<em>Leptospira interrogansis</em> b/w <em>Leptospira interrogansis</em>

Leptospira interrogansis

A spiral-shaped bacterium which causes leptospirosis (also known as Weil's disease). Leptospirosis is transmitted via direct contact with the body fluid of an infected animal or by exposure to soil or fresh water contaminated with the urine from an infected animal. Symptoms include fever, vomiting, conjunctivitis and muscular pains. Kidney failure may also occur in severe cases.

Carbon cycle

The carbon cycle is a complex cyclical process through which all of the carbon atoms in existence rotate. Just think the same carbon atoms in your body today have been used in many other molecules since time began - in a tree, in a plant and even in a dinosaur.

  • Carbon cycle - Step 1

    1/6 Under the right conditions carbon-based fossil fuels, coal, oil and gas are formed. These are mined from the ground.

  • Carbon cycle - Step 2

    2/6 Carbon is released into the atmosphere:

    1. when fossil fuels are burned
  • Carbon cycle - Step 3

    3/6 Carbon is released into the atmosphere:

    1. when fossil fuels are burned
    2. by respiration of decomposers
  • Carbon cycle - Step 4

    4/6 Carbon is released into the atmosphere:

    1. when fossil fuels are burned
    2. by respiration of decomposers
    3. by respiration of living organisms
  • Carbon cycle - Step 5

    5/6Photosynthetic microbes and green plants take in carbon during photosynthesis and produce glucose (a sugar).

    The gas oxygen is released as a waste product.

  • Carbon cycle - Step 6

    6/6 Dead organisms and waste products decay bringing the carbon into the ground.

    Overtime (millions of years) and under the right conditions some decomposed remains will be turned into fossil fuels such as coal and gas.

Algae as well as bacteria called cyanobacteria are similar to green plants because they can all make their own food through a process called photosynthesis.

Photosynthesis

Chlorophyll, the substance that makes algae and plants green, uses the energy from sunlight. In algae and plants it is contained in a structure called the chloroplast; cyanobacteria carry out photosynthesis directly in the cytoplasm of the cell. The microbe uses this energy to change carbon dioxide gas from the air and the water around them into a sugar called glucose. The sugar is either transported to other cells and used as food or stored as insoluble starch. This process is called photosynthesis. The gas oxygen is released as a waste product. This is very important as animals including humans need oxygen to live. In fact 70 – 80 % of all the oxygen we breathe comes from algae.

The chemical reaction for photosynthesis:

6H2O + 6CO2   C6H12O6 + 6O2
  Energy from sunlight  
6 molecules water + 6 molecules carbon dioxide   1 molecule glucose + 6 molecules oxygen

Carbon, which is represented by the letter C in the equation, is being transferred from the carbon in the carbon dioxide to the carbon in the glucose. This reaction forms part of the carbon cycle.

Aerobic respiration

Aerobic respiration takes place in the presence of oxygen and occurs in the opposite direction to the photosynthesis reaction. Aerobic respiration is the release of energy from glucose, which takes place inside the mitochondria of living cells.

The chemical reaction for aerobic respiration:

(stored energy)
C6H12O6 		+ 6O2   6O2 + 6CO2 + energy
     
1 molecule glucose + 6 molecules oxygen   6 molecules water + 6 molecules carbon dioxide

This reaction forms part of the carbon cycle.