Biology – College Essay Example

release electrons and generate energy.

Energy produced during aerobic respiration is transported by adenosine triphosphate (ATP) to other cells in the body. In organic cells, this process starts with carbohydrates breaking down into glucose. Glucose then reacts with oxygen in mitochondria to produce carbon dioxide, water, and more energy.

The equation for aerobic respiration is C6H12O6 + 6O2 > 6CO2 + 6H2O + energy (ATP). The stored energy of ATP is released through hydrolysis: ATP + H2O > ADP + Pi ? = 7.2 kcal/molPhotosynthesis provides glucose and oxygen for aerobic respiration in both animal and plant cells. Aerobic respiration produces carbon dioxide, water, and energy in plants and animals. Glycolysis is the process where a glucose molecule breaks down into two pyruvate molecules, occurring in various cells' cytoplasm including plant cells, animal cells, and microorganisms' cells. It involves more than six enzymes. When there is no available oxygen for oxidative phosphorylation to produce ATP through glycolysis, fermentation occurs as an alternative process. Fermentation metabolizes pyruvate to create compounds such as lactic acid, hydrogen, and ethanol. Glycolysis is essential for extracting chemical energy from glucose. The equation for glycolysis discovered in 2001 produces two ATP molecules and NADH: C6H12O6 + 2ADP + 2Pi + 2NAD+ > 2ATP + 2NADH + 2H2O + 2H+ + 2CH3COCOO-. Fermentation allows the release of chemical energy stored in food substrates. Anaerobic organisms utilize sunlight energy through glucose produced by photosynthesis. Enzymes play a crucial role as biological catalysts that accelerate chemical reactions within living cells.The enzymes contain active sites made of proteins where specific interactions with substrates occur. Initially, the substrates attach to the active sites of the enzyme through non-covalent

interactions such as ionic bonds, hydrogen bonds, and hydrophobic interactions. Once bound to the active site, the substrate goes through various mechanisms that enhance the process and convert it into appropriate products. After the reaction is complete, the products are released so that enzymes can accept new substrates. Overall, enzymatic action involves three interactions: substrate acceptance, acceleration of reactions leading to product formation, and subsequent release of those products (Starr et al., 2008).

To meet different physiological needs throughout a cell's life, enzymatic activities in living cells can be regulated through various mechanisms. One mechanism is feedback inhibition where an enzyme's activity is inhibited by its own end product. For example, threonine deaminase converts threonine into isoleucine but is inhibited by isoleucine itself (Karp, 2009). When there is a decrease in concentration of the end product, feedback inhibition becomes inactive and enzymatic action continues. Apart from feedback inhibition, enzyme activities can also be regulated through interactions with other proteins and covalent modifications (Taggart & Starr, 2006).