L02 GRQs Structure Function of Macromolecules PDF

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Guided Reading Qs: Do these before the Mastering Assignment.

L02: Structure/Function of Macromolecules (Read sections 2.6-2.10 and all of chapter 3) Reading Objectives:  Describe differences in molecular bonds that hold organic molecules together.  Explain the structure and function (and categorize) the monomers and polymers of carbohydrates, lipids, proteins, and nucleic acids.  Compare observational vs. experimental studies and retrospective vs. prospective studies  Explain the evolution of lactose tolerance ( Op t i o na l :I fy ouha v enott a k e nab a s i cc he mi s t r yc l a s sr e c e nt l y ,Ie nc o ur a g ey o ut os ki m s e c t i o ns2 . 1 2 . 5a ndt a k eno t e s ) Section 2.6-2.10 1. List the molecular bond types a. _________covalent bond_________- share electrons (1, 2, or 3 pairs); can be VERY strong. Two Types: 1. ______nonpolar covalent bonds________- electrons shared equally Example? Carbon and hydrogen 2. _____polar covalent bond_______- electrons are not shared equally creating “poles” a slightly negative and slightly positive end Example? oxygen

b. ______Ionic Bonds____________ electrons are not shared Example molecule using these bonds? NaCl (salt)

c. _____Hydrogen Bond_________- attraction between a slightly positive hydrogen (from a polar molecule) and a slightly negative atom (from a different polar molecule) Properties of this kind of bond?

Example? Water H2O

2. In photosynthesis, CO2 and H2O are the reactants. What are the products? Has matter been created or destroyed? - The products are glucose (C6H12O6) and Oxygen (O2). Chemical reactions do not create or destroy matter but rather rearrange in various ways.

Chapter 3 (Focus on the questions here—DO NOT highlight and outline the entire chapter) 1. What is an organic compound? - A chemical compound containing the element carbon and usually the element hydrogen. Which one of these is an organic compound? Water Carbon dioxide Glucose 2. What does the word hydrophilic mean? - ‘Water-loving” this pertains to polar or charged molecules (or parts of molecules) that are soluble in water. 3. Think about making a necklace with small beads. Use the necklace as an analogy to use the words macromolecule, monomer, polymer, dehydration reaction, and hydrolysis in sentences. The polymer would be your string or chain. The monomers are the beads that you put onto the polymer. The process of putting the beads on and “linking” them together would be the dehydration reaction. Your finished necklace is the macromolecule, or finished necklace. If you finish the necklace and decide you don’t like the order you put the beads in, you can take them off and rearrange or “break” the link you had before. This would be like hydrolysis. 4. Dr. Hogan (of European descent) is lactose intolerant and must pop a few pills before eating her favorite chocolate ice cream. What is she missing? What is in those pills? Do you know someone who is lactose intolerant? - Individuals that are lactose intolerant are lacking the enzyme lactase. Both dehydration reactions and hydrolysis require help from the enzymes to make and break bonds. The pills contain this enzyme. A friend of mine was lactose intolerant but didn’t take the pills, she just stayed away from dairy products which seemed to bother her the most. Look back at the chapter 3 opening essay, Americans of what descent are most likely to be lactose intolerant? Americans of northern European descent are the most likely to have complications of lactose intolerance.

5. The monomers of carbohydrates are: monosaccharides.

Name a few from the reading: glucose, fructose, galactose

The use of sugars as both energy resources and organic building blocks clearly illustrates one of our five themes of life: ____energy and matter________.

6. Describe how two monosaccharides are joined and what forms when they are chemically joined: - A dehydration reaction occurs when two monosaccharides join together. This forms more complex sugars and polysaccharides.

7. How much sugar does the typical American consume daily? __22 tsp__ Yearly?_26 bags_

What correlation has the NHANES study made with increased sugar consumption? - People that consume more than their daily calories in added sugars are at a higher risk of cardiovascular disease. 8. List and describe each of the four polysaccharides discussed in 3.7: 1. Starch: a storage polysaccharide in plants and consists of long chains of glucose monomers. 2. Glycogen: polysaccharide used for glucose storage and is found in the liver and muscle cells. 3. Cellulose: the most abundant organic compound on Earth. Found in the plant cell walls. Molecules are linked by hydrogen bonds. 4. Chitin: Structural polysaccharide found in fungal cell walls and exoskeletons of arthropods.

Next to each, describe if it is from a plant or animal. Does it function as a “storage” or a “structural” polysaccharide? Starch: Plant, storage Glycogen: Animal, storage Cellulose: Plant, structural

Chitin: Insect, structural

9. Most carbohydrates and biological molecules are hydrophilic. What chemical property is shared by lipids? They are hydrophobic.

10. What are the monomers of a triglyceride (fat) molecule? - Glycerol and fatty acids

Make simple drawings (cartoon like, not chemical) of a saturated triglyceride vs. unsaturated triglyceride:

Compare and contrast unsaturated and saturated fats in terms of structure and where they can be found. Unsaturated Fats: Each carbon atom connected by double bond has one fewer hydrogen attached to it. It has kinks and bends. Saturated Fats: No double bonds in the hydrocarbon chain and has a maximum number of hydrogen atoms attached. Can be found in animals.

11. What is the main function of fats? Long term energy storage Why do plants use starch for energy storage whereas animals use fats? - Plants are immobile but animals are mobile, and fats can store 2 times as long. 12. Module 3.9 is a Scientific Thinking Module in which you get to read about real studies and the data produced from them.

What was the hypothesis of the experimental study described? What are the limitations of this kind of experimental study in humans?

The hypothesis was that trans fats adversely affect cardiovascular health. The participants must be generally healthy individuals, only have limited dietary changes, and be short in duration. The participants also were only tracked for changes in cholesterol rather than actual disease outcomes.

What is the limitation of retrospective observational studies with humans and diet? Participants may not remember and report their dietary histories inaccurately and anyone who has already died of a heart attack cannot be included. Was the Nurse’s Health Study experimental or observational and what does this mean? The study was observational meaning they were not given any type of drug or instructed to change their diet/living habits. The study was solely based on evidence given over time by the participants. Retrospective or prospective and what does this mean? The Nurse’s Health Study was prospective meaning they look forward in their study and document participants’ health over time. Retrospective means looking backward so past health history would be analyzed. What were the results and conclusion? A relative risk of less than 1 meant decreased risk and a relative risk greater than 1 indicated greater risk. Concluding, for each 5% increase in consumed saturated fat, the relative risk would rise to 17% greater risk of heart disease. Meaning, trans fats are indeed a greater health risk than saturated fats. How did the results affect policy in the U.S.? US governmental agencies revised their policies from promoting partially hydrogenated oils to saturated fats to banning them today.

13. Draw and label a picture of a phospholipid (cartoon form, not the chemical structures): Be sure to use these labels: head, tail, hydrophobic, hydrophillic

14. Fats, phospholipids, and __steroids_______ are three main types of lipids.

15. What do anabolic steroids mimic in the body and what effects do they have? Are the effects different for males and females? They mimic effects of testosterone and dihydrotestosterone in the body. They increase protein synthesis within cells, which results in the buildup of cellular tissue, especially in muscles. This is different in males and females.

*COVID19 side question: many patients who were hospitalized with SARS-Cov2 infection were given a hydrophobic steroid called dexamethasone. Do a quick search to determine if this was an anabolic steroid or a different kind of steroid and what effect it had on the patients taking it. Dexamethasone is not an anabolic steroid but rather a corticosteroid. This type of steroid reduces inflammation. 16. What are the monomers of proteins? Amino acids 17. A proteins’ function depends on it’s _______shape___________. When a protein “unravels” or unfolds we call this _______denaturation_____________. It no longer functions. When proteins fold incorrectly they can cause disease. Which diseases? Alzheimer’s and Parkinson’s 18. There are 20 different amino acids, what part of each amino acid makes it different from the other amino acids? Their R groups

19. Protein structure (how polypeptides fold into functional proteins) A. 1o structure -amino acids (monomers) joined together through a dehydration reaction. The bonds between amino acids are peptide bonds, what kind of bond or linkage are these? Covalent bonds B. 2o structure– held together by weak ____hydrogen________ bonds between the amino group of one amino acid and the carboxyl group of another amino acid. (Don’t worry too much about this level of folding.)

C. The three-dimensional structure of a protein is called the ____tertiary structure _________ structure. *When we talk about structure and function of proteins, we are often focused on this level, this 3D structure. D. Not all proteins have a quaternary structure. Why do only some proteins have quaternary structure? Proteins that have more than one polypeptide chain have a quaternary structure. The shape resulting from the association of two or more polypeptide subunits. 20. Nucleic acids: a) What are the monomers of DNA? Nucleotides b) RNA had a big spotlight during the COVID19 pandemic thanks in part to what discovery co-lead by Dr. Kizzy Corbett, a graduate of UNC-Chapel Hill? The RNA gave coding for antibodies that could be used for COVID19 vaccines. The DNA sugar-phosphate backbone is held together by covalent bonds. What kinds of bonds hold the two strands of the double helix together? Hydrogen bonds

21. Lactose tolerance is a mutation that has arisen many times in human evolution. In which populations has this been naturally selected for as a useful adaptation? Why, what is the selective pressure in these cultures? Northern European descent. Dairy herds became a key part of survival in Europe. The natural selection favored anyone with lactose tolerance.

22. Explain how lactose tolerance involves three of the four major classes of biological macromolecules. Lactose, milk sugar, is a carbohydrate that is hydrolyzed by the enzyme lactase, a protein. The ability to make this enzyme and the regulation of when it is made are coded for in DNA, a nucleic acid....