Understanding the Biochemical Basis of Life

2. Biochemists are scientists who study the type of chemical compounds that are found in living things. • The work of biochemists has led to the realization that living organisms are composed of some of the same elements that are found in the air, water and soil.There are 92 elements know to occur naturally on Earth, however fewer than 20 elements occur in the tissues of living things. • Only 6 elements make up 99.2% of human or pumpkin tissues.

3. oxygen, carbon, hydrogen and nitrogen make up the vast majority of living tissue. • These four elements are recycled between living organisms and the soil, water and atmosphere of the Earth. These elements are first taken up by plants • some oxygen is released to the atmosphere as a product of photosynthesis, but the rest is converted into food, and passed through the food web. • as they pass through plants, consumers, and finally decomposers, and then returned to the environment in a continuous recycling of materials. • If recycling of these materials did not occur, life could not exist.

4. Some of these elements (carbon, oxygen, sulfur, nitrogen) are found in gaseous forms and their cycles involve the atmosphere. As a result they have a global nature. • elements may have a short term cycle such as when carbon is transferred from animals to plants in the form of carbon dioxide • and a long term cycle such as the transfer of carbon from a fossil fuel to a plant following combustion.

5. The elements are cycled between the living organisms and the environment in a combination of biological and geological processes that drives chemical recycling. • Biological processes include: • ·         respiration, • ·         decomposition, • ·         excretion, • ·         photosynthesis, • ·         and assimilation. • Geological processes involve • fossilization • Erosion • combustion of fossil fuels (peat, oil, coal), • weathering • formation of sedimentary rock.

6. Carbon Cycle

7. Plants takecarbon dioxide and water from their environment. • They use the energy they capture from the sun to carry on a process known as photosynthesis which converts the atoms in the carbon dioxide and water into sugar (glucose) and oxygen. • 6CO2 + 6H2O + energy → C6H12O6 + 6O2

9. The oxygen, released as a byproduct of photosynthesis, generally passes into the atmosphere. • The sugar (known as glucose) serves as food for all consumers in the ecosystem. • The consumers carry on a metabolic process known as cellular respiration. where oxygen is taken in from the atmosphere and used to break down the sugar resulting in a release of energy and the molecular products, carbon dioxide and water. Respiration chemical equation • C6H12O6 + 6O2 → 6CO2 + 6H2O + energy

10. Carbon is the centre to life.. • All living things contain carbon. • Carbon is the link that allow plants to transform sunlight into chemical energy. • The sugar (glucose) produced during photosynthesis forms the basic substance that is transferred along food chains.

11. Carbon dioxide in the atmosphere is very small, 0.03% • However, without the carbon cycle we would quickly run out of carbon dioxide, plants could not trap sunlight, and life on earth would cease.

12. Organic and Inorganic • Organic substances always contain carbon and hydrogen, and often contain oxygen and nitrogen. • Important chemicals that make up your body such as proteins, sugar and fats are considered organic. • Inorganic matter doesn’t contain a combination of carbon and hydrogen. • For example: carbon dioxide (CO2), water (H2O) and ammonia (NH3) are inorganic.

13. Inorganic carbon storage • 1.Atmosphere: a small amount in the carbon dioxide in the air we breathe and is available for photosynthesis. • 2.Ocean: a large amount is found in the oceans. This is available to algae and other water plants for phototypesets. • 3. Earths crust: the largest storage of inorganic carbon is in the sedimentary rocks, such as limestone, that have formed from the remains of living things.

14. Organic Carbon Storage • In the bodies of living organisms. • When living things die, their bodies decompose and the carbon is returned to the cycle in inorganic form.

15. Because there is limited oxygen in bogs, decomposition takes thousands of years. • Carbon may remain locked away for many year in organic form. • Carbon locked away in dead plants is know as peat. • When peat is covered in sediment for a long time it will become coal, a carbon containing fossile fuel. • Other fossil flues such as oil and gas contain organic carbon that has been trapped in the earth’s crust for millions of years.

17. Human Activity • People have discovered these fossil fuel deposits and have used them to supply our energy needs. • Humans have also affected the carbon cycle by cutting down forests.  As a result of human activity, the amount of carbon dioxide is being produced at a faster rate than nature can recycle it. • As a result of this imbalance, the amount of carbon dioxide in the atmosphere is increasing. As a result the earth is presently undergoing an enhanced greenhouse effect in which the atmosphere is gradually heating up. • If the rise in temperature occurs too fast for organisms to adapt, widespread extinction of plants and animals may be the result.

19. What are the impacts of deforestation on the carbon cycle • Removing large amounts of trees will reduce the amount of carbon dioxide that is taken out of the atmosphere due to a decreases in photosynthesis. • If threes are burned there will be an increase of carbon dioxide released into the atmosphere. • The forest acts as a carbon sink retaining carbon for long periods of time.