[Bio1] Heart dissection lab reminders

Please visit your meat vendor ahead of time to ask about the availability and price of a pig’s heart. If buying the heart more than a day before the dissection, please freeze it to avoid an unpleasant experience. The night before dissection, place it in the refrigerator portion so that it will thaw. Do not bring a frozen heart to school during dissection!

You can take a look at this video to prep for the heart dissection on Thursday (Be, Cs) and Friday (Li). Bring your copy of the first SW with the drawing of a four-chambered heart on dissection day. This is how we will make the initial incision on dissection day, much like slicing a mango. The structures you will need to identify:

  • Chambers of the heart
  1. left atrium
  2. right atrium
  3. left ventricle
  4. right ventricle
  • Valves
  1. tricuspid valve
  2. bicuspid valve
  3. aortic semilunar valve
  4. pulmonic/pulmonary semilunar valve
  • Blood vessels
  1. aorta
  2. inferior vena cava
  3. superior vena cava
  4. pulmonary artery
  5. pulmonary vein
  • Other structures
  1. chordae tendinae
  2. interventricular septum
  3. papillary muscles
  4. trabeculae carnae

[Bio1] 11/11 Pair SW for Cs and Li

  1. Please work on the pair SW mindfully.
  2. Make sure you understand each answer you write on your 1 whole sheet of paper.
  3. Submit your worksheets next week.

Vertebrate Circulation

  1. Draw and describe the plans of the circulatory systems of fishes, amphibians, reptiles, birds and mammals and explain why these are suited to these organisms.
  2. Describe what happens to the chambers (right and left atria and ventricles) and valves of the heart during each phase of the cardiac cycle. Present your summary in a tabular form.
  3. Make a flowchart tracing the flow of electrical stimulation in the heart.
  4. What causes the “lub dub” sound of heartbeat?
  5. Differentiate between the following terms: cardiac output, pulse, and blood pressure.
  6. Why does blood slow down in capillary beds?
  7. Sketch a precapillary sphincter in a capillary bed. What is the function of precapillary sphincters?
  8. Define osmotic pressure and hydrostatic pressure. Compare the osmotic and hydrostatic pressures at the arterial and venus ends of a capillary.
  9. What structures help veins transport blood back to the heart?
  10. What are the major functions of the lymphatic system?

[Bio3] Nov 10/11 Pair SW for Electron and Truth

  1. Please work on the pair SW mindfully.
  2. Make sure you understand each answer you write on your 1 whole sheet of paper.
  3. Submit your worksheets next week.

Overview: Enzymes and activation energy

View Part I of the animation at http://www.sumanasinc.com/webcontent/animations/content/enzymes/enzymes.html , click on “show narrative” and answer the questions that follow.

  • What is the activation energy (EA) of a reaction?
  • How do enzymes affect the EA of a reaction?

Enzyme structure and function
View http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html, click on “text” and answer the next question:

  • On a molecular level, how does the shape of an enzyme enable it to perform its function? Use all the following terms in your answer: active site, substrate, enzyme-substrate complex, and product.

View http://www.wiley.com/college/boyer/0470003790/animations/enzyme_binding/enzyme_binding.htm, click on “Binding Models” and answer the next question:

  • What is the difference between Emil Fisher’s lock-and-key model and Daniel Koshland’s induced fit model? What is the current model like?

Factors that affect enzyme action

  • Knowing what you know about the nature of enzymes, predict how the following factors affect enzyme function:

Factors Effect on reaction rate if factor is reduced/decreased Effect on reaction rate if factor is raised/increased Brief explanation as to why these factors affect enzyme function and reaction rates in that way

    • a. Enzyme concentration
    • b. Substrate concentration
    • c. Inhibitor concentration
    • d. Temperature
    • e. Size of container
    • f. pH
  • View http://moleculesoflife2010.wikispaces.com/file/view/Enzyme+Model.swf and test your hypotheses using controlled experiments (you may need to use a timer to assess reaction rates). Do your results agree with your predictions? Write a short summary of your results below.

View http://programs.northlandcollege.edu/biology/Biology1111/animations/enzyme.html and click on “Enzyme Inhibitors” and answer the question below.

  • What is the difference between a competitive and noncompetitive inhibitor?

View http://programs.northlandcollege.edu/biology/Biology1111/animations/enzyme.html and click on “Allosteric Enzymes” and answer the question below.

  • What are allosteric enzymes?
  • We learned in Bio2 that the haemoglobin molecule exhibits cooperativity. What happens to the structure of haemoglobin once oxygen binds to a subunit?

View http://programs.northlandcollege.edu/biology/Biology1111/animations/enzyme.html and click on “Feedback Inhibition” and answer the question below.

  • Feedback inhibition regulates metabolic pathways that use more than one enzyme. How does feedback inhibition work?