport across cell membranes. It defines that cell membranes are made of a lipid bilayer and contain embedded proteins. The key functions of the cell membrane are to regulate what enters and leaves the cell. There are two main types of transport - passive transport, which doesn't require energy and includes diffusion, osmosis, and facilitated diffusion, and active transport, which requires energy and includes endocytosis, exocytosis, and molecular transport via pumps. Osmosis is the diffusion of water across the membrane, and can result in cells becoming turgid, plasmolyzed, or bursting depending on the solution concentration.
The cell membrane is composed of phospholipids and proteins that give it a selective permeability. It regulates the flow of substances into and out of the cell. Passive transport uses diffusion and requires no energy, while active transport moves substances against a concentration gradient using ATP. The endomembrane system includes the ER, Golgi apparatus and lysosomes to modify and transport cellular products. Mitochondria produce energy in the form of ATP through cellular respiration. The cytoskeleton, made of microtubules, microfilaments and intermediate filaments, maintains the cell's structure and transports materials within the cell. The nucleus contains the cell's DNA and controls its activities.
STEM General Biology 1: The Cells
Cell Theory
Cell Structures and Functions
Prokaryotes vs. Eukaryotes
Animal vs. Plant Cells
Cell Modification
Movement of Molecules in Cells
The cell membrane is a phospholipid bilayer with embedded proteins that surrounds the cell. It functions to control what enters and exits the cell to maintain homeostasis and provides protection. The phospholipids form a lipid bilayer with hydrophilic phosphate heads and hydrophobic fatty acid tails. Proteins are embedded in the membrane. The cell membrane is selectively permeable, allowing passive diffusion of small molecules and facilitated diffusion of larger molecules through transport proteins. Active transport uses ATP to move molecules against their concentration gradient.
IT IS PPT ABOUT CELL MEMBRANE AFSHADFBHJADFKJDFBHJADFBHJDAFJHDFBVHCDBHJDJHDFSBHDFSJDFSHBJDFABHJDFSHJHDFSBJDFSBJDFSHJKDSFHJDFASKHFDSHJDFSKHKHKHFDSKHDFSKHDFSKHKDFHSKHDFSKHFSKHDFSKH
There are approximately 75 trillion cells in the human body that are derived from a single fertilized egg. The cell membrane maintains the integrity of the cell and is selectively permeable, controlling what moves in and out. It consists of a phospholipid bilayer, membrane proteins, and cholesterol. Transport across the membrane can occur through passive diffusion, facilitated diffusion, osmosis, and filtration. Active transport uses cellular energy and includes processes like endocytosis, exocytosis, and transcytosis. The basic stages of the cell cycle are interphase, mitosis, and cytokinesis.
1. Cells are the smallest living units that make up all living things. All cells arise from preexisting cells according to cell theory.
2. Eukaryotic cells contain membrane-bound organelles and a nucleus, while prokaryotic cells like bacteria lack these structures. Key organelles include the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles.
3. Molecules and ions move across the plasma membrane through passive transport mechanisms like diffusion, osmosis, and facilitated diffusion which require no energy, or through active transport which requires energy from processes like the sodium-potassium pump.
The document summarizes key aspects of cell membrane structure and function. It describes the fluid mosaic model, including that membranes are made of phospholipids, cholesterol, proteins and carbohydrates. It explains different types of membrane transport - diffusion, facilitated diffusion, osmosis, active transport. Diffusion and osmosis rely on concentration gradients but active transport works against gradients using protein carriers and ATP. Membrane transport controls exchange of materials and signals between cells and their environments.
The fundamental unit of life is cell. It is briefly explained about it in this ppt , actually you can read this for school exams too. Thank you please leave a like
- Cells are the smallest living units that make up all living things. All cells come from pre-existing cells.
- Cells can be either prokaryotic or eukaryotic. Eukaryotic cells contain a nucleus and membrane-bound organelles, while prokaryotic cells do not have a nucleus or membrane-bound organelles.
- Organelles such as the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles allow cells to carry out specialized functions and processes like respiration, photosynthesis, protein transport, and waste removal.
- Cells are the smallest living units that make up all living things. All cells come from pre-existing cells.
- Cells can be either prokaryotic or eukaryotic. Eukaryotic cells contain membrane-bound organelles and a nucleus, while prokaryotic cells do not.
- Organelles such as the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles allow cells to carry out specialized functions and processes like respiration, photosynthesis, protein transport, and waste removal.
- Molecules can move across the cell membrane through passive transport mechanisms like diffusion, osmosis, and facilitated diffusion which do not require
- Cells are the smallest living units that make up all living things. All cells come from pre-existing cells.
- Cells can be either prokaryotic or eukaryotic. Eukaryotic cells contain a nucleus and membrane-bound organelles, while prokaryotic cells do not have a nucleus or membrane-bound organelles.
- Organelles such as the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles perform specific functions to keep the cell alive.
- Cells are the smallest living units that make up all living things. All cells come from pre-existing cells.
- Cells can be either prokaryotic or eukaryotic. Eukaryotic cells contain membrane-bound organelles and a nucleus, while prokaryotic cells do not.
- Organelles such as the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles allow cells to carry out specialized functions and processes like respiration, photosynthesis, protein transport, and waste removal.
- Molecules can move across the cell membrane through passive transport mechanisms like diffusion, osmosis, and facilitated diffusion which do not require
The document summarizes the structure and functions of cell membranes. It describes the fluid mosaic model, which states that membranes are made of phospholipids and proteins that can move about freely. Phospholipids form a bilayer with hydrophobic tails facing inward and hydrophilic heads outward. Membrane proteins are either integral proteins spanning the membrane or peripheral proteins attached to one surface. The document also explains various transport mechanisms like diffusion, facilitated diffusion, osmosis, active transport, and bulk transport across membranes.
The plasma membrane separates a cell's internal environment from the outside world. It is made up of a phospholipid bilayer with integral and peripheral proteins embedded. The fluid mosaic model describes the plasma membrane as a fluid combination of lipids and proteins that can freely move about. Materials pass through the membrane via passive diffusion, facilitated diffusion, osmosis, and active transport. Large particles and molecules enter and exit the cell through endocytosis and exocytosis.
Cell is the basic structural and functional unit of all living organisms. It contains cytoplasm surrounded by a cell membrane, which encloses the nucleus and various organelles. Within the cytoplasm are membrane-bound structures like mitochondria and chloroplasts that carry out specialized functions. Multiple cells form tissues, which combine to create organs that work together in organ systems to carry out vital functions in the body.
Structure and functions of cell, transport across cell membrane, cell
division, cell junctions. General principles of cell communication,
the smallest unit that can live on its own and that makes up all living organisms and the tissues of the body
The basic tenets of the cell theory are as follows:
All living things are made up of one or more cells.
The cell is the structural and functional unit of all living things.
Cells come from pre-existing cells through the process of division.
All cells are the same in regard to chemical composition.
Cells also communicate with each other. Whether in plants, humans, or animals, they connect to create a solid, well formed organism. In humans, cells build tissues, tissues form organs, and organs work together to keep the body alive.
Experts estimate that there are around 200Trusted Source cell types in the human body.
The cell membrane regulates what enters and exits the cell through selective permeability. It is composed of a phospholipid bilayer with hydrophobic tails facing inward and hydrophilic heads outward. Membrane proteins perform various functions like identification, signaling, catalysis, and transport. Substances move across the membrane through passive diffusion down a concentration gradient or active transport against a gradient using ATP. Water moves through osmosis, entering cells in hypotonic solutions and leaving in hypertonic solutions. Cells specialize and communicate to maintain homeostasis in multicellular organisms.
The cell membrane separates the components of a cell from its environment and regulates what passes in and out through passive and active transport. Passive transport includes diffusion, facilitated diffusion, and osmosis, and moves particles from high to low concentration without energy. Active transport requires energy to move particles from low to high concentration against the gradient. Some cells also have a cell wall providing structure and protection to plant, fungi, and bacteria cells.
The cell membrane separates the components of a cell from its environment and regulates what passes in and out through passive and active transport. Passive transport includes diffusion, facilitated diffusion, and osmosis, and moves particles from high to low concentration without energy. Active transport requires energy to move particles from low to high concentration against the gradient. Some cells also have a cell wall providing structure and protection to plant, fungi, and bacteria cells.
This document provides information about the structure and functions of eukaryotic cells. It discusses the key organelles found in cells like the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria, and cytoskeleton. It explains their roles and comparative differences between prokaryotic and eukaryotic cells. Additionally, it covers the plasma membrane structure and fluid mosaic model. Finally, it summarizes different cell transport mechanisms including passive transport processes like diffusion, facilitated diffusion, and osmosis as well as active transport mechanisms like protein pumps, endocytosis, and exocytosis.
The cell membrane regulates what enters and exits the cell. It is a phospholipid bilayer with proteins embedded. Materials move across the membrane through passive diffusion, facilitated diffusion, or active transport using protein channels and pumps. Water moves across the membrane through osmosis to equalize its concentration gradient. Large particles enter through endocytosis using vesicles formed from the membrane.
The cell membrane is a phospholipid bilayer with embedded proteins that surrounds the cell. It functions to control what enters and exits the cell to maintain homeostasis and provides protection. The phospholipids form a lipid bilayer with hydrophilic phosphate heads and hydrophobic fatty acid tails. Proteins are embedded in the membrane. The cell membrane is selectively permeable, allowing passive diffusion of small molecules and facilitated diffusion of larger molecules through transport proteins. Active transport uses ATP to move molecules against their concentration gradient.
IT IS PPT ABOUT CELL MEMBRANE AFSHADFBHJADFKJDFBHJADFBHJDAFJHDFBVHCDBHJDJHDFSBHDFSJDFSHBJDFABHJDFSHJHDFSBJDFSBJDFSHJKDSFHJDFASKHFDSHJDFSKHKHKHFDSKHDFSKHDFSKHKDFHSKHDFSKHFSKHDFSKH
There are approximately 75 trillion cells in the human body that are derived from a single fertilized egg. The cell membrane maintains the integrity of the cell and is selectively permeable, controlling what moves in and out. It consists of a phospholipid bilayer, membrane proteins, and cholesterol. Transport across the membrane can occur through passive diffusion, facilitated diffusion, osmosis, and filtration. Active transport uses cellular energy and includes processes like endocytosis, exocytosis, and transcytosis. The basic stages of the cell cycle are interphase, mitosis, and cytokinesis.
1. Cells are the smallest living units that make up all living things. All cells arise from preexisting cells according to cell theory.
2. Eukaryotic cells contain membrane-bound organelles and a nucleus, while prokaryotic cells like bacteria lack these structures. Key organelles include the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles.
3. Molecules and ions move across the plasma membrane through passive transport mechanisms like diffusion, osmosis, and facilitated diffusion which require no energy, or through active transport which requires energy from processes like the sodium-potassium pump.
The document summarizes key aspects of cell membrane structure and function. It describes the fluid mosaic model, including that membranes are made of phospholipids, cholesterol, proteins and carbohydrates. It explains different types of membrane transport - diffusion, facilitated diffusion, osmosis, active transport. Diffusion and osmosis rely on concentration gradients but active transport works against gradients using protein carriers and ATP. Membrane transport controls exchange of materials and signals between cells and their environments.
The fundamental unit of life is cell. It is briefly explained about it in this ppt , actually you can read this for school exams too. Thank you please leave a like
- Cells are the smallest living units that make up all living things. All cells come from pre-existing cells.
- Cells can be either prokaryotic or eukaryotic. Eukaryotic cells contain a nucleus and membrane-bound organelles, while prokaryotic cells do not have a nucleus or membrane-bound organelles.
- Organelles such as the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles allow cells to carry out specialized functions and processes like respiration, photosynthesis, protein transport, and waste removal.
- Cells are the smallest living units that make up all living things. All cells come from pre-existing cells.
- Cells can be either prokaryotic or eukaryotic. Eukaryotic cells contain membrane-bound organelles and a nucleus, while prokaryotic cells do not.
- Organelles such as the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles allow cells to carry out specialized functions and processes like respiration, photosynthesis, protein transport, and waste removal.
- Molecules can move across the cell membrane through passive transport mechanisms like diffusion, osmosis, and facilitated diffusion which do not require
- Cells are the smallest living units that make up all living things. All cells come from pre-existing cells.
- Cells can be either prokaryotic or eukaryotic. Eukaryotic cells contain a nucleus and membrane-bound organelles, while prokaryotic cells do not have a nucleus or membrane-bound organelles.
- Organelles such as the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles perform specific functions to keep the cell alive.
- Cells are the smallest living units that make up all living things. All cells come from pre-existing cells.
- Cells can be either prokaryotic or eukaryotic. Eukaryotic cells contain membrane-bound organelles and a nucleus, while prokaryotic cells do not.
- Organelles such as the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles allow cells to carry out specialized functions and processes like respiration, photosynthesis, protein transport, and waste removal.
- Molecules can move across the cell membrane through passive transport mechanisms like diffusion, osmosis, and facilitated diffusion which do not require
The document summarizes the structure and functions of cell membranes. It describes the fluid mosaic model, which states that membranes are made of phospholipids and proteins that can move about freely. Phospholipids form a bilayer with hydrophobic tails facing inward and hydrophilic heads outward. Membrane proteins are either integral proteins spanning the membrane or peripheral proteins attached to one surface. The document also explains various transport mechanisms like diffusion, facilitated diffusion, osmosis, active transport, and bulk transport across membranes.
The plasma membrane separates a cell's internal environment from the outside world. It is made up of a phospholipid bilayer with integral and peripheral proteins embedded. The fluid mosaic model describes the plasma membrane as a fluid combination of lipids and proteins that can freely move about. Materials pass through the membrane via passive diffusion, facilitated diffusion, osmosis, and active transport. Large particles and molecules enter and exit the cell through endocytosis and exocytosis.
Cell is the basic structural and functional unit of all living organisms. It contains cytoplasm surrounded by a cell membrane, which encloses the nucleus and various organelles. Within the cytoplasm are membrane-bound structures like mitochondria and chloroplasts that carry out specialized functions. Multiple cells form tissues, which combine to create organs that work together in organ systems to carry out vital functions in the body.
Structure and functions of cell, transport across cell membrane, cell
division, cell junctions. General principles of cell communication,
the smallest unit that can live on its own and that makes up all living organisms and the tissues of the body
The basic tenets of the cell theory are as follows:
All living things are made up of one or more cells.
The cell is the structural and functional unit of all living things.
Cells come from pre-existing cells through the process of division.
All cells are the same in regard to chemical composition.
Cells also communicate with each other. Whether in plants, humans, or animals, they connect to create a solid, well formed organism. In humans, cells build tissues, tissues form organs, and organs work together to keep the body alive.
Experts estimate that there are around 200Trusted Source cell types in the human body.
The cell membrane regulates what enters and exits the cell through selective permeability. It is composed of a phospholipid bilayer with hydrophobic tails facing inward and hydrophilic heads outward. Membrane proteins perform various functions like identification, signaling, catalysis, and transport. Substances move across the membrane through passive diffusion down a concentration gradient or active transport against a gradient using ATP. Water moves through osmosis, entering cells in hypotonic solutions and leaving in hypertonic solutions. Cells specialize and communicate to maintain homeostasis in multicellular organisms.
The cell membrane separates the components of a cell from its environment and regulates what passes in and out through passive and active transport. Passive transport includes diffusion, facilitated diffusion, and osmosis, and moves particles from high to low concentration without energy. Active transport requires energy to move particles from low to high concentration against the gradient. Some cells also have a cell wall providing structure and protection to plant, fungi, and bacteria cells.
The cell membrane separates the components of a cell from its environment and regulates what passes in and out through passive and active transport. Passive transport includes diffusion, facilitated diffusion, and osmosis, and moves particles from high to low concentration without energy. Active transport requires energy to move particles from low to high concentration against the gradient. Some cells also have a cell wall providing structure and protection to plant, fungi, and bacteria cells.
This document provides information about the structure and functions of eukaryotic cells. It discusses the key organelles found in cells like the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria, and cytoskeleton. It explains their roles and comparative differences between prokaryotic and eukaryotic cells. Additionally, it covers the plasma membrane structure and fluid mosaic model. Finally, it summarizes different cell transport mechanisms including passive transport processes like diffusion, facilitated diffusion, and osmosis as well as active transport mechanisms like protein pumps, endocytosis, and exocytosis.
The cell membrane regulates what enters and exits the cell. It is a phospholipid bilayer with proteins embedded. Materials move across the membrane through passive diffusion, facilitated diffusion, or active transport using protein channels and pumps. Water moves across the membrane through osmosis to equalize its concentration gradient. Large particles enter through endocytosis using vesicles formed from the membrane.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
4. CELL WALL
• Not considered part of living protoplasm
• Formed by the cell membrane on the outside
• Consists of cellulose with other carbohydrates:
• Primary cell wall – pectin (sugary substance)
• Secondary cell wall – lignin (woody substance) or suberin
(waterproof substance)
• Functions include support, shape and protection
5. Plasmodesmata – thin cytoplasmic
threads connecting adjacent cells
can occur through…
Pits – gaps in the cell wall
6. CELL MEMBRANE
• Very thin, outer living boundary (part of protoplasm)
• Controls the movement of substances into and out of the cell =
semi/selectively permeable
• ‘Fluid Mosaic Model’ used to describe structure of membrane
7.
8. Fluid Mosaic Model:
• Cell membrane consists of a double layer of
phospholipid molecules that consist of two parts:
- The head (phosphate) faces outwards & attracts water
(hydrophilic) as it is polar
- The tail (2 fatty acid chains) faces inwards & repels water
(hydrophobic) as it is non-polar
• Embedded in & on top of these layers are protein
molecules some of which are carrier & channel
proteins (glucose, amino acids, salts, nucleic acids)
• The cell membrane is NOT static as all the
molecules move around – hence ‘fluid’
9.
10. NUCLEUS
• Controls and directs all cellular functions
• Passes hereditary characteristics from one generation
to the next
11. Diagram of a nucleus
Draw the
diagram
following the
biological
drawing rules!
12.
13. MITOCHONDRION
Plural = mitochondria
• Sites of cellular respiration
• Provides the cell with energy (ATP is the energy-carrier)
• Adaptations:
• Has many respiratory enzymes to speed up the process
• Inner membrane is folded to fit a lot of respiratory enzymes
14. Diagram of a mitochondrion
Draw the
diagram
following the
biological
drawing rules!
15.
16. ENDOPLASMIC RETICULUM
• Membranous network that forms a
continuous system of canals
throughout cytoplasm
• Connected to the cell membrane &
nuclear membrane; associated with
the golgi apparatus
• Two types:
• Rough ER has ribosomes
• Smooth ER has no ribosomes
17. • The ER transports substances
from one part of the
cytoplasm to another
• It increases internal surface
area of the cell
• It plays a role in protein
synthesis due to ribosomes
18.
19.
20. RIBOSOMES
• Small, spherical structures
• Consist of RNA & proteins
• Occur in the ER, mitochondria,
chloroplasts & in cytoplasm
• Sites of protein synthesis – amino
acids join to form a protein
21.
22. GOLGI APPARATUS
• A.k.a. golgi body or dictysome
• Consists of stacks of hollow, flat
membrane sacs known as cisternae
• Produces & processes secretions
(mucus, saliva)
• Plays a role in formation of lysosomes
• Prepares proteins for transport to other
parts of the cell
23.
24. PLASTIDS
• Organelles that occur only in plant cells
• Three types:
1. Chloroplasts
2. Chromoplasts
3. Leucoplasts
25. CHLOROPLASTS
• Occurs in photosynthesizing parts
of plants (leaves)
• Green pigment chlorophyll
absorbs light
• Sites of photosynthesis
26. Diagram of a chloroplast
Draw the
diagram
following the
biological
drawing rules!
37. VACUOLES
• Fluid-filled compartments in the
cytoplasm
• Enclosed by a semi-permeable
membrane – tonoplast
• The fluid – cell sap, contains water
& dissolved substances
• Plant cell vacuoles are large &
prominent
• Animal cell vacuoles are small or
absent
38.
39. In plant cells…
• Cell sap in the vacuole causes a pressure against the cell
wall that gives the plant cell rigidity – turgor pressure
40. Other types of vacuoles
1. Contractile vacuoles
• Occurs in unicellular organisms
• Functions in osmoregulation (water balance)
2. Lysosomes
• Occurs only in animal cells
• Filled with digestive enzymes
• Functions in protection of cell & intracellular
digestion
41. 3. Phagosomes
(food vacuoles)
• Occurs in unicellular
organisms
• Functions in digestion &
storage of food
• Fuses with lysosome to digest
4. Vesicles
• Transports substances from
Golgi body to other parts
inside or outside of cell
42. CENTRIOLES
• Cylinder-shaped organelle made of
microtubules
• Only occurs in animal cells
• Found in an area near the nucleus
called the centrosome
• Two centrioles lie at 90° angle to
each other
• Functions in the formation of
spindle during mitosis (cell division)
45. PLANT ANIMAL
Have plastids Do not have plastids
Have cell wall (made of cellulose) Do not have cell wall
Have large, central vacuole Have small, temporary vacuoles (if any)
May have plasmodesmata Do not have plasmodesmata
Do not have centrioles Have paired centrioles within centrosome
Generally have a fixed, regular shape Generally have an amorphous, irregular shape
Table comparing the difference between plant and animal cells
46. MOVEMENT OF SUBSTANCES
• Cells and the fluid that surrounds them are mostly water,
with other substances dissolved in them
• A solute is a substance that is dissolved in a solvent
Eg. The salt
• A solvent is a liquid that can dissolve substances
Eg. The water
• A solution is a liquid that has substances dissolved in it.
Eg. The salt water
47. Substances move across cell membranes by
passive transport (no energy) or active transport (takes energy)
• Types of passive transport:
1.Diffusion
2.Facilitated Diffusion
3.Osmosis
• Types of active transport:
1.Using ion pumps
2.Bulk Transport
48. Diffusion
• Diffusion is the movement of dissolved solutes or gases from
an area of high concentration to an area of low concentration
(down a concentration gradient)
• It occurs because molecules always spread out evenly into
the available space
• Small molecules such as Oxygen and Carbon Dioxide can
easily cross the cell membrane in this way
• This process is passive, no energy required
49. WATER
Molecules of solute
Membrane (cross section)
Net
diffusion
Net
diffusion
(a) Diffusion of one solute
Equilibrium
The diffusion of solutes across a membrane:
50. (b) Diffusion of two solutes
Net diffusion
Net diffusion
Net diffusion
Net diffusion
Equilibrium
Equilibrium
51. Facilitated Diffusion
• Large molecules (eg. glucose) and charged molecules (ions)
cannot easily pass through the cells phospholipid bilayer
• These molecules diffuse across the transport proteins
52. Active Transport
• Active transport is the movement of dissolved solutes
across a membrane against a concentration gradient
(moving from low to high concentration).
• This process is active & requires energy in the form of ATP.
55. • Very large molecules, such as carbohydrates and
proteins, cross the membrane in bulk using vesicles
• Bulk transport requires energy
• Two types of Bulk transport:
• Exocytosis: transport vesicles travel to the cell membrane,
fuse with it, and release their contents
• Endocytosis: the cell takes in macromolecules by forming
vesicles from the cell membrane
2. Bulk transport
58. Osmosis
• Osmosis is the diffusion of water across a selectively
permeable membrane
• Just like other types of diffusion, a substance moves from
an area of high concentration to an area of low
concentration
• The only difference is that this time the substance is water
• Therefore, water diffuses across a membrane from the
region of lower solute concentration to the region of higher
solute concentration
59.
60. Because of osmosis, a cell may either gain or lose water
depending on the environment it is in.
If a cell is in a:
• Isotonic solution: Solute concentration is the same as that
inside the cell; no net water movement across the cell
membrane
• Hypertonic solution: Solute concentration is greater than
that inside the cell; cell loses water
• Hypotonic solution: Solute concentration is less than that
inside the cell; cell gains water
Whenever possible, water moves from a
hypotonic solution to a hypertonic solution
61. Solution and cell
are Isotonic
(a) Animal
cell:
(b) Plant
cell
H2O
Burst
H2O
Turgid (normal)
H2O
H2O
H2O
H2O
Normal
Solution is
Hypotonic
Flaccid
H2O
H2O
Shriveled
Shriveled
Solution is
Hypertonic
62.
63. Did you know
that reverse
osmosis is used
as a desalination
method to purify
sea water?
64. Search for video “Reverse Osmosis Process” or copy link below
Youtube link: https://www.youtube.com/watch?v=4RDA_B_dRQ0