Cellular Respiration Webquest
Directions: Work in pairs to complete the questions, but each person must answer the questions on their own sheet of paper, in complete sentences. You may use the websites provided, but you may also use other websites or your book for extra information.
Go to:
http://www.phschool.com/science/biology_place/biocoach/cellresp/intro.html
Cellular Respiration – The BIG picture
INTRODUCTION PAGE
Concept 2:Glycolysis
Oxygen or No Oxygen – Anaerobic vs. Aerobic Respiration
If Oxygen is plentiful, pyruvate (the product of glycolysis) goes into the mitochondria where it is “processed” to produce ATP (KREBS CYCLE). However, the steps in the Krebs cycle can only occur if oxygen is available.
FERMENTATION: the result of NO OXYGEN
When oxygen is not available, fermentation occurs. In a previous step of the first animation, one type of fermentation was shown which produces alcohol (alcoholic fermentation). This type of fermentation occurs typically in yeast and in a few types of bacteria (so…these yeasts and bacteria are used to make bread, beer, and wine. SO….if this is the case, why aren’t wines, beer and bread just “full” of yeast and other creepy microorganisms?
Bread Yeast makes alcohol (at low levels) and carbon dioxide. The CO2 is the gas “trapped” in the bread when the bread rises. The alcohol is actually “cooked off”, when the bread is baked (which is why fresh baked bread smells amazing!!)
Beers have low levels of alcohol as well (5-10%) and specific yeasts are used that produce CO2 and alcohol (and the beer is “carbonated”).
Alcoholic Wine Yeasts (yes that is what they are called) can tolerate environments that are anywhere from 10-15% alcohol. So, yeast will happily convert sugars to alcohol until they “kill themselves” (produce alcohol to the point at which they can no longer survive). In order to do this, the temperature, pH and sugar levels must be “right”. The very expensive wines usually have just the right combination of these three ingredients (plus a few secret ingredients).
Human muscles can also utilize fermentation when oxygen cannot get to our cells fast enough (like when we are running like crazy to get to class and arrive breathless).
HOWEVER…Human cells cannot make alcohol during fermentation (we would be drunk all the time). Instead, we convert the pyruvate to lactic acid! Many types of bacteria, and a few types of animal and yeast cells are capable of lactic acid fermentation.
Lactic acid/other acid fermentation
Other bacteria, and some animal cells (yeast and muscle cells) are capable of anaerobic respiration also. The bacteria and yeast (mostly bacteria) are used to produce wonderful food products like cheeses, yogurt, kefir, sour dough breads, pickles, and sauerkraut. Often this type of fermentation results in a food with a typically sour taste. Each bacteria has its own unique set of reactions, and different cheeses end up with very different flavors (and sometimes big holes…like Swiss cheese).
In the human body, when we are using energy so quickly that our bodies cannot keep up with the oxygen demand, our bodies can resort to anaerobic respiration. Pyruvate is converted to lactic acid, which accumulates in the muscle cells. When the concentration becomes high enough, the lactic acid will diffuse into the blood stream, and the liver will eventually convert it back to glucose.
Go to this website (click on the link) to learn more about fermentation.
http://www.phschool.com/science/biology_place/biocoach/cellresp/fermentation.html
Use the Review button to see all the animations.
This first diagram shows the two “processes” that occur during anaerobic respiration. The first is glycolysis. What is produced at the end of glycolysis?
Click on the alcoholic fermentation animation to determine what the products of alcoholic fermentation are and what happens to NAD and NADH.
Directions: Work in pairs to complete the questions, but each person must answer the questions on their own sheet of paper, in complete sentences. You may use the websites provided, but you may also use other websites or your book for extra information.
Go to:
http://www.phschool.com/science/biology_place/biocoach/cellresp/intro.html
Cellular Respiration – The BIG picture
INTRODUCTION PAGE
- What is the purpose of cellular respiration? WRITE A SENTENCE!
- Look at the diagram on the first page of this website (introduction). It is trying to convey several messages.
- What are the two types of cells shown in the diagram in which this type of cellular respiration occurs?
- Cellular respiration begins in one part of the cell, and ends in a second part of the cell. Where does cellular respiration begin?
- What are the products (look at the arrows going “out” of the process”) of cellular respiration? (You should find THREE).
- What are the two reactants (the molecules going into the reaction)?
- Put the reactants and products together in an equation using molecular formulas (H2O is an example of a molecular formula). Use glucose for the organic molecule.
- You should know the three basic steps in respiration, where each is located, and what the reactants (what is going into each process) and what the reactants and products for each step.
- In the absence of oxygen, there are only two processes (or metabolic pathways) that can occur. These are:
- Click on the Review Button and study the diagram. What additional information does this diagram give you about
- What is the end product of glycolysis. What is made PRIOR to Acetyl Co-A?
- What is the end product of fermentation (look in the yellow box)
- What type of beverage that we consume contains the end product of this type of fermentation?
Concept 2:Glycolysis
- In Glycolysis what is your starting “food” molecule?
- In order to break down this molecule to pyruvate, what energy molecule must first DONATE energy? The downward arrows indicate what you start with (at the top) and what you produce (at the bottom).
- What molecules are generated (produced) as a result of glycolysis (be sure to list “how many”).
- The term “NET” refers to the number produced “minus” the number “used” .
- How many ATP are used?
- How many ATP are produced?
- How many NADH are produced?
- What is the “net” number of ATP and NADH used (list them separately)
- How many molecules of pyruvate are produced?
Oxygen or No Oxygen – Anaerobic vs. Aerobic Respiration
If Oxygen is plentiful, pyruvate (the product of glycolysis) goes into the mitochondria where it is “processed” to produce ATP (KREBS CYCLE). However, the steps in the Krebs cycle can only occur if oxygen is available.
FERMENTATION: the result of NO OXYGEN
When oxygen is not available, fermentation occurs. In a previous step of the first animation, one type of fermentation was shown which produces alcohol (alcoholic fermentation). This type of fermentation occurs typically in yeast and in a few types of bacteria (so…these yeasts and bacteria are used to make bread, beer, and wine. SO….if this is the case, why aren’t wines, beer and bread just “full” of yeast and other creepy microorganisms?
Bread Yeast makes alcohol (at low levels) and carbon dioxide. The CO2 is the gas “trapped” in the bread when the bread rises. The alcohol is actually “cooked off”, when the bread is baked (which is why fresh baked bread smells amazing!!)
Beers have low levels of alcohol as well (5-10%) and specific yeasts are used that produce CO2 and alcohol (and the beer is “carbonated”).
Alcoholic Wine Yeasts (yes that is what they are called) can tolerate environments that are anywhere from 10-15% alcohol. So, yeast will happily convert sugars to alcohol until they “kill themselves” (produce alcohol to the point at which they can no longer survive). In order to do this, the temperature, pH and sugar levels must be “right”. The very expensive wines usually have just the right combination of these three ingredients (plus a few secret ingredients).
Human muscles can also utilize fermentation when oxygen cannot get to our cells fast enough (like when we are running like crazy to get to class and arrive breathless).
HOWEVER…Human cells cannot make alcohol during fermentation (we would be drunk all the time). Instead, we convert the pyruvate to lactic acid! Many types of bacteria, and a few types of animal and yeast cells are capable of lactic acid fermentation.
Lactic acid/other acid fermentation
Other bacteria, and some animal cells (yeast and muscle cells) are capable of anaerobic respiration also. The bacteria and yeast (mostly bacteria) are used to produce wonderful food products like cheeses, yogurt, kefir, sour dough breads, pickles, and sauerkraut. Often this type of fermentation results in a food with a typically sour taste. Each bacteria has its own unique set of reactions, and different cheeses end up with very different flavors (and sometimes big holes…like Swiss cheese).
In the human body, when we are using energy so quickly that our bodies cannot keep up with the oxygen demand, our bodies can resort to anaerobic respiration. Pyruvate is converted to lactic acid, which accumulates in the muscle cells. When the concentration becomes high enough, the lactic acid will diffuse into the blood stream, and the liver will eventually convert it back to glucose.
Go to this website (click on the link) to learn more about fermentation.
http://www.phschool.com/science/biology_place/biocoach/cellresp/fermentation.html
Use the Review button to see all the animations.
This first diagram shows the two “processes” that occur during anaerobic respiration. The first is glycolysis. What is produced at the end of glycolysis?
- Some cells are capable of alcoholic fermentation, while others undergo lactic acid fermentation. Muscles (and lactic acid bacteria) will form _________________.
- What happens to the NADH when lactate is formed?
- If NADH goes back to its oxidized form…what molecule can it make more of?
- Why is fermentation important? Why is it so important for ATP to be continually produced, even if quantities are small?
Click on the alcoholic fermentation animation to determine what the products of alcoholic fermentation are and what happens to NAD and NADH.
- What are the products of alcoholic fermentation:
- What happens to NADH?