Agar jelly diffusion experiment gcse
Agar jelly diffusion experiment gcse. Diffusion is the movement of molecules from a region of higher concentration to a region of lower concentration; The rate of diffusion is influenced by several factors: Temperature; Surface area; Concentration gradient; Diffusion distance; You can investigate how temperature affects diffusion using beetroot. 05 cm/ minute. Nevertheless, further experimentation must be done to improve the results of the experiment. Diffusing Hydrochloric acid through agar jelly containing universal indicator solution. Most cells are no longer than 1mm in diameter because small cells enable nutrients and oxygen to diffuse into the cell quickly and allow waste to diffuse out of the cell quickly. After 12 hours, the shoots are removed from the box and the appearance of each shoot, A, B and C is recorded. 5 A student carries out an experiment to investigate the factors affecting the rate of diffusion. Hypothesis The diffusion of mythelin blue is directly proportional to its concentration‚ hence as the concentration increases; the rate of diffusion increases too. Practical to carry out is the effect of temp on rate of diffusion. 5cm x 0. 1 cm, 0. The effect of cell size on diffusion can be investigated using cubes of agar jelly to represent cells of different sizes. Diffusion across the cell membrane. The effect of surface area to volume ratio on the rate of diffusion can be investigated by timing the diffusion of ions through different sized cubes of agar; Coloured agar is cut into cubes of the required dimensions (eg. The webpage conta IGCSE 2020 0610/63 May/June (pdf) Show Video with Step-by-Step Solutions. Effect of size on rate of diffusion. Other than that it's a poor model to use for cells as cells are a lot more sophisticated with their partially permeable membranes only allowing certain substances in to the cell via carrier/channel proteins. Particles in gases and liquids move around randomly, often colliding with each other or whatever container they are in. Students are active in this lesson, with a lot of opportunity for class discussion & real world application. Background Theory. 5 repeat the same for sizes’ of 1. Allows students to identify variables and hazards. Some of the substances transported in and out of cells by diffusion are oxygen and carbon dioxide in gas exchange, and of the waste product urea The effect of size (Surface Area to Volume ratio) on diffusion can be investigated by timing the diffusion of ions through different sized cubes of agar. Koch's work was important for 3 main reasons. Diffusion of perfume particles through a room is one of the simplest examples of diffusion. Part of Biology (Single Science) Cells Save to My Bitesize Remove from My Bitesize Practical: Demonstrating diffusion in a jelly If possible, reinforce some experimental skills and ask students to identify the independent, dependent and control variables of this experiment. The student makes five wells each of diameter 10 mm in the agar. Hence, molecular weight and time has an effect in the increase, decrease, slowness, and fastness of the diffusion of substances. Five different sizes of cubes were cut from a larger block using a scalpel. are created by pouring hot molten Jul 1, 2011 路 Coloured agar is made up and cut into cubes of the required dimensions (eg. On a white tile, use the scalpel and ruler to cut 3 cubes of agar from the block. Agar plates close agar plate A Petri dish that contains agar gel and usually some nutrients. When they collide they change direction which means eventually they spread out time, the circumference (mm/min) of each substance increased since there was diffusion in the agar – water gel wells. The reaction in the experiment will be between two reactants- sodium hydroxide (NaOH) mixed into the agar jelly, and hydrochloric acid (HCl) in which the agar segments will be immersed, in each experiment. 0 and 5 mg of merthiolate is added. If there is a Method. 2 cm3 of milk. 5 g) is suspended in 50 mL of 0. 2. Study with Quizlet and memorize flashcards containing terms like Biological processes can be investigated using models. 5 cm/10 minutes = 0. 1 M sodium hydroxide and coloured with phenolphthalein Jun 5, 2015 路 6 A student is given a Petri dish containing starch mixed with agar jelly. What experiment is used to investigate diffusion in a non - living system? Click the card to flip 馃憜. These have been taught in 2 hour sessions so may need breaking up if you have shorter lessons. Subject: Biology. K. When hydrochloric acid comes into contact with the cresol red, the purple indicator will turn colourless. Lift up withdrawing a small plastic plug of agar. 0 cm x she covers each cube in a solution of a coloured dye for three minutes Experiments were designed to investigate the diffusion of dyes into agar gels at three temperatures (30, 50 and 70 °C). Antibiotic-resistant bacteria that aren't affected by the antibiotic will continue to grow on the agar around the paper discs, but non Wash your hands after doing the experiment. The agar should be made using 0. Cut up three cubes of agar jelly to these sizes: 1cm by 1cm, 2cm by 2cm, 3cm by 3cm 2. Resource type: Lesson (complete) File previews. Coloured agar is cut into cubes of the required dimensions (eg. Feb 13, 2024 路 pdf, 136. 14 KB. Part of Preliminary syllabus. g. 1). Once cube should have sides 2cm long, one 1 cm long and one 0. Stop watch. Dec 8, 2020 路 A set of lessons used to teach the unit 3 content for the exam about the diffusion practical. increases, the more substances (e. doc, 99. 3 cm, 2 cm, 1 cm, 0. The experimental set-up was designed to enable … docx, 568. He developed the use of agar jelly for growing bacterial cultures on which he could experiment. Molecules move down a concentration gradient, as a result of their random movement. Feb 22, 2018 路 NEW GCSE 2016. Theory: Diffusion: Diffusion is defined as the movement of particles from a region of higher concentration to a region of lower concentration. 4. 5. 6, 0. 0 cm and one with sides of 1. 5cm, 1cm x 1cm x 1cm and 2cm x 2cm x 2cm) 1) Place paper discs soaked in different types of antibiotics on an agar plate that has an even covering of bacteria. Pores in this membrane are small enough to prevent the passage of large molecules (such as sucrose) but allow smaller molecules (such as glucose and water) to pass through by diffusion and osmosis. Prepare some agar jelly cubes mixed with the indicator phenolphthalein and sodium hydroxide. In this prac, a Sulphuric acid solution is used. Quality Assured Category: Biology Publisher: Longman. You must insure you are accurate with your measurements and safe with the razor blade. After 20 minutes, place a small, clear metric ruler underneath the Petri dish to measure the distance (diameter) that the dye has moved. Cr. 7. The plant shoots are placed in a dark box for 12 hours. Mark received: 27/30. This practical activity uses cubes of agar containing sodium hydroxide and a pH indicator to investigate link between surface area and diffusion. Remove the cap. B Working with a partner, one of you should pick up an agar block with the forceps and slowly lower it into the bottle. Take the bottle containing the lowest concentration of acid and stand it in the centre of the Petri dish. Wefer Explains the Agar Diffusion Lab set up and calculating the surface area to volume ratio. After 24 hours she pours iodine solution on to the agar jelly. A student used cubes of agar jelly containing universal indicator, which changes colour at different pH. 1. must be sterilised Siddharth Nair. A student investigated the effect of concentration on the rate of diffusion in model cells. To purchase exam Experiments were designed to investigate the diffusion of dyes into agar gels at three temperatures (30, 50 and 70 °C). 07 MB. This can be done in an autoclave which uses steam at high pressure to kill any microorganisms/pathogens present. Example data collection and main ideas are also explained. Simple step by step explanations of concepts up to the end of KS4. Diffusion is the movement of molecules from a region of its higher concentration to a region of its lower concentration. The student observed that the contents of test-tubes M1, M2, M3 and M4 were all blue. Continue boiling the mixture for about one minute, and then remove from heat. A great practical to use for the diffusion component of BTEC NQF Applied Science. 2 cm3 of sodium carbonate solution. 2 MB. 5cm, 1cm x 1cm x 1cm and 2cm x 2cm x 2cm) Purple agar can be created if it is made up with very dilute sodium You are provided with a block of agar jelly that has been dyed with cresol red. It dissolves readily in boiling water; a dilute solution is still liquid at 42 °C (108 °F) but solidifies at 37 °C (99 °F) into a firm gel. Put the cotton wool wad into the other end of the glass tube. using sterile agar jelly close agar jelly A gel Aim: To investigate the effect of antiseptics or antibiotics on bacterial growth using agar plates and measuring zones of inhibition; You will: Use aseptic technique to place filter paper discs soaked in different antiseptics or antibiotics onto uncontaminated agar plates containing bacteria The slab of jelly became clear first Explanation As cell SA increases, as does its SA to Volume ratio, this means there is more area for the acid to diffuse and there is less distance to the centre of the jelly. Diffusion. 03 MB. Videos have been filmed using time-lapse photography over a 20 minute Biology Section 1 - Diffusion and Osmosis Experiments. Place a single drop of each dye into the agar well. 1) Pour equal volumes of the hot Agar/Indicator mix into a different petri dish, leave to cool and set overnight. After some time, the colour of each substance had spread out as shown. Measure their surface area:volume ratio 3. 89 KB. 62 KB. Tests the effect of diffusion depending on the surface area of Agar Jelly. (Total for question = 1 mark) Answer the question with a cross in the box you think is correct . Feb 21, 2016 路 We had to be careful when cutting the agar jelly as the razor blade was sharp. - Relating diffusion to surface area. Investigating Diffusion. Molecular diffusion. She fills the wells with solutions of amylase, each with a different pH. Revise how variation in species can be generated by genetics and environmental influences for GCSE Biology, AQA. 1) Place paper discs soaked in different types of antibiotics on an agar plate that has an even covering of bacteria. The basic concept of this experiment is outlined below: The agar jelly contains a pH indicator. Get a hint. Scientific Report on an Agar Jelly Experiment. 8 and 1 cm sided squares. The colour changes will help us observe the process of diffusion. Three processes contribute to The effect of cell size on diffusion can be investigated using cubes of agar jelly to represent cells of different sizes. Practical: Investigating the rate of diffusion using agar. Agar plates are used to culture (grow) bacteria and fungi in the lab. 6 years ago. Antibiotic-resistant bacteria that aren't affected by the antibiotic will continue to grow on the agar around the paper discs, but non A method used extensively for the identification and characterization of antibodies is agar diffusion. Procedure. It covers how to prepare, use and store the agar. Active transport moves substances along the concentration gradient. Aim: To check how the surface area to volume ratio affects the rate of diffusion in an agar block. 5cm, 1cm x 1cm x 1cm and 2cm x 2cm x 2cm) The variable that is kept consistent is the dependent variable such as the percentage of diffusion of pigment in the agar cubes. 5×0. Age range: 16+. pptx, 7. GCSE Biology Study Group 2023-2024; AQA A Level Biology Paper 1 2018; A level biology AQA; Biology help please; GL366 - Agars for diffusion Guidance outlining the different types of indicator used for making agar cubes for diffusion. 2) Use the cork borer to cut 5 wells into the jelly making sure all the jelly is removed from the well. O. dish 1 dish 2 KMnO. Diffusion is the movement of particles from a high to lower concentration. 5cm, 1cm x 1cm x 1cm and 2cm x 2cm x 2cm) Purple agar can be created if it is made up with very dilute sodium hydroxide solution and Universal Indicator; Alternatively, the agar can be made up with Universal Indicator only Jun 2, 2017 路 Agar jelly diffusion experiement; Watch. The time taken for each agar cube to change colour is then recorded in the table Mar 29, 2021 路 Diffusion is the movement of a substance from an area of high concentration to an area of low concentration. 0×1. Safety considerations and waste disposal instructions are also included. sodium hydroxide) and add a few drops of phenolphthalein to it before the C. (Figure 4. In the experiment, agar cubes with the indicator phenolphthalein are used to determine the diffusion of the cubes. 27 The procedure is readily performed on a microscope slide. 93 KB. Add the cubes to 100cm3 of acid and start a stopwatch 5. The dish should incubated at 25°C to restrict the growth of harmful pathogens. Wash your hands after doing the experiment. Alternatively, the agar can be made up with Universal Indicator only. (a) A student used a scalpel to cut four identical cubes from a large piece of agar. Photosynthesis Jun 2, 2008 路 The surface area to volume ratio in living organisms is very important. 5cm) 2. A great practical & Kinaesthetic based lesson on Diffusion. Terms in this set (3) Procedure of experiment of diffusion in agar jelly. The acid will diffuse into the agar cubes and change the colour of the indicator. Aim: to see the affect of the volume is to surface area ratio on the rate of reaction using agar gel. Beetroot cells contain a dark purple Biology Experiment – Agar Block. Push the soaked end into one end of the glass tube. 5 cm Feb 22, 2018 路 Resource type: Lesson (complete) File previews. 81 MB. AGAR GEL LAB REPORT. Nutrients and oxygen need to diffuse through the cell membrane and into the cells. Method: * Cut the agar into different sizes of blocks with a knife and measure the size with the help of a ruler to make an accurate experiment. Diffusion uses energy to transport molecules into cells. Hydrochloric acid. This can be seen in a cell where gases diffuse through the cell membrane. Contains the method and results tables. There are numerous practical’s within this booklet Dr. as test tubes and Petri dishes. Click the card to flip 馃憜. Using a measuring cylinder measure 40ml of hydrochloric acid (1mol) Using tweezers put all of the cubes in a beaker containing Browse HSC Subjects. It is an unbranched obtained from the of some species of or . Measure the recommended amount of agar and distilled water in to a clean, sterile flask or beaker. . Agar ( / 藞e瑟伞蓱藧r / or / 藞蓱藧伞蓹r / ), or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from "ogonori" ( Gracilaria) and "tengusa" ( Gelidiaceae ). Apparatus: * 1 Petri-dish of agar * Knife * Test tubes * Beakers * 100 cm3 of HCl * Stopwatch * Lab coat * Ruler. The depth of diffusion for all 3 cubes is 0. 0 M Hydrochloric acid and start stop-clock. They were left to stand under the same physical conditions. The time taken for each agar cube to change colour The lid of the petri dish must be taped on and opened as little as possible to prevent contamination from microorganisms in the air. Describe and explain the differences in the three shoots, A, B and C after 12 Shaadi Baba. 5cm, 1cm x 1cm x 1cm and 2cm x 2cm x 2cm) Purple agar can be created if it is made up with very dilute sodium hydroxide solution and Universal Indicator. Repeat this procedure quickly with a second wad of cotton wool and hydrochloric acid. Cut a pair of agar blocks with a knife to a size 0. The rate of diffusion is 0. These laboratory notes provide a method for producing Phenolphthalein - sodium hydroxide agar and directions for conducting the experiment. The controlled variables will be keeping the concentrations of the Sodium Hydroxide constant, to use agar jelly from the same batch (so the type of agar jelly is exactly the same), and to keep the time Diffusion is the random movement of a substance from a region of high concentration to a region of low concentration. It is Jan 10, 2019 路 centres of separate petri dishes filled with agar jelly. (1) Active transport is used to obtain molecules in a low concentration environment. 5×1. To find out how changing the concentration of an acid will quantitatively affect the rate of diffusion in agar; Introduction. We can investigate how diffusion occurs in biological cells by using cubes of agar jelly. Record how long it takes for the cubes to turn colourless 6. The petri dish should be stored upside down to stop condensation falling on to the agar. Diffusion Theory. Particles (molecules and ions) in a liquid and a gas move continuously. We can make up agar jelly with an alkaline solution (e. Phenolphthalein is a base/acid indicator that turns clear when in contact with an acid. Diffusion occurs in gases and liquids. (a) In her first experiment x she makes three agar jelly cubes, one with sides of 4. It can be used as a , a substitute, a thickener for soups, in , and desserts such Incubating the plates allows the bacteria in the agar to multiply by binary fission, this may be visible by the agar darkening or by colonies appearing; The antiseptics present in the discs will diffuse out into the agar, with the concentration decreasing with distance from the disc Diffusion can be seen in the following experiment: A pH indicator called phenolphthalein turns pink in alkaline solutions and turns colourless in acidic solutions. - Why diffusion is important to cells. Osmosis is the diffusion The Petri dishes and culture medium - agar gel, must be all sterilised before conducting the experiment by heating to a high temperature e. 10 C. 3. Put one of the cotton wool wads in the mouth of the ammonia bottle and carefully invert it to soak one side of it. are created by pouring hot molten agar gel close agar gel A jelly-like substance that is derived from a type of seaweed and 1. 1a) List the agar cubes in order of size, from largest to smallest. This resource follows the AQA Biology GCSE syllabus but is also applicable to Practical Guide 1: Gas Exchange and Transport in Plants and Animals. The variable I am observing/recording, the dependent variable, is the rate of diffusion (NaOH turns the agar cube pink as it disperses into it). Biology: Visking tubing vs Agar in factors of diffusion investigation; Agar disk diffusion method question - University assignment [Unofficial Markscheme] AQA A Level Biology Paper 1 7402/1 - 9 Jun 2022; Help! Biology; Pearson Applied Science Unit 3; OCR A- Level Biology 2023; AQA GCSE Biology Paper 1 (Higher Combined) 8464/1H - 16th May 2023 Diffusion Investigating the effect of surface area As a cell’s volume close volume How much space an object occupies. Method: Cut the agar jelly blocks into 5 squares of sides 0. 37 KB. Cut a 1 cm 3 cube of agar close agar jelly A gel made from algae, which provides an ideal growth medium. PowerPoint presentation and worksheet on diffusion and osmosis for teaching and revision. The higher the temperature, the more kinetic energy particles have and therefore the faster they can move by diffusion. These cubes can be made of agar jelly close agar jelly A gel made from algae, Jul 11, 2023 路 Obtain a Petri dish of agar; Take the plastic straw and gently stick down into the agar. Apr 1, 2019 路 [D Biology Classroom] CAIE A-level biology 9700Use agar blocks of different sizes to investigate the effect of changing SA: Vol on diffusion. 4. Sterile agar plates The agar can be made sterile by boiling; Diluted bacterial broth Experiments were designed to investigate the diffusion of dyes into agar gels at three temperatures (30, 50 and 70 °C). oxygen) it needs for cell reactions. 3) Use a pipette to carefully fill the first well with 1. Tweezers. Make up oe agar jelly with phenolphthalein ( pH indicator , pink in alkaline solutions and colourless in acidic solutions ) and dilute sodium hydroxide . Put cubes with phenolphthalein so they turn pink as they are alkaline 4. Diffusion is an entirely passive process; the movement of particles in a fluid is dependent on how much kinetic energy they have. Then fill a beaker with dilute HCl . * Put some hydrochloric acid into a test tube and make sure that it will completely May 2, 2024 路 Diffusion is the spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration. pptx, 1. Dialysis tubing (sometimes referred to as visking tubing) is a non-living partially permeable membrane made from cellulose. Creative Commons "Sharealike". 01 cm 1b) List the agar cubes in order of surface to volume ratio, from largest to smallest and compare the two lists. pptx, 2. 2, 0. The iodine solution turns the starch in the agar jelly a dark blue colour. Time how long it takes for the indicator in each cube to turn colourless 5. May 2, 2024 路 Agar is isolated from the algae as an amorphous and translucent product sold as powder, flakes, or bricks. Pink agar jelly in dilute acid. Three different substances were added to each of test-tubes M1, M2, M3 and M4: 5 drops of bromothymol blue indicator. We had to wear goggles due to the hydrochloric acid we were using. This lesson contains: - Powerpoint file (whole lesson) Questions are from the new Kerboodle GCSE 1-9 textbook. GCSE; Edexcel; Transport in cells - Edexcel Core practical - Investigating osmosis in potatoes. Explain to students that investigations of osmosis in non-living situations use Visking tubing, which acts like an artificial partially permeable membrane. 1 M phosphate buffer of pH 7. Blocks of agar jelly, containing a plant hormone, are placed on the cut surfaces of the plant shoots. Coloured agar is made up and cut into cubes of the required dimensions (eg. Controlled Variables Time time was kept constant while testing the diffusion spread of mythelin blue with each concentration. 0. Diffusion - This lesson is based on the AQA Specification - This lesson covers: - The definition of diffusion. This Surface Area and Diffusion Practical Investigation uses cubes of agar containing sodium hydroxide and a pH indicator to investigate link between surface area and diffusion. This resource is essentially a teacher/technician guide to a range of possible practical activities to investigate gas exchange and transport in both plants and animals. What was the role of the universal indicator in Feb 19, 2015 路 Hi Not sure If i've left it too late in contacting you as my exam is literally in 2 hours but I am doing the agar jelly experiment where all cube sizes are the same while I am changing the concentration gradient of the hydrochloric acid, I am doing paper 1 tonight and wondered what was on the paper and what is best to revise. Collect 3 agar cubes (2cm, 1cm and 0. pptx, 12. 1M hydrochloric acid 3. Place all cubes in the SAME beaker and cover with 20ml of 0. Lesson 1 + 2 = Practical introduction (method evaluation focus) Lesson 3 + 4 = Practical Part A (practice with agar) Lesson 5 + 6 = Part B practice 5 give a blue-black colour, whereas a similar test on a control leaf from a plant kept in the light will give a blue-black colour. The method was originally devised by Ouchterlony. For an organism to function, substances must move into and out of cells. Agar cubes of different surface area to volume ratios are placed in beakers of acid. 0 and 1. It is modelled with a simple experiment using different-sized cubes of agar containing a pH indicator. D. GCSE; OCR 21st Century; Limitation of diffusion in multicellular organisms. >100 o C. Includes a visual guide to the required practical. Replace the lid on the bottle. 89 MB. 5 cm. Write your results in a table. Because of this movement, particles will spread themselves evenly throughout a liquid or a gas. [1] [2] As found in nature, agar is a mixture of two components, the linear polysaccharide agarose It is modelled with a simple experiment using different-sized cubes of agar containing a pH indicator. Practical 2: Investigating the rate of diffusion using agar. Posted from TSR Mobile. docx, 2. Leave some space between the discs 2) The antibiotic should diffuse into the agar jelly. A Place the Petri dish base on the white tile. Method: 1. docx, 79. Agarose (0. docx, 21. Start the stopclock straight away 4. The lengths of the arrows indicate the relative distances travelled by particles of each substance. Procedure #1. When the surface of the agar cube is put in the sulphuric acid, it will become clear, but the GCSE; Edexcel; Gas exchange in animals - Edexcel Factors affecting the rate of diffusion. He discovered the specific germs that caused a number of diseases: anthrax in 1876, tuberculosis in 1882, and cholera in 1883. 0 cm, one with sides of 2. He developed a method for staining and photographing microorganisms using dye. Theory: Agar is a substance chiefly used as a for work. Which statement Step 9 Another four test-tubes were labelled M1, M2, M3 and M4. Glass petri dishes and agar gel close agar gel A jelly-like substance that is derived from a type of seaweed and used in the lab as a medium on which to grow bacteria and fungi. Diffusion with jelly cubes In this experiment, students can investigate diffusion by placing agar cubes of varying sizes in acid and observing the colour change. Repeat. . The constant variable is the features of the experiment that is kept the same throughout the entire experiment such as, the amount of time the agar cubes are left in the beaker and the amount of acid in the beaker. Although agar is insoluble in cold water, it absorbs as much as 20 times its own weight. The disc diffusion method is commonly used to test for antibiotic resistance in bacteria; It allows for multiple antibiotics to be tested at once; This is not a required practical but it helps to illustrate the use of aseptic techniques; Apparatus. Cubes of agar jelly containing universal indicator were used to represent the model cells. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Mar 10, 2019 路 Jelly cubes and diffusion practical. Use a scalpel , cut out the same size cubes from the jelly and put it into a beaker . Using heat resistant hand protection, hold the beaker/flask over a flame and stir the mixture gently using a sterile stir rod while heating. TAGS. There are no advantages except the fact that agar cubes allow diffusion. lz le oo vg kb ea tb wr gt yl