Presentation on theme: "OCR Additional Science"— Presentation transcript:
1 OCR Additional Science 10/04/2017B4 The Processes of LifeOCR Additional ScienceM BarkerShirebrook Academy
2 B4.1 How do Chemical Reactions take place in living things? 10/04/2017B4.1 How do Chemical Reactions take place in living things?
3 Photosynthesis Introduction 10/04/2017Basically, photosynthesis is the process through which a plant makes large food molecules using carbon dioxide and water and it happens in plants as well as some micro organisms:That’s a nice plant. I’m going to put it in the sun and give it lots of water and air…CO2H2O
4 Respiration Introduction 10/04/2017I enjoy taking samples using quadrats. In order to do this, I need energy. Where does this energy come from?All living things, including plants, get their energy from respiration. Respiration is basically the process of breaking down the large food molecules that were probably originally made in plants.
5 Enzyme use in nature10/04/2017Enzymes are proteins that speed up chemical uses. Here are two important natural uses for them:Photosynthesis is catalysed by enzymes in the cells.Cells use glucose to generate energy – this process is called “respiration”. Respiration happens in mitochodria and is catalysed by enzymes.
6 Enzymes10/04/2017Enzymes are biological catalysts. They help the reactions that occur in our bodies by controlling the rate of reaction.An enzyme is basically a protein molecule made up of long chains of amino acids. Cells make enzymes according to the instructions carried in their genes.EnzymeThe enzyme’s shape helps another molecule “fit” into it:SubstrateThis shape can be destroyed by high temperatures or the wrong pH:
7 The “Active Site”10/04/2017Active siteEnzymeSubstrate
8 Enzymes are denatured beyond 40OC 10/04/2017Enzymes work best in certain conditions:Enzymes are denatured beyond 40OCCould be protease (found in the stomach)Could be amylase (found in the intestine)Enzyme activityTemppH400CEnzymes are used in industry to bring about reactions at normal temperatures and pressures that would otherwise be expensive. However, most enzymes are denatured at high temperatures and can be costly to produce.
9 B4.2 How do Plants make food? 10/04/2017B4.2 How do Plants make food?
10 Photosynthesis – the 4 things you need 10/04/2017SUNLIGHTGives the plant energyCHLOROPHYLLThe green stuff where the chemical reactions happenWATERTravels up from the rootsCARBON DIOXIDEEnters the leaf through small holes on the underneath
11 Photosynthesis equations 10/04/2017Carbon dioxide + _____ glucose + _____6CO H20 C6H12O O2SunlightChlorophyllThe GLUCOSE produced by photosynthesis is used by the plant for _______ (through ____________). It is stored in the plant as ___________.Words – respiration, starch, water, oxygen, energy
12 What is the glucose used for? 10/04/20171) Glucose (sugar) can be used to make long chains of insoluble starch…Glucose moleculesStarch molecule2) Glucose can be used to make cellulose for cell walls…Glucose moleculesCellulose3) Glucose can be combined with nitrates to make proteins (for growth)…Glucose moleculesProteinsGlucose can also be used for respiration, either by the plant or by what eats it!
13 A Typical Plant Cell:10/04/2017Cell wall – made of cellulose which strengthens the cellCell membrane – controls what comes in and outChloroplasts – contains chlorophyll and enzymes for photosynthesis reactionsNucleus – controls what the cell does and stores genetic info for making proteinsLarge vacuole – contains sap and helps support the cellCytoplasm – Chemical reactions happen here
14 2 common nutrients… Nitrates: Magnesium: Used to make proteins 10/04/2017Nitrates:Used to make proteinsLack of it leads to stunted growthMagnesium:Used to make chlorophyllLack of it leads to yellow leaves
15 Carbon dioxide and oxygen pass in and out of leaves by diffusion. 10/04/2017Diffusion is when something travels from an area of high concentration to an area of low concentration. For example, consider the scent from a hamburger…The “scent particles” from this hamburger are in high concentration here:Eventually they will “diffuse” out into this area of low concentration:Carbon dioxide and oxygen pass in and out of leaves by diffusion.
16 Words – faster, low, gradient, temperature, energy Diffusion Summary10/04/2017Diffusion is when particles spread from an area of high concentration to an area of ___ concentration. The particles move along a “concentration _____” and this process takes no _____ (it’s a “passive” process”). Diffusion can be accelerated by increasing the _______ of the particles, which makes them move _______.Words – faster, low, gradient, temperature, energy
17 Words – membrane, concentrated, dilute, diffusion, gradient Osmosis10/04/2017Osmosis is a “special kind of ___________”. It’s when water diffuses from a __________ area to a less concentrated area through a partially permeable _________ (i.e. one that allows water to move through but not anything else):In this example the water molecules will move from left to right (along the concentration ______) and gradually _____ the sugar solution. Plants use osmosis to take in water through their roots.WaterSugar solutionWords – membrane, concentrated, dilute, diffusion, gradient
19 Words – concentration, energy, respiration, nutrients Active Transport10/04/2017In diffusion substances moved along a concentration gradient. In active transport, substances move against this gradient:Outside cellInside cellThis process takes ______ and this comes from ___________. It enables cells to take in substances even though there are in very small __________. Root hair cells take in ______ using active transport.Words – concentration, energy, respiration, nutrientsCell membrane
20 Diffusion and Active Transport in plants 10/04/2017MineralLess concentratedMore concentratedCarbon dioxide diffuses into the leaf through holes in the bottom surface.…while plant nutrients are taken in by root hair cells using active transport.
21 Encouraging Photosynthesis 10/04/2017Using knowledge of limiting factors, explain how plant growth is encouraged in a greenhouse:
22 Limiting Photosynthesis 10/04/2017What factors could limit the rate of photosynthesis?Temperature – the best temperature is about 300C – anything above 400C will slow photosynthesis right downCO2 – if there is more carbon dioxide photosynthesis will happen quickerLight – if there is more light photosynthesis happens faster
23 Drawing graphs of these factors 10/04/20171. TemperaturePhotosynthesis is controlled by enzymes – these are destroyed at temperatures above 400C2. Carbon dioxidePhotosynthesis increases at first but is then limited by a lack of increase in temp or light3. LightPhotosynthesis increases at first but is then limited by a lack of increase in temp or CO2
24 Recording light levels Fieldwork techniques10/04/201710/04/2017Recording light levelsUsing quadratsFieldwork techniques also involve using a key to identify plants.
25 B4.3 How do living organisms obtain energy? 10/04/2017B4.3 How do living organisms obtain energy?
26 Uses for energy from respiration 10/04/2017Animals and plants have many uses for the energy they generate from respiration:To perform the life processes, such as moving, _____ etcTo build up body _______To maintain a constant body ___________ (warm-blooded mammals only)To build up sugars, ________ and other nutrients in plantsActive __________Words – nitrates, tissue, proteins, transport, growing
27 Synthesis10/04/2017“Synthesis” means “making large molecules out of small ones”. Two examples:1) Glucose (sugar) can be used to make long chains of insoluble starch…Glucose moleculesStarch molecule2) Glucose can be combined with nitrates to make proteins (for growth)…Glucose moleculesProteins
28 Respiration Introduction 10/04/2017I enjoy taking samples using quadrats. In order to do this, I need energy. Where does this energy come from?Our energy comes from a process called respiration, which basically involves turning food and oxygen into energy and this reaction is controlled by enzymes.
29 (Aerobic) Respiration 10/04/2017All living organisms have to move, _____, reproduce etc. Each of these life processes needs ENERGY. ___________ is the process our bodies use to produce this energy:Glucose + oxygen water + carbon dioxide + ENERGYThe glucose we need comes from ______ and the oxygen from _________. Water and carbon dioxide are breathed out. The MAIN product of this equation is _________. Respiration happens in _________ in cells.Words – breathing, energy, grow, respiration, food, mitochondria
30 Muscles and exercise10/04/2017When we exercise our muscles are supplied with more oxygen and glucose, increasing the rate of respiration.Muscles store glucose as glycogen which can then be converted back into glucose during exercise.
31 Anaerobic respiration 10/04/2017Unlike aerobic respiration, anaerobic respiration is when energy is provided WITHOUT needing _________:Glucose lactic acid + a bit of energyThis happens when the body can’t provide oxygen quick enough for __________ respiration to take place.Anaerobic respiration produces energy much _______ than aerobic respiration but only produces 1/20th as much.Anaerobic respiration can also take place in other low-oxygen conditions, such as plant roots in _________ soil or bacteria in ________ wounds.Words – oxygen, aerobic, quicker, puncture, waterlogged
32 Sugar ethanol + carbon dioxide + energy Making EthanolFord Escape E85 – runs on 85% ethanol10/04/2017Ethanol is an important chemical. Many countries are increasing the amount of ethanol put into their petrol supplies:Ethanol is another product of anaerobic respiration in plant cells and some micro organisms:Sugar ethanol + carbon dioxide + energy
33 Bacteria Consider a bacteria cell in more detail: The cell contains a number of features, including:Chromosomal DNA, containing the genetic info of the cellPlasmid DNA, containing extra information such as defence mechanismsFlagella, which helps the cell move10/04/2017Consider a bacteria cell in more detail:Bacteria – containing cytoplasm and a membrane surrounded by a cell wall. The genes are NOT in a distinct nucleus.
34 The Structure of Bacteria 10/04/2017Bacteria also have plasmids (circular strands of DNA) that can be copied and move between different bacteria. This means that resistance to antibiotics can be passed on without the need for reproduction.
35 In bacteria cells, this job is done by circular DNA Respiration in Cells10/04/2017Notice that plant and animal cells (and bacteria) have many features that help respiration:1)Cytoplasm - where enzymes are madeIn bacteria cells, this job is done by circular DNA2)Nucleus – carries genetic info for making enzymes3)Cell Membrane – controls what comes in and out4)Mitochondria – contain enzymes for respiration reactions
36 Using Anaerobic Respiration 10/04/201710/04/2017Anaerobic respiration in micro organisms is used to make fuels through:Manure or other waste that can be used to release methane (biogas)Corn or sugar cane that can be broken down in a fermenter to produce alcohols like bio-ethanol.Anaerobic respiration is also used in fermentation to make bread and alcohol.