BackPhotosynthesis, Cellular Respiration, and Related Processes – Step-by-Step Study Guidance
Study Guide - Smart Notes
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Q1. What is the equation for photosynthesis?
Background
Topic: Photosynthesis Equation
This question tests your understanding of the overall chemical equation for photosynthesis, which describes how plants convert carbon dioxide and water into glucose and oxygen using light energy.
Key Terms and Formulas
Photosynthesis: The process by which photoautotrophs convert light energy into chemical energy.
General equation:
Step-by-Step Guidance
Review the reactants and products in each answer choice. Photosynthesis typically uses carbon dioxide and water as reactants, and produces glucose and oxygen as products.
Check for the presence of light energy on the reactant side, as it is required for the process.
Look for the correct stoichiometry: 6 molecules of CO2 and 6 (or sometimes 12) molecules of H2O are commonly used in the equation.
Eliminate options that do not fit the general pattern of photosynthesis (e.g., those that have ATP as a product or use glucose as a reactant).
Try solving on your own before revealing the answer!
Final Answer: A) 6CO2 + 12H2O + Light → C6H12O6 + 6O2 + 6H2O
This equation represents the overall process of photosynthesis, including the splitting of water and the production of glucose and oxygen.
Q2. Which of the following accurately describes aspects of photosynthesis? Select all that apply.
Background
Topic: Properties of Photosynthesis
This question tests your understanding of the characteristics and energetics of photosynthesis, including which organisms perform it, the type of reaction, and its purpose.
Key Terms
Catabolic: Breaking down molecules to release energy.
Anabolic: Building complex molecules from simpler ones, usually requiring energy.
Endergonic: A reaction that requires energy input.
Exergonic: A reaction that releases energy.
Step-by-Step Guidance
Go through each statement and recall whether it matches what you know about photosynthesis. For example, is it only performed by plants, or do other organisms also perform it?
Determine if the process is anabolic or catabolic, and whether it is endergonic or exergonic.
Consider the main purpose of photosynthesis: is it to generate ATP directly, or to convert solar energy into chemical energy?
Think about whether organisms that perform photosynthesis can also perform cellular respiration.
Try solving on your own before revealing the answer!
Final Answer: iii, v, vii
Photosynthesis converts solar energy to chemical energy (iii), uses light to excite electrons (v), and is an endergonic process (vii).
Q3. Fermentation is:
Background
Topic: Fermentation
This question tests your understanding of fermentation, especially its role in energy production and whether it is aerobic or anaerobic.
Key Terms
Fermentation: An anaerobic process that allows cells to generate ATP without oxygen.
Aerobic: Requires oxygen.
Anaerobic: Does not require oxygen.
Step-by-Step Guidance
Recall whether fermentation occurs in the presence or absence of oxygen.
Eliminate options that describe fermentation as aerobic or as a process that increases oxidative phosphorylation.
Consider whether fermentation is performed by all cells at all times, or only under certain conditions.
Try solving on your own before revealing the answer!
Final Answer: C) Anaerobic
Fermentation is an anaerobic process, meaning it occurs without oxygen.
Q4. Which of the following accurately describes the difference between light-independent and light-dependent reactions? Select all that apply.
Background
Topic: Photosynthesis Reactions
This question tests your understanding of the differences between the two main stages of photosynthesis: the light-dependent reactions and the Calvin cycle (light-independent reactions).
Key Terms
Light-dependent reactions: Require light, occur in the thylakoid membranes, produce ATP and NADPH.
Light-independent reactions (Calvin cycle): Do not require light directly, occur in the stroma, use ATP and NADPH to fix carbon.
Photosystems: Protein complexes involved in the light-dependent reactions.
Electron transport chain: Series of proteins that transfer electrons and help generate ATP.
Step-by-Step Guidance
Review each statement and recall which process it describes (light-dependent or light-independent).
Remember that the Calvin cycle is the light-independent reaction and involves carbon fixation.
Recall that the electron transport chain is part of the light-dependent reactions, not the Calvin cycle.
Identify which reactions produce ATP and which produce sugars.
Try solving on your own before revealing the answer!
Final Answer: iv, v, vi
Statements iv, v, and vi accurately describe the differences between the two types of reactions in photosynthesis.
Q5. Which of the following organisms can fix nitrogen?
Background
Topic: Nitrogen Fixation
This question tests your knowledge of which organisms are capable of converting atmospheric nitrogen (N2) into a biologically usable form.
Key Terms
Nitrogen fixation: The process of converting N2 gas into ammonia or related compounds.
Common nitrogen-fixing organisms: Certain bacteria and cyanobacteria.
Step-by-Step Guidance
Recall which types of organisms are known for nitrogen fixation (e.g., some bacteria, not animals or fungi).
Identify which option is a cyanobacterium, as these are well-known nitrogen fixers.
Eliminate options that are plants, animals, or fungi, as these typically do not fix nitrogen directly.
Try solving on your own before revealing the answer!
Final Answer: C) Anabaena
Anabaena is a genus of cyanobacteria capable of nitrogen fixation.
Q6. Which of the following organisms can fix carbon? Select all that apply.
Background
Topic: Carbon Fixation
This question tests your understanding of which organisms can convert inorganic carbon (CO2) into organic molecules through processes like photosynthesis.
Key Terms
Carbon fixation: The process of converting inorganic CO2 into organic compounds.
Photoautotrophs: Organisms that use light energy to fix carbon.
Step-by-Step Guidance
Identify which organisms are photoautotrophs or chemoautotrophs (e.g., plants, some archaea, some protists).
Eliminate heterotrophs (e.g., animals) that cannot fix carbon.
Consider whether each group listed is capable of photosynthesis or chemosynthesis.
Try solving on your own before revealing the answer!
Final Answer: i, ii, v
Grass (i), some archaea (ii), and some protists (v) can fix carbon.
Q7. In the Calvin cycle, what inputs are required to produce one molecule of G3P?
Background
Topic: Calvin Cycle Inputs
This question tests your knowledge of the reactants needed for the Calvin cycle to produce one molecule of glyceraldehyde-3-phosphate (G3P), a key sugar intermediate.
Key Terms
G3P: Glyceraldehyde-3-phosphate, a 3-carbon sugar produced in the Calvin cycle.
ATP and NADPH: Energy carriers produced in the light-dependent reactions and used in the Calvin cycle.
Step-by-Step Guidance
Recall the stoichiometry of the Calvin cycle: how many CO2, ATP, and NADPH are needed to produce one G3P.
Eliminate options that include molecules not involved in the Calvin cycle (e.g., O2 as an input).
Identify the correct combination of CO2, ATP, and NADPH required for one G3P.
Try solving on your own before revealing the answer!
Final Answer: D) 3 CO2, 9 ATP, and 6 NADPH
These are the inputs required to produce one molecule of G3P in the Calvin cycle.
Q8. What happens during the second phase of the Calvin cycle?
Background
Topic: Calvin Cycle Phases
This question tests your understanding of the steps of the Calvin cycle, specifically what occurs during the reduction phase.
Key Terms
Reduction phase: The phase where 3-phosphoglycerate is reduced to G3P using ATP and NADPH.
G3P: The 3-carbon sugar produced.
Step-by-Step Guidance
Recall the three phases of the Calvin cycle: carbon fixation, reduction, and regeneration.
Identify which phase involves the reduction of 3-phosphoglycerate to G3P.
Look for the answer choice that describes the use of ATP and NADPH to reduce 3-phosphoglycerate.
Try solving on your own before revealing the answer!
Final Answer: A) 3-phosphoglycerate is reduced to G3P using ATP and NADPH
This describes the reduction phase of the Calvin cycle.
Q9. During the Calvin cycle, RuBisCO acts as a:
Background
Topic: RuBisCO Function
This question tests your knowledge of the enzyme RuBisCO and its role in the Calvin cycle.
Key Terms
RuBisCO: Ribulose-1,5-bisphosphate carboxylase/oxygenase, the enzyme that catalyzes the first step of carbon fixation.
Catalyst: A substance that increases the rate of a chemical reaction.
Step-by-Step Guidance
Recall the main function of RuBisCO in the Calvin cycle (catalyzing the fixation of CO2).
Eliminate options that do not describe an enzyme or catalyst role.
Identify the answer that best matches RuBisCO's function as an enzyme.
Try solving on your own before revealing the answer!
Final Answer: B) Catalyst
RuBisCO acts as a catalyst in the Calvin cycle, facilitating the fixation of CO2.
Q10. Which of the following accurately describes the reaction pathway of light-dependent reactions?
Background
Topic: Light-Dependent Reaction Pathway
This question tests your understanding of the sequence of events in the light-dependent reactions of photosynthesis.
Key Terms
Photosystem II: The first protein complex in the light-dependent reactions.
Electron transport chain: Transfers electrons and helps generate ATP and NADPH.
Photosystem I: The second protein complex in the pathway.
Step-by-Step Guidance
Recall the correct order: Photosystem II → Electron transport chain → Photosystem I.
Eliminate options that do not start with Photosystem II.
Identify the answer that matches the correct sequence.
Try solving on your own before revealing the answer!
Final Answer: B) Photosystem II → Electron transport chain → Photosystem I
This is the correct sequence for the light-dependent reactions in photosynthesis.
Q11. Fill in the blanks. Photosystems 1 and 2 are both ___________, and they are both located within the __________ of plants and algae.
Background
Topic: Photosystem Structure and Location
This question tests your knowledge of the structure and location of photosystems in plant cells.
Key Terms
Photosystems: Protein complexes involved in capturing light energy.
Grana: Stacks of thylakoids within the chloroplast.
Step-by-Step Guidance
Recall that photosystems are protein complexes.
Remember that grana are the structures within chloroplasts where photosystems are located.
Eliminate options that do not match these descriptions.
Try solving on your own before revealing the answer!
Final Answer: E) Protein complexes; grana
Photosystems I and II are protein complexes located in the grana of chloroplasts.
Q12. In chloroplasts, chemiosmosis generates ATP using a proton gradient across the:
Background
Topic: Chemiosmosis in Chloroplasts
This question tests your understanding of where the proton gradient is established during photosynthesis.
Key Terms
Chemiosmosis: The movement of ions across a semipermeable membrane, generating ATP.
Thylakoid membrane: The site of the light-dependent reactions and proton gradient formation.
Step-by-Step Guidance
Recall that the proton gradient is established across the thylakoid membrane during the light-dependent reactions.
Eliminate options that refer to other membranes or compartments.
Identify the correct membrane involved in ATP synthesis in chloroplasts.
Try solving on your own before revealing the answer!
Final Answer: B) Thylakoid membrane
The proton gradient is across the thylakoid membrane, driving ATP synthesis.
Q13. Which of the following processes split water to produce oxygen?
Background
Topic: Oxygen Evolution in Photosynthesis
This question tests your knowledge of which part of photosynthesis is responsible for splitting water and releasing oxygen.
Key Terms
Photolysis: The splitting of water molecules using light energy.
Photosystem II: The complex responsible for water splitting.
Step-by-Step Guidance
Recall which photosystem is responsible for splitting water (photolysis).
Eliminate processes that do not involve water splitting or oxygen production.
Identify the correct photosystem.
Try solving on your own before revealing the answer!
Final Answer: D) Photosystem II
Photosystem II splits water to produce oxygen during the light-dependent reactions.
Q14. Which of the following processes utilize the electron transport chain? Select all that apply.
Background
Topic: Electron Transport Chain
This question tests your understanding of which cellular processes involve an electron transport chain (ETC).
Key Terms
Electron transport chain: A series of protein complexes that transfer electrons and generate a proton gradient for ATP synthesis.
Processes: Oxidative phosphorylation (cellular respiration), light-dependent reactions (photosynthesis).
Step-by-Step Guidance
Recall which processes involve an ETC (e.g., oxidative phosphorylation, light-dependent reactions).
Eliminate processes that do not use an ETC (e.g., glycolysis, fermentation).
Identify all correct processes from the list.
Try solving on your own before revealing the answer!
Final Answer: iii, iv
Oxidative phosphorylation and light-dependent reactions both utilize an electron transport chain.
Q15. What does it mean to ‘fix’ an inorganic element?
Background
Topic: Element Fixation
This question tests your understanding of the biological meaning of 'fixing' an element like carbon or nitrogen.
Key Terms
Fixation: The process of converting an inorganic element into an organic form usable by living organisms.
Step-by-Step Guidance
Recall the definition of fixation in a biological context (e.g., carbon fixation, nitrogen fixation).
Eliminate options that refer to nuclear or radioactive processes.
Identify the answer that describes conversion to an organic form.
Try solving on your own before revealing the answer!
Final Answer: C) To convert to an organic form
Fixing an element means converting it from an inorganic to an organic form.
Q16. Why do organisms fix elements?
Background
Topic: Importance of Element Fixation
This question tests your understanding of why biological fixation of elements is necessary for life.
Key Terms
Fixation: Making elements usable for biological processes.
Step-by-Step Guidance
Consider why elements like carbon and nitrogen need to be fixed (e.g., their inorganic forms are not directly usable by most organisms).
Eliminate options that focus on competition or isotope stabilization.
Identify the answer that explains the necessity for usability.
Try solving on your own before revealing the answer!
Final Answer: C) The elements would otherwise be unusable
Fixation makes elements usable for biological processes.
Q17. Which of the following gases is most common in the atmosphere?
Background
Topic: Atmospheric Composition
This question tests your knowledge of the relative abundance of gases in Earth's atmosphere.
Key Terms
Nitrogen: The most abundant gas in Earth's atmosphere.
Step-by-Step Guidance
Recall the major components of Earth's atmosphere (nitrogen, oxygen, argon, etc.).
Eliminate gases that are present in much lower concentrations.
Identify the most abundant gas.
Try solving on your own before revealing the answer!
Final Answer: D) Nitrogen
Nitrogen makes up about 78% of Earth's atmosphere.
Q18. How do chloroplasts support the endosymbiotic theory?
Background
Topic: Endosymbiotic Theory
This question tests your understanding of the evidence supporting the idea that chloroplasts originated from free-living prokaryotes.
Key Terms
Endosymbiotic theory: The idea that organelles like mitochondria and chloroplasts originated from symbiotic prokaryotes.
Key evidence: Binary fission, circular DNA, double membranes.
Step-by-Step Guidance
Recall the main lines of evidence for the endosymbiotic theory (e.g., organelle division, DNA structure, membranes).
Eliminate options that do not mention these features.
Identify the answer that lists all the key evidence.
Try solving on your own before revealing the answer!
Final Answer: B) They experience binary fission, have circular DNA, and a double-membrane structure
These features support the endosymbiotic origin of chloroplasts.
Q19. Select all that apply. Photoautotrophs:
Background
Topic: Photoautotrophs
This question tests your understanding of the characteristics and roles of photoautotrophic organisms.
Key Terms
Photoautotrophs: Organisms that use light energy to fix inorganic carbon into organic molecules.
Producers: Organisms that produce their own food from inorganic sources.
Step-by-Step Guidance
Identify which statements describe the use of light energy and carbon fixation.
Eliminate statements that refer to nitrogen fixation or fungi (which are not photoautotrophs).
Choose all statements that accurately describe photoautotrophs.
Try solving on your own before revealing the answer!
Final Answer: i, iv, v
Photoautotrophs use light energy to fix carbon, produce energy-rich sugars, and are considered producers.
Q20. In an environment without oxygen, how do cells generate ATP? What kinds of cells/organisms use this process most often?
Background
Topic: Anaerobic ATP Production
This question tests your understanding of how cells generate ATP in the absence of oxygen and which organisms commonly use this process.
Key Terms
Fermentation: Anaerobic process for ATP production.
Anaerobic organisms: Bacteria, archaea, yeast, and some animal cells (e.g., muscle cells under low oxygen).
Step-by-Step Guidance
Recall that in the absence of oxygen, cells switch from aerobic respiration to fermentation.
Identify which types of cells or organisms rely on fermentation (e.g., bacteria, yeast, muscle cells).
Think about the products of fermentation (e.g., lactic acid, ethanol).
Try answering in your own words before revealing the sample answer!
Sample Answer:
Without oxygen, cells perform fermentation to generate ATP. Organisms that frequently do this are bacteria, archaea, and yeast. Muscle cells can also do this by producing lactic acid.
Q21. Why are plants green?
Background
Topic: Plant Pigments
This question tests your understanding of why plants appear green to our eyes.
Key Terms
Chlorophyll: The main pigment in plants that absorbs light.
Reflection: The process by which certain wavelengths of light are not absorbed but reflected.
Step-by-Step Guidance
Recall that chlorophyll absorbs most wavelengths of light except green.
Understand that the green wavelength is reflected, making plants appear green.
Think about the role of chloroplasts in this process.
Try answering in your own words before revealing the sample answer!
Sample Answer:
The pigments in chloroplasts absorb most wavelengths of light except for green, which they reflect. Because plants have many chloroplasts, they typically reflect a lot of green light.
Q22. Sugars are created as a part of photosynthesis. What cellular process directly uses the outputs of photosynthesis to operate, and what is this process’s primary purpose?
Background
Topic: Connection Between Photosynthesis and Cellular Respiration
This question tests your understanding of how the products of photosynthesis are used in other cellular processes.
Key Terms
Cellular respiration: The process that uses sugars to produce ATP.
ATP: The main energy currency of the cell.
Step-by-Step Guidance
Recall that the sugars produced in photosynthesis are used in cellular respiration.
Identify the main purpose of cellular respiration (ATP production).
Think about how these two processes are interconnected in the cell.
Try answering in your own words before revealing the sample answer!
Sample Answer:
The sugars generated during photosynthesis are later used for cellular respiration. The primary purpose of cellular respiration is to create ATP.
Q23. List the phases of the Calvin cycle in order.
Background
Topic: Calvin Cycle Phases
This question tests your knowledge of the sequence of events in the Calvin cycle.
Key Terms
Phases: Carbon fixation, reduction, regeneration of the CO2 acceptor (RuBP).
Step-by-Step Guidance
Recall the three main phases of the Calvin cycle.
Put them in the correct order, starting with carbon fixation.
Think about what happens in each phase.
Try listing the phases before revealing the sample answer!
Sample Answer:
Carbon fixation → Reduction → Regeneration of the CO2 acceptor (RuBP)
Q24. Where in the chloroplast do light reactions occur? Where does the Calvin Cycle occur?
Background
Topic: Chloroplast Structure and Function
This question tests your knowledge of the specific locations of the light reactions and the Calvin cycle within the chloroplast.
Key Terms
Thylakoid membrane: Site of light reactions.
Stroma: Site of the Calvin cycle.
Step-by-Step Guidance
Recall that the light reactions occur in the thylakoid membranes.
Remember that the Calvin cycle takes place in the stroma.
Think about the structure of the chloroplast and where these compartments are located.
Try answering before revealing the sample answer!
Sample Answer:
Light reactions occur in the thylakoid membrane, whereas the Calvin cycle occurs in the stroma.
Q25. What do the light reactions produce that the Calvin cycle receives, and what does the Calvin cycle produce that the light reactions receive (in other words, what is exchanged between the two processes)?
Background
Topic: Exchange Between Light Reactions and Calvin Cycle
This question tests your understanding of the flow of energy and molecules between the two stages of photosynthesis.
Key Terms
ATP and NADPH: Produced by light reactions, used by the Calvin cycle.
NADP+ and ADP + Pi: Produced by the Calvin cycle, used by the light reactions.
Step-by-Step Guidance
Recall what the light reactions produce (ATP, NADPH) and what the Calvin cycle needs as inputs.
Remember what the Calvin cycle produces as outputs (NADP+, ADP + Pi) that are recycled back to the light reactions.
Think about how these molecules are exchanged between the two processes.
Try answering before revealing the sample answer!
Sample Answer:
Light reactions produce ATP and NADPH, which are used by the Calvin cycle. The Calvin cycle produces NADP+ and ADP + Pi, which are used by the light reactions.
