Biology Enzyme Quiz
Rodney Liuzzo
This Biology quiz is called 'Enzymes' and it has been written by teachers to help you if you are studying the subject at middle school. Playing educational quizzes is a fabulous way to learn if you are in the 6th, 7th or 8th grade - aged 11 to 14.
Enzymes are proteins and their molecules act as biological catalysts. This means that they speed up chemical reactions in living organisms, and in this middle school Biology quiz we are going to take a closer look at some of the different enzymes, what they do and how they work. Enzymes function because they are long molecules that are twisted and folded into a specific and usually very complex shape.
The shape allows smaller chemicals (substrate molecules) to fit into certain places called active sites. This brings the substrate chemicals close together and so they can react more easily than they would do otherwise.
Enzymes work best at specific temperatures and pH levels, for example, human enzymes work best at about 37oC. They are sensitive to temperature and pH, and change their shape under conditions of moderately high temperatures (45oC and above) and values of pH that differ from the ones in which they normally work. When they change shape like this, we say that they are denatured and the active sites will no longer work as efficiently. As the temperature or pH becomes more extreme, the active sites stop working altogether.
Enzymes are found at work in almost all places in the body of any organism, whether plant, animal or bacteria. They are catalysts for many biological processes such as respiration, photosynthesis and the synthesis of proteins. They also break down longer molecules into shorter more useful chemicals e.g. during digestion, enzymes convert large molecules into smaller molecules which can then be absorbed. Because they can be used to cut other molecules, they are used in genetic engineering. They are carefully chosen to cut specific genes from the DNA of plants and animals which can then be spliced into other DNA. They are even used in industry to catalyze reactions at normal pressure and temperature thus saving money on expensive energy-demanding equipment that would otherwise be needed.
Chemistry for Biologists resources aim to help you understand the chemistry and chemical principles that underlie a good deal of biology. These resources were hosted on the Chemistry for Biologists website, which launched in 2004 and was supported by the Royal Society of Chemistry and the Biochemical Society. From 2019 Chemistry for Biologists resources are hosted on the Royal Society of Biology website.
The resources are aimed at post-16 students taking biology (or related subjects) to A level, Scottish Higher or similar level. These will also be of use to first year undergraduates studying biology. The resources assume you have studied some chemistry (either a separate subject or as part of a balanced science course to GCSE level or equivalent). The material is organised into 17 topics, which can be approached in any order, although it might be a good idea to tackle Some basic chemistry first. Each chapter has a short multiple choice test accompanying it that you can take at any time. You can use these tests in a number of ways:
The resources originally presented 3-D rotatable structures, these are no longer supported, but we suggested that you explore instead. Just be wary of the many different isomers you will find, make sure you follow the biologically relevant examples. The rotatable molecules are important because a great deal of biochemistry depends on the three-dimensional shapes of molecules - how substrates fit the active sites of enzymes, how drug molecules fit receptors in cells, for example.
Note for Content: The number of manual tests per kit can be doubled if all volumes are halved. This can be readily accommodated using the MegaQuantTM Wave Spectrophotometer (D-MQWAVE).
Many of the enzymatic test kits are official methods of prestigious organisations such as the Association of Official Analytical Chemicals (AOAC) and the American Association of Cereal Chemists (AACC) in response to the interest from oenologists. Megazyme decided to use its long history of enzymatic bio-analysis to make a significant contribution to the wine industry, by the development of a range of advanced enzymatic test kits. This task has now been successfully completed through the strategic and comprehensive process of identifying limitations of existing enzymatic bio-analysis test kits where they occurred, and then using advanced techniques, such as molecular biology (photo 1), to rapidly overcome them. Novel test kits have also been developed for analytes of emerging interest to the oenologist, such as yeast available nitrogen (YAN; see pages 2-3 of issue 117 article), or where previously enzymes were simply either not available, or were too expensive to employ, such as for D-mannitol analysis.
Plant-based milk alternatives have gained massive popularity among consumers because of their sustainable production compared to bovine milk and because of meeting the nutritional requests of consumers affected by cow milk allergies and lactose intolerance. In this work, hemp flour, in a blend with rice flour, was used to design a novel lactose- and gluten-free yogurt-like (YL) product with suitable nutritional, functional, and sensory features. The growth and the acidification of three different lactic acid bacteria strains were monitored to better set up the biotechnological protocol for making the YL product. Hemp flour conferred the high fiber (circa 2.6 g/100 g), protein (circa 4 g/100 g), and mineral contents of the YL product, while fermentation by selected lactic acid bacteria increased the antioxidant properties (+8%) and the soluble fiber (+0.3 g/100 g), decreasing the predicted glycemic index (-10%). As demonstrated by the sensory analysis, the biotechnological process decreased the earthy flavor (typical of raw hemp flour) and increased the acidic and creamy sensory perceptions. Supplementation with natural clean-label vanilla powder and agave syrup was proposed to further decrease the astringent and bitter flavors. The evaluation of the starter survival and biochemical properties of the product under refrigerated conditions suggests an estimated shelf-life of 30 days. This work demonstrated that hemp flour might be used as a nutritional improver, while fermentation with a selected starter represents a sustainable and effective option for exploiting its potential.
Desiccation tolerance is an essential survival trait, especially in tropical aquatic organisms that are vulnerable to severe challenges posed by hydroperiodicity patterns in their habitats, characterized by dehydration-rehydration cycles. Here, we report a novel role for glucosamine as a desiccation stress-responsive metabolite in the underexplored tropical aquatic midge, Chironomus ramosus. Using high- throughput liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) analysis, biochemical assays and gene expression studies, we confirmed that glucosamine was essential during the recovery phase in C. ramosus larvae. Additionally, we demonstrated that trehalose, a known stress-protectant was crucial during desiccation but did not offer any advantage to the larvae during recovery. Based on our findings, we emphasise on the collaborative interplay of glucosamine and trehalose in conferring overall resilience to desiccation stress and propose the involvement of the trehalose-chitin metabolic interface in insects as one of the stress-management strategies to potentiate recovery post desiccation through recruitment of glucosamine.
High sugar fermentation elevates acetic acid levels in wines, which can be avoided by applying the continuous fed-batch strategy. In this study, yeast gene expressions and wine volatile compounds were evaluated by quantitative real-time PCR (RT-qPCR) and gas chromatograph mass spectrometry (GC-MS) in high-gravity (HG, 320 g/L sugars) fermentations with different batch strategies. The acetic acid concentration in continuous fed-batch fermentation wine was reduced by 51.69 %, compared with that in whole-batch fermentation wine. The acetyl-CoA synthase gene (ACS2) expression was up-regulated, whereas the glycerol-3-phosphate dehydrogenase gene (GPD1) expression was down-regulated on day 3 and day 7 during the continuous fed-batch fermentation. The volatile ester concentration in continuous fed-batch fermentation wine was 36.74 % higher than that in whole-batch fermentation wine. Overall, the continuous fed-batch strategy can modulate the expression of yeast genes involved in acetic acid metabolism and can increase volatile esters in wine under high sugar fermentation. Our findings provide a reference for the application of a continuous fed-batch strategy in high-sugar fermentation so as to improve the quality of the wine.
Despite its appealing composition, because it is rich in fibers and polyphenols, grape pomace, the major by-product of the wine industry, is still discarded or used for feed. This study aimed at exploiting grape pomace functional potential through fermentation with lactic acid bacteria (LAB). A systematic approach, including the progressively optimization of the grape pomace substrate, was used, evaluating pomace percentage, pH, and supplementation of nitrogen and carbon sources. When grape pomace was used at 10%, especially without pH correction, LAB cell viability decreased up to 2 log cycles. Hence, the percentage was lowered to 5 or 2.5% and supplementations with carbon and nitrogen sources, which are crucial for LAB metabolism, were considered aiming at obtaining a proper fermentation of the substrate. The optimization of the substrate enabled the comparison of strains performances and allowed the selection of the best performing strain (Lactiplantibacillus plantarum T0A10). A sourdough, containing 5% of grape pomace and fermented with the selected strain, showed high antioxidant activity on DPPH and ABTS radicals and anti-inflammatory potential on Caco2 cells. The anthocyanins profile of the grape pomace sourdough was also characterized, showing qualitative and quantitative differences before and after fermentation. Overall, the grape pomace sourdough showed promising applications as a functional ingredient in bread making.
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