1. CELLULAR RESPIRATION
AEROBIC AND ANAEROBIC

2. energy All cells need energy to carry out their functions.
AUTOTROPHS obtain energy by using solar energy and inorganic molecules (CO2 and H20) to produce organic molecules
HETEROTROPHS obtain organic compounds by consuming other organisms
Organic compounds (carbohydrates, protein, fats, nucleic acids) are used by all organisms for growth and repair and to perform everyday functions.

3. Cellular respiration
ATP Twig clip
Cellular respiration is the process by which chemical energy stored in organic compounds is transformed into a usable form of energy.
When energy is needed by a cell, the bonds of organic compounds are broken releasing energy which is stored in ATP.
ATP molecules are the cell’s store of immediately usable chemical energy required for cellular processes.
Has 2 high energy bonds that can be broken
Splits into a molecule of ADP and a molecule of phosphate.
ADP can combine with ADP to re-form ATP

4. Energy molecules

5. glucose
Most energy for ATP comes from the breakdown of glucose, lipids and proteins.
Glucose, a product of photosynthesis is an energy rich sugar.
Chemical energy from glucose is released in a series of steps involving many enzymes. Each energy ‘packet’ can produce an ATP molecule from ADP.
Glucose breakdown results in three products:
Carbon dioxide
Water
Energy
40% of the energy released is converted to energy stored in the bonds of ATP during aerobic respiration. The rest is lost as heat.
Glucose twig clip

6. Cellular respiration
No further ATP produced

7. Aerobic respiration Oxygen available Occurs in mitochondria Uses ADP
Complete release of energy from glucose:
Glycolysis - splitting of glucose into pyruvate
Krebs cycle – pyruvate broken down to form carbon dioxide and hydrogen
Electron transport – water formed from hydrogen and oxygen
~ The energy given off is used to convert ADP back to ATP.
Aerobic respiration twig clip

8. Aerobic respiration Stage Where is occurs What happens Outputs
Glycolysis
(does not need oxygen)
Cytosol
Glucose (6C) is broken down into 2 pyruvate molecules (3C) producing 2ATP & H+ which is picked up by NAD (carrier molecule)
2 pyruvate molecules
NADH
2 ATP (small amount)
Krebs cycle
Inner compartment of mitochondria (matrix)
Pyruvate is converted to acetyl CoenzymeA which is then broken down releasing carbon dioxide and H+ which is picked up by NAD & FAD
Carbon dioxide
FADH2
Electron transport
Inner membrane of mitochondria (cristae)
Oxygen combines with the H+ (brought in by the carrier molecules) to form water. ATP is released
Water
32 ATP

9. Anaerobic respiration
Oxygen unavailable
Also known as fermentation
Occurs in the cytosol
Prevents build-up of pyruvate so glycolysis can continue.
Converts pyruvate into:
lactic acid (in most animals)
carbon dioxide and alcohol (in plants/ microorganisms such as yeasts and bacteria)
No more ATP is produced!
Anaerobic respiration twig clip

10. Cellular respiration In cytosol In cytosol In mitochondria
No further ATP produced

11. aerobic and anaerobic respiration summary

12. Cellular respiration & photosynthesis

13. Chloroplast twig clip
Chlorophyll twig clip
Photosynthesis recap
Plants obtain energy from the sun to make their own organic compounds (glucose).
Water and carbon dioxide are also required.
Chloroplasts are the organelles where photosynthesis occurs
They are located in mesophyll cells (central part of leaves in vascular plants).
In non-vascular plants such as mosses, chloroplasts are found throughout the leaves and often in other parts such as stems.
Chloroplasts contain the green pigment chlorophyll (absorbs the light)
Photosynthesis occurs in 2 stages:
Light-dependent (in grana)
Light Independent (in stroma)
Parts of a leaf twig clip
**Why do leaves change colour???

14. photosynthesis
Photosynthesis is critically important for life on Earth
Photosynthesis reaction:

15. Factors that control the rate of photosynthesis:
Light intensity
Carbon dioxide concentration
Temperature
Availability/concentrations limit the rate of photosynthesis.
For each factor there is an optimum amount at which photosynthesis occurs at the fastest rate
Below optimum – photosynthesis rate is slower
Above optimum – photosynthesis rate may also be slower