BY 102 Zach Nolen Lab 2 Nutrition and

BY 102 Zach Nolen Lab 2 Nutrition and the Cell

Why is nutrition important?

Why is nutrition important? �It is important to know about nutrition, so that we can understand how the food that we eat helps to keep our bodies functioning. �The Science of Nutrition is the relationship between food (nutrients) and the health of the body. �Fortunately, in America, we do not have to worry about planning our meals to ensure that we get all of our required nutrients. �However, generally our eating habits are not the best when choosing what is best for us to eat.

Types of Nutrients �Six types of nutrients: Protein Carbohydrates Lipids Vitamins Minerals Water

Proteins �Proteins are composed of amino acids, which are linked together by peptide bonds and are called polypeptides. �Proteins play a role in proper muscle development, regulation of body fluids, development of hormones, and the production of enzymes. �Antibodies are a type of protein

Proteins �There are 20 different amino acids found in animal and plant proteins. �Of these, 9 are “essential” which means that they can not be made by the body and must be obtained through diet. �About 20% of our total body weight is proteins � 50% of the body’s protein is muscle, while the other 50% is divided between bone, skin, enzymes, blood cartilage, etc.

Differences between plant and animal protein. �Animal protein is referred to as “complete” protein because all essential amino acids can be found in a single source. �Plant sources are referred to as “incomplete” because they do not contain all essential amino acids. �A complete source of protein can be obtained from plants by eating a combination of grains and beans.

Carbohydrates �Carbohydrates function as a major source of energy for the body. �A single macromolecule is called a monosaccharide (glucose), two sugar molecules are called a disaccharide (sucrose). �Long chains of sugar molecules are called a polysaccharide (starch). �It is recommended that 55 -60% of daily caloric intake be made up of carbohydrates. �If there is not enough energy from carbohydrates, the body will begin to break down proteins to create energy.

Carbohydrates �Plants are the main source of carbohydrates. �What is the only non-plant source of carbohydrates? Lactose in milk �Carbohydrates are broken up into three groups: simple sugar, starch, and dietary fiber. �Nearly 70% of daily carbohydrate intake is supplied by simple sugars, which has increased from 33% at the beginning of the 20 th century.

Lipids �Lipids are commonly known as fat, which our bodies need. �In healthy men and women, what percent of body weight is fat? Men: 15 -18%; Women: 18 -23% �There are several terms used to describe dietary fat: Saturated – solid at room temp (animal fat) Unsaturated – liquid at room temp (vegetable oils) Trans-fatty acid – hydrogen enriched vegetable fats (margarine and shortenings); very unhealthy

Lipids �Excess fat consumption leads to weight gain, which can lead to fat in the blood which causes heart problems. �Recommended fat consumption should be 30% of our caloric intake. �Excess fat consumption can lead to high cholesterol which can cause heart problems.

Vitamins and Minerals � Vitamins are organic substances required in very small amounts that perform specific metabolic functions in the body. � There are 13 vitamins that are required for good health. � Generally, if you have a balanced diet, then you should receive adequate amounts of vitamins. � If you do not have a balanced diet, you may wish to take vitamin supplements to improve general health. � Minerals are basic elements (iron), not some complex molecules. � We will not be testing for vitamins and minerals in this lab.

Testing for different nutrients �To test for proteins, we will be using Biuret’s reagent. �To test for carbohydrates, we will be using Benedict’s solution to test for simple sugars and Lugol’s solution to test for starch. �To test for lipids, we will be using Sudan IV (which I will add).

- + Results - + Biuret’s Test Lugol’s Test Benedict’s Test Sudan IV Test + -

Review Questions What are the 6 types of nutrients? What solution do we use to test for: 1. 2. Protein? Starch? How many vitamins are essential for good health? 4. In healthy individuals, which gender has a higher percentage of fat? 3.

Before you leave lab! �Clean up! �Take tape off of test tubes �Make sure you clean used test tubes and place in the bin next to the sink �Wipe down your work station �Let me check your station before you leave

Before next lab! �Review topics covered in lab today �Read the next lab (Lab 4) �Do the online prelab �Complete questions 1 -15 on page 18 -19 (omit #12)