Essay on Breakdown of Lipids (Triglycerides) into ATP

The human body has two clashing pathways of power systems used in energy production. The first system is an anaerobic system known as glycolysis. The amounts of glycogens that the body stores are, however, limited. This pathway takes place without oxygen to produce ATP by breaking sugar into three compounds. The pathway is vital for anaerobic muscles and breakdown of excess sugar by the use of enzymes found in the cell cytoplasm. In addition, the body has another system known as the aerobic system. This system takes place in the mitochondrion, and the metabolic processes within the mitochondrion produce water and carbon dioxide. Fats, carbohydrates, and proteins are broken down in this pathway. Energy produced in this pathway can work in the body for a longer time than that of glycolysis (Vanderkooi, 2014).

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The aerobic process is oxygen dependent where two compounds of C are converted to CO2 in a pathway known as the citric acid cycle. There is also an oxidative phosphorylation pathway within the aerobic process which forms water (H2O). Most ATPs in the body are produced by the aerobic system. Insufficient or unavailability of oxygen in the body may lead to death since body tissues depend on the ATP supplied by the mitochondrion. The ATP production process involves the breakdown of proteins, fats carbohydrates into other smaller categories.

Sugar is found and synthesized in the body in various forms. Some common types of sugar are; glucose, fructose, lactose, and maltose. Carbohydrates are, on the other hand, occur in pure and complex forms such as starch and flour which are disintegrated to monosaccharide in the intestines and stomach (Vanderkooi, 2014). Fat digestion, unlike in sugar and carbohydrates, starts with the breakdown of fatty acids.

In summary, carbohydrates, proteins, and fats are converted into H2O and CO2 by enzymes in a specific sequence. In the first pathway, sugar is metabolized through the process of glycolysis in the cytoplasm. The process breaks 6 sugar into 3 carbon compounds namely; lactate and pyruvate. In the process, ATP is produced. In the mitochondrion, an enzyme known as pyruvate dehydrogenase further disintegrates the 3 Carbon compounds into 2 Carbon compound like acetate releasing CO2 as a substrate. More compounds of H are also formed and stored as NADH. The process can be summarized by the following diagram flow diagram.

Glycerol Pyruvate Acetyl-CoAOxidation of Pyruvate leads to the release of NADH that transfers electrons to their transport chains and an acetyl-CoA which then enters the TCA cycle.

In another pathway, fatty acids are converted into acetyl CoA, FADH, and NADH through a process of b-oxidation. The process takes place when the glucose is insufficient in the body. Fat is stored in the adipose tissue in the form of triglycerides. Under low insulin and high adrenaline and glucagon, the body is prompted to activate protein lipase. Fat is then broken to fatty acids through hydrolysis by enzyme lipase and then bound to albumin in blood. The fatty acids move into fat cells where they are joined by Acyl-CoA (Vanderkooi, 2014). The two are transported to the mitochondrion where Acyl-CoA is to Acetyl CoA which is later converted to CO2 and Adenosine Triphosphate is produced.

Differences between saturated and unsaturated fatty acids

Fatty acids are commonly classified as saturated and unsaturated. Unsaturated fatty acids are further subdivided into polyunsaturated and monounsaturated. There are various characteristics that differentiate saturated and unsaturated fatty acids. By definition, saturated fatty acids are chains of carbon atoms with maximum hydrogen atoms attached to them. The fatty acid is said to be totally saturated with hydrogen atoms, and the each carbon atom is ultimately joined to another other by single bonds. Unsaturated fatty acids arise when a couple of hydrogen atoms miss leaving two carbon atoms attached to each other by one or more double bonds (Engelking, 2015). The fatty acids are said to be unsaturated because of the incomplete number hydrogen atoms.

Saturated fatty acids usually have straight chains due to the single bonds while the chains in unsaturated fatty acids bend at the double bond ends. Saturated fatty acids are commonly found in adipocytes or fat storage cells in animals while unsaturated fats are largely found in plant cell etioplasts. Unsaturated fatty acids can be converted to a saturated state through hydrogenation. All fatty acid chains begin with an OH layer made up of a covalent double bond between oxygen and hydrogen (Engelking, 2015).

3D model of the chemical structure of a saturated fatty acid

The purple molds represent carbon atoms, large white ones are for oxygen, and the small white ones are hydrogen atoms. The chain is straight and is made of single bonds (represented by single lines) all over.

3D model of the chemical structure of an unsaturated fatty acid

In the picture below, the purple molds are the carbon atoms, the large white molds are oxygen atoms, and the small white molds are the hydrogen atom. Single bonds are represented by single lines between hydrogen and carbon atoms while double bonds are shown by double lines in between two carbon atoms. A junction like shape is also present at the point of double bonding.

A diagram demonstrating the fluid mosaic structure of cell membrane

The plasma membrane is described by a simplified diagram known as the fluid mosaic model. The membrane is a phospholipid double layer with wholly or partially embedded protein molecules. Hydrophilic potion heads face outwards and inside the cell while the hydrophobic potion heads face each other. Proteins in the membrane appear as either integral or peripheral proteins. Peripheral ones are located either inside or outside of the membrane surface while the integral proteins are found inside the membrane. The membrane is asymmetric in nature with the filaments of the cytoskeleton held inside and the chains of carbohydrates located on the surface (Luckey, 2014).

How non-fat diets can affect the body

Fats perform a vital role in the metabolism of energy and maintenance of nerve impulse transmission. Fats act as reservoirs of energy and at times regulate body temperature, as well as, producing and regulating of steroid hormones. A diet with low or no fats increases triglyceride levels in the body increasing susceptibility to cardiovascular diseases. A diet with no fats can also reduce the high and low-density lipoprotein (Lunn, J., & Theobald, 2006). Low-fat diets can consequently lead to a decrease in omega three fatty acids which would, in turn, cause mood swings and depressions. Fats act as insulators to protect tissues and organs.

Cell membranes are made up of a double layer of lipids known as the phospholipid oil layer. The layer protects and insulates nerve fiber alongside high cholesterol levels. Cholesterols are molecules that are significant to the proper functioning of cell membranes, fat soluble vitamins absorption, sex hormone synthesis and fat digestion. The body produces considerably ten times the amount of cholesterols people consume in a diet. Cholesterol is paramount in the body and should only be reduced from individuals with over enough body cholesterols and a malfunctioning LDL receptor (Engelking, 2015).

Fats and lipids are also highly valuable since they play numerous roles on the cell structures. Fats can be converted into various hormones to supply the body with the hormone in cases of low glucose supply. Scientifically, fats are made of a bond of oxygen, carbon, and hydrogen. They are composed of not less than two parts one being the glycerol, a type of alcohol acting as a building block, and the other being fatty acids. Fatty acids are equally crucial in the synthesis of fats and lipids.

At the biochemistry level, fats and oils are triglycerides. They act as energy storing molecules whose bond is broken to produce the energy. Fats are further classified as saturated and unsaturated. The body cells require the double bonds produced by unsaturated fatty acids since the body cannot naturally produce them. The double bonds from unsaturated fats protect the body against cardiovascular diseases. Glycerol combines with fatty acids to produce water in cases of extreme dehydration. The OH part of the glycerol reacts with the HO of fatty acid to produce water. As discussed earlier, fatty acids are broken down to form the biological source of energy known as ATP. Fats actually form more ATP than carbohydrates and proteins do. Lack of fatty acids in the diet can, therefore, lead to disorders and symptoms such as; dry skin, depressions, immunodeficiency diseases, stunted growth and liver, and kidney abnormalities (Lunn, J., & Theobald, 2006).

Cardiovascular diseases are commonly caused by high levels of triglycerides in the blood. They are also closely associated with metabolic syndrome, diabetes, and obesity. High triglyceride levels are as a result of an excessive conversion of carbohydrates to fats in the liver. High blood triglycerides can be reduced by consuming meals with high-fat and low-carb content. Cholesterol is perceived as either good or bad cholesterol by the body. High-density Lipoprotein (HDL) is cholesterol that is taken as good by the body. HDL is said to reduce cases of heart diseases. HDL compounds are found in fats, thus eating more fats can increase HDL levels in the blood thereby shielding the body against heart disease (Egart et al. 2011).

Studies also show that low levels of fat in the body reduce the level of testosterone. Testosterone is an important male sex hormone. Testosterone is produced by cholesterols found in fat. Low testosterone counts lead to low libido, depression, osteoporosis, high body fat and reduced muscle mass. Eating non-fat diets leads to low cholesterol intake hence reduced levels of testosterone (Lunn, J., & Theobald, 2006).

Controversially, low-fat diet can interfere with Low-Density Lipoprotein (LDL) pattern. LDL or bad cholesterol is found in three forms; large, dense and small. Studies show that small and dense LDLs lead to heart diseases. High carbohydrate intake raises small and dense LDL levels while a diet with cholesterol and saturated fat leads to large LDL. Therefore, diets with low fats tend to shift the LDL pattern from large to small and dense LDL. The shift, in turn, leads to a risk of cardiovascular diseases (Egart et al. 2011).

References

Egert, S., & Kratz, M., & Kannenburg, F., & Fobker, M., & Wahrburg, U. (2011). Effects of high-fat and low-fat diets rich in monounsaturated fatty acids on serum lipids, LDL size and indices of lipid peroxidation in healthy non-obese men and women when consumed under controlled conditions, 72, 71-79.

Engelking, L. R. (2015). Saturated and Unsaturated Fatty Acids. Textbook of Veterinary Physiological Chemistry, 345-350. doi:10.1016/b978-0-12-391909-0.50054-2

Luckey, M. (2014). Membrane Structural Biology: With Biochemical and Biophysical Foundations. Cambridge University Press, United Kingdom.

Lunn, J., & Theobald, H.E. (2006) The health effects of dietary unsaturated fatty acids, 186, 178-224.

Vanderkooi, J., M. (2014). Your Inner Engine: An introductory course on human metabolism. CreateSpace Independent Publishing Platform.