...illuminated by electron. Electron microscope is expensive and not portable compared to the light microscope. The Electron microscope is then of two types. We have the Scanning Electron microscope and the Transmission Electron microscope. Features Light Microscope Electron Microscope Comments Cell Components Seen Animal Cell:- Nucleus, Nucleolus...
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...fluid. Although, it had not yet been observed. It was the neurophysiologist Lina Stern who came up with the concept of the blood-brain barrier in 1921. She had been puzzled by the fact that medicines and serums injected into the body did not reach the brain, and came to the conclusion that there must be a special filter to protect the organ; she called it the "hematoencephalic barrier." WHAT IS BLOOD BRAIN BARRIER? A semipermeable membrane seperating the blood from the cerebrospinal fluid, and constituting a barrier to the passage of cells , particles and large molecules. It is a protective network of blood vessels and cells that filters blood flowing to the brain. Blood Brain Barrier is a membrane that controls the passage of substances from the blood into the central nervous system.It is a physical barrier between the local blood vessels and most part of the central nervous system itself, and stops many substances from travelling across it. ANATOMY OF BLOOD-BRAIN BARRIER The BBB is semi-permeable; that is, it allows some materials to cross, but prevents others from crossing. In most parts of the body, the smallest blood vessels, called capillaries, are lined with...
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... To find out how the concentration of sucrose solution affects the rate of osmosis in a potato and what happens to the length and mass of the potato. What is osmosis? Osmosis is the movement of the water molecules across a partially permeable from a region of high water concentration to a region of low water concentration. Osmosis is a special case of diffusion The biochemical process in living cells always takes place in a solution. A solution is made up of a solvent (the dissolving fluid) and solute (the particles dissolved in the solvent). In living organisms, the solvent is water and the solution is called aqueous solution. Living cells are separated from their surroundings by the partially permeable cell surface membrane. The contents of the cell, the cytoplasm, are one aqueous solution and the surroundings of the cell, for example pond water, is another aqueous solution. If the two solutions do not have the same concentration of various substances, molecules may move away from one to the other by diffusion, if the membrane is permeable these substances. To summarise osmosis: The diffusion of water molecules, down a water potential gradiant across a partially permeable membrane. Cells and osmosis A cell is surrounded by a partially permeable membrane, and water may cross the membrane easily. If cell is placed in a solution of lower water potential, water leaves the cell by osmosis. If the cell is placed in...
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...BIOLOGY 10 Introduction to Biology Laboratory Manual Prepared by: KLLabrador Table of Contents |Exercise |Title |Page No. | |1 |Observation and Description |2 | |2 |Formulation, Testing of Hypothesis, |6 | | |and Experimental Design | | |3 |The Use of Models and Controls |9 | |4 |Plant and Animal Tissues |14 | |5 |Cellular Respiration |22 | |6 |Photosynthesis |27 | |7 |Phylogeny and Systematics: Survey of Plant and Animal Families |30 | | ...
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...Mediaphys Lesson 1. Discuss the structure of the plasma membrane and explain the process of active and passive transport through the membrane. A. The plasma membrane consists of lipids and proteins. The structure of the plasma membrane is the phospholipid bilayer which is the basic formation of biological membranes. It forms a constant barrier between two aqueous compartments. In the case of the plasma membrane, the compartments are the inside and outside of the cell. The proteins that are implanted within the phospholipid bilayer carry out the detailed functions of the plasma membrane that includes selective transportation of molecules and cell-cell gratitude. The passive process of the plasma membrane doesn’t use energy to move substances down their absorption grade. Active transport process of the plasma membranes processes use energy to move substances across the membrane. Osmosis Lab 2. Explain your observations in detail in terms of concentration gradient, diffusion, osmosis, osmotic pressure, passive transport, and active transport. A. The osmosis lab was a really awesome lab. It gave you the excitement for three days to see how much the egg has changed. Concentration gradient is a ongoing change in the concentration of solutes in a solution as a function of distance through a solution. The concentration gradient of the egg was almost seeing through. You could see the eggs membrane and the yellow oak that was in the center of the egg. Diffusion is the tendency of...
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...Pharmacokinetics Pharmacokinetics is a branch of pharmacology which studies what happens when foreign substances enter the human body. It looks at what happens to the substances when they are administered, up until the point at which they are excreted. In humans, the substances that are normally studied are hormones, toxins or other pharmaceutical agents such as paracetamol or aspirin. The knowledge of Pharmacokinetics is used to come up with an effective plan on how to administer drugs to patients. Some of the main goals of pharmacokinetics are to enhance the efficiency and reduce the toxicity of drugs. Pharmacokinetics comprises of 5 pathways, these are: Administration, adsorption, distribution, metabolism and elimination. Administration in pharmacokinetics is studying how the drug is going to be delivered into the body. A few methods include: Oral, Skin, lungs, eyes, and ears. For a drug to reach the target cells, it must be able to move across membranes and enter the blood stream via adsorption. If the drug has poor solubility or has an inability to pass through cell membranes, then this can affect how well the drugs intended effects work. The membranes that separate tissues from blood capillary’s are composed of lipids, this means that lipid soluble drugs will readily cross these membranes, whereas ionised drugs will not. Absorption also links into drug administration, as if a drug that was taken orally did not get adsorbed properly by the body, then it signals the means...
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...the toxicant. Toxicodynamics is an examination of the way these effects happen. There are many similarities as well as important differences between the toxicokinetics and pharmacokinetics of most substances. The same applies to pharmacodynamics and toxicodynamics (Olson, n.d.). The approach for conducting toxicokinetics studies that is recommended by most scholars generally involves three steps. Goehl (1997), "Step 1 is a preliminary study, which uses a minimum number of animals to estimate the range of blood/tissue concentrations, the required quantitation limit for the analytical method, and the optimal sampling times for the definitive toxicokinetic studies. Step 2 is the definitive study and generates blood and/or tissue concentration data for calculating the toxicokinetic parameters. Step 3 is the toxicokinetic study conducted in conjunction with the toxicology study to determine the internal dose and the effects of age and continuous exposure on kinetic parameters” (Toxicokinetics in the National Toxicology Program). There are four primary routes of exposure to chemical contaminants; injection, ingestion, topical and inhalation. Because of the chemical being directly introduced into the body, injection is the only method where the entire amount is absorbed regardless of how much is given. Chemicals may be injected intravenously directly into a vein or intramuscularly. The other methods of...
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...body; morphology Physiology: study of the function of the body; how does it work Fields of anatomy Gross anatomy: what you can see with the naked eye - Regional anatomy: studying just the head (looking at its muscles, etc) - Systemic anatomy: 11 body systems - Surface anatomy: study superficial anatomy; surface structures, then identify it deeper; surface landmarks Microscopic anatomy: seen with microscope - Cytology: cells - Histology: study of tissues Developmental anatomy: study of changes of the body from conception to full maturation Comparative anatomy Radiographic anatomy: using special tools - CT, NMR, MRI Chapter1 : Page 6- intro to organ systems, different characteristics The Cell Cytology: study of the cell Why study cells? - Cells concentrate needed molecules, expel waste, synthesize larger molecules with complex functions, generate/store/use energy for metabolic processes, move (transport) - Diseases begin at the cellular level (ex: cells dividing uncontrollably.. cancer) - You are made of 75 trillion cells Cells divided into: - Sex cells: sperms/eggs - Somatic cells: cells of the body Looking at the structure of a cell can show the cell’s function Environment of the cell - Cytoplasm (intracellular fluid) - Cytoplasm (intracellular fluid - Extracellular fluid: usually fluid like, consists of resources Acts as a cellular freeway.. allows movement of medium across the cell 1) Usually watery fluid 2) It is the matrix of connective tissues ...
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...Bio 100 EXAM 2 STUDY GUIDE CH 5 THE WORKING CELL 1. Properties of plasma membranes – fluid mosaic a. Lipids do what –Make up the phospholipid bilayer b. Proteins do what –embedded in lipid bilayer. Transports molecules across the membrane 2. Diffusion – movement down concentration gradient – Molecules move from HIGH concentration to LOW concentration until equilibrium is achieved 3. Passive transport/simple diffusion – diffusion across membrane. Needs no energy, energy comes from concentration gradient. c. Small molecules such as? –O2, CO2, Estrogen, Testosterone 4. Osmosis – water down concentration gradient – If there is a solute on both sides of a membrane but it is not permeable to the solute, water will move until the solute concentration is equal on both sides. 5. Tonicity – effects of hypotonic (LOW TONICITY) and hypertonic (HIGH TONICITY) solutions on cells - if solute outside or inside cell cannot cross membrane, osmosis occurs. When there is more of a solute inside a cell (hypotonic environment), osmosis occurs and water goes INTO the cell, the cell then explodes because of too much water. When there are less solutes inside a cell (hypertonic environment), water goes OUT of the cell and the cell shrinks. 6. Facilitated diffusion – (type of passive transport & relies on transport proteins) d. Transport proteins (embedded in lipid membrane) Form hydrophilic tunnels or they bind their passenger, change shape...
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...function of animal cells In this assignment, I will be producing a report discussing and analysing the movement of materials in and out cells using different methods. These include passive transport. This is a process which doesn’t require energy, diffusion, facilitated diffusion and osmosis are included in this. Active transport is a process which does need energy to function. Endocytosis and exocytosis are examples of this. Diffusion and the factors affecting how well it can occur will also be talked about. http://chemwiki.ucdavis.edu/@api/deki/files/26918/=17.6.new.jpg?revision=1 The phospholipid bilayer is a structural component that makes up all cell membranes. The lipid bilayer is named so because there are two layers of fat cells within the membrane. They are made up of a glycerol backbone with a phosphate group and two fatty acid chains attached to it. The phosphate group is polar while the fatty acids are no polar. Phospholipids are the main molecules found in the plasma membrane. The plasma membrane protects the interior of the cell which also has selective permeability. Most of the cell membrane is impenetrable to water soluble substances as it’s made up of lipids. Those water soluble substances and other molecules can pass through the membrane when it is made up of proteins. They can pass through by a channel protein or carrier protein. Cells need a membranes in order to control what substances go in and out. It also compartmentalises individual cell processes by...
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...www.asbiology101.wordpress.com An introduction to the microscope and magnification MAGNIFICATION AND RESOLUTION Because cells are too small to be seen with the naked eye, the light microscope was developed to produce enlarged and more detailed images of cells. The magnification of an image is how much bigger it appears under the microscope than it is in real life, and is worked out using the following formula: magnification = image size ÷ actual size unit metre decimetre centimetre millimetre micrometre nanometre picometre symbol m dm cm mm μm nm pm metres 1 0.1 0.01 0.001 0.000 001 0.000 000 001 0.000 000 000 01 However, magnification on its own does not increase the level of detail seen, it just increases the size. The term resolution refers to the ability to see two distinct points separately. For example, if the resolution of a light microscope is 200nm (0.2μm), this means it can see any two different points as separate objects if they are 200nm apart or more; but if they are any closer than this amount, they appear as one object. THE LIGHT MICROSCOPE Light microscopes use a number of lenses to produce an image that can be viewed directly at the eyepiece. Light passes from a bulb under the stage, through a condenser lens and then through the specimen. This beam of light is passed through an objective lens and then the eyepiece lens. The light microscope usually has a number of objective lenses which can be rotated into position...
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...Biology- The scientific study of life. Life is structured on a size scale ranging from the molecular (smallest components of life) to the global (Earth) scale. Biology encompasses a large variety of life on earth. Uses of Biology in every day life: Molecular Biology – (Biology that deals with the smallest components of life such as cells, DNA, RNA) is used to solve crimes and reveal ancestry. Ecology- The scientific study of interactions among organisms and their environment is used to address environmental issues. Neuroscience- Field in biology that deals with brains; and Evolutionary science- the study of the evolution of organisms are being used to reshape psychology and sociology. Characteristics of Life: Living things are organized – The organs or vital components that make up a living organism each perform a specific function in an organized way such that it allows the organism to live. Regulation – All living organisms have the ability to regulate and accommodate to changes in their environment in order to stay alive. Growth and Development – Living organisms have the ability to grow and develop. Energy Utilization – Living organisms use energy or convert energy from a food source in order to carry or be able to perform different functions. For example, the human body utilizes carbohydrates found in food as a source of energy. With this energy, humans are able to perform simple tasks such as walking, talking, breathing, etc. Response to environment – Similar...
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...and subsequent ecosystems are of great importance in understanding human impact on our planet. Ecotoxicology is a type of environmental toxicology that deals with the effects of environmental toxins on ecosystems, habitats and the organisms that live in those ecosystems. The wide range of organisms and environmental factors requires detailed analysis from multiple scientific disciplines. Toxicokinetics and Toxicodynamics Toxicokinetics is a branch of toxicology that can be viewed as the study of how the body deals with toxicants at different stages after exposure. These stages are absorption, distribution, and elimination. Toxicokinetics studies the ever changing processes that occur within the body during and after absorption of a toxicant. This includes where and how absorption takes place, how the body distributes the toxicant, the effects of metabolism, the toxic effects rendered and the excretion of the toxicant. “In other words, toxicokinetics is a reflection of how the body handles toxicants as indicated by the plasma concentration of that xenobiotic at various time points.” (Michael A. Trush, 2008, p. 1) Toxicodynamics describes what occurs when a toxicant interacts with a specific entity and the biological effects that take place as a result. These “biological targets” can include DNA, proteins, and a variety of receptors. Toxicants interact with these targets and receptors that lead to alterations that may impact the function of their targets as well as structural...
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...Chapter 1: Introduction to Zoology Concept of Science • Frings and Frings - defined science as an organized body of knowledge that is gained and verified by exact observation and experimentation and organized by logical thinking. • Schafersman - defined science as a method of discovering reliable knowledge about nature. • Science is factual. • Science is not merely compiled. • Science is a way of asking questions about the natural world. • Guided by natural laws (physical & chemical). • Questions must be testable. Always open to new evidence. • Falsifiable. • It applies scientific and CRITICAL THINKING. When is scientific thinking applied? 1. When one uses the scientific method 2. When one investigate nature or the universe 3. Practice by all scientists 4. Not reserved solely for scientist, anyone can think like a scientist Fields of Science 1. Social Science – deals with human relationships 2. Abstract science – deals with abstract ideas 3. Natural sciences • Physical Science – deals with non-living entity • Biological Science – deals with the living entity The Scientific Method - The most important tool in search for truth - An organized method of gathering information based on observation and controlled testing of hypothesis 1. Observation and/or Review of Literature 2. Problem 3. Hypothesis Formulation 4. Testing of hypothesis 5. Conclusions or generalizations Theory Scientific fact/principle/law Theory – is...
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...knowledge of cell biology and genetics b. Defining what a microbe is: * a microbe is a living organism that requires a microscope to be seen c. Where did microbes come from? Evolutionary origins, fossil evidence; prokaryotic cells eukaryotic cells * bacteria is the oldest known life form. Oldest datable geographical evidence was 3.8 bya * eukayotic cells arose from divergent prokaryotic lines. Endosymbioses came from mitochondria and chloroplasts. Unicellular types came from simple multicellular forms metazoans; significance of cyanobacterial ancestors * presence of cyanobacteria-like chains of cells in stomatolite fossils represent growth of cyanobacteria * cyanobacteria photosynthesize like plants; they use H2O to synthesize O2. d. Microbial taxonomy & phylogeny (3 domains: Archaea, Bacteria, & Eukarya ) * the 3 domains (bacteria, archaea, and eukaryotes) evolved from a common cell * Archaea and bacteria include prokaryotes * Eukarya includes algae, plants, fungi, animals, and protists eukaryotes * Monera includes all 3 domains i. Taxonomic groupings: microbes in the different kingdoms of those domains ii. Similarities & differences: eukaryotic & prokaryotic cells; genomes iii. Metagenomics e. Who are the microbes: bacteria/archaea/fungi/protists/viruses; characterize/describe these * Bacteria: cells lacking a nucleus * Fungi: are in eukarya domain. A heterotrophic eukaryote with chitinous cell walls. ...
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