Login with Facebook

Mass transport in a biological system

The transformations can be represented simply as a term of production or consumption, while in the second, since the transformation takes place on the contour surfaces of the system, the corresponding reaction is introduced as a boundary condition for the system.

- The reactions that take place within a single-phase, be it a gas or a liquid, are called homogeneous reactions. They, therefore, take place anywhere within the fluid mass, so they can be considered as evenly distributed within the control volume. Therefore, they can be represented analytically as a source term or well in the differential equations that describe the system;

- The reactions which, however, involve more than one phase are called heterogeneous reactions. They take place at the contour surfaces of the fluid volume and, therefore, must be represented analytically through conditions at the source or well boundary in the differential equations that describe the system.

These reactions determine the consumption of nutrients and the production of biomass and are also accompanied by production or consumption of energy. A classic example of biological reaction is that of the irreversible type of decomposition of the organic substance, which can be expressed, in general form, as:

Here C6H12O6 is glucose which can be taken as an example of an organic substance to biological decomposition. This reaction takes place when the slurry is introduced into an aquatic ecosystem. In fact, the organic substance contained in the slurry is oxidized by bacteria. In particular, under aerobic conditions, due to the action of aerobic microorganisms, proteins are transformed first into amino acids and then into CO 2, H2O and nitrogen and sulfur salts, carbohydrates into CO 2 and H2O, the fats first in fatty acids and then also in CO2 and H2O.

Another classic biological reaction, in a sense inverse to the previous one, is that of photosynthesis which produces glucose starting from CO2, with the mediation of sunlight h v :

The two reactions of respiration and photosynthesis are extremely important in the cycle of dissolved oxygen in a water body, which is, as is known, a very important quality parameter for the aquatic ecosystem. However, it should be noted that these two inverse reactions do not usually take place in the same place and that they are rather slow compared to the time scale of some Environmental Hydraulics problems

The mass transport through the plasma membrane

To meet its biological needs of adaptation to the environment and reproduction, the cell must introduce the materials it needs for nutrition and respiration and, at the same time, eliminate waste products (excretion).

The passage of materials between the internal environment of the cell and the extracellular environment is regulated by the plasma membrane. Its lipid bilayer constitutes an insurmountable barrier for most of the large biological molecules that are polar and water-soluble and ions, to allow the passage of the large molecules and ions necessary for the life of the cell, membrane proteins intervene, some of them which form pores or channels, while others have binding sites for specific molecules. Due to its selective characteristics regarding the passage of molecules and ions, the plasma membrane is called semipermeable.

The passage of substances through the membrane can take place according to two mechanisms. The first one does not involve energy consumption and is called passive transport; the second involves energy consumption by the cell and is distinguished by active transport, endocytosis, and exocytosis.

Passive transportation

Passive transport is the movement of substances in solution through the membrane that does not require energy expenditure by the cell. The membrane does not interfere with the direction of movement of the particles since this occurs thanks to the existence of gradients, i.e., concentration differences. The particles move spontaneously from areas of high concentration to areas of low concentration, such as those existing outside respectively and inside the membrane itself (movement proceeds until equilibrium conditions are established). In other words, the movement of the particles takes place by exploiting the potential energy due to the presence of the concentration gradient. There are three forms of passive transport: simple diffusion facilitated diffusion and osmosis.

Simple diffusion is the movement of gas or fat-soluble molecules through the phospholipid double layer of the plasma membrane. The diffusion speed is influenced by the concentration of the substance it diffuses, the temperature and the pressure. Diffusion continues until the concentration gradient is canceled, that is when the concentration of the gas or molecule becomes equal to the two sides of the membrane.

The facilitated diffusion is the transport of ions, amino acids, and monosaccharide mediated by membrane proteins. Some of these (channel proteins) can form permanent channels across the membrane. Other proteins (transporters) have specific binding sites for certain molecules; once the bond has taken place, the transporter changes its shape and, consequently, the bound molecule is transferred and released from the other side of the membrane. Since the plasma membrane has a limited number of transporters, the speed of facilitated diffusion is lower than that of simple diffusion.

Osmosis is the diffusion of water through the plasma membrane. The passage of water is allowed by the presence of pores formed by the assembly of a certain number of intrinsic proteins. Osmosis ends when osmotic equilibrium is reached. Under these conditions, the speed of the water flow on both sides of the plasma membrane is the same in both directions, and there is no longer a clear passage of molecules from one side to the other. The three forms of passive transport, depending on differences (gradients) in concentration, are reversible, that is, they occur in one direction or the other according to the gradient.

Active transport

Active transport is the movement of materials across the plasma membrane against the concentration gradient (i.e., from low concentration areas to high concentration areas) and with energy consumption by the cell. The substances transported from the inside to the outside can be waste products (the presence of which, even in very small quantities, could damage the cell). They transported from the outside to the inside are nutrients present in low concentration in the extracellular environment and ions that must be present in the cell at lower concentrations than those of the extracellular liquid.

Active transport is regulated by intrinsic membrane proteins (called pumps because they move molecules against the concentration gradient), equipped with binding sites for a specific molecule to be transported and for ATP. Hydrolysis (splitting) of ATP provides the energy necessary for the carrier protein to change shape and transport the molecule across the membrane. Once the molecule is released, the transporter protein regains its original configuration.

Endocytosis is the transport of materials inside the cell by means of vesicles. The cell surrounds the particle to be introduced with its plasma membrane until it is incorporated into a vesicle, which then merges with a lysosome; inside the latter, the assumed particle is demolished by proteolysis enzymes. Endocytosis represents the method of food intake of some protozoa, such as amoeba. In this case, the process takes the name of phagocytosis, the amoeba surrounds the food with extensions of the cytoplasm called pseudopods, then englobes it and digests it using its own lysosomes.

Exocytosis is the transport of materials outside the cell. In practice, it is the opposite of endocytosis. The substances that must be removed from the cell are enclosed in a vacuolebiological system, which moves to the periphery of the cell so as to merge with the plasma membrane.



Comments




Send Comment

Need a custom
essay?

We will write it for you.
Order now

Free Essay Examples

Free essays:

Analysis of Business Cycles
Analysis of Fiscal and Monetary Policies
An Overview Of Economic Studies
A Guide to Pricing Strategies
Biosensors for cancer diagnosis
Business Analysis: Pricing strategies and Demand Curve
Broadcasting: How to Be Good In Front of the Camera
Bioconjugates for the Drugs Delivery
Cells of Immune system
Challenges that IT Managers are facing
Cochlear implant: what it is and how it works
Current challenges to the health of women
Doppler ultrasound or simply eco Doppler
DNA extraction
Dynamic Systems Modeling with Machine Learning
Digital Imaging: What Is It?
Economy analysis: Business Cycle and Economic Trends
Exchange rate and foreign currency risk
Economic Factors Affecting Decision Making In A Business
Economy Analysis: Inflation, Unemployment And Policies
Factors Influencing Interest and Exchange Rates
Fiscal and Monetary Policies in Response to 2008/2009
Fermentation: how it works and what it is used for
Financial Markets and Functions
Genetic regulation networks: modeling in biology
How can immigrants blend in the American society?
How to make your business survive at economic crisis
How to choose the topic of the senior capstone project
Importance of corporate sustainability
Interaction of Consumer and Firm Choices in Markets
Introduction to Microeconomics
Introduction of Microfabrication techniques
Journalism: What is News?
Journalism: Broadcast media and Television Presenters
Journalism: Sources of News
Journalism and Law
Key Determinants of National Income
Key Factors That Affect Pricing Decisions
Kinetic models in biology and Related fields
Know about the different forms of traditional African dances
Latest technology trends
Latest dance trends
Methods of labeling of nucleic acid that enable their detection
Macroeconomics: International Economic Issues
Neuromuscular disorders
National Economies, Fluctuation, and Responses to Fluctuations
Neurotransmitters: what they are and different types
Nanomedicines to target tumors
Overcoming Hiring Challenges for Nonprofit Organization
Principles of Microeconomics - Producer Theory
Principles of Microeconomics - Consumer Theory
Principles of Economics
Role of technology in the modern business environment
Role of Homeostasis in Human Physiology
Role of a digital artist
Role of gender studies
Skills in Journalism: Effective Interview
Systems biology - An understanding the functioning of biological systems
Self-assembly for biological systems
School of American Ballet
Types of corporate responsibility
The Role of Government Policy in Improving Economic Outcomes
Types of bioreactors and their applications
Technological perspectives and reflections of neural engineering
Understanding Perfect and Imperfect Competition
Ultrasound: physical principles and image formation
Understanding social entrepreneurship
Understand the importance of investigative journalism
Various theoretical perspectives of sociology
Virtual reality, what it is and how it works
What are the Causes of financial instability?
What is business ethics and code of ethics
4 Facts about Origin of Mathematics!
5 techniques to create an animation
10 strategies to maximize corporate profits
13 Best colleges for political science in the world
6 Medical Technologies that revolutionized the healthcare in 2020
All you need to know about the ACA Code of ethics
Architecture and Democracy: An Introduction
Architecture and Democracy: Democratic Values
Architecture and Democracy: Democratic Procedures
All You Need to Know About a Synthesis Essay
An essential guide to understanding Film Theory
Application of Artificial Intelligence in Cyber Security
Applications of electrical engineering
Augmented reality: what it is, how it works, examples
Advantages And Disadvantages Of Social Networking
All you need to know about Cryptography
Applications of astrophysical science
All you need to know about architecture engineering
Applications of geological engineering
Artificial intelligence and medicine: an increasingly close relationship
An insight into Computational Biology
ACA code of conduct
A Rose for Emily
Applications of Mathematics in daily life
Architecture mistakes to avoid
All you need to know about Toxicology
All you need to know about Holistic Medicine
All you need to know about linguistics
An introduction to Linguistics and its subfields
All you need to know about Anxiety disorder
All you need to know about Drones
A Brief Insight into Political Science
Assumptions related to feminism
All you need to know about Byzantine emperors
All you need to know about labour economics
An insight into xenobots -the first-ever robots
An ultimate guide about Biomaterials
A Comprehensive Introduction to the Mona Lisa
Analysis methods of Transport through biological membranes
An ultimate guide about biochemical reactions
Analysis of brain signals
Artificial Gene Synthesis
Application to synthetic biology of CAD methods
All you need to know about metabolic pathways
Applications of BIOMEMS
All you need to know about the epidemiology
Asian vs. western leadership styles
All you need to know about Smart prosthesis
Analysis of Economy: Output of Goods and Services (GNP), and GDP on Economic success
A Guide to Pricing Strategies
An Overview Of Economic Studies
Analysis of Fiscal and Monetary Policies
Analysis of Business Cycles
How to Write a Personal Essay
Housing Needs in America
How to Write a Description Essay
How to Create an Excellent Scholarship Essay?
How to write a cause and effect essay
How to Hire the Best Essay Writing Service Provider?
How to Write a College Application Essay?
How to get the most out of your English lectures
How to write Expository Essay
How to succeed in your psychology class?
How to Write an Academic Essay in the Shortest Time?
History of Journalism
How Different Sectors are Using Artificial intelligence (AI)
How to write an informative essay
How to deliver persuasive essays?
How to Give a Convincing Presentation
How to write an essay on leadership?
Historical Art Still Around Today
Humanoid robot: what it is, how it works and price
History of Chemistry
Healthcare Advanced Computer Power: Robotics, Medical Imaging, and More
Healthcare AI: Game Changers for Medical Decision-Making and Remote Patient Monitoring
How to understand different types of English
How to Cope with Chronic Pain
How African American choreographers and dancers have influenced American dance
How mobile robot can do in logistics or in production
How To Become a Successful Entrepreneur
History of the Philosophy of Feminism
How is the climate changing?
How to Track Your Content Marketing ROI
How to Gun control In the USA?
Historical and contemporary role of labour in the modern world
How breast cancers are classified?
How the cells of our body communicate?
How the Lymphatic System Works?
How Digestive System Works
How to complete your capstone projects effectively?
How to write a research project
Healthcare technologies that help patients with better self-management
How to choose the topic of the senior capstone project
How to make your business survive at economic crisis
How can immigrants blend in the American society?
The Looming Energy Crisis in America
Top benefits of performance-based engineering
The More Languages You Know, The More Times You Are a Man
Things to consider while writing an Argumentative Essay
Top Ways to Improve Your Academic Writing Skills
Tips to Excel in Creative Writing
The origins of films in the early 19th century
Top career options in Architecture
The Elevator Pitch
Top finance trends 2020
The basic Structure and functionality of robots
The Way to Success
The election system of the President in the United States of America
Two-party System in United States of America
Top trends in urban design
The history and theory of African American filmmaking
Top benefits of creative writing
Tinnitus Guide: Common Symptoms and Treatment Options
The language of dance
The digital image processing management
Top famous politicians of the World
Top methods of political science!
The history of the feminist movement
The blood flow in cardiovascular system - Biofluid Mechanics
The best of Leonardo Da Vinci
The Structure and Function of Macromolecules
The structure of cell: a research on the bricks of the human body!
Tissue and organ construction: Adhesion and recognition between cells
The kinetics of the transformation processes
The Modeling of Biological Systems
Tips for writing a great thesis statement
The Defense mechanisms against infections
The impact of the technological innovations in medicine
Top journalism trends to know about
The relation between mass media & politics
Theranostics: Diagnosis and Care through Nanoparticles
The practical Applications of X-rays
The applications of Ultrasound in medicine
Transfer mechanisms of genetic information in Bacteria
The regulation of cellular metabolism in the diagnosis
The Principles of MRI Contrast agents
The technical basis of optical coherence imaging
The New Media: Emerging Trends
The Structure of Interest Rates and the Yield Curve
Technological perspectives and reflections of neural engineering
Types of bioreactors and their applications
The Role of Government Policy in Improving Economic Outcomes
Types of corporate responsibility
What is a Definition Essay?
What are diagnostic essays?
What is the relation between art structural engineering?
What is a Narrative Essay
What are robotics and intelligence systems?
What are the benefits of studying health sciences?
What is artificial intelligence and why it matters?
What is comparative Literature?
Why study neuroscience
What is Wi-Fi and how does it works
What is French history famous for?
What are Humanistic Studies?
What is covered in Biophysics?
What is modern journalism?
What is Virtualization? Benefits & Applications
What are modern public relations?
What is plasma physics?
What is teacher preparation?
What is rapid prototyping for 3D printing?
What is contemporary European Politics?
Why should you learn American Ballet?
What is engineering physics?
What is the purpose of African American Literature?
Ways to learn the Rhythm
What is digital art used for?
What are Enzymes and how do they work
Who is the father of political science?
Why Study Political Science - Job?
What is the Philosophy of Feminism?
What is a quantum computer?
Ways B2B Startups Streamline Their Conversion Strategies
Why do biomedical signals need processing?
What are the long term effects of climate change?
Why study labour relations
What is Holoprosencephaly?
What is antisocial disorder?
What are the important principles of evolution?
What is the cytoplasm and its function?
What is biopolymers?
What Makes a Good Leader
Women empowerment in modern generation
What is the history of political thought?
What is Gene recombination
What is synthetic biology
What is business cost analysis?
What is Inflation
What are the consequences of unemployment?
What is lithotripsy and its types?
What is transition elastography?
What is the purpose of deep brain stimulation?
What is a Brain-Computer Interface (BCI)
What is neuroethics?
What is Market and Supply and Demand
What is optogenetics?
What are the techniques to record brain activity?
What happens if the interest rate increases?
What is immunotherapy?
What is the economic role of the financial market?
What are the factors behind illegal immigration?
What is the lymphocyte activation?
What is financial market and its types?
What is the structure of financial markets?
What are the methods of measuring business performance?
What is the Credit market?
What is business ethics and code of ethics
What are the Causes of financial instability?