In carbohydrates if the sample turned a cloudy orange-yellow brown colour, single sugars are present, which means that results are positive. In the starch experiment if the results turned a dark purple to black colour it indicates starch is present, meaning that the results are then positive. For the fats experiment we rubbed each piece of food onto the paper and any square that turned transparent " window" a grease spot contains fat or lipid and thus tests positive.
2. Starch molecules are large carbohydrates polymers. Find and post a picture of the starch molecule structure. What are the building blocks that starch molecules are made of?
The building block for starch is the simple sugar known as glucose.
3.Thomas and Josh had interesting results to their simple sugar test - if you are following either of their blogs, look at their picture of their test tubes after they took them out of the hot water bath.
After 2 minutes, only 2 of the test tubes were yellow/orange, and the rest remained blue. They took the two positive test tubes out of the hot water bath and left the others in the hot water bath for 2 more minutes. At the end of the two extra minutes all the test tubes indicated a positive result. Based on your knowledge of carbohydrate molecules, why do you think they got these results?
Based on my knowledge of simple carbohydrates they will be broken down if subjected to heat, but the more complicated and diverse samples just need more time(heat) to be able to test positive.
4. Making connections - Describe the passage of one of your food items through the digestive system, starting with the mouth & ending at the anus. Include the specific enzymes, accessory organ secretions & internal conditions the food/chyme would pass through from start to finish.
First, let's take for example the bread that we used in the experiment. So it all begins in the mouth, where the teeth manually breaks down the food, and then the chemical digestions starts. The salivary glands produce saliva and lubricates food which allows you to swallow. It contains an enzyme by the name of salivary amylase, which breaks down starch molecules(which is in the bread) into a molecule named maltose.
The bolus then passes through the pharynx and through a muscular tube called the esophagus, which is connected to the throat and stomach. This is where peristalsis happens, an involuntary muscle contraction that moves food along the digestive tract.On a side note the epiglottis is a flap that opens and closes when swallowing to keep food out of the trachea. Anyway, the bolus then passes through the cardiac sphincter, a valve at the top of the stomach and makes its way finally into the stomach.
The stomach produces gastric juice, which encompasses HCL(hydrochloric acid), mucus and an enzyme called pepsin. The mucus lines the stomachs wall and protects it from HCL, which is slowly breaking down the food within. The enzyme pepsin breaks down protein molecules into what is called polypeptides. In addition , when food is in the stomach it is called chyme.
The gall bladder, liver and pancreas are accessory organs. The pancreas releases pancreatic juice which contains pancreatic amylase, trypsin, lipas, nuclease, and sodium bicarbonate. The pancreatic amylase breaks down starch into maltose and then glucose, trypsin breaks proteins into peptides, lipas from lipids to glycerol and fatty acids, nuclease from nucleic acid to nucleotides and sodium bicarbonate neutralizes the chyme entering the small intestine from the stomach. The liver produces bile, detoxifies alcohol and toxins and produces blood proteins etc.
The chyme then enters the small intestine through the pyloric sphincter which is located at the bottom of the stomach. The small intestine absorbs nutrients, small molecules, amino acids and fatty acids. The large intestine absorbs water and contains the bacteria ecoli. Once through the large intestine the chyme turns into feces and is stored in the rectum. It is then released through the anus on the violation of the subject.
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