BIO 3360 Homework 1
Homework 1 is due on or before the date & time for Exam 1
Instructions: Answer each of the following by typing the answer on your own document or beneath each question that you paste onto your word document. You may submit it in person to me or electronically as an attachment to firstname.lastname@example.org
It will be graded on thoroughness and accuracy. Each question is worth 2 points unless otherwise stated, for a total of 100 points.
- How would you define physiology and what are the disciplines that contribute to studying animal physiology?
- What is homeostasis? Give an example.
- Compare and contrast negative feedback with positive feedback.
- Home heating systems such as a furnace are regulated via negative feedback. Describe how such a system might work. (5 pts)
- Why do physiologists need to understand evolution?
- What is a van der Waal bond?
- Discuss the composition of biological membranes. Include in the discussion, the types and properties of different lipids. (9 pts)
- How can cells alter the fluidity of membranes and why is this capacity important to cellular function? (4 pts)
- How does the structure of a plasma membrane depend on the amphipathic nature of phospholipids?
- Distinguish between integral (or transmembrane) proteins and peripheral proteins.
- What is kinetic energy?
- What does it mean if a molecule moves "down its concentration gradient?"
- How would osmosis help to maintain your blood volume?
- With water swelling of brain cells following injury, would one want to bathe these cells in an isotonic, hypotonic, or hypertonic solution (choose one)?
- What do facilitated diffusion and active transport have in common? How are they different? (4 pts)
- Explain how the Na-K pump exchanges ions across the cell membrane.
- If you bought a saltwater fish in the pet shop and put it in freshwater at home, what would happen to the fish's cells?
- Solution A is 100% water and solution B is water mixed with sugar in a 50/50 ratio. If the two solutions are separated by a semipermeable membrane ONLY permeable to water, which way will the water diffuse?
- The absorptive cells of the small intestine take up sodium and glucose simultaneously from the lumen of the intestine into the bloodstream. What type of membrane carrier is described in this example?
- Explain why the heart muscle cannot obtain its oxygen from the highly oxygenated blood inside of the heart chambers by the simple process of diffusion.
- A cell has a concentration of 100mM KCl inside and 10mM KCl outside. Assume that the cell membrane is freely permeable to potassium ions. Describe the concentration gradient of K in this cell as well as the electrical gradient of this cell. Calculate the actual equilibrium potential using the Nernst equation. (5 pts)
- Hyperkalemia is an excess of potassium in the extracellular fluid. What effect would this have on the resting membrane potential of a neuron? (4 pts)
- Suppose a poison were to slow down the Na/K pumps of nerve cells. How would this affect the resting membrane potentials of the neurons? (4 pts)
- Why do some cells respond to a chemical messenger while other cells ignore it?
- Would you expect the chemical signaling molecules involved in signaling via gap junctions to be hydrophilic or hydrophobic? Why. (4 pts)
- What would be the effect of increasing receptor number on the response of a target cell to the ligand for that receptor?
- Where are hormone receptors located in target cells?
- Sketch a G protein-coupled receptor that leads to a second mesenger pathway in the target cell. (10 pts)
- Cancer cells divide quickly and chemotherapeutic agents typically inhibit this process to slow down the spreading of the cancer. Chemotherapy side effects are based on damage to the lining of the mouth, the skin, and especially the lining of the intestine. Based on your knowledge of the tissue type found in these locations, explain these side effects. (5 pts)
- Name the four main features of a transport epithelium. (4 pts)
- What are the differences between transcellular and paracellular transport?
- Name the layer upon which epithelium rests that is between its deepest cells and the underlying connective tissue.
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