An Investigation Into the Inhibiting Effect of Tomato Juice on the Germination of Cress Seeds

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An Investigation Into the Inhibiting Effect of Tomato Juice on the Germination of Cress Seeds Introduction ============ I intend to analyse the inhibiting effect of tomato juice on the germination of tomato juice. In this introduction I will answer important questions such as; what are inhibitors? How might inhibitors affect germination? , etc. When answering the questions, I will be considering different areas of the syllabus (e.g. genetics, inter-specific competition, enzymes and inhibitors, practical skills, etc.) This will help me appreciate the theory behind the investigation and hence help me formulate an effective plan and method. Inhibitors are chemicals, which inhibit the action of an enzyme. There are two main types of inhibitors: reversible and non-reversible. Non-reversible inhibitors permanently damage enzymes. They attach themselves to the enzyme molecule and cause important bonds to break, causing irreparable damage. This denatures the enzyme and does not allow it to function. Diagram showing non-reversible inhibition: Normal arrangement Change caused by non-reversible inhibitor Reversible inhibitors inhibit the action of enzymes but do not do permanent damage. Once the reversible inhibitor is removed; the enzyme will return to normal. Reversible inhibitors can be divided into two types: competitive and non-competitive. Competitive inhibitors compete with the substrate molecules for a place on the enzyme's active site. Although enzymes are specific the inhibitors have a structure similar to the substrate molecule and so can fit into the active site. This will stop the substrate locking with t... ... middle of paper ... ... the juice of other fruit to see if they have the same effect · Disinfect the seeds before use to destroy any bacteria and mould that could affect the results · Carry out the experiment in a temperature controlled lab. · Carry out the experiment in a lab where the light intensity is monitored and kept constant · Use more reliable apparatus · Ensure the pH does not change (buffer solution) · Use more accurate measuring equipment (e.g. pipette) to reduce percentage error) · Read measurement at eye level to reduce parallax error · Give the seeds longer to germinate and hence make it easier to distinguish between seeds that have germinated and those that have not. A Level Biology coursework: An investigation into the inhibiting effect of tomato juice on the germination of cress seeds

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