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Btec Applied Science Unit 3
What is a hypothesis? - An Idea that you can test using practical experiments What are the Key features of a good hypothesis? - A good Hypothesis must: Be able to be tested scientifically Relate one dependent variable to on independent variable What is a Null Hypothesis? - States that there is no relationship or causality, for example, no relation between the temperature and the rate of reaction. What does qualitative data refer to? - It refers to the appearance or value of something, such as the colour observed or whether the bubbles are produced. What does Quantitative data refer to? - It refers to numerical measurements made, such as the volumes and times measured. What is SOP? - The Standard Operating Procedure. This is an established procedure or method used to carry out a routine activity. It ensures consistent results every time. What are some examples of SOPs? - Titration, Handling of chemicals, disposal of waste, qualitative analytical tests, preparing solutions What are risk assessments? - It identifies hazards, evaluates the risks associated with those hazards and it determines ways to eliminate or control those risks. What is a Hazard? - When the equipment or substance can cause harm, for example a hot plate or hydrochloric acid What is a risk? - The harm that the hazard could cause and the chances of it happening, for example the risk of using a hot plate is getting burnt.
What is the independent variable? - The variables you change during an investigation. What is the Dependent variable? - The variables you are investigating and measure during an investigation. What is the control variable? - The variables you keep constant during an investigation. What should a method be? - A step-by-step set of instructions, Be logically ordered, allows you to take sensible measurements, and allows you to test your hypothesis. When planning your method what do you need to make sure? - That it will procedure a range of results, reliable results, precise results, and accurate results. What are some types of data? - The data can be continuous such as the age of plant ir number of plants. Some data can be a mixture of numbers and names such as the number of different types of plants found in a garden. What data is normally displayed on a bar chart? - Continuous data. You need to make sure its a smooth curve of best fit, and that the curve goes through or near most of the points. What are bar charts used for? - They are used for discrete data but can be used to compare different sets of data. What is the Pattern on the graph? - The shape of the graph. It is the line that goes up as time goes by but eventually levels off What is the trend on a graph? - The relationship between factors on the graph or in the table. The full trend is that the volume increases as the time increases but then levels off after a certain amount of time. What is the sample size? - The number of people sampled in the investigation. To be confident in your conclusions you need a large sample size to give strong evidence.
What are proteins made up of? - amino acids What four chemical groups are attached to the central (alpha) carbon? - A hydrogen atom. A amino acid. A carboxyl group. A variable R group (side chain). How many different R groups are there? - There are 20 different R groups which means there are 20 different amino acids. What are amino acids linked together by? - Peptide Bonds. What does a condensation reaction occur between? - Two amino acids. What is produced in a condensation reaction? - Water. What is a dipeptide formed by? - Two amino acids linked by a peptide bond. What do three amino acids form? - A tripeptide What do many amino acids join to form? - A polypeptide What is a polypeptide with more than 50 amino acids called? - A protein. What is an active site? - The part of an enzyme where the biochemical reaction takes place. What is a secondary structure? - Where a polypeptide chains form orderly shapes. What are secondary structures held in shape by? - Hydrogen bonds between the -NH of one of the peptide link and the -C=O of another amino acid What is tertiary structure? - a three dimensional shape of a secondary structure
What does the tertiary structure give? - It gives the enzyme the shape of its active site. What are the most common shapes of secondary structures? - Coiled α-helix and folded β-pleated sheet What does the active site consist of? - A small number of amino acids which form a specific shape because of the proteins secondary and tertiary structure. When an enzyme catalyzes a reaction where does it take place? - It takes places on the active site of an enzyme. What do enzymes work specifically to? - catalyse one type of biochemical reaction. In a biochemical reaction what are substrates converted to? - They are converted into products. What does the substrate bind to? - The active site. Only specific substrates will bind to a particular enzymes site. What shape does the substrate have? - They have a complementary shape to the shape of the active site on the enzyme. What happens after the reaction? - The product is released and the active site is available to catalyse further reactions. The active site is a specific shape that only the substrate will fit, What happens to the active site is the temperature goes too high? - The temperature is too high, the hydrogen bond will break. This means the enzyme changes its shape so the active site loses its shape. The enzyme is denatured and co no longer act as a catalyst. What is a catalyst? - It is a substance that speeds up a reaction. It can take part in the reaction but is left unchanged at the end of the reaction.
What happens if the specific conditions are not present? - The enzyme-catalysed reaction may slow down or might not work at all What is the optimum temperature? - Each enzyme has a optimum temperature at which it works fastest. What happens as the temperature increases to the optimum temperature? - The reaction rate also increases. What happens below the optimum temperature? - There is less energy which means there is fewer collisions and therefore a slower reaction. What happens above the optimum temperature? - The hydrogen bonds in the enzyme breaks and the enzyme and active site loses its shape and therefore there is no catalysis What do enzymes have? - An optimum pH What does pH affect on the active site? - The charge. If the pH changes then the charges on the active site changes ad the substrate may no longer be able to bind to it What can the concentration of the enzyme and substrate affect? - The rate of reaction. What happens if the concentration of the substrate is too high? - There will be no more active sites for them to bind to. Increasing the concentration of the substrate will no longer affect the rate of reaction What happens if the concentration of the enzyme is too high? - There are too many free available active sites compared to the substrate molecules, the rate of reaction no longer increases. What is diffusion? - Diffusion is the movement of substances from a region of high to low concentration. What can diffusion occur across? - It can occur across a membrane. As long as the molecules are small enough to pass through the membrane then diffusion will occur
What factors affect the rate of diffusion? - Size- The larger molecules move more slowly then smaller ones, so the rate of diffusion decreases. Temperature- A higher temperature increases the energy molecules have and so they move faster, increasing the rate of diffusion. Distance through a substance- The greater the distance that the molecules must travel through a substance, the slower the rate of diffusion. Surface area- As surface area increases, the area of which molecules cans spread is increased and so he rate of diffusion increases. Shape of the surface of which the molecule is diffusing- the shape of the surface of which the molecule is diffusing can affect the rate of diffusion. What does the kinetic theory explain? - It explains the properties of different states of matter. It also explains diffusion What is the arrangement of particles in a solid? - They are close together in a regular pattern. What is the arrangement of particles in a liquid? - They are close together in a random pattern. What is the arrangement of particles in a gas? - They are far apart and in a random pattern. What are the properties of solids? - They are in a fixed shape and they cannot flow. They cant be compressed or squashed. What are the properties of liquids? - They take shape of a container, they flow and move randomly. They cannot be compressed or squashed. What are the properties of gases? - They completely fill container and they can flow and move randomly. They can be compressed or squased. Where can diffusion happen within? - A mixture of liquids, a mixture of gases, and a mixture of liquids and gases.
What are the effects of too little rainfall in plants? - Yellow leaves, dry leaves and ground cracks What are the effects of too much rainfall in plants? - Yellow leaves, Rotted roots, minerals and nutrients washed away and soil erosion. How do plants take up mineral ions? - Through their roots What does random sampling mean? - It means that each potential sample has the same probability of being selected. When is random sampling used? - When the area under the study is large. When it is fairly uniform and when there is limited time. What can piolet study's do? - They can help you work out your sampling size. What is the minimum sample size? - The minimum sample size is the number of samples at which the number of different species found starts to level off What Abiotic factors can affect plant population? - The soil type/ moisture/ pH. Topography, for example steepness of slopes. Temperature. What is a quadrat? - A quadrat is a small area of habitat, which sometimes has a grid within it. The frame is placed in the ground and the plants and animals inside are counted. What is a point frame? - It contains a number of pins. What is a line transects? - Sampling lines are set up across the area to be sampled. Species can be recorded along the whole length of the line, this is continuous sampling. Or when species can be recorded at set intervals along the line, this is systemic sampling.
What is a belt transcet? - It is similar to a line transect but it gives information on the abundance of species. Quadrats are placed at set intervals along the line and numbers of each species are counted within them What do you need to consider when investigating fuels? - How much energy they produce, What pollutants they produce and how a fuel is chosen for specific purposes. What is the reaction for combustion of fuels? - It is exothermic, therefore energy is releases as heat. What is the word equation for combustion? - Fuel + Oxygen -> Carbon dioxide + Water (+ heat energy) What is flammability? - It is one of the most useful properties of fuels as itshow easily they catch fire. This can be a hazard and should be treated like it. What is toxicity? - Fuels can carry impurities that are toxic. What does sulfur dioxide react with to produce acid rain? - They react with moisture in the air. What does acid rain do? - It erodes limestone buildings and statues. It acidifies lakes and rivers. It kills aquatic plants and animals. What happens if there is limited oxygen in combustion? - Incomplete combustion occurs which can produce carbon monoxide and soot. What is the wordequation for incomplete combustion? - Fuel + Oxygen -> carbon monoxide + water (+ Heat energy) What is carbon monxide? - It is a poisonous gas and can cause headaches, dizziness, nausea and death. What is the word equation for soot? - CH4 + O2 -> C =+ 2H2O
What is a variable resistor? - It is used to change the current in a circuit. It goes in series in the circuit What is a diode? - It only allows current to flow one way through a circuit. It is in series in the circuit What is power? - Power is the rate of doing work? It is the amount of energy consumed per unit of time. What can power refer to? - It can refer to physical work or electrical power. What does the work done equal - Work done = The amount of energy supplied or transformed. What is the equation for electrical power? - power = voltage x current. p=VI What is the equation for physical power? - Power = work done/ time (P=W/t) What is a fuse? - A fuse is a component of a circuit that will 'blow' if there is a fault in the circuit
