You were asked in biology to do laboratory work on the topic “The action of the enzymes of saliva on starch”? Look for all the necessary explanation in this article.
Content
- Laboratory, practical work on the topic “The action of the enzymes of saliva on starch”: questions for presentation
- Laboratory, practical work “The action of the enzymes of saliva on starch”, why the starch is decaying under the influence of saliva, forming sugar: target, equipment, work, withdrawal
- Laboratory, practical work on the topic “The action of the enzymes of saliva on starch”: biology 8th grade of the wheels, answers GDZ in the table
- How to make experience on laboratory work on the topic "The action of the enzymes of saliva on starch": photo for presentation
- The action of saliva on starch: video
- Video: Laboratory work on biology grade 8. The action of saliva on starch
In the eighth grade, students conduct various experiments in chemistry and biology lessons. Based on the results obtained, they write laboratory work, drawing conclusions. In this article we will consider the implementation of laboratory work on the topic "The action of saliva enzymes on starch". Read further.
Laboratory, practical work on the topic “The action of the enzymes of saliva on starch”: questions for presentation
Digestion— this is a set of reactions of disorder and absorption of the necessary substances with cells. Many are mistaken, thinking that the breakdown of nutrients begins in the stomach. In fact, digestion of food is already in the oral cavity, where the mechanic begins. and chem. impact.
- Mechanical influence means grinding, wetting with salivary enzymes and food formation. lump.
- Thanks to saliva, it becomes slippery and easily passes through the esophagus.
Chemical effect— the influence of saliva enzymes on the food lump, the breakdown of carbohydrates. The proof of chemical processing is laboratory work on the topic "The action of saliva enzymes on starch".
To better understand and evaluate laboratory work, presentation, the following theoretical issues should be revealed:
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Thanks to the enzymes of saliva, complex carbohydrates (starch, glycogen) are split to simple carbohydrates (glucose). |
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For saliva enzymes, a slightly alkaline environment is required (it is provided by mucin and saliva lysozyme), normal body temperature. When these conditions of the reaction of the breakdown of carbohydrates do not occur, does not occur. |
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There will be no reaction. All fermented substances are destroyed with boiling. |
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The starch under the action of a solution of iodine is stained in a blue shade. This reaction can be observed on any product containing starch. For example:cut of raw potatoes + drop of iodine \u003d blue spot on potatoes. |
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The easiest way to understand the effect of enzymes on complex carbohydrates- This is an experience with a piece of bread. If a piece of bread is chewed for a long time, then a sweet taste appears in the mouth. Why? The bread contains starch. According to its chemical properties, it has neither taste nor smell. Under the influence of fermented substances, the saliva of starch is broken down to glucose. Sweet glucose tastes. |
Having theoretical representations of digestion in the mouth, you can proceed to the lab. work.
Laboratory, practical work “The action of the enzymes of saliva on starch”, why the starch is decaying under the influence of saliva, forming sugar: target, equipment, work, withdrawal
The main component of any laboratory, practical work isgoal— the desired result, which will be obtained as a result of the process. C.the process of the process on the topic "The action of saliva enzymes on starch" is:
- To study the influence of saliva enzymes on starch.
The goal is set. Next stage— preparation of materials and equipment.Laboratory work will be required:
- Cotton wheels
- Starch
- Iodine solution
- Petri cup for iodine solution
- Cotton buds
We soak cotton wheels in starch solution and dry (this is best done the day before the experiments).Cooking the aqueous solution of iodine: 100 ml of water + 20/30 drops of alcohol solution of iodine. Materials are ready for use. Progress:
- To get good results, you must observe a certain sequence of actions.
- Work on the topic "The action of saliva enzymes on starch" Includes stages.
- Look more details in the table.
| Stages of work | Observations, conclusions |
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There are no changes at this stage. |
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The disk turned blue. The place where the letter was drawn was not painted. |
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The letter from the saliva remains colorless. |
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During the lab. The work studied the influence of fermented substances of saliva on starch. They proved that the starchy product is broken down by fermented saliva substances. Prototype— the stolen cotton pad is painted in a blue shade when interacting with the iodine district. The place of a cotton pad, treated with saliva, is not painted. In this place, a starch breakdown reaction was held to simple sugar. |
Conclusion - pin full swing, under the influence of saliva, it breaks up, forming sugar:
- Thus, it was clearly possible to prove that digestion of food begins in the oral cavity.
- This is facilitated by substances - enzymes that are in saliva.
Laboratory, practical work on the topic “The action of the enzymes of saliva on starch”: biology 8th grade of the wheels, answers GDZ in the table
Laboratory and practical work on the topic "The action of saliva enzymes on starch" was described above. But often the chemistry teacher sets his homework on this topic. Here are the answers to d/s No. 130 according to the textbook "Biology, Grade 8" Kolesov D. in.:
| Exercise | Answer |
| Fill the gaps. Upon receipt of a white pattern on a blue background:the substrate is __ 1__.the enzyme is __ 2__.The white pattern turned out because __ 3__.If you boil the saliva, then a similar experience __ 4__. |
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In each line of the question, enter the answer under the number in the column nearby. For example, the substrate is starch and so on. Laboratory work is easy to execute and gives 100% result Subject to experimental conditions.
How to make experience on laboratory work on the topic "The action of the enzymes of saliva on starch": photo for presentation
If you were asked to make experience on a lab on your own. work on the topic "The action of saliva enzymes on starch", then look below all the necessary descriptions and photos for the presentation.
- Prepare equipment and materials.
- Dissolve starch in water well, stirring thoroughly.
- Put on the stove and cook until the starch is completely dissolved, so that the mixture turns into a paste - 5 minutes.
- Put a cut of gauze into the mass.
- Pull out and let the fabric dry.
- Prepare a starch reagent: mix a little water and a few drops of iodine.
- Moisten a cotton wool in saliva.
- Draw the letter on the dried cut of gauze, which was praised in the starchy mixture.
- Squeeze the fabric in your hand to heat it.
- Dip iodine with water.
- Get out and you will see the letter that was painted with a cotton swab. She did not paint.
The stolen cut of Marley turned blue. The site where the saliva was bright. Read the conclusion on this topic above in the text.
The action of saliva on starch: video
If you need to do laboratory work on the topic “The action of the enzymes of saliva on starch”, then below you will find a video to help for d/s. The same video is suitable for presentation.
Video: Laboratory work on biology grade 8. The action of saliva on starch
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