Enzymes And Their Importance In Plants And Animals 224nr

Enzymes and their importance in plants and animals Enzymes are known as biological catalysts. This means they speed up chemical reactions without being used up. They also lower the activation energy which allow particles to have enough energy to react. Enzymes are proteins and work by the active site attaching itself to substrate molecules in which molecules together to form larger ones. Substrates are able to bind with the enzyme due to the shape of the active site being complementary to the substrate. The active site and substrate are specific shapes which fit together, this is known as the ‘lock and key’ theory. The diagram below shows how products are formed using an enzyme and substrate.

Enzymes require specific conditions in order to function well. There are three main factors which affect how well enzymes work and whether they become denatured; these conditions consist of moisture, temperature and pH. If any condition is not suitable for a specific enzyme then the active site becomes damaged and changes shape, this prevents the enzyme from working sufficiently and the enzyme then becoming denatured. The approximate temperature an enzyme works best at is around 37 degrees Celsius (body temperature), in which enzyme activity increases as the temperature increases. This is because a higher temperature gives molecules more kinetic energy resulting in more frequent collisions. Due to the more frequent collisions, kinetic energy is transferred quicker to neighbouring particles so the activity of the enzyme is therefore increased. However, after a certain point (usually 40 degrees Celsius) the temperature becomes too hot for the enzyme to function properly (causing the enzyme denature).

The correct pH also affects the shape of an enzyme; whilst enzymes in the stomach work best in lower pH conditions, enzymes in the small intestine work best at higher pH conditions. Moisture is a condition which is often forgotten when discussing suitable conditions for enzyme activity. In fact, enzymes require water hydrolysis in order to carry out their function of breaking down substances. Conversely, animal and plant cells use the process of condensation (removing water). To sum up, the appropriate moisture conditions play a major role in how well enzymes work. Enzymes have many uses in animals. They are a vital part of the digestive system in which they are produced from digestive juices to break down molecules for digestion. There are three main enzymes; Protease, amylase and lipase. Protease is produced in the salivary gland, pancreas and small intestine, it’s function is to break down proteins into smaller chains of amino acids. Amylase is also produced in the salivary gland, pancreas and small intestine however it’s function is to break down starch into sugars (maltose). Unlike amylase and protease, lipase is only produced in the pancreas and small intestine. Its main function is to break down lipids into fatty acids and glycerol. Without enzymes, the digestive system would be inefficient, due to the fact that enzymes propel foods to be broken down and then stored in the gall bladder to be released (as faeces or in urine). Enzymes are not solely required for digestion- but also for homeostasis and respiration. Firstly, homeostasis involves regulating blood glucose levels. When blood glucose levels are too high, insulin is produced, insulin then activates an enzyme used to speed up the condensation of glucose molecules to glycogen. This process is known as glycogenesis. Secondly, respiration requires energy, enzymes are particularly useful in lowering the activation energy by catalysing the reaction between carbon dioxide and water, as well as in the removal hydrogen molecules. Additionally, enzymes are useful for catalysing the breakdown of the neurotransmitter acetylcholine, this is most useful during synapses with one molecule of acetylcholinesterase breaking down 25,000 molecules of acetylcholine every second. Essentially, enzymes are useful in the nervous system as they speed up many reactions to carry out rapid, effective responses. Enzymes also play a vital part in plants. As well as lipase, amylase and protease, plants also have cellulase. Cellulase is an enzyme which is used to digest carbohydrate bonds (most commonly polysaccharide). This is most crucial for providing food as well as building up the cell wall for plants. Not just for plants, but cellulase is used as additive for food and drink due to it being able to bind well. In addition, it can be used as a reinforcing material.

Enzymes are also used in photosynthesis. The enzyme rubisco is used to catalyse the process of carbon dioxide being made into a carbohydrate (glucose)- the enzyme rubisco is most important in this light independent stage. Another enzyme used in photosynthesis is phosphoenolpyruvate carboxylase (PEP). This enzyme is used to catalyse the uptake of carbon dioxide as well as conserve water by closing the stomata. This is extremely useful to ensure that the plant is able to have enough carbon dioxide for photosynthesis as well as water, which is essential for plant growth and balancing out hot temperature conditions. Enzymes can also be used for genetic modification in plants. When transferring new genes to a plant, enzymes can be used to ‘cut out’ and place genes into the DNA of a plant cell. This is extremely useful when trying to acquire plants with certain characteristics (such as being resistant to insects). There are many differences between animal and plant enzymes. Whilst in animals, enzymes have a short range of pH levels, plants have a much wider range. This means that plant enzymes are able to pre-digest as well as digest faster and easier. To conclude, enzymes speed up reactions, change shape upon certain conditions and have many uses. Without enzymes, mechanisms within plants and the human body would be ineffective and in fact organisms would not be able to respire, digest, photosynthesise or even transmit impulses from the brain during a response. Enzymes are proteins and help to and break up chains of amino acids, they are even extracted from plants for commercial use and they are used carefully in sight of the fact that they can denature.

Sources http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/enz ymes/enzymes1.shtml http://www.biology-pages.info/E/Enzymes.html http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/geneticvariation/re productionrev5.shtml http://www.foodenzymeinstitute.com/articles/what-do-plant-enzymesdo.aspx?list=bydate