Compare the major features of chemoheterotrophic and photoautotrophic nutritional processes.
The major difference between these nutritional processes is that chemoheterotrophic (cellular respiration) utilizes chemical resources and photoautotrophic (photosynthesis) uses light. Photoautotropic processes use light energy to produce glucose, while chemoheterotrophic processes use this glucose to create actual energy.
Explain the inputs, major processes, and outputs of glycolysis, fermentation, and aerobic cellular respiration.
Breaks down glucose into two molecules of pyruvate.
Can occur with or without the presence of oxygen.
Input: 1 Molecule of Glucose
Output: 2 Molecules of Pyruvate (and 2 ATP and 2 NADH)
In the absence of O2, Glycolysis teams up with Fermentation to produce ATP. This is because Fermentation generates NAD+ by oxidizing NADH, which is renewable energy that powers Glycolysis.
Prevents the buildup of NADH in the cytoplasm.
Less energy is yielded than in Aerobic Cellular Respiration.
Aerobic Cellular Respiration:
Oxygen is present which yields more energy than Anaerobic Cellular Respiration (Fermentation).
Takes place in mainly the mitochondria of the cell
Glycolysis, Citric Acid Cycle, and Electron Transport Chain are the 3 main stages of Aerobic Cellular Respiration.
Input: 1 Molecule of Glucose (fed into the process of Glycolysis)
Output: Maximum Amount of 38 ATP produced
Trace the movement of energy and matter through all cellular respiratory processes.
A carbon atom enters into cellular respiration as a glucose molecule, which is broken down by glycolysis, forming CO2 from C6H12O6. This glucose molecule is ultimately broken down to form 2 molecules of pyruvate which are fed into the Citric Acid Cycle where carbon is present in each step and is renewed over and over (hence, from the name, cycle).
Match all cellular respiratory processes to their locations in a typical eukaryotic cell.
Citric Acid Cycle - Within the Mitochondrial Matrix
Oxidative Phosphorylation - Inner Mitochondrial membrane
Electron Transport Chain - In the cristae of the mitochondrion (the plasma membrane)
Explain the inputs, major processes, and outputs of the light reactions and the Calvin Cycle.
Creates ATP and NADPH for Calvin Cycle to use.
Input: Light Energy and H2O
Output: O2, ATP and NADPH
Synthesizes simple sugars from CO2
Input: ATP, NADPH and CO2
Output: ADP, NADP+ and Sugar
Trace the movement of energy and matter through all photosynthetic processes.
A carbon atom enters into photosynthesis as CO2 and is oxidized, taking part in producing C6H12O2 and H2O.
6CO2 + 12H2O + Light Energy ---> C6H12O2 + 6H2O
Photosystem II and Photosystem I finish their reactions and pass the baton to the Calvin Cycle.
Carbon enters into the Calvin Cycle as CO2 and leaves as a sugar named glyceraldehyde 3-phosphate (G3P).
Match all photosynthetic processes to their locations in a typical eukaryotic, autotrophic cell.
Calvin Cycle - stroma of the chloroplasts
Light Reactions - in thykaloids
Describe the process of chemiosmosis and compare its function in photosynthetic and respiratory pathways.
Chemiosmosis is the process of moving ions across the concentration gradient. In respiratory pathways, the protons pass across the concentration gradient to generate ATP that can be utilized in more than one way. In photosynthetic pathways, it occurs in the light reactions where ATP is generated for the Calvin Cycle and building of glyceraldehyde 3-phosphate (the sugar produced by photosynthesis)
Explain the relationship between photosynthesis and cellular respiration at the molecular, organismal, and ecosystem levels of organization.
Cellular respiration is the reverse equation of photosynthesis, and vice versa. The products of one reaction are the reactants of the other. Photosynthesis being 6CO2 + 6H2O → C6H12O6+ 6O2 and cellular respiration being C6H12O6 + 6O2 → 6CO2 + 6H2O. In an organism, such as a plant, photosynthesis generates the glucose that is used in cellular respiration to create ATP. The glucose is then turned back into carbon dioxide, which is used in the process of photosynthesis. In an ecosystem, trees use photosynthesis to produce oxygen for all of us to breath. We require this oxygen in our bodies to perform the process of cellular respiration.
Explain how energetic requirements contribute to the adaptations of organisms. Provide examples to support your statements.
Over time, organisms tend to adapt to the amount of energy available in order to thrive. For example, some species of yeast are aerobic (require oxygen for cellular respiration) and give off gas, while others can be anaerobic (do not require oxygen) and not give off gas. This is most likely due to the environments that these different species of yeast developed in having either too little or too much O2 for cellular respiration.
Propose experimental designs by which the rate of photosynthesis and respiration can be measured and studied.
You can determine the rate of photosynthesis by measuring the uptake of CO2. You can put a plant in a ziplock bag and observe the concentration of CO2 using a CO2 monitor. To study the rate of photosynthesis more in depth, one could run trials with various plants (taking into account leaf size) and measure the uptake of CO2 for each. Additionally, you can also study the rate of cellular respiration by either measuring the amount of glucose or oxygen consumed.
Describing 2–3 different strategies that organisms employ to obtain free energy for cell processes (e.g., different metabolic rates, physiological changes, variations in reproductive and offspring-rearing strategies).
1. Organisms can obtain energy by eating other (once living) things, as shown in the transfer of energy between the levels of consumers in an ecosystem.
[Source: Field Studies Council]
We all get our energy from the sun whether or not we are eating plants that took part in photosynthesis, or we are eating animals that ate plants, or animals that ate animals that ate plants! If we don’t have food to break down, we don’t energy to drive cell processes, and therefore we die.
2. Additionally, based on an organism’s diet, it can have an extremely different metabolic rate than that of another. For instance, the sloth. It feeds entirely on tree leaves which makes for a diet that is not very nutritious since most of the calories in the leaves are closed up by hard-to-digest cellulose. Additionally, the metabolic rate of the sloth is nearly 1/2 that of other mammals their size. This extremely slow metabolism assists sloths in dealing with the small amount of energy that they gain from their diet by taking longer to process the little calories they consume.
Refine or revise a visual representation to more accurately depict the light-dependent and light-independent (i.e., Calvin cycle) reactions of photosynthesis and the dependency of the processes in the capture and storage of free energy.
Pose scientific questions about what mechanisms and structural features allow organisms to capture, store, and use free energy (e.g., autotrophs versus heterotrophs, photosynthesis, chemosynthesis, anaerobic versus aerobic respiration).
One question someone may ask is how, even without oxygen, cellular respiration can continue to take place and generate ATP. This is because, since Glycolysis can take place with or without oxygen, it can couple with Fermentation to resume the production of ATP. This is because Fermentation generates NAD+ which powers Glycolysis, rendering it able to continue even without the presence of oxygen. However, a downfall of this process is that it generates much less ATP than aerobic cellular respiration since Fermentation (anaerobic cellular respiration) produces only 2 ATP, while aerobic cellular respiration can produce up to 38 ATP.
Create a visual representation to describe the structure of cell membranes and how membrane structure leads to the establishment of electrochemical gradients and the formation of ATP.