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1 Name: Mid-Term Assignment BIOL 101, Fall 2021 Due date: Nov. 11, 2021 Answer each of the questions below in the spaces provided. Please read each question carefully, follow the instructions, and remember to answer all parts of each. The assignment is worth a total of 100 points. 1. (3 points) Briefly explain one of the seven properties of life, and give an example. 2. (2 points) Name and briefly explain/describe one feature or structure that is common to ALL cells. 3. (2 points) What are two major differences between bacteria and eukaryotes? 4. (2 points) The diameter of a typical bacterial cell is 1 μm. What is this in mm and nm? 5. (1 point) All isotopes are radioactive. A. True B. False 6. (1 point) The formation of covalent bonds occurs A. spontaneously B. only in chemical reactions 7. (3 points) Explain why oils such as vegetable oil are not soluble in water. 8. (4 points) Explain what happens to a crystal of the ionic compound NaCl (table salt) when it is dissolved in water. Ie: how does NaCl interact with water? 9. (6 points) Water has a high surface tension and therefore forms relatively large ‘beads’ compared to other liquids on hard surfaces. Explain why this occurs. You must include in your answer a drawing that includes at least two water molecules, any charges or partial charges on them, and how they ‘associate.’ 10. (2 points) Consider the following reaction. I. Sucrose is a: A. monosaccharide B. disaccharide C. polysaccharide II. The figure represents a A. dehydration reaction B. hydrolysis reaction For the following questions (11 to 15), consider the molecular structure below, representing a short segment of cellulose: 11. (2 points) Where do you find cellulose in nature, and what is its function? 12. (1 point) What is cellulose made of? 13. (3 points) Are cellulose polymers hydrophobic or hydrophilic? Clearly explain your rationale (you can circle and name relevant groups on the diagram to help in your answer). 14. (3 points) Are cellulose polymers soluble in water? Explain your rationale. 15. (3 points) Cellulose polymers are linear. Briefly relate this structure to the function of cellulose. 16. (2 points) Lipids are a major group of macromolecules that occur in all living organisms. List at least two functions of lipids: 17. (1 point) The molecule shown to the right is a A. saturated fat B. unsaturated fat (specifically a cis fat) C. unsaturated fat (specifically a trans fat) 18. (2 points) Would you expect a given volume of this fat (in Question 17) to occur as a solid or a liquid at room temperature? Give a brief rationale for your answer. 19. (1 point) Below is the generalized molecular structure of a monomer that makes up proteins. What are these monomers called? 20. (1 point) Circle and label (name) one functional group in the structure above (in Question 19). 21. (4 points) The white of chicken eggs contains storage proteins; the function of these simple proteins is to provide amino acids to a growing embryo (the chick) in a fertilized and incubated egg. When you cook egg white, the structure changes significantly, from clear and semi-liquid to an opaque more solid state. Explain, generally, why this happens. You should refer to changes in protein structure. Are covalent bonds (eg: peptide bonds holding amino acids together) broken in this process? 22. (1 point) Many types of proteins require more than one folded polypeptide strand in order to function. A. True B. False 23. (3 points) The sequence of a short stretch of one DNA strand is shown below. Below the sequence, write out the sequence of the complementary base-pairing strand (as it would occur in a complete DNA molecule). -A T T G C A T G G C A- 24. (1 point) Which polymer is the most stable in the cell: A. DNA B. RNA 25. (1 point) The two strands of the DNA double helix are held together by: A. covalent bonds B. ionic bonds C. hydrogen bonds D. Van der Waals forces 26. (1 point) Information in the cell flows from DNA to ___________ to protein. 27. (1 point) All cells have a cell wall. A. True B. False 28. (4 points) On the below model of a plant cell, label a chloroplast, a mitochondrion, the nucleus, and the large central vacuole. 29. (1 point) What is the function of the chloroplast? 30. (1 point) What is the role of ribosomes? 31. (3 points) Many animal cells, such as cells of the small intestine, have microvilli. Indicate where these structures are in the model below (circling them is fine), and briefly explain their role/function. 32. (1 point) Phospholipid bilayers can self-assemble in aqueous solutions and are considered to be more fluid than solid. A. True B. False 33. (3 points) Solutions can be described as being isotonic, hypertonic, or hypotonic to the cell. Explain what happens to a red blood cell if placed in a hypotonic solution and why this happens. 34. (4 points) Phospholipids, which are key to the structure of cell membranes, will assemble spontaneously when mixed together in water. Explain why. A drawing may help in answering this question. 35. (6 points) Cell membranes are selectively permeable. Explain what that means, and why it is important to the cell. What is the role of membrane-spanning and membrane-associated proteins in this selective permeability? 36. (3 points) Consider the model shown below, of a protein transporter in a cellular membrane moving the solute indicated with an “X” into the cell. Would this transport be active or passive? Briefly explain a rationale for your answer. 37. (3 points) Bacterial cells are usually very small (1 to 2 μm in diameter). Explain why this is. Ie: what limits cell size? 38. (3 points) What is the difference between a drug and a vaccine? 39. (4 points) Explain why RNA viruses, such as Covid-19 and the influenza viruses, evolve more rapidly than DNA viruses. Clarify in your answer what is meant by ‘RNA virus’! 40. (1 point) Bacteria evolve much more slowly than Eukaryotes as they do not have sexual reproduction in their life-cycles. A. True B. False 41. (6 points) Explain what a biofilm is, and how it provides protection for the participating bacterial cells. Please include a model to illustrate the typical biofilm structure in your answer, and give one example of how biofilm formation is directly relevant to human society.