Download 15. corn into milk lab

Name:__________________________________ Date:_____________ P#:___
Lab: Corn Into Milk
(Page 55-58 or Unit 1: L.E. 6)
1. Place your data (+/-) in the table below and then transfer that data to the
class table.
Substance
Corn
Benedicts
Biuret
Iodine
Oil
Milk
2. Refer to your nutrient gizmo packet for determining positive and negative
results. Activity A. Questions 1-4.
A. Benedict's reagent is used in a test (Benedict's test) commonly used for
the presence of reducing sugar(s), however other reducing substances
also give a positive reaction. This includes all monosaccharides and many
disaccharides, including lactose and maltose.
B. The Biuret reaction can be used to assess the concentration of proteins
because peptide bonds occur with the same frequency per amino acid in
the peptide. The intensity of the color, and hence the absorption at
540 nm, is directly proportional to the protein concentration.
C. The Iodine test is used to test for the presence of starch. Iodine solution
— iodine dissolved in an aqueous solution of potassium iodide — reacts
with the starch, producing a purple-black color.
D. Paper test is a confirmatory test for fats and oils. Here, oil or melted fat is
dropped on a piece of paper to form a translucent grease spot.
3. Digestion and nutrients: When we eat such things as bread, meat, and
vegetables, they are not in a form that the body can use as nourishment.
Our food and drink must be changed into smaller molecules of nutrients
before they can be absorbed into the blood and carried to cells throughout
the body. Digestion is the process by which food and drink are broken
down into their smallest parts so that the body can use them to build and
nourish cells and to provide energy.
The digestive system is a series of hollow organs joined in a long, twisting
tube from the mouth to the anus. Inside this tube is a lining called the
mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny
glands that produce juices to help digest food.
Digestion involves the mixing of food, its movement through the digestive
tract, and chemical breakdown of the large molecules of food into smaller
molecules. Digestion begins in the mouth, when we chew and swallow, and is
completed in the small intestine. The chemical process varies somewhat for
different kinds of food.
4. Movement of Food Through the System:
• Mouth: Seconds • Esophagus: Seconds • Stomach: Up to 3 ½ Hours • Small Intestine: Minutes • Large Intestine: Hours
In the mouth, carbohydrates are broken down by amylase into
maltose (disaccharide) and then move down the esophagus, which produces
mucous for lubrication, but no digestive enzymes.
In the duodenum, disaccharides are broken down into
monosaccharides by enzymes called maltases, sucrases, and lactases; the
monosaccharides produced are then absorbed into the bloodstream and
transported to cells to be used in metabolic pathways to harness energy.
In the stomach, proteins are broken down into peptides, which are
then broken down into single amino acids that are absorbed in the bloodstream
though the small intestine.
Lipids are digested mainly in the small intestine by bile salts
through the process of emulsification, which allows lipases to divide lipids into
fatty acids and monoglycerides.
Monoglycerides and fatty acids enter absorptive cells in the small
intestine through micelles; they leave micelles and recombine into chylomicrons,
which then enter the bloodstream.
Fat-soluble vitamins are absorbed in the same manner as lipids; water-soluble
vitamins can be directly absorbed into the bloodstream from the intestine.
* Complete analysis questions 2-4 on located page 58 in your composition
book.