Weekly Study Guide 4
Last revised: Friday, February 14, 2003

A. Overview for this week.

Answer keys for the 3 exam versions were posted Friday morning. I won't have exam grades until Monday afternoon, and will need time to process them. I will post grades at our website by Tuesday afternoon if possible, otherwise probably on Wednesday.

We will begin this week by studying how membranes are organized and how they function. Then we will move on to metabolism, the study of how and why cells coordinate their chemical processes. We will focus mainly on catabolism, the conversion of chemical bonds into energy, along with the generation of ATP.

B. Lecture Topics and Assigned Reading.

Mon . 17 Feb.
Membranes and Transport
Ch. 8
Wed. 19 Feb.
Membranes and Transport (cont.)
Metabolism.
Ch. 8
Ch. 9
Fri. 21. Feb.
Metabolism (cont.)
Ch. 9

C. Take the online Self-Quizzes associated with these lectures.

See links at bottom of lecture note web pages.

D. Visit Campbell Website. Do assigned activities.

Ch. 8
Activity 8A: Membrane Structure (2 pages)
Activity 8B: Selective Permeability (2 pages)
Activity 8C: Diffusion (2 pages)
Activity 8D: Osmosis and Water Balanace (4 pages)
Activity 8E: Facilitated Diffusion (2 pages)
Activity 8F: Active Transport (2 pages)
Activity 8G: Exocytosis and Endocytosis (6 pages)

Ch. 9
Activity 9B: Overview of Cellular Respiration (1 page)
Activity 9C: Glycolysis (2 pages)
Activity 9D: The Krebs Cycle (3 pages)
Activity 9E: Electron Transport (5 pages)
Activity 9F: Fermentation (3 pages)

E. Consult the study questions below as you read the text.

Chapter 8.
  1. What molecules compose cell membranes, and in approximately what approximate %?
  2. What types of functions do membrane proteins carry out? What function(s) do membrane lipids serve?
  3. What is the fluid mosaic model?
  4. Which of the following molecules could travel across a plasma membrane without a protein carrier? water, glucose, oil, hemoglobin, sodium ion, messenger RNA, ethanol.
  5. Which of the molecules listed in the previous question would require a specific carrier in order to be transported into a cell? Is there anything on the list that you would not expect to see transported across a membrane under any circumstances? If so, what?
  6. Explain what is meant by the terms “isotonic”, “hypertonic”, “hypotonic”, “lysis”, “plasmolysis”, “shrinkage” and “osmosis”. What is the equivalent salt concentration of a human cell?
  7. A wilted lettuce leaf is placed in fresh water. What happens? Which of the terms mentioned above are involved?
  8. A cook pickles some tomatoes in concentrated brine. Fungi and bacteria (cells with walls) can no longer grow. Explain. Which of the terms mentioned above are involved?
  9. How does “facilitated diffusion” differ from “passive diffusion”? How does “facilitated diffusion” differ from active transport? Which of these processes would be affected by a drug that binds tightly to proteins and blocks their activity?
  10. Ion gradients are vitally important to cells. With respect to human cells, which of the following ions are normally kept at very different concentrations across cell membranes: Ca++, Na+, K+, Cl-? Which ions are in higher concentration outside the cell? Inside the cell?
  11. What is the difference between symport, antiport, and ATP pumps? What is the immediate source of energy for each process?
  12. (a) Identify each of the following terms: phagocytosis, pinocytosis, receptor-mediated endocytosis, and exocytosis. Give an example of a situation in which each would occur.
    (b) Explain the process by which iron gets from the bloodstream into human cells. Compare this with the uptake of glucose.
Chapter 9.
  1. Be able to recognize the structure of ATP, ADP, and AMP (see fig. 6.8). Why is ATP so useful in cell metabolism?
  2. What are “redox reactions”? Why are they important in biology?
  3. Explain why removal of a hydrogen atom (H) is called an oxidation. Where’s the electron? (Hint: what is a hydrogen atom made of?)
  4. What is the difference between an electron carrier and a terminal electron acceptor? Give examples of each.
  5. What does NAD+ do in biological systems? Relative to other biological molecules, how much NAD+ is there in a cell? Choose from: (a) a lot; (b) comparable to the concentration of amino acids; (c) extremely little. What happens to a cell when all its NAD+becomes reduced to NADH? How can the cell get more NAD+? What happens to the hydrogen atoms?
  6. Be familiar with the process by which cells break down glucose sugar (glycolysis followed by respiration). How much energy does this process yield aerobically? anaerobically? How efficient are these two processes?
  7. Where does glycolysis occur? What are the end products? How many oxidation reactions are involved?
  8. What does the TCA (Krebs) cycle accomplish? What is the starting material? What are the final products?
  9. How is a mitochondrion organized? Be able to identify the matrix, the cristae, and the intermembrane space in which H+ ions accumulate during proton gradient formation. What kinds of molecules make up the electron transport chain? Where do electrons entering this chain originate? Where do they end up?
  10. What is a proton gradient? How is it generated? Once made, how can a cell use it to make ATP? What is the role of ATP synthase?
  11. Note that the term “chemiosmosis” refers to the coupling of enzyme reactions to the generation of transmembrane proton gradient. Are the terms “chemiosmotic phosphorylation” and “oxidative phosphorylation” interchangeable?
  12. What is meant by the term “fermentation”? Identify two organisms that can ferment. Identify two characteristic fermentation products. Are these edible? Identify common food/beverage in which you would find each of these two products.
  13. Contrast fermentation with respiration in each of the following respects: (1) what happens to electrons in NADH? (2) how efficient is the process? (3) where do the electrons made available in oxidation reactions wind up?

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