Document 392059
What is Respiration? a process of oxidizing food to release energy inside cells Burning of Food A demonstration of energy released from food oxygen food (sugar) Burning energy water carbon dioxide food(sugar) + oxygen carbon dioxide + water + energy (heat + light) does not occur in living cells because the reaction is too fast and cells would die as they become so hot Respiration reactions are catalyzed by enzymes main food substance which oxidized in cells is glucose C6H12O6 + 6O2 enzymes 6CO2 + 6H2O + energy as it takes place in all living cells, it is called cellular respiration which is used to produce energy for cells to use Comparison of Burning and Respiration Similarities - both involve oxidative processes - both require the use of oxygen and food and they produce the same products of carbon dioxide and water - both reactions release energy Differences Burning Respiration takes place in air or oxygen takes place in cells a single-step process no enzymes involved a series of chemical reactions controlled by enzymes Differences Burning energy release is Respiration energy release is vigorous and not under slower and under control control energy is released in energy is released in form of heat and light (a form of heat and an flame can result) energy-rich compound To Demonstrate Heat Production by Respiring Animals using a Differential Air Thermometer graph paper clip clip A B stoppered air-filled test tube cotton wool stoppered airfilled test tube U-shaped capillary tube filled with coloured liquid cotton wool mouse What is the function of the clips ? Ans: To equalize the pressure on the two sides of the capillary tube. graph paper clip clip A B stoppered air-filled test tube cotton wool stoppered airfilled test tube U-shaped capillary tube filled with coloured liquid cotton wool mouse Why should the containers be wrapped in cotton wool ? Ans: It acts as an insulator to prevent heat loss. graph paper clip clip A B stoppered air-filled test tube cotton wool stoppered airfilled test tube U-shaped capillary tube filled with coloured liquid cotton wool mouse Which is preferable, a capillary tube with a wide bore or one with a narrow bore ? Ans: A capillary tube with a narrow bore is preferred than the wide one as it is more sensitive and will give better results. graph paper clip clip A B stoppered air-filled test tube cotton wool stoppered airfilled test tube U-shaped capillary tube filled with coloured liquid cotton wool mouse What happens to the levels of the coloured liquid ? Ans: The coloured liquid rises up the left arm of the Ushaped capillary tube. graph paper clip clip A B stoppered air-filled test tube cotton wool stoppered airfilled test tube U-shaped capillary tube filled with coloured liquid cotton wool mouse Why ? Ans: Because the mouse in container B carries out respiration to release heat energy which warms up the air in the test tube. To Demonstrate Heat Production by Germinating Seeds using Thermos Flasks B A thermos flask germinating seeds Seeds killed by boiling cotton wool thermometer Which thermos flask shows a higher temperature at the end of the experiment ? Ans: Flask A showed a higher temperature at the end of the experiment. B A thermos flask germinating seeds Seeds killed by boiling cotton wool thermometer Why ? Ans: It is because living seeds produce heat energy. B A thermos flask germinating seeds Seeds killed by boiling cotton wool thermometer What is the purpose of washing the seeds with a disinfectant ? Ans: To kill any bacteria and fungi present on the seeds. B A thermos flask germinating seeds Seeds killed by boiling cotton wool thermometer It is advisable not to fill the flasks completely with seeds. Why ? Ans: To provide air for the seeds to respire. B A thermos flask germinating seeds Seeds killed by boiling cotton wool thermometer Why are the flasks supported in the upside-down position ? Ans: The flasks are supported in the upside-down position because carbon dioxide, produced during respiration of the living seeds, is a heavier gas and may escape through the cotton wool. hot air rises up, and inverting it will ensure that heat will not escape through the cotton wool. it is easier to read the thermometer as the thermos flasks are not transparent. To Show Production of Carbon Dioxide by a Respiring Animal to suction pump A B bell jar C lime water potassium hydroxide solution lime water glass plate mouse Why is it necessary to bubble the incoming air through potassium hydroxide solution before it is supplied to the mouse ? Ans: It is used to remove carbon dioxide in the incoming air. to suction pump A B bell jar C lime water potassium hydroxide solution lime water glass plate mouse Which solution changes colour at the end of the experiment ? What does this show ? Ans: The lime water in flask C turns milky. It is because carbon dioxide is given off by the mouse. To Show the Release of Carbon Dioxide by Germinating Seeds thread thread muslin bag seeds (heat-killed) germinating seeds moist cotton wool A hydrogencarbonate indicator solution B Why is it necessary to wash the seeds with a disinfectant ? Ans: It is used to kill microorganisms. thread thread muslin bag seeds (heat-killed) germinating seeds moist cotton wool A hydrogencarbonate indicator solution B What is the function of the moist cotton wool inside the muslin bag ? Ans: It prevents the seeds from drying out. thread thread muslin bag seeds (heat-killed) germinating seeds moist cotton wool A hydrogencarbonate indicator solution B What has happened to the hydrogencarbonate indicator solution in the two tubes ? Ans: Indicator solution in tube A turns yellow while the indicator solution in tube B remains unchanged. thread thread muslin bag seeds (heat-killed) germinating seeds moist cotton wool A hydrogencarbonate indicator solution B What can be concluded from this experiment ? Ans: Carbon dioxide is released by the germinating seeds. Uses of the Energy Released during Respiration Human Other Animals Plants muscle produce light keep warm produce sound contraction in fireflies absorb food by active transport in some birds produce smell in some mammals absorb mineral salts by active transport transport food substances ATP energy is mainly released as heat and ATP during respiration in cells however, during respiration, some ATP should be consumed first before other ATP can be formed the ATP consumed is used to form other ATP from ADP and phosphate groups ADP + phosphate + energy ATP (from breakdown of glucose) ATP is a high-energy compound while ADP is a low-energy one ATP can only store energy for a short period ATP is made inside organelles, mitochondria, which is scattered in the cytoplasm of a cell Anaerobic Respiration respiration in human is mainly aerobic respiration as oxygen is essential when oxygen is not needed during respiration, it is called anaerobic respiration yeast and muscle cells are examples which they can respire anaerobically for a short time Alcoholic Fermentation without oxygen, yeast cells respire as follows: C6H12O6 enzymes 2CO2 + 2C2H5OH + energy (ethanol) amount of energy released anaerobically is smaller when compared with the aerobic method aerobic respiration anaerobic respiration amount of energy released large small oxidation of glucose completely place of occurrence mitochondria partly cytoplasm Industrial Use of Yeast Fermentation alcohol produced is used for: brewing beer making wine carbon dioxide released is used for: baking bread Lactic Acid Fermentation extra oxygen is required for undertaking sternuous exercise people cannot supply enough oxygen to muscles even they breathe faster and deeper muscle need to produce energy anaerobically by breaking down glucose into lactic acid C6H12O6 enzymes 2C3H6O3 + energy lactic acid will cause muscle fatigue and muscle cramps if they are allowed to accumulate a large amount of oxygen is needed to break down the accumulated lactic acid into carbon dioxide and water or turn to glycogen in liver for storage so we pant after doing exercise the amount of oxygen required to get rid of lactic acid is called oxygen debt To Show Anaerobic Respiration of Germinating Seeds in Oil germinating seeds gas wire gauze paraffin oil syringe at the start after two days hydrogencarbonate indicator solution Does the boiling tube contain a gas after 2 days? Ans: Yes. germinating seeds gas wire gauze paraffin oil syringe at the start after two days hydrogencarbonate indicator solution What happens to the hydrogencarbonate indicator solution when the gas is bubbled through it? Ans: The solution turns yellow. germinating seeds gas wire gauze paraffin oil syringe at the start after two days What is the gas produced? Ans: It is carbon dioxide. hydrogencarbonate indicator solution germinating seeds gas wire gauze paraffin oil syringe at the start after two days hydrogencarbonate indicator solution What can be learned about the respiration of germinating seeds from this experiment? Ans: Germinating seeds can respire anaerobically and release carbon dioxide in the absence of oxygen. To Show Production of Ethanol and Carbon Dioxide during Fermentation of Glucose by Yeast thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and hydrogencarbonate indicator solution then cooled down Why is it important to boil the glucose solution? Ans: This drives off any dissolved oxygen. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and hydrogencarbonate indicator solution then cooled down Why must the glucose solution be cooled down before yeast is added? Ans: It is because yeast would be killed when hot. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and hydrogencarbonate indicator solution then cooled down What is the function of liquid paraffin? Ans: It prevents the mixture from coming into contact with air. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and hydrogencarbonate indicator solution then cooled down What has happened to the hydrogencarbonate indicator solution? Ans: The hydrogencarbonate indicator solution has changed from red to yellow. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and hydrogencarbonate indicator solution then cooled down What does this show? Ans: This shows that yeast can respire anaerobically to produce energy. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and hydrogencarbonate indicator solution then cooled down What has happened to the reading of each thermometer? Ans: The reading of the thermometer of the experimental set-up rises. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and hydrogencarbonate indicator solution then cooled down At the end of the experiment, what new substance would you expect to find in the glucose solution containing living yeast? Ans: We can find alcohol in it. Comparison of Aerobic and Anaerobic Respiration Similarity Sugar is broken down to release energy ATP is made Both are controlled by enzymes Differences aerobic respiration anaerobic respiration oxygen requirement essential nil oxidation of sugar complete oxidation energy released large amount incomplete oxidation small amount end products occurrence aerobic respiration anaerobic respiration inorganic: CO2 and H2O organic: ethanol or lactic acid in most living cells in lower organisms (e.g. bacteria and yeast) and vertebrate muscles Differences between Respiration and Photosynthesis aerobic respiration photosynthesis produces carbon dioxide and water requires carbon dioxide and water energy is released energy (light) is absorbed an oxidative process a reductive process aerobic respiration a breaking down process occurs in all living cells at all times occurs in mitochondria photosynthesis a synthetic process occurs in green plants only when light is available occurs in chloroplasts ~ END ~
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