Biology Spec points covered Starter options Practical activity Teacher-led activity CB1a Microscopes B1.3 B1.4 B1.5 B1.6 Explain how changes in microscope technology, including electron microscopy, have enabled us to see cells with more clarity and detail than in the past Demonstrate an understanding of size and scale in relation to microscopy, including magnification calculations. Demonstrate an understanding of the relationship between quantitative units, including (a) milli (10-3), micro nano (10-9), pico (10-12) (b) calculations with numbers written in standard form Produce labelled scientific drawings from observations of biological specimens using microscopes 1) Ask students how microscopes work, and establish the idea that they magnify small things, making them and their details easier to see. Explain that the study of cells would not be possible without the invention of the microscope and ask students to suggest why. 2) Write the words kilo-, milli-, micro-, nano- and pico- on the board, in random order. Write the prefixes in size order on the board and then show how the units are related (kilo- multiplies the base unit by 1000, milli- divides it by one thousand, micro- divides it by 100 000 etc.). Students use microscopes to examine pre-prepared slides of small objects (e.g. hair, pollen). Students will produce a range of drawings annotated with names of objects and calculated magnifications. Equipment: Microscope, selection of pre-prepared slides (e.g. hair, pollen, fish scales, synthetic fibres, mushroom gills, ear wax, pond water, newsprint). Help students to understand the difference between resolution and magnification by using the idea of digital cameras. Those with many megapixels have a higher resolution than those with only a few. Digital resource: Size and scale animation CB1b Plant and animal cells B1.1 Explain how the sub-cellular structures of eukaryotic and prokaryotic cells are related 1) Ask students to write a simple definition of a cell. Ask for a volunteer Use a microscope to look at simple animal and/or plant cells and identify their Hold up a metre rule and ask students to estimate the width,
Digital: Inside a cell video CB1c Cell Specialisation B1.1 B1.4 B1.6 Explain how the sub-cellular structures of eukaryotic and prokaryotic cells are related to their functions, including: (a) animal cells - nucleus, cell membrane, mitochondria and ribosomes (b) plant cells - nucleus, cell membrane, cell wall, chloroplasts, mitochondria and ribosomes ... Demonstrate an understanding of size and scale in relation to microscopy, including magnification calculations Produce labelled scientific drawings from observations of biological specimens using microscopes 1) Write the word 'adaptation' on the board. Write down adaptations of three animal species. Reinforce the link between adaptation and environment to show the purpose of the adaptation. Explain that different kinds of cell have different forms and different functions. This leads to the idea that the form of different kinds of cells is adapted to their function. 2) Challenge students to sketch the main features of different kinds of cells that have different functions related to cell structures with which they are familiar. Students should annotate their sketches to identify the features that are adaptations to their Students study prepared slides of some specialised human cells. Students identify adaptations within the cells. Equipment: Prepared and labelled slides of human cells and tissues (Suitable slides include: human sperm cells, human egg cell, ciliated cells lining the oviduct, microvillar epithelial tissue of small intestine.); light microscope and light source, transparent ruler or graticule. Work with student to think up a simple mnemonic that will help with remembering the difference between haploid and diploid, such as HAploid cells have HAlf the normal chromosome number. Using two sizes of sieve with the same mesh to show how quickly the same amount of powder (e.g. flour) can be sieved through it. Make the link between surface area and rate of absorption. Digital: To follow
function. CB1d Inside Bacteria B1.1 B1.5 Explain how the sub-cellular structures of eukaryotic and prokaryotic cells are related to their functions, including: ... (c) bacteria - chromosomal DNA, plasmid DNA, cell membrane, ribosomes and flagella. Demonstrate an understanding of the relationship between quantitative units, including (a) milli (10-3), micro nano (10-9), pico (10-12) 1) Write the word ‘bacteria’ on the board. Discuss with students the sub-cellular structures that they would expect to find in bacterial cells. 2) Remind students that both plant and animal cells are described as being eukaryotic because they have nuclei. Establish the idea that eukaryotic cells contain nuclei but prokaryotic cells do not. Students examine live yoghurt cultures to look for bacteria. Even at the highest magnifications, bacteria will appear very small. Students should draw outlines of any bacteria they can see. Equipment: Live yoghurt (liquid varieties are more useful), sterile toothpicks/cocktail sticks, access to beaker of 1% Virkon in which to dispose of used toothpicks, light microscope, microscope slide, coverslip, water or methylene blue stain, paper towel, gloves, pipette. Optional: microscope with ×100 oil-immersion objective, video camera and display, non-live yoghurts. Write up A × 10n on the board and explain how standard form works. Use arrows to illustrate how the unit moves by the number of times shown by the power of ten, both to the left and right for positive and negative powers. Digital resource: Cell parts and functions interactive B1e Enzymes and nutrition B1.12 Explain the importance of enzymes as biological catalysts in the synthesis of carbohydrates, proteins and lipids and their breakdown 1) Show students a piece of fruit that has started to go soft due to decay by a mould fungus. Explain that the fungus is Students investigate the action on starch solution of amylase from their own saliva or with prepared amylase solution, using the iodine test. Demonstrate to students how starch can be synthesised from a potato.
B1.5 into sugars, amino acids and fatty acids and glycerol … (b) calculations with numbers written in standard form growing through the fruit with microscopic fungal threads and 'eating' it. Try to link the idea of softness to digestion in order to absorb small food molecules, as in the human gut. 2) Ask students to work in pairs or small groups to write down as many processes and reactions as they can remember that happen in living organisms. Then ask them to try to identify those processes or reactions where smaller units are joined to make something large, and those that show where something large is broken down into smaller units. The starch/amylase mixture with the iodine solution should cause a change in colour from yellow to blue-black. This indicates the presence of starch. As the amylase starts to break down the starch, the change in colour should reduce until all the starch is broken down and the colour of the iodine returns to yellow. Equipment: test tube containing 5 cm3 1% starch suspension, test tube containing 1 cm3 1% amylase solution (or 0.5% pancreatin solution) or saliva collected by student (see instructions above), water bath at 30 °C (or refer to instructions on packaging if using bacterial amylase), 5 cm3 syringe or pipette, beaker of water for washing pipette, eye protection, iodine solution, well tray (spotting tile). Optional: if using saliva – hypochlorite (bleach) solution or 1% Virkon solution for disinfection of equipment and Equipment: potato, knife, pestle and mortar or blender, bench centrifuge and tubes, water, iodine solution, pipettes, 5 cm3 1% glucose-1-phosphate solution (prepared just before the lesson and stored in a fridge till used), water bath at 25 °C, test tubes and rack, well tray (spotting tile). Digital resource: Starch and amylase Presentation
benches, small beaker or other container for collecting saliva, Benedict's solution, water bath at 70 °C, additional syringe or pipette. B1f Enzyme action B1.7 B1.8 Explain the mechanism of enzyme action including the active site and enzyme specificity Explain how enzymes can be denatured due to changes in the shape of the active site 1) Explain that an egg white is made up of proteins. Boil an egg white in a boiling tube. Remove the solidified white from the tube with a spatula. Remind students that enzymes are proteins, and ask them to suggest how enzymes might be affected by heat. Equipment: Fresh egg, boiling tube, boiling water bath , tongs, spatula. 2) Students work in groups to write a 'story' that will describe the role of enzymes in digestion, such as 'Enzymes are essential for the digestion of food.' Students investigate the effect of temperature on the time taken for amylase to digest starch. The length of time for the reaction to reach completion (as indicated by the iodine solution remaining yellow) should change with temperature. Equipment: For each temperature tested: test tube containing 5 cm3 1% starch suspension, test tube containing 1 cm3 1% amylase solution (or 0.5% pancreatin solution) or saliva collected by student, water bath at appropriate temperature, 5 cm3 syringe or pipette, beaker of water for washing pipette, eye protection, iodine solution, well tray (spotting tile). Demonstrate that enzymes are specific to particular substrates by testing a range of enzymes on a range of substrates. This could be done by using the separate enzymes found in laundry detergents (available from the NCBE) on a range of clothes 'stains' made with a particular substrate (e.g. cooking oil (lipid), egg white (protein), ketchup (carbohydrate)) on a piece of clean old cotton fabric such as sheeting. Equipment: cloths of old white sheeting or similar, stained with a range of substrates that contain only one kind of
Optional: if using saliva – hypochlorite (bleach) solution or 1% Virkon solution for disinfection of equipment and benches, small beaker or other container for collecting saliva. biological molecule (each cloth should have the same range of stains, and there should be one cloth for each type of enzyme to be used), range of enzymes that have different substrates Digital resource: Enzymes animation B1g Enzymes activity B1.9 B1.11 B1.10 Explain the effects of temperature, substrate concentration and pH on enzyme activity Demonstrate an understanding of rate calculations for enzyme activity Investigate the factors that affect enzyme activity 1) Cut an apple or pear in half (slices of celeriac also work well), and sprinkle lemon juice over the cut surface of one half. Explain that cutting the fruit breaks open cells, releasing enzymes that were inside. Ask students to describe the changes they see happening, and try to suggest a reason for any differences between the two halves 2) Ask how you would tell from the results of two experiments using This practical investigates the effect of pH on amylase, the enzyme that catalyses the breakdown of starch to smaller sugar molecules. The iodine test identifies the presence of starch, but does not react with sugar molecules The optimum pH for human salivary amylase is pH7. Other amylases may vary from this value, but there should be one pH that clearly allows greater enzyme activity than the others. Equipment: For each pH tested: test tube containing 5 Use a suitable enzyme and substrate such as using catalase/hydrogen peroxide and measure the volume of oxygen collected every 30 s for 5 minutes. Measure and record the pH of the enzyme/substrate solution at the start of the experiment.Record the cumulative gas volume over time, and plot the values on a graph of gas volume against time Students should make the link between the
starch and amylase which had the faster rate. Students consider what they would need to know in order to calculate the rate of the reaction. cm3 freshly made 1% starch suspension (mix 5 g soluble starch with a little cold water, pour into 500 cm3 of boiling water and stir well, then boil until you have a clear solution), test tube containing 1 cm3 1% amylase solution (or 0.5% pancreatin solution) or saliva collected by student, water bath at optimum temperature for the enzyme (e.g. 37 °C), buffer solution at a set pH (see table above), 5 cm3 syringe or pipette, beaker of water for washing pipette, eye protection, 0.01 mol dm-3 iodine solution, well tray (spotting tile). Optional: if using saliva – hypochlorite (bleach) solution or 1% Virkon solution for disinfection of equipment and benches, small beaker or other container for collecting saliva. rate of reaction slowing down and the amount of substrate left in the solution decreasing. Equipment: hydrogen peroxide solution (using one of following concentrations: 10, 15, 20, 25, 30 vol) in clean brown bottle, 2-holed bung with delivery tube in one hole connected to rubber tubing, conical flask, large syringe (at least 20 cm3), trough containing water, 2 cm3 syringe, 50 cm3 or 100 cm3 measuring cylinder, clamp stand and boss, stopclock or stopwatch, eye protection. Digital: Substrate concentration presentation B1h Transporting substances B1.15 Explain how substances are transported by diffusion, osmosis and active transport. Show students the diffusion of potassium manganate(VII) in water Students measures the percentage change in mass of strips of potato placed in Demonstrate diffusion and osmosis in the small intestine using a
Chemistry Spec points covered Starter options Practical activity Teacher-led activity C1a States of matter C2.1 C2.2 C2.3 C2.4 Describe the arrangement, movement and the relative energy of particles in each of the three states of matter: solid, liquid and gas Recall the names used for the interconversions between the three states of matter, recognising that these are physical changes Explain the changes in arrangement, movement and energy of particles during these interconversions Predict the physical state of a substance under specified conditions, given suitable data (links to a Maths statement). In pairs, using paper or mini-whiteboards, students draw and write what they already know about the particles in the three states of matter. Groups feedback one or more of their answers to the class. Students record the temperature and appearance of a molten test substance. The temperature should decrease rapidly until the substance begins to solidify, at which point the temperature should remain constant. When the substance has solidified, its temperature should begin to decrease again. Equipment: Eye protection, stop clock, test tube rack. Boiling tube containing the molten test substance with a thermometer. Demonstrate the sublimation and deposition of iodine. Boiling water is not hot enough to melt or boil the iodine, so why does a vapour form and crystals re-form? Discuss the changes in arrangement, closeness and movement of the particles in the two state changes. Equipment Eye protection, iodine (maximum 0.25 g), stand, boss, clamp, round-bottomed flask, boiling tube, crushed ice, mineral wool, large beaker, kettle for hot water. Digital Changes of state animation
C3.7 precautions for a range of practicals including those mentioned in the specification Investigate the composition of inks using simple distillation… C2e Drinking water C3.4 C0.6 C3.8 Describe an appropriate experimental technique to separate a mixture, knowing the properties of the components of the mixture Evaluate the risks in a practical procedure and suggest suitable precautions for a range of practicals including those mentioned in the specification Describe how a waste and ground water can be made potable, including the need for sedimentation, filtration and chlorination b sea water can be made potable by using distillation c water used in analysis must not contain any dissolved salts 1) Students write down ways in which tap water is used. 2) Show the class a beaker (or photo) of discoloured water, with suspended fine particles and pieces of floating leaf. Students discuss which separation techniques they could use to separate water from the mixture, or to remove contaminating substances from the water. Equipment: Beaker of discoloured water, produced by mixing some soil and leaves with water. Students use alum and filters to clean dirty water. The water will become clearer as particles form a sediment. Equipment: Eye protection; beaker, stirring rod, scissors, plastic fizzy drinks bottle; coarse gravel, fine gravel, sharp sand; alum (aluminium potassium spatula; dirty water, e.g. produced by mixing soil with water. Demonstrate a simple solar still. Ask students to identify the hazards presented by the simple distillation of water and how to control the risks. Demonstrate adding silver nitrate solution to distilled water, and to water containing chloride ions, to show the effect of dissolved salts. Discuss the reasons why water used for analysis should not contain dissolved salts. Equipment: eye protection, 0.05 mol dm–3 silver nitrate solution, deionised water, sodium chloride
C1.5 Describe the nucleus of an atom as very small compared to the overall size of the atom C3b Atomic mass and numbers C1.6 C1.7 C1.8 Recall that most of the mass of an atom is concentrated in the nucleus Recall the meaning of the term mass number of an atom (links to a Maths statement). Describe atoms of a given element as having the same number of protons in the nucleus and that this number is unique to that element Calculate the numbers of protons, neutrons and electrons in atoms given the atomic number and mass number (links to a Maths statement). 1) Students brainstorm everything they know about ‘elements and the periodic table’ 2) Challenge students to think up ways of telling different atoms apart. Students weigh samples, of different elements, made up so the masses of the samples will be in the same proportions as the masses of the atoms. Students then use the data, for carbon and magnesium, to work out the ratios of the mass numbers, and the masses of samples, in their simplest form. Students should conclude that the ratios of the mass numbers of the atoms of elements are the same as the ratios of the masses of their atoms. Equipment: electronic balance (at least accurate to +/- 0.1 g), labelled containers, with sealed lids, containing samples of four elements: carbon (4.5g), magnesium (9g), sulfur (12g) and copper (24g) Display the nuclide notation (AZSymbol) for some simple atoms on the board, and initiate a class discussion on how models of the nuclei of these atoms could be made. Demonstrate how the nuclei of some of the atoms described on the board can be constructed using polystyrene balls of different colours (e.g. red for protons and green for neutrons) and adhesive putty. Equipment: coloured polystyrene balls and adhesive putty and some prepared nuclei. Digital: Protons, neutrons and electrons interactive activity 0
C3c Isotopes C1.9 Describe isotopes as different atoms of the same element containing the same number of protons but different numbers of neutrons in their nuclei Calculate the numbers of protons, neutrons and electrons in atoms given the atomic number and mass number (links to a Maths statement). Explain how the existence of isotopes results in some relative atomic masses of some elements not being whole numbers Calculate the relative atomic mass of an element from the relative masses and abundances of its isotopes (links to a Maths statement). 1) Write the following terms on the board: element, atom, nucleus, protons, neutrons, electrons and electron shells. Ask students to work in pairs to write one sentence that contains all the terms. 2) Show the students five boxes, labelled with different masses, in easy whole numbers. E.g. box A = 2 kg; box B = 4 kg; box C = 6 kg; box D = 10 kg and box E = 15 kg. Discuss the idea of relative amounts with students and how we can calculate how much greater or smaller one thing is compared with another. Give students six boxes containing a set number of heavy gauge washers (e.g. 1 box containing 2 washers, 3 boxes containing 4 washers and 2 boxes containing 6 washers). Tell students the mass of the empty boxes. Working in groups, students measure the masses of the boxes and work out the mass of their contents. Students then carry out calculations on the relative masses of the contents of the boxes. Equipment: (per group) electronic balance, 6 opaque boxes, which are sealed but can be opened, each containing a set number of heavy gauge washers (e.g. 1 box containing 2 washers, 3 boxes containing 4 washers and 2 boxes containing 6 washers Using polystyrene balls and sticky pads demonstrate the structure of the nuclei of different isotopes of lithium (6Li and 7Li). Using a balance demonstrate to the students that isotopes of the same element have different masses. (Discuss why electrons are removed/omitted from the models) Define the term ‘isotope’ and discuss why they are still atoms of the same element. Digital: to follow
to collision interactions upwards force from the spring) and elicit the idea that the mass is not moving because these forces are balanced. Then ask students to think about why the spring is pulling up – it is pulling up because the mass is pulling it down. Introduce the term 'action-reaction' pairs. interacting objects in an equilibrium situation. Students should find that the forces on all forcemeters are the same. The pull of the 1.0 kg mass on the forcemeter is 10 N and the pull of the forcemeter is also 10 N. Equipment: masses and mass hanger totalling 1.0 kg; pulley fastened to the edge of the bench; lengths of string; 3 forcemeters (0−10 N) adjusted to read zero when held horizontally; box of crumpled newspaper descriptions of both action-reaction pairs and balanced forces, and ask students to explain the difference. Digital: TBC P2f Momentum P1.19 P1.20 [Apply Newton's third law] to collision interactions and relate it to the conservation of momentum in collisions. Recall and use the equation: momentum (kilogram metre per second, kg m/s) = mass (kilogram, kg) x velocity (metre per second, m/s) p = m x v Use Newton's second law Set up an air track with two gliders. Show them what happens when they collide. Add some mass to one of the gliders. Demonstrate, Add more mass and demonstrate again. Students should be able to see that the greater the mass of the second glider, the more slowly it moves after the collision. Students use a runway and trolley to make measurements of a variety of different trolley movements from which they calculate the momentum. If carried out carefully, this experiment conserves momentum very accurately. The similarity in the figures for momentum before and after collision can be highlighted to show that momentum is being Remind students that the forces on the colliding objects are equal in size and in opposite directions (Newton's Third Law). As the forces only occur while the two objects are in contact, the forces are also applied for the same time to each object. Then rearrange the acceleration formula
P1.25 brakes e) the state of the road f) the amount of friction between the tyre and the road surface. Describe the factors affecting a driver’s reaction time including drugs and distractions low-speed than impacts. Digital: Stopping distances interactive P2i Crash Hazards P1.26 P1.26 Explain the dangers caused by large decelerations… estimate the forces involved [in large decelerations] in typical situations on a public road. 1) Ask students to suggest different causes of crashes. Ask them to then think about what determines the amount of damage and what safety features are built into cars to mitigate dangers to people. 2) Show students a video on the internet showing the landing of the Mars Pathfinder probe or the Spirit and Opportunity landers. These missions used airbags to cushion the final descent of the probe. Ask students to try to explain how the Students test different designs of crumple zone on a dynamics trolley. The deformation of a piece of Blu-tack® can be used to indicate relative force. However, much better quantitative data will be obtained if a force sensor is used. Alternatively, a smartphone that includes an accelerometer can be used. Students should find that the presence of some kind of crumple zone affects the impact force. Show students two statements and discuss which of the two statements is correct: ● If two vehicles, both travelling at 60 mph, collide head-on, the crash is much worse than a car travelling at 60 mph hitting a wall. ● It's only worse because there are two lots of people to be injured and two cars to be damaged. The forces on the car are just the same. This question addresses a common