Presentation on theme: "Unit One: Cell Biology. S3 Biology Course Unit 1 S3 CFE Biology Units: Cell Biology – now till October Multicellular Organisms – October – Feb Life on."— Presentation transcript:
Unit One: Cell Biology
S3 Biology Course Unit 1 S3 CFE Biology Units: Cell Biology – now till October Multicellular Organisms – October – Feb Life on Earth – February onwards
S3 Biology Course Unit 1 How is the course assessed? There will be an end of topic test at the end of Unit 1 and Unit 2. This will test your knowledge of the unit and your problem solving (calculations, %, line/bar graphs).
S3 Biology Course Unit 1 Course Work As well as the tests, there are three pieces of course work to do: Unit 1: Practical investigation Unit 2: Short Scientific Report Unit 3: Research Assignment
S3 Biology Course Unit 1 Key area 1: Cell structure Learning objectives: Identify and name the structures in a plant cell Identify and name the structures in an animal cell State the functions of the structures found in plant and animal cells Be able to work out the size of a cell
S3 Biology Course Unit 1 Prior Knowledge From CSI Speyside you should know: That cells are the basic unit of all living things How to use the microscope Some parts of animal and plant cells and what their role in the cell is.
S3 Biology Course Unit 1 Examining plant cells Your teacher will remind you how to make a microscope slide. Look at the onion cells under the x10 lens and draw what you can see in your jotter.
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S3 Biology Course Unit 1 Typical plant cell Collect and label this diagram of a plant cell
S3 Biology Course Unit 1 Functions Use page 19 of the N5 textbook to find out what the following parts of the cell do: Nucleus Cell membrane Cytoplasm Cell wall (Sap) VacuoleChloroplast Ribosome Mitochondria Display this in your jotter as a table or list.
S3 Biology Course Unit 1 Examining animal cells Your teacher will show you how to make a slide of your cheek cells. Using x 10 magnification draw what you can see.
S3 Biology Course Unit 1 X 100
S3 Biology Course Unit 1 Typical animal cell Collect and label this diagram of an animal cell
S3 Biology Course Unit 1 Common structures Make two columns in your jotter: Plant and AnimalPlant cells Cells Only Fill in which cell parts should go in each column.
S3 Biology Course Unit 1 Just how tiny are cells? “How big?”How big? This link will show you how tiny cells are. Cells can be seen more clearly using a microscope.
S3 Biology Course Unit 1 Magnification Total magnification is worked out by multiplying the eyepiece lens magnification by the objective lens magnification. Eyepiece Lens Objective Lens
S3 Biology Course Unit 1 Copy and complete this table Eyepiece lens magnification Objective lens magnification Total magnification X 10X 4 X 10 X 100
S3 Biology Course Unit 1 Working out the size of a cell Field of view Number of cells Length = of each cell (mm) e.g. 2 ÷ 5 = 0.4 mm So each cell measures 0.4 mm. The field of view is the area you can see down the microscope. Field of view = 2 mm
S3 Biology Course Unit 1 Field of view = 2 mm Collect a version of this diagram. Your teacher will tell you how many cells to draw in the circle. Calculate the length of your cell in millimetres (mm). Swap with other and calculate the length of their cells.
S3 Biology Course Unit 1 Key area 2: Cell membrane and Transport Learning objectives: Describe what the cell membrane is made of Describe what is meant by “diffusion” Explain how the process of diffusion occurs across the cell membrane
S3 Biology Course Unit 1 Prior Knowledge From Science in everyday life you should know: The three states of matter are – solid, liquid and gas. The particles behave in different ways depending on if they are in a solid, liquid or gas.
S3 Biology Course Unit 1 How are particles arranged? SolidLiquidGas Copy this table. Using a circle to show the particles – fill in the space to show how the particles are arranged.
S3 Biology Course Unit 1 How are particles arranged? SolidLiquidGas
S3 Biology Course Unit 1 How to liquids and gases move? Your teacher will take you outside (or to the auditorium) to pretend to be particles. Based on what you did, write a couple of sentences describing how particles of liquid or gas move.
S3 Biology Course Unit 1 The cell membrane in close up Copy this diagram
S3 Biology Course Unit 1 The cell membrane is made of lipids and proteins. The lipids are arranged in a double layer. The proteins are in a patchy arrangement. Some stick all the way through making channels called “pores”.
S3 Biology Course Unit 1 Diffusion What happens to the smell when you spray perfume in one corner of the room?
S3 Biology Course Unit 1 Gas or liquid particles are constantly moving and bumping into each other. This means that they spread out from an area where there are lots of particles to an area where were are no particles.
S3 Biology Course Unit 1 This process is called diffusion. Diffusion is the movement of molecules of a substance from an area of high concentration to an area of low concentration until they are evenly spread.
S3 Biology Course Unit 1 Diffusion through a membrane Water Visking tubing Starch + Glucose solution StarchGlucose In bag In water at the start In water after 20 mins
S3 Biology Course Unit 1 Take a small sample of the water from around the test tube. Test for starch and sugar Test for starch 1. Put sample on tray 2. Add 4 drops of IODINE 3. If starch is present it goes from brown to black Test for sugar BOILING WATER 1. Put sample in test tube – IN a beaker of BOILING WATER 2. Add 4 drops of BENEDICTS SOLUTION 3. If sugar is present it goes from blue to orange
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Conclusion: Glucose molecules can diffuse through Visking tubing but starch molecules cannot. Explanation: Visking tubing is a selectively permeable membrane.
S3 Biology Course Unit 1 A Selectively Permeable Membrane A selectively permeable membrane contains tiny holes through which only tiny molecules can diffuse. Cell membranes are also selectively permeable.
S3 Biology Course Unit 1 They control the movement of substances in and out of cells. Small molecules which can diffuse through a selectively permeable membrane are: oxygen glucose water carbon dioxide
S3 Biology Course Unit 1 Large molecules which cannot diffuse through are: Starch Protein
S3 Biology Course Unit 1 Starch Glucose Oxygen Carbon dioxide Protein Substances which can and cannot diffuse into or out of cells
S3 Biology Course Unit 1 Why is diffusion important? Diffusion is essential to living things. All cells need to take in food (e.g. glucose and amino acids) and oxygen. These are used for respiration (see later in this unit) to produce energy.
S3 Biology Course Unit 1 Key area 3: Making new cells Learning objectives: Explain that cells must divide to increase the number of cells in an organism. State the cell division is controlled by the nucleus. Explain why the original cells must divide to produce two identical daughter cells. Describe the main stages of mitosis.
S3 Biology Course Unit 1 Prior knowledge From CSI Speyside you should know: The nucleus of the cell contains chromosomes. Chromosomes are a set of instructions which tell the cell how to work.
S3 Biology Course Unit 1 What is cell division? Cell division is how an organism makes new cells for growth, development and repair. In cell division one cell divides to make two new cells. The two new cells are called daughter cells and they are identical to the original cell. In unicellular organisms cell division is a way of reproducing.
S3 Biology Course Unit 1 Nucleus contains 46 chromosomes. These carry information. Each piece of information is packaged on a gene. e.g. gene with information for eye colour Inside the nucleus
S3 Biology Course Unit 1 Humans have 46 chromosomes in every nucleus inside every body cell. This is called our chromosome complement Chromosome complement
S3 Biology Course Unit 1 The importance of the chromosome complement The chromosome complement contains all of the codes needed by each cell. It must be copied exactly for each new cell in cell division so that none of the codes (which are the cell’s instructions) are left out.
S3 Biology Course Unit 1 Stage 1 nucleus containing long uncoiled chromosomes. each chromosome doubles to form to identical chromatids.
S3 Biology Course Unit 1 doubles 1 chromosome1 chromosome made of two chromatids
S3 Biology Course Unit 1 each chromosome becomes thicker – forming a short coiled chromosome (made of two chromatids). Stage 2
S3 Biology Course Unit 1 1 long uncoiled chromosome made of two chromatids shortens and coils 1 short coiled chromosome made of two chromatids centromere – holds 2 chromatids together.
S3 Biology Course Unit 1 a spindle forms and attaches at the centromeres. Stage 3 the chromosomes line up at the equator of the cell.
S3 Biology Course Unit 1 the chromatids are pulled apart and move to different poles. Stage 4 N pole S pole
S3 Biology Course Unit 1 a nuclear membrane forms around each group of chromatids – now called chromosomes. Stage 5 the cytoplasm begins to divide.
S3 Biology Course Unit 1 Stage 6 two daughter cells each containing the same numbers of chromosomes as the original cell.
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Collect this diagram of cell division. Write a sentence describing what is happening at each stage of the process. Use page to help.
S3 Biology Course Unit 1 Key area 4: Producing proteins Learning objectives: State that proteins are made of different sequences of amino acids. Describe some of the main functions of proteins. Describe the structure of DNA. Explain how the DNA helps the cell to make different proteins.
S3 Biology Course Unit 1 Prior knowledge From Science in Medicine you should know: Proteins are large molecules made up from 21 different amino acids. From CSI Speyside you should know: Chromosomes are made of a molecule called Deoxyribonucleic acid (DNA).
S3 Biology Course Unit 1 Proteins Proteins are large molecules made by joining small subunits called amino acids together. There are 21 different amino acids. Different proteins have different combinations of the amino acids.
S3 Biology Course Unit 1 The amino acid chains can then fold into different shapes which allow the proteins to do different jobs in the cell. Antibody Keratin (hair) Cell membrane pore
S3 Biology Course Unit 1 Humans have human genes Organisms differ because they have different genes. Gerbils have gerbil genes Bananas have (yes, you’ve guessed it) banana genes! Nobody else in the whole world has the same DNA as you! What makes organisms different?
S3 Biology Course Unit 1 Genetic information The nucleus of living cells contain chromosomes which are made up of a string of genes.
S3 Biology Course Unit 1 Chromosomes and their genes are made of a molecule called DNA DNA stands for deoxyribonucleic acid. Each chromosome is a very long molecule of tightly coiled DNA. The DNA molecule looks like a twisted ladder this spiral shape is called a DOUBLE HELIX
S3 Biology Course Unit 1 The double helix ‘ladder’ of a DNA molecule is held together by ‘rungs’ made from pairs of chemicals called bases. There are four types of bases, and they are usually identified by their initials. A T C G DNA bases
S3 Biology Course Unit 1 Base pairs hold the two strands of the DNA helix together. It is the sequence of these bases along a DNA molecule that forms the genetic code. AT CG CG AT
S3 Biology Course Unit 1 The genetic code Every three bases in the DNA (codon) tells the cell which amino acid to use to help build proteins. T A T C G G T A C G T A AlanineGlycineProlineCysteine DNA sequence Amino acids joined together in protein
S3 Biology Course Unit 1 Translating the DNA code Your teacher will give each group a DNA sequence. Divide the sequence into groups of three (codons) then use the chart to work out which coloured bead you will need. Put the beads in order based on your sequence.
S3 Biology Course Unit 1 1 st position 3 rd position TCAG YellowGreenRedBlueT YellowGreenRedBlueC YellowGreenRedBlueA YellowGreenRedBlueG Light BlueWhitePinkRedT Light BlueWhitePinkRedC Light BlueWhitePinkRedA Light BlueWhitePinkRedG WhiteGreenLight BlueBlueT WhiteGreenLight BlueBlueC WhiteGreenRedBlueA PinkGreenRedGreenG STOPBlueYellowPinkT STOPBlueYellowPinkC Yellow PinkA Yellow PinkG 2 nd position T C A G Use this chart to help you to build your final protein
S3 Biology Course Unit 1 Key area 5: Enzymes Learning objectives: State that enzymes are found in all cells and speed up chemical reactions. Explain why enzymes are described as “specific” Give examples of “building up” and “breakdown” enzymes and explain what they do.
S3 Biology Course Unit 1 Prior knowledge From Science In Medicine you should know: The digestion of starch in your mouth was carried out by a substance in your saliva called an enzyme.
S3 Biology Course Unit 1 Catalysts A catalyst speeds up a chemical reaction, but is unchanged in the process and can be used over and over again. In living things, catalysts are known as enzymes.
S3 Biology Course Unit 1 If cells did not have enzymes in their cytoplasm, then the chemical reactions which happen in our cells would happen so slowly that life would be impossible!
S3 Biology Course Unit 1 An example of an enzyme: CATALASE Hydrogen peroxide (H 2 O 2 ) is a liquid similar to water (H 2 O), but with one extra oxygen. Over a long period of time hydrogen peroxide naturally breaks down into water and oxygen.
S3 Biology Course Unit 1 The word equation for this reaction is: Hydrogen peroxide water + oxygen This process can be sped up using an enzyme.
S3 Biology Course Unit 1 Into each test tube – measure out 5 ml of Hydrogen peroxide AND 5 drops of detergent. CAUTION!! Hydrogen peroxide is a dangerous chemical. Safety goggles must be worn!! 1.Add nothing 2. Potato 3. Carrot 4. Liver Leave for 10 minutes. Measure the height of the foam bubbles.
S3 Biology Course Unit 1 Estimating the catalase activity of different food groups Aim: Dependent variable: Independent variable:
S3 Biology Course Unit 1 Test tube contentsHeight of foam (mm) Nothing – “CONTROL” Potato Carrot Liver
S3 Biology Course Unit 1 Conclusion Only the plant and animal tissues speed up the breakdown of hydrogen peroxide. This is because the cells contain catalase. Catalase is an enzyme found in living cells.
S3 Biology Course Unit 1 Catalase Hydrogen peroxide water + oxygen The tissue which contained the most catalase was ______________.
S3 Biology Course Unit 1 Breakdown and Building Up Catalase is an enzyme involved in chemical breakdown. “Breakdown” means chopping up larger molecules into smaller molecules.
S3 Biology Course Unit 1 Other enzymes do the opposite – the build large molecules from smaller molecules.
S3 Biology Course Unit 1 An example of a “Build up” enzyme: Phosphorylase Glucose-1-phosphate is a chemical made by plants during photosynthesis. It is stored in plant cells be converting it into a large molecule called starch.
S3 Biology Course Unit 1 Phosphorylase Glucose-1-phosphateStarch
S3 Biology Course Unit 1 Substrates and products The substrate is the substance the enzyme works on. The product is the substance the enzyme makes. Enzyme SubstrateProduct
S3 Biology Course Unit 1 How enzymes work Enzymes are made of protein. This protein has a special shape which is unique to each enzyme. Enzyme Active site
S3 Biology Course Unit 1 Enzyme The active site is the correct shape to fit the substrate. Substrate Enzyme Substrate Turned into the products
S3 Biology Course Unit 1 Enzyme Substrate Other substrates are the wrong shape to fit in the active site of the enzyme. Therefore the enzyme will only work with one substrate. This is described as being SPECIFIC.
S3 Biology Course Unit 1 “Specific” When talking about enzymes, SPECIFIC means that the ENZYME WILL ONLY WORK WITH ONE SUBSTRATE.
S3 Biology Course Unit 1 One enzyme = one substrate 5 ml Starch 5 ml Starch 5 ml Starch 5 ml Starch 3 ml Water 3 ml Amylase3 ml Pepsin 3 ml Lipase Put in waterbath for 10 minutes. Test all 4 test-tubes with Benedict’s Solution
S3 Biology Course Unit 1 Investigating the specificity of enzymes Aim: Dependent variable: Independent variable:
S3 Biology Course Unit 1 Conclusion The test-tube containing Starch and Amylase had the most sugar. This shows that only Amylase can convert starch to sugar. Amylase is said to be SPECIFIC to starch.
S3 Biology Course Unit 1 Investigation Design an experiment to investigate: “Factors affecting the enzyme activity using the catalase enzyme” Carry out and write up this experiment – your teacher will give you advice.
S3 Biology Course Unit 1 Factors affecting the enzyme activity using the catalase enzyme Aim: Dependent variable: Independent variable:
S3 Biology Course Unit 1 Key area 6: Respiration Learning objectives: State what cells use energy for. State the summary word equation for aerobic respiration. Explain when animal cells might use anaerobic respiration. State the summary word equation for anaerobic respiration
S3 Biology Course Unit 1 Prior knowledge In Science in Medicine you learned that: Cells get energy from this chemical reaction: sugar + oxygen energy + carbon + water dioxide
S3 Biology Course Unit 1 Why do cells need energy? Cells use energy from respiration to… Make your muscles work Carry out chemical reactions Growth and repair of cells Making larger molecules Maintain body temperature
S3 Biology Course Unit 1 Which foods have the most energy? Different types of food contain different amounts of energy. The three main food groups are: Carbohydrates Proteins Fats
S3 Biology Course Unit 1 Estimating the energy content of foods Aim: Dependent variable: Independent variable:
S3 Biology Course Unit 1 NUTRIENTEXAMPLEWATER TEMPERATURE (ºC) At startAfter burning food % Increase Carbohy- drate Sucrose ProteinGelatine Fat or oilSunflower Oil Your teacher will demonstrate how to set up and carry out this experiment safely.
S3 Biology Course Unit 1 Conclusion: Most energy in the body comes from breakdown of carbohydrates. Carbohydrates are made of the sugar glucose.
S3 Biology Course Unit 1 Aerobic respiration Aerobic respiration means “with air” and is happening in you body now. GlucoseOxygen 38 energy molecules Carbon dioxide Water Comes from breakdown of your food Breathed in by your lungs Breathed out by your lungs
S3 Biology Course Unit 1 What happens if you do heavy exercise? During sports your muscles run out of oxygen because they are working so hard the heart and lungs cannot keep up sufficient supply. When this happens anaerobic respiration occurs.
S3 Biology Course Unit 1 Anaerobic respiration Glucose 2 energy molecules Lactic Acid Comes from breakdown of your food Builds up in your muscles making them painful Anaerobic respiration only produces 2 energy molecules compared with the 38 produced by normal aerobic respiration.
S3 Biology Course Unit 1 Key area 7: Photosynthesis Learning objectives: State that photosynthesis is the process used by plants – where carbon dioxide and water is used to produce sugar and oxygen. Identify and describe the role of the cells in a leaf. State the summary word equation for photosynthesis. Describe how you can measure the rate of photosynthesis and name one factor which affects the rate of photosynthesis.
S3 Biology Course Unit 1 Prior knowledge You should know from the Planet Earth unit: Plants produce their own food from sunlight. This process happens in the leaves. This process requires a chemical called chlorophyll.
S3 Biology Course Unit 1 Leaf Structure Collect and label this diagram of a leaf
S3 Biology Course Unit 1 PartFunction Upper and lower Epidermis Layer of cells on top and bottom of leaf which protect the leaf. Palisade MesophyllThese cells contain loads of chloroplasts. Site of photosynthesis Spongy MesophyllThis layer has air spaces to allow diffusion of gases in the leaf StomataPores on underside of leaf to allow gases to enter or leave. Made of two guard cells.
S3 Biology Course Unit 1 Photosynthesis Photosynthesis occurs in the palisade mesophyll cells. These cells contain chloroplasts. Chloroplasts contain a green pigment called chlorophyll which traps light energy from the sun.
S3 Biology Course Unit 1 Carbon dioxide water Light energy GlucoseOxygen Enters leaf through the stomata Enters plant through the root Is a waste product which exits the leaf through the stomata Chlorophyll
S3 Biology Course Unit 1 What happens to the glucose? Use page 84 of the text book to complete this diagram: Glucose
S3 Biology Course Unit 1 Measuring the rate of photosynthesis How fast photosynthesis occurs can be estimated by counting the number of bubbles of oxygen produced each minute. Your teacher will show you how to set up this experiment.
S3 Biology Course Unit 1 Measuring the effect of light intensity on the rate of photosynthesis Aim: Dependent variable: Independent variable:
S3 Biology Course Unit 1 Distance from the light (cm) Number of oxygen bubbles produced in ______ minutes