Aerobic and Anaerobic Resp .Learning Objectives •Describe anaerobic respiration as the breakdown of glucose to pyruvic acid by glycolysis. •State that anaerobic respiration in

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  • Aerobic and Anaerobic

    Respiration

    Intermediate 2 Biology

    Unit 1: Living Cells

  • Learning Objectives

    Name the type of energy stored in food.

    Describe the energy change when food is burned.

    State the units used in measuring energy content of food.

    Define the term respiration.

    Name the food molecule that is the main source of energy in cells.

  • Energy Facts

    Energy facts

    Cannot be created or destroyed

    Can be converted from one form to

    another

    Takes a variety of forms

    Measured in kilojoules

  • Energy

    Food is a store of chemical energy.

    When food is burned, chemical energy

    is converted into heat and light

    energy.

  • Energy in Living Organisms

    Work

    Synthesis of complex substances

    Active transport e.g. sodium-potassium pump

    Movement

    Bioluminescence

    Maintenance of body temperature

    Production of electricity

    Maintenance, repair and division

  • Respiration

    The chemical process by which energy

    is released from cells is called

    respiration.

    The main source of energy for

    respiration in cells is glucose.

    This process is controlled by a series of

    enzymes.

  • Progress questions

    Fireflies can produce light in a process

    called bioluminescence. Outline the

    energy transformations that occur in

    fireflies as they use energy from their

    food to produce luminescence.

    Comment on the statement below.

    Respiration produces energy to form ATP.

  • Learning Objectives

    Give the full name of ATP and draw a simplified diagram of its structure.

    Name the molecule from which ATP is formed in cells and draw a simplified version of its structure.

    Explain where the energy for the formation of ATP in cells comes from.

    Explain what the energy from the breakdown of ATP is used for.

  • Structure of ATP

    Adenosine triphosphate (ATP)

    Adenosine

    Three phosphate groups

    Diagram of ATP

  • ATP

    a high energy molecule

    continually being hydrolysed and

    resynthesised.

  • Formation and breakdown of

    ATP

    The combining of ADP + Pi to make ATP is an energy requiring process.

    The breakdown of ATP to ADP + Pi is an energy releasing process.

    The energy required for the formation of ATP from ADP + Pi comes from the respiration of glucose.

  • Transfer of chemical energy by ATP

  • Role of ATP

    ATP is the energy source for: Muscle contraction

    Cell division

    Building up (synthesis) of proteins

    Transmission of nerve impulses

    If ATP is added to muscle tissue, it causes the muscle fibres to contract. The overall effect is that the muscle tissue shortens in length.

  • Think!!

    Explain why ATP is known as the

    universal energy currency.

  • Learning Objectives

    Describe aerobic respiration (using the

    words glucose, pyruvic acid, glycolysis,

    carbon dioxide and water).

  • Chemistry of Respiration

    Respiration is the process by which

    chemical energy is released during the

    breakdown of glucose

    It occurs in every living cell

    Involves the regeneration of ATP

  • Regeneration of ATP

    A Pi Pi

    Pi

    Adenosine DiPhosphate (ADP)

    + Inorganic Phosphate (Pi)

    A Pi Pi Pi

    Adenosine TriPhosphate (ATP)

    High

    energy

    bond

    Takes in energy

    Gives out energy

  • Glycolysis

    Splitting of

    glucose into

    two molecules

    of pyruvic acid

    Results in the

    production of

    2ATP molecules

  • Glycolysis

    C C C

    C C C

    1 Glucose

    C C C

    C C C

    2 Pyruvic Acid

    2 ADP + 2Pi 2 ATP

  • Aerobic breakdown of pyruvic

    acid

    Pyruvic acid is broken down in a series of enzyme controlled steps.

    Each pathway leads to formation of Water

    Carbon dioxide

    18 molecules of ATP

    As this takes place twice for each molecule of glucose the total gain of ATP is 36

  • Aerobic breakdown of pyruvic

    acid

  • Investigating the activity of

    enzymes in aerobic respiration

  • Investigating the activity of

    enzymes in aerobic respiration During respiration, glucose is broken down,

    hydrogen is released at various stages

    This removal of hydrogen is controlled by an enzyme

  • Yeast contains stored food which can be used as a respiratory substrate

    Resazurin dye changes colour when it gains hydrogen)

    blue pink colourless

    (no hydrogen) (lots of hydrogen)

  • Investigating the activity of enzymes in

    aerobic respiration

    Set up the three test tubes as shown

    below. 10ml glucose

    10ml yeast

    5 ml dye

  • Investigating the activity of enzymes in

    aerobic respiration

    Shake tubes vigorously for 20 seconds, and place in a water bath set at 37oC.

    Leave for a few minutes

    Draw a diagram of your results

    Can you explain your results.

  • Investigating the activity of

    dehydrogenase enzyme in yeast

    Tube A

    Colour change from blue via pink to

    colourless.

    Hydrogen has been rapidly released and

    has reduced the dye.

    For this to happen enzymes present in

    yeast cells must have acted on the

    glucose, the respiratory substrate, and

    oxidised it.

  • Investigating the activity of

    dehydrogenase enzyme in yeast

    Tube B Change from blue pink colourless

    Reaction is slower since no glucose was added.

    enzymes could only act on any small amount of respiratory substrate already present in the yeast cells.

    Tube C Boiling has killed the yeast and denatured the

    enzymes.

  • AEROBIC RESPIRATION

    EXPERIMENTS

  • Energy content of food

  • Release of heat energy during

    respiration

  • Respirometer do living things produce carbon dioxide?

  • Respirometer

    Measuring the rate of respiration

  • Respirometer

    A respirometer measures the rate of

    respiration

    Sodium hydroxide is a chemical that

    absorbs carbon dioxide

    Oxygen taken in by the animal causes

    a decrease in volume in the enclosed

    gas, the coloured liquid rises up the

    tube.

  • Learning Objectives

    Describe anaerobic respiration as the breakdown of glucose to pyruvic acid by glycolysis.

    State that anaerobic respiration in animals is reversible and results in the production of lactic acid.

    Describe the effect of lactic acid on muscle cells and subsequent repayment of the oxygen debt.

    State that anaerobic respiration in plants is irreversible and results in the production of ethanol and carbon dioxide

  • Anaerobic Respiration

    Partial breakdown of glucose in the

    absence of oxygen

    Glycolysis occurs as normal

    2ATP are produced

    Pyruvic acid then gets converted into

    Lactic acid in animals

    Carbon dioxide and ethanol in plants and

    yeast (this is irreversible)

  • Anaerobic Respiration in

    Animals

  • Anaerobic Respiration in animals

    In muscles cells, lactic acid is formed during anaerobic respiration

    A build up of lactic acid reduces the efficiency of muscles leading to muscle fatigue

    Oxygen debt is the oxygen that needs to be repaid during

    a rest period

    Lactic acid is converted to pyruvic acid and respired aerobically

  • Anaerobic respiration in plants

    and yeast

  • Anaerobic Respiration in plants

    and yeast

    When oxygen is absent plants and

    yeast respire anaerobically

    Carbon dioxide is lost from each molecule

    of pyruvic acid

    Ethanol is formed

    This is irreversible

  • Learning Objectives

    Describe an experiment, including a

    labelled diagram of the apparatus, to

    investigate anaerobic respiration in

    yeast and say what happens.

  • Comparing aerobic and

    anaerobic respiration

    Aerobic

    respiration

    Anaerobic

    respiration

    Need for

    oxygen

    Energy yield

    Degree of

    breakdown of

    glucose

    End products

  • Comparing aerobic and

    anaerobic respiration

    Aerobic

    respiration

    Anaerobic

    respiration

    Need for

    oxygen

    Oxygen

    required

    Oxygen

    absent

    Energy yield 38 ATP 2 ATP

    Degree of

    breakdown of

    glucose

    complete partial

    End products Carbon dioxide and water

    Animals lactic acid

    Plants ethanol and

    CO2