WARM UP #3: Proteins
Selected student responses

QUESTION 1: When we eat the cells of another animal or plant (like muscle cells - hamburger, or leaf cells - spinach) what happens to the protein in those cells that we eat? How are we able to use cow proteins or spinach proteins for the growth and development of our human bodies?

From Angie Q1 = Those proteins are broken down into amino acids. Many proteins that we eat can be made into other proteins and used to kill bacteria, oxygen support, and increase rates of reaction. I think, I wasn't sure on this one.

From Jess Q1 = Digestion of proteins to amino acids is completed with enzymes secreted by the pancreas. Proteins from most animal cells are complete, which means that their ratios of amino acids match human nutritional needs. Proteins from most plant cells are incomplete, which means that they lack one or more essential amino acids.

From Ricca: Q1 = When eating cells from other animals the human metabolism breaks down proteins into polypeptide chains into amino acids. The human body uses the amino acids to make polypeptide chains and then makes protein. The human body uses these proteins as structural building blocks and structural repair.

From Steve Q1 = In cells such as hamburger or leaf cells, the protein we eat is used in the building of new and damaged muscles. The proteins gained is broken down into simpler forms so that our body can use it for energy. In all cases the proteins forms are changed* so that they can be used by our bodies. (*broken down into amino acids)

From Dr. Marrs: Just like “pop beads” that can be taken apart and rearranged, the proteins we eat consist of chains of amino acids that can be disassembled and re-used by our bodies. Regardless of the source of proteins (meat, spinach, mushrooms), enzymes in our digestive system break those protein polymers down into amino acids (the monomer) and rearrange those monomers to make whatever new proteins we need at that time – new enzymes, new hair growth, new hemoglobin, new antibodies, etc etc!

QUESTION 2: Why do people who are vegetarians usually mix combinations of foods, like beans and rice, or peas and corn, in the same meal? Why are meat and eggs said to have 'complete' protein?

From madonna: Q2 = People who are vegetarians usually mix combinations of foods, like beans and rice, or peas and corn, in the same meal to make sure that they get all of the proteins (amino acids) that they are missing by not eating meat into their daily diets. Each of the things in the different combinations contributes something different that they are missing by not eating meat. Meat and eggs are said to have 'complete' protein because they contain everything that makes a protein complete* (*all 20 amino acids).

From tabs Q2 = When you are a vegetarian, there are many foods that are not complete proteins because they do not contain all of the essential amino acids. In order to have a complete protein you must have these, so they combine foods so that they have all of the essential amino acids needed in their diet.

From Hello Q2 = I think that vegetarians mix combinations of foods together because it gives them the nutrients they need for a healthy meal. It allows them to have a suitable amount of amino acids. Meats and eggs are defined to have complete protein because their ratios of amino acids match human nutritional needs.

From JT: Q2 = Vegetarians usually eat incomplete proteins so they mix other foods like beans, rice, and peas to get a combination of two incomplete proteins that can provide a complete amino acid mixture, the foods have to be eaten together to provide the right balance of amino acids. Meat and eggs have 'complete' protein becauce they contain an adequate amounts of all the essential amino acids.

From Dr. Marrs: Vegetable protein is often lacking in one or more essential amino acids, and is said to have ‘incomplete’ protein (incomplete for humans, that is!). For instance, corn is usually deficient in the amino acid lysine. If you tried to exist on only corn, you would probably become severely malnourished or even die, because your body would be unable to make any proteins that contained the lysine building block, for instance, hemoglobin! Beans, on the other hand, contain lysine, but are deficient in other amino acids. However, if a person mixes beans and corn…say to make succotash…they together now have all 20 amino acids, and humans can exist just fine on this combo without ever eating meat in their diet. Yum. Animals require all 20 amino acids, because all 20 are used in making the majority of their proteins. So, when we eat protein from animals (meat, eggs, cheese, milk) we are getting all 20 amino acids that the cow or chicken we are eating had to get from the food they ate – grains, grass, etc! Some delicious vegetarian combos: macaroni and cheese, peanut butter and bananas, chocolate chip cookies with nuts, and of course, beans and rice. Want more info? See Vegetarians and nutrition or vegetarian athletes.

QUESTIONS 3/4: Thanks for the answers to the questions on Warm Ups. I will use this data in my research about learning! Here is a sampling of the range of responses ; )
Q3 = YES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! The warm ups are a great way for me to figure out a scientific question without the embarrassment of answering the question wrong.
Q3 = Yes, the warm ups help me to get way interested. It makes me feel like I have an introduction to the material, just enough to get interested, then I look forward to class to get to know more details about it.
Q3 = Yes, the questions are a little hard to find the answers to, but I don't get too stressed out over them, because you answer them in class so that I understand them.
Q3 = I really don't like the warmups because I am worried that my answers will be way off than other people's and that is really embarrassing.
Q3 = Although I don't absolutely despise warm-ups, I appreciate them for the extra points.