What Causes The Greenhouse Effect Environmental Sciences Essay

Global warming is an ecological problem that is currently believed to be affecting the Earth’s environment. Global warming is the gradual increase of the Earth’s atmospheric temperature. It is caused by the “Greenhouse Effect”, which is the investment of heat in Earth’s atmosphere by particular gases, like carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). This containment of the gases holds the heat in the Earth’s atmosphere because it allows the light from the sun to pass through, but it absorbs the heat exuded back from the Earth’s surface. Cellular respiration contributes to the problem of global warming, because through its processes it takes in oxygen gas and then exhales carbon dioxide. Photosynthesis helps to prevent this problem, though, because it does the opposite of cellular respiration; it takes in carbon dioxide and then yields oxygen gas (O2).

Cellular respiration is the process of oxidizing certain food molecules, like glucose, to produce carbon dioxide and water. There are three main processes within cellular respiration: glycolysis, the Krebs cycle, and the electron transport chain. Each process plays a significant role in harvesting energy from the food molecules and producing ATP (adenosine triphosphate), which is a high energy molecule that is used for energy consuming activities throughout cells. Cellular respiration takes place in both eukaryotic and prokaryotic cells, as well. Glycolysis is the catabolism of carbohydrates by specific enzymes with the discharge of energy and manufacture of pyruvic (or lactic) acid. It occurs in the cytosol of a cell, unlike the other two processes of cellular respiration. Glycolysis can occur in the absence of oxygen, which is called fermentation, but since this procedure doesn’t yield a high amount of energy it isn’t as practical as the aerobic process. Glycolysis phosphorylates the glucose by adding two phosphates to the molecule at the expense of two ATP molecules; the glucose is then split into two 3-carbon compounds, and the 3-carbon molecules go through a series of different steps to produce pyruvate. Acetyl-CoA is fashioned from the pyruvate, which then enters the second process of cellular respiration, the Krebs cycle. Unlike glycolysis, the Krebs cycle takes place in the mitochondria of a cell. The Krebs cycle is a series of processes that entirely oxidizes the Acetyl-CoA molecule. The cycle must be completed two times to yield four carbon dioxide molecules, six NADH molecules, two ATP molecules, and two FADH2 molecules. The Krebs cycle requires oxygen to be present to occur, making it aerobic. The procedure following the Krebs cycle is the electron transport chain, which consists of a series of special enzyme proteins that shuttle electrons from NADH to a terminal electron acceptor, such as oxygen (McGraw-Hill, 2006). Through a series of redox reactions, a gradient is formed, and, moreover, ATP is produced. All of these processes demonstrate the inner workings of cellular respiration, and show how it uses oxygen and gives off carbon dioxide. The exhalation of carbon dioxide during cellular respiration is mixed into the air, adding to the already present amount within the atmosphere. Carbon dioxide is a main ingredient for greenhouse gas, which helps to not allow heat to escape from the Earth’s atmosphere. As long as living organisms undergo respiration (the metabolism of sugars to produce energy for basic metabolic needs), or as organisms die and decompose, carbon compounds are going to be broken down and are going to add CO2 to the atmosphere (Barbalace, 2006).

Photosynthesis has quite the opposite effect. By dictionary definition, photosynthesis is the synthesis of organic compounds from carbon dioxide and water (with the release of oxygen) using light energy absorbed by chlorophyll. The overall reaction that occurs during photosynthesis is that six water molecules are added to six carbon dioxide molecules to yield glucose and six oxygen molecules. Photosynthesis usually occurs in the chloroplasts of plant cells. Carbon dioxide enters the leaves of plants through stomata, which are minuscule orifices in the epidermis of leaves, and oxygen gas exits out of the same passageway. There are two main parts of photosynthesis, the light dependent reactions and the Calvin cycle. The former requires light to operate, while the latter are light independent, or dark, reactions. In the light dependent reactions, the energy received from light is changed into energy that is carried by electrons; the electrons are then picked up by electron transport systems, that use the energy to produce ATP and another molecule called NADPH. Those two products are used in the next process of photosynthesis, the Calvin cycle. In this cycle, carbon dioxide is integrated into a five carbon molecule that is called ribulose biphosphate (RuBP), and then in a series of chemical reactions, hydrogens and electrons from the NADPH are progressively added to form an uncomplicated, energy rich, phosphorylated carbohydrate called GP3, or PGAL (Decelles, 2002). These products are then used to make glucose, among other carbohydrates. This displays how photosynthesis rearranges the atoms of carbon dioxide molecules and water molecules to create new carbohydrates, which plants then use to supply their cells with energy. Photosynthesis converts the raw materials of CO2 and H2O into oxygen gas, which benefits the atmosphere and helps to slow down global warming. It recycles the carbon dioxide cellular respiration emits into a molecule that is no longer a greenhouse gas constituent.

Global warming itself is an extremely controversial topic. A few believe that it does not pose a real problem, although quite a lot of believe that it does. Global warming is the assertion that the environment of Earth is slowly heating up, and as a result, the organisms inhabiting it will eventually be dramatically affected. The “Greenhouse Effect” is what occurs when heat is trapped, and increases when more heat energy is supplemented. When talking about global warming, the greenhouse effect is set in the parameter of Earth’s atmosphere. The greenhouse effect occurs planet wide when solar radiation either bounces off of or is radiated forth from the Earth, and instead of passing through the atmosphere and outward into space, is absorbed by all kinds of extra amounts of and extraneous gases and particles (“The Greenhouse Effect”, 2010). Cellular respiration contributes to the extraneous gases, while photosynthesis helps to prevent the growing amounts, although other sources of carbon dioxide are decreasing the photosynthetic reactions affect.

At one point, the pollution of carbon dioxide from cellular respiration and the conversion of carbon dioxide into oxygen gas were seemingly equal. A sort of equilibrium was reached between the two processes, with photosynthesis appearing to cancel out the outwardly harmful effects of cellular respiration. As of recently, though, manmade pollution has been affecting our atmosphere, adding more carbon dioxide into the ozone along with that emitted from cellular respiration. The primary cause of global warming is carbon dioxide emissions; carbon dioxide is being pumped into our atmosphere at an alarmingly face pace; eight billion tons of carbon dioxide entered the air just last year.  (“Causes of Global Warming”, 2010). It does not help that trees are being chopped down for logging, development, and other purposes, so there is less carbon dioxide being removed from the atmosphere, causing its levels to rise. There is more carbon dioxide being released into the air than is being converted into oxygen through photosynthetic reactions. This unequal release of gasses into the Earth’s atmosphere is what poses the environmental problem of global warming. The Earth was built to sustain the effects of cellular respiration, but fossil fuels excessively being burned, trees being cut down, and cellular respiration emit too much carbon dioxide for the Earth to recycle.