22
Investigating cells Aerobic Respiration Mr G Davidson

Investigating cells Aerobic Respiration Mr G Davidson

Embed Size (px)

Citation preview

Page 1: Investigating cells Aerobic Respiration Mr G Davidson

Investigating cells

Aerobic Respiration

Mr G Davidson

Page 2: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 2

Energy

Energy cannot be created.Energy cannot be destroyed.Energy exists in a number of different forms, e.g. heat, light, sound, electrical, etc…

Page 3: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 3

Chemical Energy

This is stored energy.When one chemical substance is changed into another during a chemical reaction, this stored energy is often released.It may be released as heat, light, sound, etc..

Page 4: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 4

Chemical Energy

The sun is the primary source of energy for this planet.It is possible to trace the path of this energy from the sun to the cells in organisms.

Page 5: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 5

Chemical Energy

Not all the energy released by the sun arrives in the cells.Each time an energy conversion takes place some energy is “lost”.This lost energy is not destroyed – it simply passes out of the pathway in another form and is therefore, wasted energy.

Page 6: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 6

Energy Changes in Organisms

Energy is always associated with changes.Energy is continually being converted from one form to another.Animal and plant tissues contain chemical energy in the form of carbohydrates and fats.

Page 7: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 7

Energy Changes in Organisms

This energy can be converted into a variety of forms.Organisms consist of vast numbers of different kinds of cells.All cells need energy.Each cell or group of cells has a particular function to carry out.Individual cells are capable of carrying out several different energy conversions.

Page 8: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 8

Energy from Foods

All cells need a supply of food.Food contains chemical energy.The foods eaten by animals contain carbohydrates, proteins and fats.

Page 9: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 9

Energy from Foods

Foods can be analysed to find out the proportions of carbohydrate, protein and fat.These proportions are often given as percentages.It is also possible to find out how much energy a particular food contains.This is measured in kilojoules per gram. (kJg -1)

Page 10: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 10

Energy from FoodsFood

% Carbohydrate

% Fat % ProteinEnergy

Content (kJ/g)

Olive oil 0 100 0 39

Gelatin (dried) 0 0 100 19

Almonds 5 54 17 27

Sugar 100 0 0 19

Sausages 13 25 11 15

Pastry 8 33 55 25

If the numbers of the percentages don’t total 100, If the numbers of the percentages don’t total 100, then the food also contains water.then the food also contains water.

Page 11: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 11

The energy content of food is measured using a food calorimeterfood calorimeter.

Energy from Foods

ThermometerThermometer

Known volume of waterKnown volume of water

Known mass of foodKnown mass of foodThe food is set alight and the rise The food is set alight and the rise in temperature of the water is in temperature of the water is calculated.calculated.

Page 12: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 12

Food Calorimeter

Page 13: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 13

Respiration

Carbohydrate in the form of glucose is transported to each cell in an organism.The process by which cells release the energy stored in glucose molecules is called CELLULAR RESPIRATION.CELLULAR RESPIRATION.There are 2 types:

Aerobic respirationAerobic respiration – this occurs when there is a plentiful supply of oxygen to the cell.Anaerobic respirationAnaerobic respiration – this occurs when there is no oxygen available to the cell.

Page 14: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 14

Oxygen UptakeIt is possible to measure changes in oxygen content using a RESPIROMETER.Each type of respirometer contains a chemical to absorb and therefore remove carbon dioxide given out by the organism.The respirometer measures both the volume of oxygen taken up by a respiring organism, and the volume of CO2 released.They are equal.

GLUCOSE + OXYGENGLUCOSE + OXYGEN ENERGY + CO ENERGY + CO22 + WATER + WATER

Page 15: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 15

Page 16: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 16

Carbon dioxide Release

Before a gas can be identified, it must be collected or located.Once this is done an identification test can be carried out.

Page 17: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 17

Carbon dioxide ReleaseBicarbonate indicator solution changes colour from red to yellow when carbon dioxide is present.In order to prove that any CO2 detected around a respiring organism, has come from that organism, we have firstly to remove the CO2 from the organism’s air supply.

Page 18: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 18

Burning SugarIf glucose is burned it releases carbon dioxide. It also releases

water.

Glucose

Bicarbonate indicator

Page 19: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 19

Burning SugarThe carbon dioxide causes the

bicarbonate indicator to turn yellow.

Glucose

Bicarbonate indicator

Page 20: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 20

Burning SugarYeast is a fungus which can respire aerobically or anaerobically.If it has a goes supply of glucose and oxygen then CO2 is also released.This would seem to indicate that respiration and burning are quite similar in that the waste products are the same.

Page 21: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 21

Energy Release

Warm blooded animals maintain their body temperature above that of their surroundings.This means the animal is losing its heat to its surroundings.This heat energy must be coming from energy locked up in food.The heat energy is released as part of respiration.Plants also give off heat because they are respiring also.

Page 22: Investigating cells Aerobic Respiration Mr G Davidson

18 April 2023 G Davidson 22

Why Cells Need Energy

Energy in cells is continually being converted from chemical energy to other forms according to the needs of the cell.All living cells respire.When a cell or entire organism ceases to respire it dies.Metabolism is a word used to describe what happens inside cells or whole organisms.