Tuleen, Fish...here's a link to Chapter 7's lessons.
Here some study aids to help you with photosynthesis and respiration. You can also find more detailed notes here and here.
Lesson Objectives: You should be able to...
1. Draw and annotate the inside of a mitochondrion.
2. Explain how cellular respiration is the controlled release of energy from organic compounds.
3. Compare and contrast anaerobic and aerobic respiration.
4. Describe the process of cellular respiration as it relates to a mitochondrion.
Links: Photosynthesis & Respiration Anaerobic Respiration
Textbook Readings: Chapter 2, section 2.8 & 2.9
Mission 1: The Mighty Mitochondria!! Back in chapter one, we discussed cell ultrastructure and organelles. The mitochondria are the sites where energy is produced to power the cell...and everything else. Muscle cells have lots and lots of mitochondria; can you guess why? Neurons do not have as many; can you guess why?
In order to get into cellular respiration, you need to understand the structures and functions of the inside of a mitochondrion. Where does each component of cellular respiration take place? We will come back to this in Mission 2.
Task #1: Draw and annotate the inside of a mitochondrion. Describe and define the structures and functions of the following: (a) matrix, (b) cristae, (c) inner membrane, (d) outer membrane, and (e) ribosomes. Please make it large enough so that I can see the structures and can read the functions. Here is your model. I want a nice, neat, colorful mitochondria. This task is due at the beginning of the next class.
Image courtesy of brittanica.com
What you need to listen for/learn: (a) the differences between aerobic and anaerobic respiration, (b) where the energy is in glucose and where it goes when bonds break, (c) why respiration must take place within the mitochondria (and what happens if it didn't), (d) summarize the three steps of respiration and include the location and products of each step, (e) why anaerobic respiration sometimes must take place and its effects on the body, (f) explain the difference between alcoholic fermentation and lactic acid fermentation, and (g) relate the steps of respiration to the structure of the inner mitochondrion.
**Also, take note of the roles of NADH, FADH, and NAD+, as well as oxygen, protons and electrons in the respiration process.
Cells metabolize organic nutrients by slow oxidation. Enzymes break the covalent bonds holding nutrients (such as glucose) together. Energy is released in the form of ATP (adenosine triphosphate). Glycolysis is the first step. It takes place in the cytoplasm. A 6-carbon glucose is broken down into two 3-carbon molecules called pyruvate. Two ATP are required for glycolysis to take place and the process yields 4 ATP. This is a net gain of two ATP at the end of glycolysis.
The two pyruvate enter a mitochondrion and each loses a carbon dioxide to become acetyl-CoA. The Krebs Cycle begins here. Two more carbon dioxide molecules are released during this process. More ATP is generated during the Krebs Cycle. The final step is the electron transport chain (ETC), which is a series of oxidation-reduction reactions. The majority of ATP comes from the ETC (34 molecules from one molecule of glucose).
Your textbook doesn't go into detail about the electron transport chain, but you can read about it here.
Aerobic respiration occurs in the presence of oxygen. But what happens if there's no oxygen? Anaerobic respiration occurs. This process, called fermentation (which starts with glycolysis), has two main pathways: alcoholic and lactic acid. Alcoholic fermentation takes the 3-carbon pyruvate molecules and turns them into 2-carbon ethanol molecules while producing carbon dioxide as waste.
Lactic acid fermentation happens when a person cannot supply their cells with enough oxygen. In this condition, excess pyruvate is produced and converted into lactic acid molecules, which are also 3-carbon structures. No carbon dioxide is produced. The benefit of lactic acid fermentation is that glycolysis is allowed to continue with a small gain of ATP. This is reason why your muscles become sore after exercise if you're not breathing properly.
Task #2: I want to see detailed notes on Mission 2's lesson prompts. Draw and label the pathways for glycolysis, alcohol fermentation, and lactic acid fermentation.
Mission 3: Super GREEN!!! Photosynthesis is the converse process of respiration. Here, light energy is converted into glucose and oxygen. It takes place in the chloroplasts of plants. The pigment chlorophyll is what makes plants green. Here is an image of the electromagnetic spectrum, courtesy of Google.
Photosynthesis occurs in two stages: the light-dependent and light-independent. Light-dependent reactions (LDR) obviously involve the sun. Light energy is converted into ATP and split water into hydrogen and oxygen (called photolysis). The oxygen is released as a waste product (which we need to breathe). So the products of LDR are hydrogen and ATP.
Light-independent reactions (LIR) do not necessarily require sunlight in order to take place. The ATP and hydrogen are used as forms of chemical energy to convert carbon dioxide and water into useful molecules for the plant. It takes six carbon dioxide molecules to form one glucose molecule.
Fixation is the process by which this happens. Carbon dioxide and water are fixed into glucose and oxygen is produced as a waste product. Fixation requires energy, which comes from the ATP and hydrogen created in the LDR, which came from sunlight.
The rate of photosynthesis is dependent upon environmental factors, such as intensity of light and air temperature. During the daytime, the rate may be very high for a particular plant. At night, the rate of photosynthesis may drop to zero. Measuring the rate of oxygen production or carbon dioxide intake is an indicator of photosynthetic rate as long as a correction is made for cell respiration.
Task #4: Write a paragraph explaining the complementary processes of photosynthesis and respiration and why they form a continuous cycle. Should be a minimum of six sentences and incorporate vocabulary.