| What happens in photosynthesis? | Plants need light for their source of energy and to trap this light energy plants use the reaction: photosynthesis |
| Is photosynthesis endothermic or exothermic reaction? | Photosynthesis takes in energy and therefore is an endothermic reaction |
| Where does photosynthesis take place? | Photosynthesis takes place in a plant’s leaves that contain chlorophyll which absorbs light energy |
| What is the word equation for photosynthesis? | Carbon dioxide + water – light /chlorophyll - glucose + oxygen |
| What is the chemical equation for photosynthesis? | CO2 + H2O – C6H12O6 + O2 |
| What would happen if the light intensity to a plant was increased? | If light energy is increased, a plant has more energy to carry out a photosynthesis, so the reaction gets faster. |
| How can you tell if something is a limiting factor? | When something is a limiting factor every time it is increased or decreased the rate of the reaction will also increase or decrease |
| What are the five limiting factors in photosynthesis? | The five limiting factors in photosynthesis are light intensity, temperature, carbon dioxide concentration, chlorophyll water availability and nutrient elements |
| What does the glucose produced in photosynthesis release in respiration? | Glucose produced in photosynthesis is used to release energy in respiration that takes place in the mitochondria |
| What molecule does the glucose produced in photosynthesis release? | Glucose produced in photosynthesis can also be used to produce the insoluble storage molecule, starch. This starch can be converted back to glucose by the plant when it’s needed. |
| What can the glucose produced in photosynthesis be converted into? | Glucose produced in photosynthesis is converted into fats and oils, which are used by the plant as storage form of energy |
| What does the glucose in photosynthesis make up? | The glucose produced in photosynthesis makes up the cellulose that’s contained in plant’s cell walls |
| What compound does the glucose produced in photosynthesis produce? | The glucose produced in photosynthesis can also produce amino acids which are used by plants to synthesise proteins |
| How are amino acids made from glucose? | Plants absorb nitrate ions from the soil to make amino acids from glucose produced in photosynthesis |
| What is the first step in the photosynthesis required practical? | Start by taking a boiling tube and place it 10cm away from an LED light source, an LED is used as large amounts of heat will change the temperature of the experiment and LED’s release a small amount of heat. But if you are using a regular light bulb, place a beaker of water between the light and the boiling tube which will absorb the heat produced by the bulb. |
| What is the boiling tube now filled with and what is put into the boiling tube after this? | Now fill the boiling tube with sodium hydrogen carbonate solution which releases carbon dioxide needed for photosynthesis. Next put a piece of pond-weed into the tube with the cut end at the top, leave for 5 minutes to acclimatise to the tube. At the top of the pond-weed bubbles of oxygen are produced by photosynthesis should be visible. |
| How are the oxygen bubbles now recorded? | A stopwatch is started while the number of bubbles produced in one minute are counted. Repeat these two more times and calculate the number of bubbles produced in one minute. |
| What happens at this point in the photosynthesis practical? | After the oxygen bubbles are recorded do the whole experiment again from the start at 20cm away from the LED, then at 30cm, then 40cm, and so on. |
| What problem arises with the oxygen bubbles in this practical? | In this practical the number of bubbles can be too fast to accurately count, and the bubbles are not always the same size, a large bubble would count the same as a small bubble. |
| How can the problem of inaccurately counted bubbles be solved? | This problem can be solved by measuring the volume of oxygen produced instead of counting bubbles. To do this the pond weed is placed under a funnel and as the bubbles it produces rise, they are caught in a measuring cylinder over the top of the funnel. Then the measuring cylinder is used to measure the volume of the oxygen gas produced. |
| How are limiting factors determined once the first limiting factor has plateaued? | Once a limiting factor no is no longer increasing, it plateaus on the graph and now something else is a limiting factor. This limiting factor is determined by recording the rate of photosynthesis against another limiting factor such as testing out the CO2 concentration. If the increase of the rate of photosynthesis and CO2 concentration increases past the light intensity, this is the new limiting factor until the graph plateaus again. |
| why would framers want to increase the rate of photosynthesis in greenhouses? | Farmers would want to increase the rate of photosynthesis because this increases the yield of crops they produce. |
| How do farmers increase the rate of photosynthesis? | Farmer's light and heat their greenhouses in addition to adding extra carbon dioxide. |
| How is the energy humans need supplied? | The energy we need is supplied through respiration, an exothermic reaction that continually happens in all living cells. |
| What is the word equation for aerobic respiration? | Glucose + oxygen - (energy) - carbon dioxide + water |
| What is the chemical equation for aerobic respiration? | C6H12O6 + O2 – CO2 + H2O |
| What Is the word equation for anaerobic respiration? | anaerobic respiration = Glucose - (energy) - lactic acid |
| Why does anaerobic respiration release less oxygen than aerobic respiration? | Anaerobic respiration releases less oxygen than aerobic respiration because the oxidation of glucose is incomplete. |
| What is the word equation for anaerobic respiration (fermentation) in plant/yeast cells? | Anaerobic respiration in yeast cells= Glucose - (energy) ethanol + carbon dioxide |
| How does anaerobic respiration cause bread to cook? | Anaerobic respiration causes bread to cook because the carbon dioxide produced by fermentation causes bubbles in the dough which allows it to rise |
| Why do we need aerobic respiration when we exercise? | Aerobic respiration is needed because increased demand of energy for muscle contraction the body has when exercising means body cells need more oxygen. |
| How is this extra oxygen supplied? | The extra oxygen body cells need is supplied by an increased breathing rate and volume that get more oxygen into the bloodstream. Then the heart rate increases to pump this oxygenated blood around the body |
| What happens when not enough oxygen is supplied to the muscles? | When not enough oxygen is supplied to the muscles anaerobic respiration happens |
| What happens to the muscles during long periods of exercise? | During long periods of exercise lactic acid builds up and causes muscles to become fatigued, causing them to stop efficiently contracting. The lactic acid needs to be removed. This creates an oxygen debt. |
| What happens to lactic acid in anaerobic respiration? | Lactic acid is produced which is then transported out the muscles by the blood. Then it’s taken to the liver and converted back to glucose in a series of chemical equations. |
| What is the extra amount of oxygen the body needs after exercise called? | Oxygen debt is the amount of extra oxygen the body needs after exercise to deal with the accumulated lactic acid made in anaerobic respiration. Therefore, rapid breathing may continue after exercise. |
| What is metabolism? | Metabolism is the sum of all the chemical equation in a cell or the body |
| What three main things is glucose converted into, in plants? | In plants, glucose is converted into cellulose which strengths a plant’s cell wall and starch which is a storage form of glucose. Glucose also reacts with nitrate ions to make amino acids which are used to synthesis proteins |
| What is glycogen? | In humans and animals, glucose is converted into the molecule glycogen which is the storage form of glucose |
| What is combined with glycerol to make the lipid molecule? | 1 glycerol molecule is combined with 3 fatty acid molecules to make lipids, found in the cell membrane |
| How does metabolism break down proteins? | Excess proteins are broken down into the chemical urea which is excreted by the kidneys |
