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WJEC Double Science Biology Unit 1.1
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Cells Learning Objectives:
All Draw annotated diagrams of plant and animal cells. Most Describe the functions of each of the organelles. Some Compare and contrast the structure of the plant and animal cells.
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Cells Starter Draw labelled diagram of diagrams of: a plant cell
an animal cell Write down the function of each organelle (cell part).
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Cells Starter Draw the plant and animal cells and label.
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Cells Starter Draw the plant and animal cells and label using the following terms nucleus, cell membrane, cell wall, cytoplasm, chloroplast, vacuole, mitochondria
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Cells Organelle Function Nucleus Cytoplasm Cell membrane Mitochondrion
Cell wall Chloroplast Vacuole
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Cells Organelle Function
Contains chromosomes which carry genetic information and controls cell activity Site of most cell reactions Controls the entry and exit of substances Site of aerobic respiration Contains cellulose and gives structural support for plant cells Site of photosynthesis Contains a watery sugar solution (sap), a swollen vacuole pushes the rest of the cell contents against the cell wall, making the cell firm
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Cells Cell membrane, cell wall, cytoplasm, nucleus, vacuole, chloroplast, mitochondria Organelle Function Contains chromosomes which carry genetic information and controls cell activity Site of most cell reactions Controls the entry and exit of substances Site of aerobic respiration Contains cellulose and gives structural support for plant cells Site of photosynthesis Contains a watery sugar solution (sap), a swollen vacuole pushes the rest of the cell contents against the cell wall, making the cell firm
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Cells Organelle / Feature Animal Cell Plant cell Nucleus Cytoplasm
Cell membrane Mitochondria Cell wall Chloroplast Vacuole Shape Position of nucleus
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The light microscope Learning Objectives:
All Describe how to use a light microscope to view animal and plant cells and outline how to prepare a slide, staining it so that more detail can be seen. Most Explain that calculation of total magnification is achieved by the multiplication of the power of the eyepiece lens by the power of the objective lenses. Some Discuss the limitations of light microscopy in studying cell structure and compare and contrast the light microscope and the electron microscope.
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The light microscope
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The light microscope
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The light microscope Plenary
What are the advantages of the light microscope? What are the limitations of the light microscope? What are the advantages of the electron microscope? What are the limitations of the electron microscope?
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Specialised Cells Learning Objectives:
All Identify that different types of cells have different structures. Most Describes the functions of some specialised cells. Some Explain how the structure of some specialised cells helps their function.
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Specialised Cells Plants and animals are multicellular (consist of many cells). Not all cells look the same. Plants and animals contain many different types of cells. Each type of cell is adapted to carry out a particular job or function. Some cells have a special structure and features to help them perform a specific function. This is known as cell specialism.
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Sperm cell Head contains enzymes & nucleus Adapted to fertilise eggs.
Found in the testes Tail The head contains enzymes which allow it to digest into an egg cell so that the sperm nucleus can fertilise the egg. A sperm is very small and has a long tail to provide motility so that it can move towards an egg cell.
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Egg (Ovum) Cell Contains half the chromosomes from the mother.
Found in the Ovaries. An egg cell is large and bulky. It contains a food store for the fertilised egg to develop into an embryo. Cytoplasm containing yolk Layer of jelly Nucleus
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Palisade Cell Adapted for photosynthesis. Found in the top of a leaf. Packed with chloroplasts to help make plant food. Nucleus Chloroplasts
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Ciliated Cell Adapted to prevent mucus, dust and bacteria entering the lungs. They line all the air passages in the lungs. They have tiny hairs called cilia. Hairs sweep mucus with trapped dust and bacteria back up the throat. Nucleus cilia
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Root Hair Cell Thin cell wall makes it easy for minerals to pass through. Adapted for absorbing water and minerals from the soil. Vacuole Root hair thin cell wall Found in a plant root. The root hair give the cell a large surface which helps it to absorb water and minerals. Cell membrane
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Nerve Cell (neurone) Nucleus Their function is to carry nerve impulses to different parts of the body. Found in the brain, spinal cord and nerves. They have a very long axon to carry impulses quickly. The axon is coated in electrical insulation. They have connections at each end.
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Red Blood Cell Adapted to carry oxygen. Found in blood.
Large surface area, for oxygen to pass through. Contains haemoglobin, which joins with oxygen. Has no nucleus so there is more room to carry haemoglobin.
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Specialised cells Plenary Why are nerve cells so long?
Where are egg cells found? What is palisade cell specialised to do? Why does a root hair cell have a thin wall? The hairs in a ciliated cell are known as? What is a sperm cell specialised to do? How are red blood cells different from other cells?
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Levels of organisation Learning Objectives:
All Describe the levels of organisation in organisms: cells, tissues, organs, systems, organism. Most Describe the structure of an organ system and explain how the organs function together to perform an overall role in the body. Some Explain how organ systems interact in an organism.
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Levels of organisation
Starter List as many organs as you can think of. Group the organs with related functions together.
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Body organs information
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Levels of organisation
Plenary Identify plant organs and summarise the function of each plant organ.
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Diffusion Learning Objectives:
All State that diffusion is the movement of substances down a concentration gradient. Most Describe the role of the cell membrane in diffusion. Some Explain that diffusion is a passive process, allowing only certain substances to pass through the cell membrane, most importantly oxygen and carbon dioxide
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Diffusion Starter Explain what you understand by the term ‘diffusion’.
Give examples of where you have seen diffusion in action, in chemistry.
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Diffusion Plenary Define diffusion.
List where diffusion happens in living organisms.
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Osmosis Learning Objectives:
All State that osmosis is the diffusion of water through a selectively permeable membrane from a region of high water (low solute) concentration to a region of low water (high solute) concentration. Most Predict which potato chips will lose or gain water by osmosis and explain. Some Describe and explain turgid, flaccid and plasmolysed cells.
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Osmosis Starter Watch the osmosis video
List the key points about osmosis tyrd/video Dtes
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Osmosis in potato chips
Plenary Why is it a good idea to remove all the potato skin? Why do we dry the chips on a paper towel before weighing them? Does your graph show any anomalies or inconsistencies? Explain in biological terms what is happening to the potato chips in the different blackcurrant squash solutions. What do you think is the approximate concentration of the cell contents of the potatoes? You could modify this investigation to find out how quickly osmosis happens. Write down a hypothesis you would be testing and a plan for how to do the experiment. Include the variables you would need to control to get reliable results.
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Active Transport (Higher Tier) Learning Objectives:
All State that active transport is an active process whereby substances can enter cells against a concentration gradient. Most Explain that respiration provides the energy required in the form of ATP. Some Identify examples of where active transport is used in living organisms.
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Active Transport (Higher Tier)
Starter Define diffusion Define osmosis Compare and contrast diffusion and osmosis
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Active Transport (Higher Tier)
Plenary Multiple choice quiz rd/test
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Enzymes Learning Objectives:
All Recall that enzymes are proteins which speed up the rate of chemical reactions. Most Describe enzyme activity in terms of molecular collisions between enzyme and substrate and explain the 'lock and key' model. Some (Higher) Explain that different enzymes are composed of different amino acids linked to form a chain which is then folded into a specific shape. The substrate fits into the active site of an enzyme to form an enzyme-substrate complex.
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Enzymes Enzymes are biological catalysts – protein molecules that speed up chemical reactions. They catalyse chemical reactions in living cells such. Examples of these chemical reactions are: Respiration Photosynthesis Protein synthesis
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Enzymes – Active Sites The shape of an enzyme determines how it works. Enzymes have active sites that substrate molecules (starting molecules or reactants) fit into when a reaction happens. The active site has to be the right shape for the substrate molecules to fit into. This means that enzymes have a high specificity for their substrate – a particular type of enzyme will only work with one or a smaller number of substrates. The mechanism involved is called the 'lock and key' mechanism. Just as a lock will only accept one key, an enzyme will only accept one substrate.
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Enzymes In this example the enzyme is breaking a large molecule into smaller molecules. Enzymes can also work in reverse, building larger molecules from small molecules.
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Enzymes and temperature
At low temperatures, enzyme reactions are slow. They speed up as the temperature rises until an optimum temperature is reached. After this point the reaction will slow down and eventually stop. The graph shows what happens to enzyme activity when the temperature changes. In the example, enzyme activity increases steadily between 0 ºC and 40 ºC. It peaks at 40 ºC (the enzyme's optimum temperature) then decreases rapidly.
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Enzymes and pH Different enzymes work best at different pH values, their optimum pH. Many enzymes work fastest in neutral conditions. Making the solution more acidic or alkaline will slow the reaction down. At extremes of pH the reaction will stop altogether. Some enzymes, such as those used in digestion, are adapted to work faster in unusual pH conditions. For example, stomach enzymes have an optimum pH of 2, which is very acidic. The graph shows what happens to enzyme activity when the pH changes. In the example, enzyme activity increases between pH 4.5 and pH 8. It peaks at pH 8, then decreases.
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Enzymes What are enzymes made of? What is a substrate?
What do enzymes do? What is a product? How is the 3D shape of enzyme created? What is an active site? Enzymes Why can enzymes be reused? What happens when an enzyme and substrate collide? What is the lock and key theory? What is an enzyme substrate complex? How does pH affect enzymes? How does temperature affect enzymes? What factors affect enzyme activity? Where are enzymes found in the human body?
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Enzymes Plenary List five things you’ve learned about enzymes today.
Write down one thing about enzymes that you need to learn in more detail.
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Function of enzymes Learning Objectives:
All Describe the effect of temperature and pH on enzyme activity including the effect of boiling which denatures most enzymes. Most Understand the term optimum as a particular temperature or pH at which the rate of enzyme action is greatest. Explain that as temperature increases there are increased collisions between enzymes and substrates. Some Explain that in a denatured enzyme the specific shape of the active site is destroyed and can no longer bind with its substrate, so no reaction occurs.
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Enzymes Starter What are enzymes made of?
Enzymes are catalysts. What do catalysts do? What do we call the reactant molecules? What happens when an enzyme and substrate collide? What part of the enzyme does the substrate fit into? What is made at the end of the reaction? How does the reaction affect the shape of the enzyme molecule? What factors affect enzyme activity?
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The effect of pH on salivary amylase
1. What is the optimum pH of: Pepsin Amylase Arginase 2. What is the pH range of: 3. Why doesn’t an enzyme work outside it’s pH range? 4. Explain why the different type of food molecule are digested in different regions of the gut?
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Enzymes Plenary What do we call the best temperature or pH for enzyme activity? What happens to the movement of molecules as the temperature increases? What happens to enzyme activity above the optimum temperature? What happens to the shape of the enzyme active site above the optimum temperature? How does denaturing affect the formation of an enzyme-substrate complex? What happens to enzymes when they are in solutions outside their pH range? How is the digestive system adapted to enzymes with different optimum pH values?
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Learning Objectives: All Most Some
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Learning Objectives: All Most Some
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