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Photosynthesis & Cellular Respiration Review
Name:____________KEY___________________________Period:_______
Vocabulary: Match the phrases on the left with the term that best fits. Use answers only one time.
K 1. Organisms that make their own food A. Chloroplasts
__ A __2. Site of photosynthesis B. Chemical
__ L __3. Process occurs in a mitochondrion C. Aerobic
__ E __4. Light absorbing molecule in the chloroplast D. ATP
__ B __5.Light energy is converted into __________ E. Chlorophyll energy during photosynthesis F. Photosystem
__ C __6. Process requires oxygen G. Oxygen
__ J __7. Gas used by plants in the light-independent H. Glycolysis reactions.
__ D __8. Energy storing molecule of the cell I. Heterotrophs
__ H __9. The anaerobic process of splitting glucose J. Carbon Dioxide and forming two molecules of pyruvic acid K. Autotrophs __ I __10. Organisms that do not make their own food L. cell respiration __ G __11. Gas used by organisms for aerobic respiration
__ F __12. Arrangement of light-catching pigments within the chloroplast.
Directions: Answer each of the following questions in a clear and concise manner.
- Describe in your own words what cell respiration is and why it is needed. Cellular respiration is the process by which chemical energy stored in glucose is released and captured as ATP. Cellular respiration is needed since ATP is a useable form of energy storage.
- Write the equation for cell respiration in word form and molecular formula. C 6 H 12 O 6 + 6O 2 6H 2 O + 6CO 2 + energy (ATP)
Glucose + oxygen gas water + carbon dioxide + ATP
- In what step of cell respiration does glucose get broken down? What does it get broken down into and why is that important?
- Glycolysis will produce 2 NADH, 2 ATP (net gain) and 2 pyruvic acid
- Glycolysis is needed to produce the pyruvic acid to enter the Kreb’s cycle if oxygen is present or undergo fermentation is oxygen is not present. This step is able to produce energy for the organism in either situation.
- Explain what happens during the Krebs Cycle. During the Kreb’s cycle, the pyruvic acid created in glycolysis enters into the Kreb’s cycle and produces a total of 4 NADH, 2 FADH 2 (which are high energy electron carriers used later on in the electron transport chain) and 2 ATP per glucose molecule.
- Explain how the electron transport chain is able to produce ATP from ADP. Discuss the similarities differences of this process in cellular respiration and photosynthesis. Since both the mitochondria and the chloroplast are double membrane organelles, both are able to create a H+^ concentration gradient. As the H+^ ions move down the concentration gradient, they pass through ATP synthase to create ATP. The differences are that the amount of ATP produced in the chloroplast is not as great as in the mitochondria. Also, the energy to fuel the protein pumps in the chloroplast is fueled by the high energy electron which is excited by a photon of light and in the mitochondria the ETC is fueled by high energy electron carriers, NADH and FADH 2
- What is the difference in an aerobic process and anaerobic process? Aerobic means oxygen is present (more ATP produced during cellular respiration) Anaerobic means oxygen is not present (less ATP produced during cellular respiration)
- Name the three processes of aerobic cellular respiration. How many ATP’s does each process produce, and what is the total ATP produced from one glucose molecule?
3 Processes of Cellular Respiration: # ATP produced:
glycolysis Net gain of 2 ATP
Kreb’s Cycle 2 ATP
Electron Transport Chain 32 ATP
- What is fermentation and why is it used? Fermentation is the process by which an organism will produce a small amount of ATP when oxygen is not present.
Total ATP per 1 glucose =___ 36 ____
- Summarize the events of the “photo” reaction. Be sure to include all inputs and outputs. Water splitting photosystem- energy captured from a photon of light and as excited electron in the chlorophyll molecules fall back to the resting state, energy is released and funneled to a nearby molecule. Eventually an electron from the specialized chlorophyll A molecule is excited and captured by the primary electron acceptor. The lost electron in the chlorophyll A molecule is replaced by the splitting of water and oxygen gas and H+^ are produced in the process. The high energy electron is passed to the first electron transport chain which supplies energy to the proton pumps. The proton pumps pump H+^ from an area of low concentration to an area of high concentration. As a concentration gradient is formed H+ diffuse through the ATP synthase molecule and produce ATP. The once high energy molecule has now lost the energy it transferred to fuel the pumps and is now low energy. This low energy electron is used in the NADPH producing photosystem to replace the electron lost in the Chlorophyll A molecule when an electron is excited and donated to the primary electron acceptor. The high energy electron that is donated is passed to the second electron transport chain and the same process used before happens again but this time rather than ATP being produced, NADPH is produced. Both the ATP and NADPH are sent to the Calvin cycle as high energy molecules used to fuel the reactions to synthesize glucose.
- Summarize the events of the “synthesis” reaction. Be sure to include all inputs and outputs.
In the Calvin cycle, carbon dioxide from the atmosphere enters the chloroplast. The carbon atom from the carbon dioxide is fixed to the 5 carbon organic molecule present in the Calvin cycle with the help of the enzyme rubisco. Once the carbon atom is fixed to the 5 carbon molecule a 6 carbon molecule is formed. Through a series of reactions fueled by the ATP and NADPH produced during the light reaction, the 6 carbon molecule splits and produced two 3-carbon molecules or G3P molecules. One G3P molecules is reserved for glucose production and the other is used to regenerate the 5- carbon organic molecule needed for carbon fixation. After six turns of the calving cycle with 1 carbon dioxide entering each time, there is an end result of 2 reserved G3P which combine to make glucose and the remaining 10 G3P are used to regenerate the 5-carbon organic molecule (6 in total).
- Discuss why leaves appear green in the spring and reddish-orange in the fall.
In the spring the amount of chlorophyll a & b is in a higher amount than carotenoids. Since chlorophyll a & b reflect the blue-green spectrum, the green color will mask the orange-red spectrum reflected by the carotenoids. In the fall, as the trees prepare for winter, the production of chlorophyll a & b is decreased but the carotenoids levels stay the same and will be greater than chlorophyll a & b. The carotenoids will now mask the green color reflected by chlorophyll and the leaves appear orange-red.
- Discuss the difference between stoma and stroma.
Stoma- pore located on the underside of a leaf that allows for gas exchange St r oma- the space between the thylakoids of a chloroplast that is the location of the “synthesis” reaction/Calvin cycle.
- Discuss how the leaf structure is efficient for photosynthesis. Be sure to discuss the function of all key structures. The structure of a leaf is efficient for photosynthesis. The high concentration of chloroplasts located in the palisade cells, which are located just under the upper epidermis allow for the absorption of sunlight energy. Since the cells are densely packed, all possible space is utilized to ensure the greatest amount of absorption. The need for water, is supplied either through the xylem cells located in the vein which can carry water from the roots, or water vapor can enter through the stoma located on the underside of the leaf. The stoma will also take in the needed carbon dioxide which is a reactant for the Calvin cycle and large air spaces are present for the large amount of gas exchange. The oxygen gas that is produced as a by-product during the light reaction is released to the atmosphere through the stoma. Once the glucose is produced during the Calvin cycle, the phloem cells will translocate the material for other parts of the plant.
- Fill in the chart comparing and contrasting cell respiration and photosynthesis.
Photosynthesis Cell Respiration Organelle for process Reactants 1. light (energy)
- water
- carbon dioxide
1.glucose 2.oxygen
Products 1.glucose 2.oxygen
1.carbon dioxide 2.water 3.ATP (energy) Steps of the process 1.light/”photo” reaction 2.Calvin cycle/”synthesis or light independent or dark” reaction
1.glycolysis 2.Kreb’s Cycle 3.Electron Transport Chain
- Animals do not perform photosynthesis; however, it is essential to our survival. Explain this.
A palisade cell (mesophyll) B upper epidermis
- Label the leaf cross section below C cuticle
D chloroplast
E air space
F stoma
G guard cell
H phloem
I xylem
J spongy cell (mesophyll)
