• my on-line schedule   (I try to keep this updated.)
• Here's a link to something that both courses (Biol 1000 and Biol 1001) might find useful:
  • Photosynthesis (light reactions)

• my Biol 1000 page   Last updated March 15, 2004
• Lab Section 92 (MW 7:30-9:00pm, SC 105):
• Lab Exam 1, Lab Quiz 1, & Lab Chapters 1 & 2 scores are now available on-line.  (out of 52 pts possible)

• my Biol 1001 page   Last updated March 20, 2004
• Lab Section 72 (Sat. 11:45am-2:30pm, SC 111):
  Last updated March 20, 2004
• Lab Quiz 1, Homework 1, Homework 2 (D/O graph), and Lab Exam 1 scores and statistics are now available on-line.  (out of 60 pts possible)

The following are some questions on general respiration concepts that you might find useful (I used them when I taught a different course).  Consult your notes to determine how much of this you will need to know.

Important Respiration Concepts

1.  Physiological respiration involves inhaling __________ and exhaling __________.

2.  Cellular respiration involves the metabolic reactions concerned with the retrieval of _________ stored in the chemical bonds of ______________.

3.  These organelles, found in plant and animal cells, are the sites where cellular respiration takes place within the cells: _________________________.

4.  Organisms that use oxygen to oxidize glucose are called _______________.  [Try to name some examples of these kinds of organisms (think about what organisms you've seen in lab, and in your everyday life)].

5.  Organisms that can carry on respiration without oxygen are called ________________.  This process is also called _________________.  [Have you learned about any of these kinds of organisms in lecture?]

6.  The products of alcoholic fermentation are:  ________________, ___________, and __________.

7.  The products of lactic acid fermentation are: ________________ and __________.

8.  The products of aerobic respiration are: ____________, ____________, and _________.

9.  The term “oxidative phosphorylation” refers to the addition of ______________ to ________, forming _______.

10.  Where do the glucose carbons end up at the end of aerobic respiration (cellular respiration)? __________
            alcoholic fermentation? ______________    and    lactic acid fermentation? ______________ (both are forms of anaerobic respiration)
 
11.  What are the stages of respiration, and where do they occur?  Which of these stages is used in anaerobic respiration?

12.  Compare the efficiency of aerobic and anaerobic respiration in terms of end products and net gain of ATP.  What is the advantage of anaerobic respiration?

13.  Why do aerobic organisms need oxygen?  (Hint:  what happens to the 2 electrons at the end of the electron transport system;  what is the role of oxygen?)

14.  What are the inputs of aerobic respiration?  What is the purpose of respiration?

15.  Why does lack of oxygen cause muscle to produce lactic acid?  (HINT:  what is the purpose of oxygen in respiration?)

16. a)  At what point in the respiration cycle do anaerobic and aerobic respiration begin to differ?

16. b)  How does this explain the difference in net energy production?

(answers)

QUESTIONS TO THINK ABOUT

1.  Understand the overall respiration reactions.  What goes in, what comes out?
2.  How do they apply to the experiments in lab?  What did we measure, and how?
3.  Understand the major steps in aerobic respiration, and where they occur.
     (Where is important because it helps to explain why some organisms can't undergo aerobic respiration.)
4.  What are the differences in net energy production in aerobic vs. anaerobic respiration?

5.   Compare & contrast photosynthesis with respiration
      (in general terms, such as overall products & reactants).
 

Answers to Important Respiration Concepts

1.  Physiological respiration involves inhaling oxygen and exhaling carbon dioxide (and water).

2.  Cellular respiration involves the metabolic reactions concerned with the retrieval of energy stored in the chemical bonds of glucose (food).

3.  These organelles, found in plant and animal cells, are the sites where respiration takes place within the cells: mitochondria.

4.  Organisms that use oxygen to oxidize glucose are called aerobes.  [Some examples of aerobes are:  humans, mice, larvae, and germinating beans.]

5.  Organisms that can carry on respiration without oxygen are called anaerobes.  This process is also called fermentation.  [An example (organism) is yeast.]

6.  The products of alcoholic fermentation are:  ethanol, carbon dioxide, and ATP.

7.  The products of lactic acid fermentation are: lactic acid and ATP.

8.  The products of aerobic respiration are: carbon dioxide, water, and ATP.

9.  The term “oxidative phosphorylation” refers to the addition of inorganic phosphate to ADP, forming ATP.

10.  Where do the glucose carbons end up at the end of aerobic respiration (cellular respiration)?  carbon dioxide
            alcoholic fermentation?  ethanol and carbon dioxide    and    lactic acid fermentation?  lactic acid
 
11.  What are the stages of respiration, and where do they occur?  Which of these stages is used in anaerobic respiration?

Glycolysis occurs in the cytoplasm.  The formation of Acetyl-CoA (matrix), the Kreb's cycle (matrix), and ETS/chemiosmosis/oxidative phosphorylation (inner membrane)  all occur in the mitochondria.

12.  Compare the efficiency of aerobic and anaerobic respiration in terms of end products and net gain of ATP.  What is the advantage of anaerobic respiration?

• Because more carbon-carbon bonds of glucose are broken in aerobic respiration, aerobic respiration is able to synthesize more ATP.
• The advantage of anaerobic respiration is that it doesn't require oxygen to produce ATP.  (Oxygen isn't always easily accessible - think about what happens in your muscles when you run a sprint.)

13.  Why do aerobic organisms need oxygen?  (Hint:  what happens to the 2 electrons at the end of the electron transport system;  what is the role of oxygen?)

Oxygen is the final electron acceptor in the ETS.  (Without the oxygen there to "pull out" the electrons at the end, the process would back up, levels of pyruvate would build up, and the cell would switch to fermentation to "recycle" the NAD+.

14.  What are the inputs of aerobic respiration?  What is the purpose of respiration?

• Oxygen and glucose "go in" to aerobic respiration (and a little ATP to get the process started).
• The purpose of respiration is to release chemical bond energy from organic "food" molecules, and to convert some of that energy into chemical bond energy in the form of ATP.

15.  Why does lack of oxygen cause muscle to produce lactic acid?  (HINT:  what is the purpose of oxygen in respiration?)

Without oxygen to act as the final electron acceptor in the ETS, the ETS backs up, the Kreb’s cycle backs up, and pyruvate builds up.  This build-up of pyruvate turns on the anaerobic lactic acid fermentation pathway in muscle, and lactic acid is produced as the cell recycles its NADH to NAD+, allowing glycolysis to continue.

16. a)  At what point in the respiration cycle do anaerobic and aerobic respiration begin to differ?

Aerobic and anaerobic respiration begin to differ at the end of glycolysis, and pyruvate is the end-product of glycolysis.  In anaerobic respiration, pyruvate is converted to ethanol (and CO₂) or lactic acid.  In aerobic respiration, however, pyruvate is completely oxidized to CO₂ and H₂O.

16. b)  How does this explain the difference in net energy production?

In terms of ATP production, anaerobic respiration stops after glycolysis, so only 2 net ATP are generated, but aerobic respiration continues after glycolysis, completely oxidizing pyruvate.  This releases more of the energy stored in the chemical bonds of glucose, allowing more ATP to be synthesized (plus the 2 net ATP produced during glycolysis).  (Ethanol and lactic acid have unharnessed energy that is unavailable to the cell.)

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