Essay on Psysiology chapter 4

1. An understanding of chemistry is important for an understanding of biology because biology needs the models of chemistry to better describe life.

Enzymes speed up metabolic reactions necessary for life. Without them certain vital processes would not take place and the body would be unable to function.

Materials move into and out of cells through either passive transport or active transport. Passive transport includes diffusion and osmosis. Molecules tend to move from crowded to less crowded in order to achieve a balance or to reach homeostasis. The cell membrane is selectively permeable which allows the movement of substances, especially oxygen, water, food molecules, carbon dioxide, and waste products, into or out of the cell without the use of energy. Movement occurs when there are unequal concentrations of a substance inside and outside of the cell.

* Cells allow things to go in and out of the organism (allows diffusion to happen so good things go in and bad things go out)

The body and cells need a constant supply of energy for a variety of reasons. Energy is needed to carry out mechanical work which involves the change in location or orientation of a body part or the cell itself. A major example is the energy required for the contraction of muscles. Molecular transport also requires energy. The movement of molecules from an area of low concentration to an area of higher concentration requires energy since this is opposite to the normal movement of molecules. This process is also called active transport. Examples include the movement of nutrient raw materials into a cell and the movement of waste materials out of the cell. Electrical work is also included under molecular transport

Mitochondria – Spherical bodies in the cytoplasm where energy is produced. The cell uses this energy to perform the specific work necessary for cell survival and function.

• Enzymes are involved in processes such as the breakdown of carbohydrates and converts them into energy for the body to use.

Enzymes are a key aspect in our everyday life and are a key to sustaining life. They are biological catalysts that help speed up the rate of reactions. They do this by lowering the activation energy of chemical reactions (Biology Department, 2011).

Biochemistry is continuously working, even without visual proof. Chemical reactions are happening all around and within us. One example where biochemistry plays a major role is in the storage of energy. There are two biomolecules that are responsible for energy storage: polysaccharides and lipids. Polysaccharides deal with the short-term storage and are readily available for conversion to

Catalysis They serve as enzymatic catalysts that speed up biochemical reactions while remaining unchanged in the process. Without these biological catalysts, chemical reactions would occur so slowly that life as we know it could not exist. With them, chemical reactions can occur at rates as much as 10 billion times faster than would be possible without enzymes. Enzymes are critical to digestion and metabolism, they are required to release nutrients from foods so they can be absorbed and utilized by the body.

Enzymes are central to every biochemical process. Due to their high specificity they are capable of catalyzing hundreds of reactions that signifies their vast practical importance.

There are thousands of chemical reactions that occur in an organism that make life possible. Most of these chemical reactions occur too slowly on their own. Enzymes are protein catalysts that speed up chemical reactions in a cell. Catalysts are not changed by the reactions they control, and are not used up during the reaction. Enzymes therefore, can be used over and over again. Enzymes are large complex proteins made by the cell and allow chemical reactions to take place at the temperature of the cell. These catalysts are needed in only very small amounts because a single enzyme molecule can complete the same reaction thousands of times in one minute.

Enzymes are very efficient catalysts for biochemical reactions. They speed up reactions by providing an alternative reaction pathway of lower activation energy. Like all catalysts, enzymes take part in the reaction - that is how they provide an alternative reaction pathway. But they do not undergo permanent changes and so remain unchanged at the end of the reaction. They can only alter the rate of reaction, not the position of the equilibrium. Enzymes are usually highly selective, catalyzing specific reactions only. This specificity is due to the shapes of the enzyme molecules.

In order for cells and organisms to “live” they need to perform certain tasks such as produce energy through respiration, send messages, maintenance and reproduction. To enable the cell to do so, it contains within small structures called organelles, each organelle is different and carries out a specific function.

Enzymes are proteins that act as catalysts and help reactions take place. In short, enzymes reduce the energy needed for a reaction to take place, permitting a reaction to take place more easily. Some enzymes are shape specific and reduce the energy for certain reactions. Enzymes have unique folds of the amino acid chain which result in specifically shaped active sites (Frankova Fry 2013). When substrates fit in the active site of an enzyme, then it is able to catalyze the reaction. Enzyme activity is affected by the concentrations of the enzymes and substrate present (Worthington 2010). As the incidence of enzyme increases, the rate of reaction increases. Additionally, as the incidence of substrate increases so does the rate of reaction.