UP #3: Macromolecules
With selected student responses
QUESTION 1: Starch (like bread, pasta) is a glucose polymer that gives us energy, but cellulose, an almost identical glucose polymer, is indigestible. Why do you think that ONE of these almost identical molecules can be digested, while the other can't? Why is cellulose (non-nutritive and indigestible) a very necessary part of our diet?
From Nicki Q1 = Though starch and cellulose are nearly identical in the way that they are made, we lack the type of digestive system that is necessary in order to break down cellulose. Because of that reason, cellulose passes directly through our system as dietary fiber, which rids our bodies of all the extra "stuff" that we don't need.
From Jenn Q1 = We do not have the special bacteria that other animals and insects have, therefore making it so that we can not breakdown cellulose.
From KA Q1 = Starch can be easily hydrolyzed, or broken down into its glucose building blocks. Cellulose is indigestible because we lack the digestive machinery to break the bonds between the monosaccharides of cellulose and release the energy-rich glucose. Celllose is necessary to our diet because it is an excellent source of fiber.
From PP Q1 = These two molecules are incredibly similar but are connected differently which makes all the difference in the ability to digest. Starch is used to power the body and create energy. Cellulose helps food in our digestive tract to pass through.
From Rachel Q1 = The bonds that bind starch and cellulose are different. Starch has an a bond while a cellulose has a b bond. Our intestines cannot digest the b bond. The b bond is for structural support. We do not want our structural support to be able to be broken down, that is why we need it in our diet.
From Dr. Marrs: Starch and cellulose are both long glucose polymers - glucose monomers linked together. Starches are a storage form of sugar that cells reserve for when they need energy. The glucose monomers in starch are connected by an a-bond and are easily broken down by starch-digesting enzymes in our body and in the bodies of plants and other organisms. In cellulose, however, the glucose monomers are connected by a b-bond that cannot be broken either by the plants that make them or many organisms that eat them for food. (Some bacteria can digest these bonds, though). This makes cellulose an excellent structural material for plant cell walls (and houses = wood), and gives us the benefit of fiber in our diet.
QUESTION 2: Butter and oil are both fats. Why is butter a solid at room temperature, but corn oil a liquid? What is "soft margerine"?
From SP Q2 = Butter is saturated fat. All of the Carbons are saturated with hydrogen bonds so they are more dense and thus are solid at room temperature. While oil (vegetable, olive, corn) is an unsaturated fat that has less hydrogen and remains in its liquid state at room temperature. "Soft Margerine" is liquid oil converted to a solid shortening by man to have as many hydrogens needed to get the desired consistancy.
QUESTION 3: When we eat the cells of another animal (like muscle cells - hamburger, or leaf cells - spinach) what happens to the protein and the DNA in those cells that we eat? How are we able to use cow proteins and cow DNA, or spinach proteins and spinach DNA for the growth and development of our human bodies?
From RV Q3 = If we were supposed to pick this up from the book, I TOTALLY missed it somewhere even though I read the material. My guess would be that the proteins and DNA are broken down and used as energy for cellular activity and also in our metablism function.
From Nate Q3 = We digest them and use their cells and DNA for energy or to turn ourselves into cows (Ha Ha)
From Mercury Q3 = When we take in these proteins and they turn into amino acids. We need all 20 of the amino acids in our diets to stay healthy. By eating different types of plant and animal proteins we are able to get all 20 of the amino acids into our diet.
From BB Q3 = The protein and DNA we consume from these sources is converted into whatever we can use and need in our bodies. We can use proteins as enzymes, as transports for substances inside the cells, as the makeup of muscle tissue, or as regulators and messengers.
From SP Q3 = Our body breaks down the peptide bonds that hold the amino acids together that make up proteins. We then use these amino acids towards the growth and development of our bodies. Some functions of proteins include: speeding up chemical reactions, building muscles, hair growth, giving us antibodies to fight against diseases.
From Dr. Marrs: I would add to the answer just above that our bodies do the same thing with the DNA we eat - our body breaks it back down into nucleotides (the building blocks of DNA) and uses it to make the DNA our body needs. Our body can break both proteins and amino acids down even further to carbon or nitrogen and again rearrange these atoms to make things our cells need.
QUESTIONS, questions and more questions..
Q4 = Please indicate the major areas that our
study time should address when trying to prepare for any exam in
Q4 = Will we need to know how to make some of these little charts?
Q4 = Are we expected to know all the terminology out of the book? Are we responsible for the enire chapter or just what is covered from our notes. Should we spend a great amount of time on the objectives in the back of class notes? Will the test be 50 questions or a 100 multiple choice.
Q4 = Is there going to be a diagram on the Eukaratic Cells? Will we have to label things?
Q4 = The warm up questions are often not answered by the text, and unless I miss a lot, not in the lecture either. My warm-ups answers are merely educated guesses.
Q4 = Will you curve test scores on the exam? How many questions from each chapter will there be? Should we read every lecture note we have or what exactly should we do to prepare???
Q4 = i would like to review the major people that we have gone over so farand their theory's
Q4 = I would like to discuss how animal's and plant's DNA do help with the Making of protein and our muscle structure.
Q4 = I think that it would be great if you could give us some suggestions on how to prepare for the test. Definitions, readings, notes,
Q4 = i would like to talk more about Carbohydrates, Lipids, proteins, etc...I am a little confused on how each one works.
Q4 = I also thought that you mentioned earlier in the semester that all of the material for the exam would come from the lecture notes but I now see in the syllabus that it states that we will be responsible for material in the text not covered in the lecture notes. I skipped over most of the material that wasnt in the lecture notes!
Q4 = I am a little confused about the hydrogn bonds in different plants and animals. I would like to go over differences between startch and sugars again
Q4 = Is there anyway to keep track of the points that we have earned? Do you put grades on oncourse?