Which of the following substances is not absorbed? A. amino acid B. sugar C. fatty acid D. fiber I'm not sure but I think is fatty acid.

Expert Answers
durbanville eNotes educator| Certified Educator

A diet consists of certain components, ordinarily - proteins, fats (lipids), carbohydrates, vitamins and minerals.

Amino acids are organic substances that make up the proteins in the body. Meat is a 'complete' protein and vegetables, incomplete proteins, should be eaten in the right combinations to create a 'complete protein.' They are essential to our existence.

Sugar is a 'simple' carbohydrate and, although providing energy when it is absorbed, its absorption is so fast that it has little nutritional value and can create 'sugar highs' and 'lows' when it is not consumed wisely.

Fatty acids - and particulary 'essential' fatty acids- are needed for our very existence but the body cannot make them so absorption is essential for health.

There are two types of fiber - soluble and insoluble. Insoluble fiber is a carbohydrate that

 humans cannot digest, known as cellulose

The insoluble fiber would be the element that is NOT absorbed by the body. So the answer here would be (D) - Fiber.

lloricwriter | Student

Fiber cannot be absorbed by the body.

Proteins are broken down by proteolytic enzymes such as trypsin into small peptides and amino acids so that they can be digested absorbed by the small intestine.

Carbohydrates are broken down into sugars (monosaccharides such as glucose) by pancreatic amylase along with starch so that they can be absorbed.

Lipids or fats are converted by lipase from the pancreas into glycerol and fatty acids. This conversion process is also assisted by bile from the liver which emulsifies fats and they are broken down further by the lipase so that they can be absorbed by the villi in the small intestine.

Fiber, such as those seen in the cell wall of green plants, are made of beta-glucose. Humans lack the enzyme for splitting the bonds in these beta-glucose particles, whereas organisms like termites can digest and absorb it.

user9564597 | Student

Answer is 

D. fiber


it is absorbed by body. 

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