Most cells are very small. What physical and metabolic constraints limit cell size? What problems would an enormous cell encounter? What adaptations might help a very large cell survive?
Assignment 2: Most cells are very small. What physical and metabolic constraints limit cell size? What problems would an enormous cell encounter? What adaptations might help a very large cell survive? The cell is an amazing structure. A single cell, alone, can function as a single entity: independently acquiring the nutrients it needs to survive, adapting to its environment, and eliminating the wastes it accumulates. Other cells, however, would rather be a part of a community of cells, like a tissue or higher organism. These cells often become specialized; they may specialize in motility, or they may be better suited for absorption and secretion. Whether these cells are suited for autonomous living, or become specialized for a specific function, the size of the cell is a general feature that relates to its function. Some cells, like bacteria, can be as small as a few microns. Other cells, like neurons, have axonal extensions that can travel a few meters long in some organisms. For the most part, however, cells are very small. So, what are the constraints that limit the cell to its small physical size? What types of problems would a cell that diverges from these constraints encounter? Finally, how do those cells that are very large, compared to the majority of cells, adapt to their larger size? These are the questions that will be explored. Cells are small. The
Agglutination & lysine of sheep red blood cells
Agglutination & lysine of sheep red blood cells Introduction They are many uses in science for agglutination for example the determination of which blood group an individual belongs to. However agglutination is commonly the adhesion of particles. Biological agglutination occurs in the clumping of cells in response to an antibody, the adhesion of small particles that are suspended in a solution, which are then (usually) precipitated in allergic reactions, when cells clump together to prevent antigens from entering, Antigens are usually proteins or polysaccharides, that could be on bacteria, but not actually the bacteria it self. But in biology/immunology many agglutination experiments are carried out in order to identify antibodies, which are specified to go against cellular antigens. In the 1st part of the experiment we were given immune rabbit serum and non-immune rabbit serum which, was acting against sheep red blood cells as an antigen. The second part of the experiment was antibodies that produce lysins in the presence of a complement, which is similar to the agglutination process, and both processes are measured using the same technique. Aims & Objectives The main objective of this experiment was to observe what actually happens in the agglutination and lysis reactions, also to help us understand the processes more clearly, and to determine the agglutination and
Discuss the possible role of dopamine in incentive salience? How might this lead to some of the symptoms of schizophrenia?
Institute of Psychiatry MSc Neuroscience 2007 - 2008 FULL TIME STUDENT ESSAY Module 3: Essay Question No: 7 TITLE Discuss the possible role of dopamine in incentive salience? How might this lead to some of the symptoms of schizophrenia? WORD COUNT: 2911 CANDIDATE NUMBER :0707502 PAGE NUMBER: 16 Discuss the possible role of dopamine in incentive salience? How might this lead to some of the symptoms of schizophrenia? In my essay, I will be focusing how dopamine release in the ventral stria mediates incentive salience which makes the brain direct attention to biological significant stimuli and how incentive salience is disrupted in psychiatric disorders such as schizophrenia which is responsible for some of the symptoms. Schizophrenia is one of the most severe mental illnesses that affect individuals in their late teens and early twenties.Hallucinations, most commonly auditory ones, delusions and disorders of the form of thinking ("thought disorder") are implicated in schizophrenia and are so called "positive" symptoms. Patients also suffer from negative symptoms such as apathy, social withdrawal and poverty of speech. The illness commonly follows a characteristic remitting relapsing course of positive symptoms. The neurochemical basis of schizophrenia is supported by a number of models and these are useful as they provide a testable framework for studying the
The Effect Of Osmosis In Animal Cells, Plant Cells & A Model System
The Effect Of Osmosis In Animal Cells, Plant Cells & A Model System Introduction The purpose of this experiment is to determine as well as observe the movement of water molecules going in and coming out of model system, animal cell and plant cell through a process called osmosis. Osmosis is referred to the movement of water molecules through a semi-permeable cell membrane from an area of low solute concentration to an area of high solute concentration within a biological cell system (Karp, 2010). In other terms osmosis can also be referred to as the movement of water molecules through a cell membrane from an area of high water concentration to an area of low water concentration (Karp, 2010). In this lab the membrane of the cells that are tested are permeable to water molecules, but impermeable to solutes. Permeability refers to substances that can enter, while impermeability means that substances can not enter (Karp, 2010). Within this experiment when the process of osmosis is observed between two solutions, the solute concentrations between the two solutions are compared in either three ways; they can either be isotonic, hypertonic or hypotonic. An isotonic solution is a solution that has the same concentration of solute to the solution being compared with (Bowen, 2010). In this case, the concentration of solute in the cell is equal to the concentration of the fluid that
What is the concentration of the Cell Sap in a Potato?
What is the concentration of the cell sap in a potato? Preliminary investigation- 0.0 M Initial mass --> 1.03 g Final mass --> 1.09 g Change in mass --> + 0.06 g 0.1 M Initial mass --> 1.03 g Final mass --> 1.06 g Change in mass --> + 0.03 g 0.9 M Initial mass --> 1.20 g Final mass --> 1.14 g Change in mass --> - 0.06 g Background knowledge- Water is essential to not only plants but all living things that need to carry out the 7 life cycles which are, movement, respiration, sensitivity, nutrition, excretion, reproduction and growth. Similarly, water is needed for photosynthesis to occur as it is stated in the formula; Water + Carbon Dioxide --> Oxygen + Glucose In this process the plant is able to make glucose with water and carbon dioxide. The formula will not work properly. Being able to transport water to all of the cells of the plant is vital. A plant has lots of thin tubes that carry liquids up and down the plant, they are called, the plants Transport System. Part of that system is the Phloem tube which carries glucose and the Xylem vessels need to carry water throughout the plant. Likewise, water keeps the plant cool and keeps the cells turgid giving it support so that it can get the most sun rays for photosynthesis to occur at a maximum. When the plant cells start to take up
Proteins. The experiment aimed to extract proteins from green papaya through salting out with the use of ammonium sulfate. Ultrafiltration was then done in preparation to ion-exchange chromatography which would be employed to purify the crude protein extr
PROTEINS I. Objectives: The experiment aimed to extract proteins from green papaya through salting out with the use of ammonium sulfate. Ultrafiltration was then done in preparation to ion-exchange chromatography which would be employed to purify the crude protein extract. Amersham Hi-Trap Sephadex Desalting Column would be utilized to further purify the samples. SDS-PAGE was then be employed to isolate and further analyze and purify the proteins in the sample. Finally, silver stain was utilized to visualizeand keep track of the purity of the proteins. II. Introduction: Proteins are complex organic macromolecules that are built from the 20 common building blocks called amino acids arranged in a linear chain linked together by peptide bonds between the carboxyl and the amino groups of adjacent amino acid residues. Usually, proteins contain 200-300 amino acids although some are made up of thousands of amino acids like titin, the largest known protein found in skeletal and cardiac muscles containing 34350 amino acids. Proteins are vital to every organism as it participates in virtually every process within cells like metabolism, cell cycle, immune responses, cell signaling, cell locomotion, transport of materials in body fluids and a lot more. In this experiment, green papaya was utilized as the source of protein. Green papaya is the unripe fruit of the plant Carica papaya
Identifying different biological macromolecules
IDENTIFYING DIFFERENT BIOLOGICAL MACROMOLECULES Introduction Biological macromolecules consist of very small organic molecules that are linked together to produce large molecules (Garcia, 2002). These large molecules are called polymers (Garcia, 2002). In particular, for macromolecules like carbohydrates and proteins, the polymer molecule is created when small molecules called monomers are covalently bonded to one another (Garcia, 2002). There are four major types of biological macromolecules. The four groups are carbohydrates which consist of polysaccharides and monosaccharides, proteins, lipids and nucleic acids (Garcia, 2002). Biological macromolecules are relevant because they are the building blocks of cells in both animals and plants (Karp, 2010). These types of molecules not only form the structure of a cell, but also carry out the cells' activities (Karp, 2010). The existence of macromolecules in living organisms is what provides life and separates them from the rest of the world (Karp, 2010). The purpose of this experiment is to test for the presence of macromolecules in various liquid solutions. In this lab we will explore two of the four types: carbohydrates and proteins. In carbohydrates the monomer unit is called a simple sugar while in proteins the monomers that are linked together are called amino acids (Garcia, 2002). Particularly, in carbohydrates when a
An experiment to investigate the change in cell potential with concentration.
8/1/04 Emma Duckworth 7E An experiment to investigate the change in cell potential with concentration. Aim: The purpose of this experiment was to investigate how changing the silver ion concentration in a silver half cell affects the potential of the silver electrode. Apparatus: ==> Chemicals/ substances: * Copper (II) sulphate solution * Copper foil * Silver nitrate solution (make up to 6 different concentrations) * Silver wire * Distilled water * Saturated potassium nitrate solution ==> Additional apparatus: * Safety goggles * 7 beakers * 6 pieces of filter paper * High resistance voltmeter * 2 connecting leads with crocodile clips Diagram: Method: ==> Set up the following cell, using 1 M copper (II) sulphate solution and 0.1 M silver nitrate solution, including a voltmeter and a salt bridge: Cu(s) Cu 2+ ((aq), 1M) Ag+ ((aq), x M) Ag(s) ==> Measure the potential difference of the cell with the voltmeter and note its polarity. Remove the salt bridge as soon as possible. ==> Dilute the 0.1 M silver nitrate solution to 0.01 M silver nitrate solution, renew the salt bridge and then measure the potential difference of the cell with this concentration (0.01 M) of silver nitrate solution in the silver half cell. ==> Repeat this for each of the listed concentrations (0.1 M, 0.01 M, 0.001M, 0.0001 M, 0.003 M, 0.00033 M) of silver nitrate
Animal Physiology - The Nervous System - To understand Resting and Action Potential
Animal Physiology The Nervous System AIM: To understand Resting and Action Potential All living cells have electrical differences across the membrane this is called the membrane potential and is defined as the electrical potential measured from within the cell relative to the potential of the extracellular fluid. Only some cells (neurones and muscle)have the ability to change the membrane potential and are known as Excitable cells. Neurone signals start as a change in the electrical gradient across the membrane , the signal is then transmitted along the length of the neuron to the axon tip. The gradient depends on the ion flow across the membrane (The ions move through ion channels in the membrane) An unexcited neurone is at its resting state - refer to figures 21,22 booklet 1. Figure 22 shows that the invertebrates may have large neurones as in the giant squid, they are good model systems. NB: The electrical currents of membrane potentials are formed from the net flux of charged particles that move across the membrane. Resting Membrane Potentials (RMP) The RMP arises as a small build up of negative charges forming just inside the neurone, there is also an EQUAL build up of positive charges on the outside of the neurone. The RMP is measured in millivolts (mV) and typically lies between -40 and -90 mV. The RMP arises from differences in the ion concentrations
The Rate of Enzyme Reactions
BIOL 130-017 Room: B2 151 Time: Wed 930AM - 12:20AM Date of Experimentation: 11/04/09 The Rate of Enzyme Reactions Introduction The purpose of this lab was to investigate what factors affect the direction of an enzyme reaction. The variables tested in this experiment were substrate concentration, enzyme concentration and reaction time. Enzymes are important biological catalysts that are required to drive chemical reactions for normal cell function. A catalyst is a substance which promotes chemical change without being consumed in the reaction. (Hasselberger, F.X. 1978) They are also important metabolic mediators, responsible for every reaction in the cell. (Karp, G. 2007) In this experiment two types of enzymes were used to test the variables of the experiment. The enzymes were salivary amylase and phosphorylase. Enzymes are used to accelerate the rates at which a favourable chemical reaction proceeds, however there are factors that affect the effectiveness of the enzyme activity. First, all of the chemical reactions take place at an active site. This is the part of the enzyme molecule that is directly involved with the binding of the substrate. Substrates are reactants bound by an enzyme. (Kuby, S.A. (1991). When the substrate concentration increases, the rate of enzyme activity will increase as well. This is because there are more interactions between the