3.3 Respiration - aerobic Flashcards
Comparison of photosynthesis and respiration.
Photosynthesis. Respiration
Produces food. Uses food
Stores energy. Releases energy
Uses CO2 & H2O ProducesCO2 & H2O
Release o2. Uses O2
Occurs in light. Occurs in dark.
Aerobic respiration, definition and formula
Aerobic respiration is controlled oxidation in a living cell.
Glucose + Oxygen > Carbon dioxide and Water
C16 H12 O6+ 6 O2= > 6 CO2 + 6H2O + energy (38ATP)
Oxidation
Chemical process by which sugars, produced during photosynthesis, are converted into starch.
Aerobic repiration
- Glycolysis - glucose is split >produces PYRUVATE.
Synthesis if
ATP in cytoplasm. - PRYUVATE and OXYGEN used in mitrchondria to derive carbon dioxide, water, ATP and heat.
Krebs cycle, part one
Takes place in mitochondria.
Pyruvic acid enters matrix.
Converted into a two carbon compound called ACETYL COENYME A by removal of a molecule of CO 2.
ACETYL COENZYME A is joined by OXALOACETATE ( a four carbon compound).
This passes through cyclic series of reactions> hydrogen and carbon dioxide atoms are removed.
6 carbon molecule is converted back into OXALOCELATE .
Cycle starts again.
Krebs cycle, part two.
Sucrose + 6O2 + 38 ADP + 38Pi > 6CO2.+ 6H20 + 38ATP
Mitrochodria - function
Synthesis if ATP.
Major source of energy
Glycolysis
First stage if respiration.
Takes place in cell cytoplasm.
Does not require oxygen.
Each molecule of glucose, which contains 6 carbon atoms, is split in half.
Each half contains carbon atoms.
Each of these is converted in PYRUVI ACID.
PYRUVI ACID Is used in second stage.
Glycolysis produces a net gain of two molecules of ATP for each molecule of glucose.
The Krebs cycle, electron transport chain and flows of energy.
The Krebs cycle and electron transport chain together yield 38ATP molecules for each molecules glucose.
Photosynthesis, plant growth and respiration are related to flows of energy, namely carbon.
Carbon is available, having been absorbed during photosynthesis, in molecule of glucose C6 H12 O6, it is broken down to form CO2 and H2O in a process which starts when glucose molecules are broken down to form ATP.
Definition of net and gross photosynthesis
Total photosynthesis - total amount of photosynthesis which occurs in plant.
Gross photosynthesis minus respiration =net photosynthesis
When net photosynthesis stands at 0 there is no gain of energy- gross photosynthesis = respiration.
This is tremendous THE COMPENSATION POINT.
Factors affecting respiration.
Oxygen availability.
Water
Temperature
Lack of substrate (substance in which enzymes act)
Anaerobic respiration
Glucose > Ethanol + carbon dioxide + energy (2ATP)
Description of anaerobic respiration.
Modified form of respiration.
Does not use oxygen in breakdown of sugars.
Gives less energy than aerobic respiration.
Gain of two molecules of
ATP for each molecule of glucose.
Ethanol is a by-product if aerobic respiration, this is detrimental to plants as it inhibits plant root growth.
PYRUVIc acid acts as acceptor of hydrogen produced during glycosis
Causes of anaerobic respiration in horticulture.
Water logged soils - air containing oxygen normally held in soil pores is displaced by water.
Compacted soils - few pores in soil, pores contain air (with oxygen) > lack of oxygen available to plant root.
Fruit and veg crops to tightly packed in storage- poor ventilation in store can lead to lack of oxygen in store.
Temperature in respiration.
Other factors being equal, as temperature rises then respiratory rate rises
Respiration roughly doubles for every 10o C
Above 30o C enzymes are de-natured and metabolism slows down.
Warmer soil> higher respiration > more root growth.
Cold storage > temp 0o - 10o C > slower respiration.
