Name: Block: Date: 22. Describe the 5 major functions of proteins. Study Guide - KEY - Page 1 of 8

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1 Name: Block: Date: Biology 12 Biologically Important Molecules - Study Guide 1. a) List 5 characteristics of living things. b) Using this list, is a Forest Fire is alive or non-living? What characteristics would indicate that it is alive? What characteristics would indicate that it is not alive? 2. a) What do we mean when we say "Scientific Method"? b) What is the importance of the scientific method? 3. a) What is the difference between a hypothesis and a theory? b) Give two examples. 4. a) What is a CNTRL? b) Give one specific example example. b) Explain the role of a control in an experiment. 5. Your pharmaceutical company thinks it has a great new headache medicine called PainDrain. Design a proper scientific experiment that would effectively test the efficacy of PainDrain. This must be detailed, logical, specific, and use the scientific method. 6. Define homeostasis and describe at least three examples. 7. What is meant by negative feedback in biological systems? 8. Using words and diagrams, give two examples of homeostatic control through negative feedback in human systems. 9. a) What is meant by positive feedback in biological systems? b) Describe one example of homeostatic control through positive feedback in human systems. 10. Elements can combine using different types of bonds. Describe each bond and explain the differences between the following types of bonds: a) ionic b) covalent c) hydrogen. Give an example of each type of bond. 11. Draw a labeled diagram of a water molecule. Why, and in what ways, is water such a unique molecule? 12. In what specific ways does the polar nature of water promote the maintenance of life? 13. Make a copy of the ph scale into your notes and fill in the following information < > < > 14. What is an acid? Give two examples. What ph range do acids have? 15. What is a base? Give two examples. What ph range do bases have? 16. Is pure water an acid or a base? Explain. 17. Some acid rain has a ph of 2. How much more acidic is this than distilled water? 18. Why is the maintenance of ph crucial to biological systems? 19. What is a buffer? Why are buffers significant to biological systems? 20. Two common buffer systems in biological systems are carbonic acid-bicarbonate ion (H2C3, HC3 - ) in blood and acetic acid-acetate ion (CH3CH, CH3C - ) in some cells. Using the example of the carbonic acid-bicarbonate ion system, show what happens when this system encounters: a) H + ions b) H - ions 21. a) What is a polymer? b) What is the relationship between polymers and synthesis & hydrolysis? c) Give 4 examples of polymers. a. Polymer a macromolecule consisting of covalently bonded monomers; for example, a polypeptide is a polymer of monomers called amino acids b. Monomers are joined together to form polymers through dehydration synthesis. Polymers are broken down into smaller units/monomers through hydrolysis c. Carbohydrates, lipids, proteins, nucleic acids 22. Describe the 5 major functions of proteins. a. Structural proteins such as keratin (in hair and nails) and collagen (supports ligaments, tendons, and skin) b. Hormones many of these messengers that influence cell metabolism are proteins c. Movement the proteins, actin and myosin, account for the movement of cells and contraction of muscles. [microtubles] d. Transport some proteins transport molecules in our blood (x. hemoglobin) e. Antibodies in blood and other body fluids are proteins that combine with foreign substances, preventing them from destroying cells and upsetting homeostasis. Study Guide - KEY - Page 1 of 8

2 f. Channel proteins allow substances to enter and exit, which CARRIER proteins transport molecules into and out of the cell g. Enzymes speed up chemical reactions so that the body can function efficiently 23. Which elements are found in proteins? Which one is most characteristic of proteins? a. Carbon, hydrogen, oxygen, nitrogen, Sulphur b. Nitrogen. Essention in all amino acids. Not found in nucleic acids, carbohydrates, or lipids. 24. a) Draw the generalized formula for an amino acid, and label the groups. b) How many amino acids are found in nature? c) In what way do these amino acids differ from each other? a. b. 20 amino acids c. Amino acids differ based on their R groups. R groups are the functional groups of the amino acid. The variation is what allows us to have such a diverse number of proteins. 25. Using the formation of a bond between two amino acids as an example, explain what is meant by the following terms: a) dehydrations synthesis b) hydrolysis Use a labeled diagram and a careful description to assist your explanation. a. Dehydration synthesis is the creation of large molecules (polymers) from joining together smaller molecules (monomers) by the removal of water. For proteins, polypeptides are created by joining amino acids. The bond created between amino acids is called a peptide bond. b. Hydrolysis os breaking down polymers into small molecules. The splitting of bonds is achieved by the addition of water. Study Guide - KEY - Page 2 of 8

3 Name: Block: Date: 26. What do we call the type of bond that forms between amino acids? Peptide bonds 27. What is the difference between a polypeptide and a protein? The basic distinguishing factors are size and structure. Proteins generally consist of greater than amino acids. Polypeptides are smaller and not generally folded into specific shape, whereas proteins are folded into a correct/distinct shape. 28. Starting with primary structure, describe the 4 levels of organization in proteins. a. Primary structure is the linear sequence of the amino acids joined by peptide bonds b. Secondary structure amino acids do not stay in a huge line. If left lying there, amino acids will naturally form an alpha helix (right hand spiral) or beta sheets. These shapes are held in place by hydrogen bonds between amino acids at peptide bonds. c. Tertiary structure the final 3D shape. The structure is maintained by various types of bonds between atoms on R-groups. These bonds bend and fold the molecule into its final shape. Example: Keratin is a protein that always has the exact same amino acid sequence and always folds in exactly the same way or it does not function properly. d. Quaternary structure some proteins contain more than one polypeptide (with their own primary, secondary, and tertiary shapes) combined together and arranged into their quaternary structure. 29. What determines the function of a protein? The final shape is extremely important to the function of the protein. The same protein always bends into the exact same shape. If the protein loses its normal shape, it can t function. 30. What has happened to a protein that has become denatured? Using examples, list 3 things that cause a protein to become denatured. When proteins are exposed to certain non-optimal conditions, an irreversible change in shape called denaturation occurs because normal bonding between R-groups is disturbed. Denaturing agents include: heat, changes in ph (concentrated acids or alkali), ultraviolet rays, x-rays, high salt concentration, heavy metals 31. a) Define carbohydrate and give the general formula for a carbohydrate. b) What elements are found in carbohydrates c) List the main functions of carbohydrates in living organisms. a. Carbohydrates (monosaccharides) are sugars. A general formula is CxHyx where the common ratio is 1:2:1. b. Carbon, hydrogen, and oxygen. They must have all 3 and no other elements. c. Functions a. Principle source of energy for living things b. Structural form certain cell structures (not many) Ex- cell walls c. Cell to cell recognition Study Guide - KEY - Page 3 of 8

4 32. Draw diagrams of the pentose monosaccharide ribose, and the hexose monosaccharide glucose. b) What do I mean when I say "pentose" and "hexose"? c) What do monosaccharide names have in common? a. b. Pentose is a 5 carbon sugar and Hexose is a 6 carbon sugar. c. Commonality to names is the -ose ending. Ex- glucose 33. a) What is the formula for glucose? b) What is glucose used for in cells? a. C6H126 b. To provide ready energy 34. Differentiate between monosaccharides, disaccharides, and polysaccharides and give one example of a disaccharide, and 3 examples of polysaccharides. Monosaccharide are simple carbohydrates containing a low number (3-7) of carbons. Disaccharides consist of 2 monosaccharids covalently bonded during a dehydration synthesis reaction. Ex: glucose + glucose = maltose. Glucose + galactose = lactose (in milk). Glucose + fructose = sucrose (food sweetener. Polysaccharides are long polymers that contain many glucoses (100 s to 1000 s). Ex: starch, glycogen, and cellulose. Chitin is another structural polysaccharide that is found in the exoskeleton of crabs etc, and can be used as thread for sutures. 35. What are the major differences in structure and function among the common polysaccharides glycogen, starch, and cellulose? Use a table format for your answer. DESCRIPTIN STARCH GLYCGEN CELLULSE Plant or Animal plant animal plant Function Storage glucose Store excess Strength in cell walls molecule glucose molecules Unit molecule glucose glucose glucose Type of Branching Limited branching Highly branched No branching (straight chain) Type of Linkage Alpha - normal Alpha - normal Beta- alternating Study Guide - KEY - Page 4 of 8

5 Name: Block: Date: 36. a) In vertebrates like humans, where do we find rich stores of glycogen? b) Why do you suppose we find glycogen here? a. Liver b. Glucose travels in blood and all blood passes through liver. Allows for taking excess glucose and creating glycogen or if body is in demand, breaking bonds to release glucose into the blood. 37. a) What are lipids? b) What are their functions in the human body? c) Are they soluble or insoluble in water? d) List the three major types of lipids. a. rganic molecules that are insoluble in water. This inability to dissolve in water is due to the fact that they are neutral (no polar groups). They have an oily, greasy, or waxy consistency and tend to be water repelling. b. Energy storage (contain more energy/gram than other bio molecules. For long term storage. In plants stored as oils and in animals stored as fat. Fat also insulates against heat loss and forms a protective cushion around vital organs). Structural (form certain structures. Example:phospholipids (membrane bilayer). They also form waxes). Steroids (large class with specific structure and various functions. Examples: sex hormones and cholesterol). c. Insoluble 38. a) What is the difference between a polar molecule and a non-polar molecule? b) Give two examples of polar molecules and two examples of non-polar molecules. a. Polar molecules have an unequal sharing of electrons resulting in electrical attraction. Nonpolar molecules are neutral (ie no polar groups). b. Polar- water, ammonia. Non-polar- fats, oils 39. What is the meant by hydrophobic and hydrophyllic? Relate hydrophobic and hydrophyllic to polar and non-polar molecules. Hydrophobic is a fear of water and hydrophyllic is water loving. Nonpolar molecules that repel the water molecules are said to be hydrophobic whereas molecules forming ionic or a hydrogen bond with the water molecule are said to be hydrophilic. 40. a) What are Neutral Fats formed from? b) What is another name for neutral fats? c) What is the primary function of neutral fats in the human body? a. Formed by dehydration synthesis reaction between glycerol and 3 fatty acids. b. Triglycerides c. Make up adipose tissue in body (fat tissue) ane functions as long term energy storage, insulates and protects. 41. a) Draw a molecule of glycerol combining with 3 fatty acids to form a neutral fat. b) What is the name for this type of reaction? a. b. Dehydration synthesis Study Guide - KEY - Page 5 of 8

6 42. a) What are the difference between a saturated fatty acid and a non-saturated fatty acid? b) Which types of fats are liquid at room temperature? c) Which type of fat are solid at room temperature? d) Which types of fat are associated with high blood pressure, cancer and heart disease? d) draw a diagram of a saturated neutral fat and a monounsaturated neutral fat. a. Saturated has the maximum number of hydrogens (no double bonds) and unsaturated has double bonds beteen some of the carbons, thus less hydrogens. b. Plant oils are usually liquid at room temperature c. Animal fats are solid at room temperature d. Saturated fats e. 43. a) What are the functions of Phospholipids? b) Describe and sketch the structure of phospholipids. c) How do they differ from neutral fats? d) sketch a picture of a "phospholipids bilayer. d) What sorts of molecules would be able to easily pass through a lipid bilayer? a. Important components of cell membranes b. c. one fatty acid is replaced by a phosphate group with a charged group attached d. e. Gases, hydrophobic molecules, and small polar uncharged molecules Study Guide - KEY - Page 6 of 8

7 Name: Block: Date: 44. a) What are steroids? b) What are their functions in the human body? c) What is the name of the molecule from which steroids are derived? d) Draw a molecule of cholesterol. e) Is cholesterol inherently bad? Why or why not? f) What is the source of excess cholesterol in human beings? a. Type of lipid molecule having a complex of four carbon rings; examples are cholesterol, progesterone, testosterone b. Can function as chemical messengers and form many important hormones that have a wide variety of affects on cells, tissues, and organs (sex characteristics, ion balance) c. Cholesterol d. e. Cholesterol is not always bad Good Cholesterol High-density lipoprotein, called HDL or good cholesterol," picks up cholesterol from the cells and transports it back to the liver for recycling or waste removal. Good refers not to the kind of cholesterol, but to the fact that this transport vehicle takes cholesterol out of circulation. So a higher HDL number means better cholesterol control and protection for the heart, according to Eleanor Whitney and Sharon Rolfes in Understanding Nutrition. Bad Cholesterol Low density lipoprotein, called LDL or bad cholesterol, carries cholesterol to every cell in the body for potential use in cell membranes or for making hormones and vitamin D. The cells take only what they need, so high levels of LDL can result in deposits of excess cholesterol in the arteries, causing restricted blood flow. Eventually, a blood clot may block a narrowed artery and result in a heart attack or stroke. A lower LDL number means better health. f. The liver produces cholesterol naturally. Excess is generally from dietary cholesterol. Example: meat, poultry,full-fat dairy products 45. Why do fat and oil molecules not normally not disperse in water? Given their lack of positive or negative charge, they are not attracted to a polar molecule like water. Given that oil essentially repels the water, it is called hydrophobic or water fearing, as opposed to hydrophilic or water loving. 46. Define emulsification. Breaking up of fat globules into smaller droplets by emulsifiers (can cause fats to mix with water). Example: fatty foods, fats are emulsified by bile prior to digestion 47. a) List the major functions of nucleic acids. b) What are the two different types of nucleic acids? 48. Describe the structure and draw labeled diagrams of the two basic types nucleotides (purines & pyrimidines). Clearly label the constituent parts. N N 49. Draw a molecule of DNA to show how the nucleotides are connected. N Your drawing should show both sides of the DNA molecule. N P P Study Guide - KEY - Page 7 of 8 P

8 CH CH C CH C P 50. Draw and describe the general structure of Adenosine Triphosphate. b) What is the function of ATP? c) Where is the energy in ATP bonds stored? d) Explain the diagram on the right 51. Make a review table like the following table of the most important biological polymers, and the unit molecules which make them up. Polymer Summary of Functions Unit Molecule Sketch of Unit Molecule Protein Starch Glycogen mit Cellulose mit DNA mit Molecule Summary of Functions Constituent Molecules Sketch of Molecule Triglyceride mit CH Phospholipid 3 CH 2 CH 2 CH 2 C CH 2 CH 2 CH 3 CH3 Steroid H 2 - CH 2 N+ CH 3 ATP H Study Guide - KEY - Page 8 of 8