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Flashcards by Usman Rauf, updated more than 1 year ago
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Created by Josh Price
about 9 years ago
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Copied by Usman Rauf
about 9 years ago
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| Question | Answer |
| What do the basic processes of life carried out by all living things depend on? | Chemical reactions in cells that require energy released by respiration. |
| What is photosynthesis? | A series of chemical reactions that use energy from sunlight to build large food molecules in plant cells and some microorganisms (eg. phytoplankton). |
| What is respiration? | A series of chemical reactions that release energy by breaking down large food molecules in all living cells. |
| What are enzymes? | Proteins that speed up chemical reactions. |
| How do cells make enzymes? | They read the instructions carried in genes. |
| Explain the lock and key model. | Molecules have to be the correct shape to fit into the active site of an enzyme. |
| How do enzymes react to temperature? | Enzymes need a specific constant temperature to work at their optimum level. If the temperature is too high, they denature (stop working) because the shape of the enzyme changes, so the molecules no longer fits into the active site. |
| How can you achieve the perfect balance between different temperatures for enzyme activity? | Find the highest temperature which the enzyme is capable of working at, so that the rate of reaction increases, before it denatures. |
| What effect does pH have on enzyme activity? | The shape of the enzyme's active site changes if bonds holding the protein chain together are broken. Altering the pH of the environment alters the concentration of H+ bonds available, which disrupts the Hydrogen bonds in the enzyme. If the active site changes shape, then the enzyme has been denatured. |
| What is the word equation for photosynthesis? | Carbon Dioxide + Water -------> Glucose + Oxygen |
| What is the symbol equation for photosynthesis? | 6CO2 + 6H2O -------> C6H12O6 + 6O2 |
| What are the main stages of photosynthesis? | a) Light energy is absorbed by the green chemical chlorophyll b) The energy is used to bring about the reaction between carbon dioxide and water to produce glucose (a sugar) c) Oxygen is produced as a waste product |
| How may the plant use the glucose produced during photosynthesis? | a) Convert it into chemicals needed for growth of plant cells, for example cellulose, protein, and chlorophyll b) Convert it into starch for storage c) Use it in respiration to release energy to power chemical reactions in the cells |
| What is the structure of a plant cell? | - |
| What are the functions of the chloroplasts, cell membrane, nucleus, and cytoplasm? | Chloroplasts: Contain enzymes and chlorophyll for the reactions in photosynthesis. Cell membrane: Allows gases and water to pass in and out of the cell freely, while controlling the passage of other molecules. Nucleus: Contains the DNA which carries the genetic code for making enzymes and other proteins used in the chemical reactions of photosynthesis. Cytoplasm: Enzymes and other proteins used in photosynthesis are made here. |
| Give an example of a mineral being taken up by plant roots to make some chemicals needed by cells. | Nitrogen from nitrates in the soil is used to make proteins. |
| What is diffusion? | The passive overall movement of molecules from a region of their higher concentration to a region of their lower concentration. |
| Where does diffusion occur during photosynthesis? | Oxygen and carbon dioxide diffuse through the plant leaves. |
| What is osmosis? | Osmosis is a specific case of diffusion and it is the overall movement of water from a dilute to a more concentrated solution through a partially permeable membrane. |
| Where does osmosis occur during photosynthesis? | The movement of water into plant roots occurs by osmosis. |
| What is active transport? | The overall movement of chemicals against their diffusion gradient across a cell membrane. The process requires energy from respiration. |
| How do plants use active transport? | They absorb nitrate ions dissolved in water in the soil. |
| What factors may limit the rate of photosynthesis? | Temperature Carbon Dioxide Light Intensity |
| How is a transect taken? | Samples are taken at regular intervals along a straight line to investigate how plants change gradually from one area to another. |
| Why do all living organisms require energy released by respiration? | It is used for some chemical reactions used in cells. For example, those used in movement, synthesis or large molecules, and active transport. |
| What does 'synthesis or large molecules' include? | a) Synthesis of polymers required by plant cells such as starch and cellulose from glucose in plant cells. b) Synthesis of amino acids from glucose and nitrates, and then proteins from amino acids in plant, animal, and microbial cells. |
| What does aerobic respiration take place in? | Animal and plant cells, and some microorganisms. |
| What is the word equation for aerobic respiration? | Glucose + Oxygen -------> Carbon Dioxide + Water (+ Energy Released) |
| What is the symbol equation for aerobic respiration? | C6H12O6 + 6O2 ----> 6CO2 + 6H2O |
| What does anaerobic respiration take place in? | Animal, plant, and some microbial cells in conditions of low oxygen or absence of oxygen. For example... Plant roots in waterlogged soil Bacteria in puncture wounds Human cells during vigorous exercise |
| What is the word equation for anaerobic respiration in animal cells? | Glucose -----> Lactic Acid (+ Energy Released) |
| What is the word equation for anaerobic respiration in plant cells? | Glucose ----> Ethanol + Carbon Dioxide (+ Energy Released) |
| _________ respiration releases more energy per ________ molecule than ________ respiration. | Aerobic More Anaerobic |
| What is the structure of an animal or microbial cell? | - |
| What are the functions of the mitochondria, cell membrane, nucleus (or circular DNA), and cytoplasm? | Mitochondria: Contains enzymes for the reactions in aerobic respiration. Cell Membrane: Allows water and gases to pass through freely while controlling the passage of other molecules. Nucleus: Contains the DNA which carries the genetic code for enzymes used in the chemical reactions of respiration. Cytoplasm: Where enzymes are made. Location of enzymes in anaerobic respiration. |
| What are some of the applications for the anaerobic respiration of microorganisms? | Biogas: Bacteria use nutrients in the manure for anaerobic respiration and produce methane gas, which can be used as a fuel. Ethanol: Yeast cells take sugars and convert them into ethanol during anaerobic respiration (fermentation). Bread: Yeast uses sugars in the flour for respiration and the carbon dioxide it produces makes the bread rise. |
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