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 water carbon dioxide energy

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 enzymes C6H12O6 + 6O2 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

takes place in air or oxygen takes place in cells Differences Burning Respiration takes place in air or oxygen takes place in cells a single-step process a series of chemical reactions no enzymes involved controlled by enzymes

Differences Burning Respiration energy release is vigorous and not under control energy release is slower and under control energy is released in form of heat and light (a flame can result) energy is released in form of heat and an energy-rich compound

Investigation 9.1 To Demonstrate Heat Production by Respiring Animals using a Differential Air Thermometer

U-shaped capillary tube filled with coloured liquid clip graph paper B A stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool cotton wool mouse What is the function of the clips ? Ans: To equalize the pressure on the two sides of the capillary tube.

U-shaped capillary tube filled with coloured liquid clip graph paper B A stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool cotton wool mouse Why should the containers be wrapped in cotton wool ? Ans: It acts as an insulator to prevent heat loss.

U-shaped capillary tube filled with coloured liquid clip graph paper B A stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool 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.

U-shaped capillary tube filled with coloured liquid clip graph paper B A stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool cotton wool mouse What happens to the levels of the coloured liquid ? Ans: The coloured liquid rises up the left arm of the U-shaped capillary tube.

U-shaped capillary tube filled with coloured liquid clip graph paper B A stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool 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.

Investigation 9.2 To Demonstrate Heat Production by Germinating Seeds using Thermos Flasks

Which thermos flask shows a higher temperature germinating seeds cotton wool thermometer B Seeds killed by boiling 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.

Ans: It is because living seeds produce heat energy. thermos flask germinating seeds cotton wool thermometer B Seeds killed by boiling Why ? Ans: It is because living seeds produce heat energy.

What is the purpose of washing the seeds with a disinfectant ? thermos flask germinating seeds cotton wool thermometer B Seeds killed by boiling What is the purpose of washing the seeds with a disinfectant ? Ans: To kill any bacteria and fungi present on the seeds.

It is advisable not to fill the flasks completely with seeds. Why ? thermos flask germinating seeds cotton wool thermometer B Seeds killed by boiling It is advisable not to fill the flasks completely with seeds. Why ? Ans: To provide air for the seeds to respire.

Why are the flasks supported in the upside-down position ? thermos flask germinating seeds cotton wool thermometer B Seeds killed by boiling 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 Investigation 9.3 To Show Production of Carbon Dioxide by a Respiring Animal

potassium hydroxide solution lime water to suction pump C B A potassium hydroxide solution glass plate mouse bell jar 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.

potassium hydroxide solution lime water to suction pump C B A potassium hydroxide solution glass plate mouse bell jar 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 Investigation 9.4 To Show the Release of Carbon Dioxide by Germinating Seeds

hydrogencarbonate indicator solution seeds (heat-killed) germinating seeds muslin bag thread moist cotton wool A B Why is it necessary to wash the seeds with a disinfectant ? Ans: It is used to kill microorganisms.

hydrogencarbonate indicator solution seeds (heat-killed) germinating seeds muslin bag thread moist cotton wool A B What is the function of the moist cotton wool inside the muslin bag ? Ans: It prevents the seeds from drying out.

hydrogencarbonate indicator solution seeds (heat-killed) germinating seeds muslin bag thread moist cotton wool A 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.

hydrogencarbonate indicator solution seeds (heat-killed) germinating seeds muslin bag thread moist cotton wool A 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 contraction produce light in fireflies absorb mineral salts by active transport keep warm produce sound in some birds transport food substances absorb food by active transport produce smell in some mammals

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

+ energy (from breakdown of glucose) ADP + phosphate + energy (from breakdown of glucose) ATP 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: enzymes C6H12O6 2CO2 + 2C2H5OH (ethanol) + energy amount of energy released anaerobically is smaller when compared with the aerobic method

anaerobic respiration aerobic respiration amount of energy released large small oxidation of glucose completely partly place of occurrence mitochondria 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 enzymes 2C3H6O3 + energy C6H12O6 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 Investigation 9.5 To Show Anaerobic Respiration of Germinating Seeds in Oil

hydrogencarbonate indicator solution at the start after two days paraffin oil germinating seeds gas syringe hydrogencarbonate indicator solution wire gauze Does the boiling tube contain a gas after 2 days? Ans: Yes.

hydrogencarbonate indicator solution at the start after two days paraffin oil germinating seeds gas syringe hydrogencarbonate indicator solution wire gauze What happens to the hydrogencarbonate indicator solution when the gas is bubbled through it? Ans: The solution turns yellow.

hydrogencarbonate indicator solution at the start after two days paraffin oil germinating seeds gas syringe hydrogencarbonate indicator solution wire gauze What is the gas produced? Ans: It is carbon dioxide.

hydrogencarbonate indicator solution at the start after two days paraffin oil germinating seeds gas syringe hydrogencarbonate indicator solution wire gauze 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.

Investigation 9.6 To Show Production of Ethanol and Carbon Dioxide during Fermentation of Glucose by Yeast

hydrogencarbonate indicator solution thermometer yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution liquid paraffin thermos flask Why is it important to boil the glucose solution? Ans: This drives off any dissolved oxygen.

hydrogencarbonate indicator solution thermometer yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution liquid paraffin thermos flask Why must the glucose solution be cooled down before yeast is added? Ans: It is because yeast would be killed when hot.

hydrogencarbonate indicator solution thermometer yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution liquid paraffin thermos flask What is the function of liquid paraffin? Ans: It prevents the mixture from coming into contact with air.

hydrogencarbonate indicator solution thermometer yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution liquid paraffin thermos flask What has happened to the hydrogencarbonate indicator solution? Ans: The hydrogencarbonate indicator solution has changed from red to yellow.

hydrogencarbonate indicator solution thermometer yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution liquid paraffin thermos flask What does this show? Ans: This shows that yeast can respire anaerobically to produce energy.

hydrogencarbonate indicator solution thermometer yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution liquid paraffin thermos flask What has happened to the reading of each thermometer? Ans: The reading of the thermometer of the experimental set-up rises.

hydrogencarbonate indicator solution thermometer yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution liquid paraffin thermos flask 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

anaerobic respiration Differences aerobic respiration anaerobic respiration essential oxygen requirement nil complete oxidation incomplete oxidation oxidation of sugar energy released large amount small amount

anaerobic respiration inorganic: CO2 and H2O end products organic: ethanol or lactic acid in most living cells in lower organisms (e.g. bacteria and yeast) and vertebrate muscles occurrence

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

a breaking down process a synthetic process aerobic respiration photosynthesis a breaking down process a synthetic process occurs in all living cells at all times occurs in green plants only when light is available occurs in mitochondria occurs in chloroplasts

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