Osmosis is defined as 'the movement of water molecules from an area of high water concentration to an area of low water concentration, across a semi-permeable membrane' (Collins, 1999).
Prediction Osmosis is defined as 'the movement of water molecules from an area of high water concentration to an area of low water concentration, across a semi-permeable membrane' (Collins, 1999). If you get information from books put the copied text in brackets and at the end put the authors surname and date the book was published in brackets. Then put the full details of the book at the end of the course work in the 'References' In a high concentration of water the amount of solute (e.g. sugar) is low. This could be called a weak or dilute solution. In a low concentration of water the amount of solute (e.g. sugar) is high. This could be called a strong or concentrated solution. When two such solutions are divided by a semi-permeable membrane the water will move from the area of high concentration to the area of low concentration, until both sides are equal (have reached equilibrium). This can be seen in living cells. The cell membrane in cells is semi-permeable and the vacuole contains a sugar/salt solution. So when a cell is placed in distilled water (high water concentration) water will move across the semi-permeable membrane into the cell (lower water concentration) by osmosis, making the cell swell. This cell is now referred to as turgid. If done with potato cells the cells would increase in length volume and mass because of the extra water. If these
How temperature affects the rate of photosynthesis.
Biology A2 Coursework How temperature affects the rate of photosynthesis Contents: Title: Page number: Abstract Introduction Preliminary experiment Aim Prediction Apparatus Diagram Method Key variables Safety Results Graph (individual) Graph (class) Statistical analysis (t-test) Conclusion Discussion Evaluation Bibliography Abstract: The aim of the experiment was to observe and analyse the affect of temperature on the rate of photosynthesis. This rate was measured by the rate of oxygen produced (mm3/min), by a photosynthesising plant (elodea), under different temperatures. A specialised apparatus called a potometer was used to observe this affect. A certain length of elodea (50mm) was cut at a slant at one end, and was placed in a test tube and was immersed in the pondweed water it was accustomed to. The cut end of the elodea was attached to a delivery tube which was connected to a measuring tube which was further attached to a syringe by rubber tubing. This whole apparatus (the potometer) was then placed in varying temperatures to measure the affect of the temperatures on the rate of oxygen production. For each temperature the length of the oxygen bubble released by the plant was measured by pulling it into
An Investigation into Species Diversity with distance along a Pingo.
An Investigation into Species Diversity with distance along a Pingo Aim: The aim of this investigation is to identify the relationship between species diversity and distance along a pingo. This will be achieved by identifying the number of different species along the profile of a pingo in Foulden Common, Norfolk. Statistical tests will be done on the data to test the results' significance. Two abiotic factors will be investigated; including edaphic factors, in particular soil moisture and pH, and the effect of climate; light intensity at each zone will be measured to see the effect it has on the vegetation growth of the area. Introduction: Foulden Common is situated in Norfolk. It is classified as ancient chalk grassland and for that reason is a Site of Special Scientific Interest. It is diverse is species and topography, containing pingoes, anthills, open pasture and set aside. My study will focus on the pingoes, and the vegetation they are home to. The pingoes found on the Common are relic glacial landforms. They are likely to have formed during the Pleistocene (the last Ice age about 2 million years ago). There are two different types of pingo; a closed-system pingo and an open-system pingo. The closed-system pingo forms from a local supply of water, they often form on the sites of small lakes. Initially the water would insulate the underlying sediments,
autodirigidas
Universidad de Buenos Aires Facultad de Ciencias Exactas y Naturales Licenciatura en Cs. Biológicas Int. Güiraldes 2620 Ciudad Universitaria - Pab. II, 4º Piso CPA: C1428EHA Ciudad Autónoma de Buenos Aires ARGENTINA. ?: +54 11 4576-3349 ? Fax: +54 11 4576-3384 Conmutador: 4576-3300 Int.: 206 http://www.bg.fcen.uba.ar Carrera: Licenciatura en Ciencias Biológicas Código de la carrera: 05 Código de la materia: CARÁCTER: [SI / NO] PUNTAJE: Curso obligatorio de licenciatura (plan 1984) NO -- Curso optativo de licenciatura (plan 1984) SI -- Duración de la materia: 6 Semanas Cuatrimestre en que dicta: 2º Cuatrimestre Frecuencia en que se dicta: ANUAL Horas de clases semanales: Discriminado por: Hs. Teóricas 6 Problemas _ Laboratorios 6 Seminarios 2 Carga horaria semanal: 4 Carga horaria total cuatrimestral: 224 Asignaturas correlativas: Genética I - Física II Forma de Evaluación: 2 parciales teórico- práctico. Exámen final Profesor/a a cargo: Dr. Dante Agustín PAZ Firma y Aclaración: Fecha: / / DEPARTAMENTO DE BIODIVERSIDAD Y BIOLOGÍA EXPERIMENTAL FACULTAD DE CIENCIAS EXACTAS Y NATURALES UBA BIOLOGÍA CELULAR Objetivos de la asignatura. Proporcionar al alumno el conocimiento de los métodos de estudio aplicables para el conocimiento de la estructura y función de las
The comparison of bacterial content in a range of milks.
Yasmin White 1210 The comparison of bacterial content in a range of milks Introduction Milk is a nutritious food. It is an excellent source of calcium, phosphorus, riboflavin, and vitamin D and a good source of protein, vitamin A, potassium, and several B vitamins. These constituents differ widely in molecular size and solubility, therefore milk is a complex physiochemical system. The enzymes found in cow's milk are: protease, amylase, lactase, lipase, xanthine oxidase, phosphatase, aldolase, catalase, and peroxidase. It's the lipase here that can cause hydrolytic rancidity. The smallest molecules, those of salts, lactose, and water-soluble vitamins, are in 'true solution'. The proteins, including the enzymes, are in the colloidal state (suspension in the liquid) because of the large size of their molecules. Lactose (milk sugar) is a white crystalline disaccharide, it has the same molecular formula as sucrose (C12H22O11) but it differs in structure, making it an isomer. It contains the simple sugars, glucose and galactose. Galactose is catalysed by lactase. When milk sours, the lactose is converted by bacteria to lactic acid, this causes a change in the milk's consistency. Milk is often naturally contaminated with bacteria. Lactobacillus and Streptococcus Lactis (the two most common lactic acid bacteria) produce lactic acid during fermentation: Bacteria: Bacteria are
The effects of organic effluent from the seweage on the biodiversty in a freshwater stream.
AIM: The aim of this investigation is to find out the effects of organic effluent from the seweage on the biodiversty in a freshwater stream. This will be done by looking at biotic(such as food supply, competition and predation) and abiotic factors (such as oxygen concentration in water, light and nitrate levels in the water) neccessary for the servival of most sea organisms. Biotic index will be used to determine levels of organic effluent from the seweage in the fresh water stream and Diversty index will be obtained to see how diverse species are in a given area of the stream according to the levels of organic effluent present.The areas selected will be at random and they will be selected by considering all the health and safety measures when I reach the fresh water stream.This method will ensure that the results obtained are reliable. I will back up my results for the biotic index and the diversty index by carrying out BOD, light and nitrate levels test for the abiotic factors so that the biodiversty of selected areas can be explained by taking into consideration the various levels of organic effluent. BACKGROUND RESEARCH: Water is vital for the existance of life. The man uses water for various reasons. e.g. 1. Used for drinking and for domestical livestock. 2. Seweage is removed by water. 3. It is used to irrigate crops. 4. It has industrial uses e.g a coolant
Human biology short notes
Name of organelle Structure Function Cell membrane Composed of mainly proteins and lipids Forms the outer boundary of the cell Partially permeable (Selective)- has special pores Controls the transfer of substances into and out of the cell Prevents cell contents from escaping or mixing with the neighboring cells medium Cytoplasm Structure less, semi- fluid, jelly like substance Provides a medium for chemical reactions Suspends organelles within the cell Nucleus Spherical body Contains a nucleolus Neucleoplasm suspends chromatin Nuclear membrane contain special pores Controls cellular activities Contains chromosomes responsible for cell division Plastids *Chloroplast (Only in Plant Cells) Colourless plastids contain starch (used as a food store) Plastids which contain a green pigment- chlorophyll are called chloroplast Chlorophyll present absorbs the energy from the sunlight and uses it for photosynthesis in plants Cell wall (Only in Plant Cells) Made up of mainly cellulose Forms the outer boundary of the plant cell Not selective Non-living Keeps the rigid structure of the cell Since it is not selective allows any dissolved substances to pass through Mitochondria Doubled membrane- inner membrane is highly folded to increase the surface area Responsible for generating energy for cellular activities Aerobic
Stem Cell Research
The research of stem cells, particularly embryonic stem cells is a controversial issue in our society today. Stem cell research has an incredibly large potential in medicine and could dramatically affect the treatment of many human illnesses that would have previously been incurable. However there are many groups of people within our society that protest against the use of embryonic stem cells because they believe that it is not right to destroy living cells that have the potential to develop into living human beings. Numerous debates have occurred because of peoples' differing views on this topic. What Are Stem Cells? Stem cells are undifferentiated cells1; meaning they are cells in the body that have not yet become specialised. They have the potential to develop into any of the 220 specialised cells in the human body.2 For example stem cells can develop into cardiac muscle cells in the heart in the circulatory system, or into nerve cells in the nervous system. Each type of specialised cell has a unique structure that is specifically suited for its particular function. For example, nerve cells have thin, long extensions, which help them to transport electrical messages around the body more efficiently. 3 Once cells specialise, they cannot revert back to their previous stem cell state. This means that they can no longer specialise to form any other cell. Therefore it is
Investigating the effect of temperature on the rate of photosynthesis
Investigating the effect of temperature on the rate of photosynthesis Contents Page Abstract:............................................................................... Aim:.................................................................................... Introduction:.......................................................................... Light dependent reactions in photosynthesis- Cyclic photophosphorylation............................ Non-cyclic photophosphorylation...................... Light independent reactions of photosynthesis................. Factors affecting the rate of photosynthesis..................... Limiting factors..................................................... Prediction:.............................................................................. Preliminary experiment: Method............................................................... Results ............................................................... Evaluation............................................................ Apparatus:.............................................................................. Method:................................................................................. Diagram:...............................................................................
Absorption Spectrum of Chlorophyll.
Absorption Spectrum of Chlorophyll Group R1 Indradeo Hemraj Craig Rineer Sushmitha Kurapati Mariza Clement BE 210 Spring 1997 The absorption spectra of chlorophyll from spinach leaves and okra pods were determined along with the relative amounts of chlorophyll a and chlorophyll b in each of the two plants. The chlorophyll was extracted using 100% acetone and the absorption spectrum was determined over a range of 400-700 nm using a Spectronic 20D spectrophotometer. The relative amounts of chlorophyll a and chlorophyll b were determined using equations from the literature based on the absorbance data. Plots of absorbance versus wavelength were generated and the location of the peaks determined the wavelengths at which the chlorophyll extracts maximally absorbed. The chlorophyll extracts from both spinach and okra had two absorbance peaks. The mean absorbance maxima for spinach were (430 ? 3) nm and (662 ? 3) nm while those of okra were (430 ? 4) nm and (664 ? 4) nm. Normalization of the spectra from the spinach and okra extracts did not show the spectra of the two plants to be statistically different. Use of the literature equations gave chlorophyll a to chlorophyll b ratios of 1.49 ? 0.18 for spinach and 1.67 ? 0.45 for okra, and a t-test at the 95% confidence level did not prove the two ratios statistically different. The ratio for
