8056677
Description
Flashcards by CiNa Hicks, updated more than 1 year ago
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Created by CiNa Hicks
about 7 years ago
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| Question | Answer |
| What is an enzyme? | A globular protein that increases the rate of biochemical reactions by lowering the activation energy threshold (i.e. a biological catalyst) |
| What is an activation site? | A region on the surface of an enzyme to which substrates bind and which catalyses the reaction. |
| What is a substrate? | Reaction in a biochemical reaction. |
| Describe 3 examples of enzymes? | Amylose: substrate = starch, product = glucose Protease: substrate: plypeptides, product = amino acids Lipase: substrate = triglycerides, product = glycerol & (3) fatty acids |
| What suffix is commonly applied to enzymes? | Ase |
| State the functions of polar regions of amino acids on the active site of the enzyme? | The polarity of ‘R’ groups plays a role in the tertiary structure of globular proteins Plays a role in shaping enzymes and their active site Attracting substrates to the active site |
| Explain enzyme-substrate specificity and fit model of enzyme activity. | |
| What is meant by the term collision in enzyme catalysis? | The coming together of a substrate molecule and an active site is known as a collision |
| Explain why not all collisions between enzymes and substrates result in catalysis? | The substrate may be at any angle to the active site when the collision occurs Successful collisions are ones in which the substrate and active site happen to be correctly aligned to allow binding to take place |
| Why is the presence of water critical for most enzyme reactions? | Most enzyme reactions occur when the substrates are dissolved in water. All molecules dissolved in water are in random motion, with each molecule moving separately. |
| Why do enzymes tend to move more slowly than substrates? | If not immobilised the enzyme can move too, however enzymes tend to be larger than the substrate(s) and therefore move more slowly Enzymes are bigger than the substrate(s) |
| Explain how denaturation of an enzyme affects its ability to catalyse reactions? | |
| What effect does temperature have on the rate of an enzyme-controlled experiment? | Increasing the temperature will increase the speed and motion of both enzyme and substrate Higher kinetic energy will result in more frequent collisions between enzyme and substrate |
| Lower and optimal temperature on the rate of reaction | Low temperatures result in insufficient thermal energy for the activation of a given enzyme-catalysed reaction to being achieved At an optimal temperature (may differ for different enzymes), the rate of enzyme activity will be at its peak |
| What does a too hot temperature do to the rate of reaction? | Higher temperatures = stability to decrease, as the thermal energy disrupts the hydrogen bonds holding the enzyme together. This causes the enzyme (particularly the active site) to lose its shape, resulting in a loss of enzyme activity (denaturation) |
| What effect does pH have on the rate of an enzyme-controlled experiment? | Alter the charge & shape of the enzyme. Enzymes have an optimum pH and moving outside of this range will always result in a diminished rate of reaction Different enzymes may have different optimum pH ranges |
| What effect does changing the shape or charge have on the enzyme? | Changing the shape or charge of the active site will diminish its ability to bind to the substrate, halting enzyme function |
| What effect does substrate concentration have on the rate of an enzyme-controlled experiment? | |
| List 8 commonly used enzymes in the industry? | |
| List 3 ways in which enzymes can be immobilised. | Aggregations of enzymes bonded together Attached to surfaces, e.g. glass Entrapped in gels, e.g. alginate gel beads |
| What are the advantages of immobilising enzymes? | |
| List 3 commercial reasons that lactose free milk is produced. | As a means to increase the sweetness of milk (glucose and galactose are sweeter in flavour) As a way of reducing the crystallisation of ice-creams (glucose and galactose are more soluble than lactose) As a means of shortening the production time for yoghurts or cheese |
| Lactose structure C12H22O11 | |
| Outline the process by which lactose-free milk is produced? immobilised enzymes |
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