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Questions and Answers
What is one primary reason ATP is considered suitable as the universal energy currency in cells?
What is one primary reason ATP is considered suitable as the universal energy currency in cells?
Which process does NOT contribute to ATP production in cells?
Which process does NOT contribute to ATP production in cells?
Where does glycolysis occur in eukaryotic cells?
Where does glycolysis occur in eukaryotic cells?
What is the end product of glycolysis?
What is the end product of glycolysis?
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Which stage of aerobic respiration takes place in the mitochondrial matrix?
Which stage of aerobic respiration takes place in the mitochondrial matrix?
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How is ATP synthesized during oxidative phosphorylation?
How is ATP synthesized during oxidative phosphorylation?
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Which of the following substrates produces the highest amount of ATP in respiration?
Which of the following substrates produces the highest amount of ATP in respiration?
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What role do hydrogen atoms play in the process of ATP synthesis?
What role do hydrogen atoms play in the process of ATP synthesis?
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What occurs when the distance between a lamp and an apparatus is increased?
What occurs when the distance between a lamp and an apparatus is increased?
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Which of the following best describes homeostasis?
Which of the following best describes homeostasis?
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What is the primary role of receptors in the homeostatic process?
What is the primary role of receptors in the homeostatic process?
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What is negative feedback in homeostasis?
What is negative feedback in homeostasis?
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What effect does increased bicarbonate concentration have on carbon dioxide levels?
What effect does increased bicarbonate concentration have on carbon dioxide levels?
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Which of the following processes occurs during ultrafiltration in the nephron?
Which of the following processes occurs during ultrafiltration in the nephron?
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Which organ produces urea from the deamination of excess amino acids?
Which organ produces urea from the deamination of excess amino acids?
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What is the primary role of NAD and FAD in cellular respiration?
What is the primary role of NAD and FAD in cellular respiration?
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What type of feedback loop is crucial for maintaining homeostasis?
What type of feedback loop is crucial for maintaining homeostasis?
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During lactate fermentation in mammals, what is produced from one molecule of glucose?
During lactate fermentation in mammals, what is produced from one molecule of glucose?
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What happens when oxygen is unavailable during cellular respiration?
What happens when oxygen is unavailable during cellular respiration?
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What is the main result of ethanol fermentation in yeast?
What is the main result of ethanol fermentation in yeast?
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Why does aerobic respiration yield more energy compared to anaerobic respiration?
Why does aerobic respiration yield more energy compared to anaerobic respiration?
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Which redox indicator can change color as it undergoes reduction during investigations of yeast respiration?
Which redox indicator can change color as it undergoes reduction during investigations of yeast respiration?
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In lactate fermentation, what can lactate be converted into if oxygen becomes available?
In lactate fermentation, what can lactate be converted into if oxygen becomes available?
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What is the main disadvantage of anaerobic respiration?
What is the main disadvantage of anaerobic respiration?
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What is a limiting factor in photosynthesis?
What is a limiting factor in photosynthesis?
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When light intensity is low, which factor typically becomes the limiting factor?
When light intensity is low, which factor typically becomes the limiting factor?
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What happens to the rate of photosynthesis when carbon dioxide concentration increases?
What happens to the rate of photosynthesis when carbon dioxide concentration increases?
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What occurs to the photosynthesis rate when temperature exceeds the optimum level?
What occurs to the photosynthesis rate when temperature exceeds the optimum level?
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At which temperature range does photosynthesis operate most efficiently for most plants?
At which temperature range does photosynthesis operate most efficiently for most plants?
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As light intensity increases, when does the rate of photosynthesis begin to level off?
As light intensity increases, when does the rate of photosynthesis begin to level off?
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Which of the following factors does NOT typically limit photosynthesis?
Which of the following factors does NOT typically limit photosynthesis?
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Which observation would indicate that temperature is the current limiting factor in photosynthesis?
Which observation would indicate that temperature is the current limiting factor in photosynthesis?
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What is the main difference between cyclic photophosphorylation and non-cyclic photophosphorylation?
What is the main difference between cyclic photophosphorylation and non-cyclic photophosphorylation?
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What process is driven by the proton gradient created during photophosphorylation?
What process is driven by the proton gradient created during photophosphorylation?
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Which statement accurately describes the light-dependent reactions of photosynthesis?
Which statement accurately describes the light-dependent reactions of photosynthesis?
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What is the role of GP (glycerate-3-phosphate) in the Calvin cycle?
What is the role of GP (glycerate-3-phosphate) in the Calvin cycle?
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During the light-dependent reactions, what happens to the excited electrons?
During the light-dependent reactions, what happens to the excited electrons?
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What defines a limiting factor in the process of photosynthesis?
What defines a limiting factor in the process of photosynthesis?
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What is produced when protons flow back into the stroma through ATP synthase?
What is produced when protons flow back into the stroma through ATP synthase?
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Which statement is true about the outcomes of non-cyclic photophosphorylation?
Which statement is true about the outcomes of non-cyclic photophosphorylation?
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Study Notes
The need for energy in living organisms
- Living organisms require energy for various functions, including:
- Movement: muscle cell contraction and vesicle transport
- Active Transport: sodium-potassium pump and transport of H+ during stomatal opening
- Anabolic reactions: DNA replication and protein synthesis
Features of ATP as the universal energy currency
- ATP is easily hydrolyzed, releasing a useful quantity of energy
- ATP is relatively stable under normal cellular pH conditions
ATP synthesis
- Substrate-linked phosphorylation: ATP synthesis using energy directly from another chemical reaction, like glycolysis and the Krebs cycle
- Chemiosmosis: ATP synthesis across the inner membrane of mitochondria and chloroplasts, using energy from the movement of hydrogen ions (protons) down their concentration gradient. This occurs during oxidative phosphorylation and the light-dependent reactions of photosynthesis.
Relative energy values of carbohydrates, lipids, and proteins
- Different substrates have different amounts of hydrogen atoms.
- Hydrogen atoms play a crucial role in chemiosmosis, where they are used to produce ATP.
- A higher number of hydrogen atoms in a substrate leads to more energy production.
Stages of aerobic respiration
- Glycolysis: cytoplasm
- Link reaction: matrix of mitochondria
- Krebs cycle: matrix of mitochondria
- Oxidative phosphorylation: inner membrane of mitochondria (cristae)
NAD and FAD in respiration
- NAD and FAD are key for transferring hydrogen atoms (protons and electrons) from metabolic reactions to the electron transport chain in the inner mitochondrial membrane.
- This transfer facilitates ATP production through oxidative phosphorylation.
Oxidative phosphorylation
- The process of generating ATP using the energy released from the movement of electrons in the electron transport chain.
- Electrons are passed from molecule to molecule releasing energy.
- This energy is used to pump protons across the inner mitochondrial membrane, creating a proton gradient.
- Protons flow back across the membrane through ATP synthase, driving ATP production.
Anaerobic respiration
- Occurs in the absence of oxygen.
Lactate fermentation in Mammals
- Site: cytoplasm
- Yield for 1 glucose molecule: 2 ATP and lactate.
- Lactate can be converted back to pyruvate when oxygen becomes available.
Ethanol fermentation in Yeast
- Site: cytoplasm
- Yield for 1 glucose molecule: 2 ATP, ethanol, and CO₂
Energy yield from aerobic vs anaerobic respiration
- Aerobic respiration generates significantly more ATP than anaerobic respiration because it utilizes both glycolysis and oxidative phosphorylation.
- Anaerobic respiration only uses glycolysis, producing only 2 ATP molecules.
- In the absence of oxygen, the link reaction, Krebs cycle, and electron transport chain are shut down; NAD is not regenerated.
Investigations using redox indicators
- Redox indicators like DCPIP and methylene blue change color when they undergo reduction.
- They can be used to determine the rate of respiration in yeast by observing the rate of color change due to the reduction of the indicator.
- The factors that affect the rate of respiration, such as temperature and substrate concentration, can be investigated using these indicators.
Cyclic photophosphorylation
- This is a process in photosynthesis where electrons are cycled back to PSI instead of being used to reduce NADP+.
- Occurs when light intensity is low.
- It generates ATP but does not produce NADPH or oxygen.
Photophosphorylation
- Light energy excites electrons in chlorophyll and other photosynthetic pigments.
- Excited electrons move through an electron transport chain releasing energy.
- Energy released pumps protons across the thylakoid membrane, creating a proton gradient.
- Proton gradient drives ATP synthesis through ATP synthase, a process called chemiosmosis.
- NADP is reduced to NADPH.
Calvin cycle
- Occurs in the stroma of chloroplasts.
- Carbon fixation: CO₂ is incorporated into an organic molecule.
- Reduction: carbon compounds are reduced using energy from NADPH and ATP.
- Regeneration: RuBP is regenerated for continuous carbon fixation.
Calvin cycle intermediates
- GP (glycerate-3-phosphate) is used to produce some amino acids.
- TP (triose phosphate) is used to produce carbohydrates, lipids, and amino acids.
Limiting factors of photosynthesis
- Light intensity: Photosynthesis is limited by light intensity at low levels.
- Carbon dioxide concentration: Photosynthesis is limited by CO₂ level at higher light intensities.
- Temperature: Photosynthesis is limited by temperature at optimal levels.
Effects of changes in limiting factors on photosynthesis
- Light intensity: Increasing light intensity increases the rate of photosynthesis up to a certain point, beyond which the rate levels off.
- CO₂ concentration: Increasing CO₂ concentration increases the rate of photosynthesis up to a maximum rate.
- Temperature: Increasing temperature increases the rate of photosynthesis up to an optimum temperature, beyond which the rate declines.
Investigations using whole plants
- Light intensity: The rate of photosynthesis increases with increasing light intensity until other factors become limiting.
- CO₂ concentration: The rate of photosynthesis increases with increasing CO₂ concentration until CO₂ is no longer limiting.
- Temperature: The rate of photosynthesis increases with temperature up to an optimum temperature, beyond which the rate decreases due to enzyme denaturation.
Homeostasis
- Homeostasis is the maintenance of a relatively stable internal environment in living organisms.
- Importance for mammals: Maintaining a stable internal environment is crucial for optimal cell function and overall health.
- Control is achieved through regulating the composition of blood, which in turn influences the composition of tissue fluid.
- Key factors: Factors influencing homeostasis include temperature, pH, water potential, and glucose concentration of the tissue fluid.
Principles of Homeostasis
-
Stimuli: Changes in the internal or external environment that disrupt homeostasis.
- Internal stimuli: Changes within the body, e.g., blood glucose levels, body temperature.
- External stimuli: Changes outside the body, e.g., ambient temperature, oxygen availability.
- Receptors: Specialized cells or proteins that detect stimuli and send signals to a control center.
-
Coordination systems:
- Nervous system: Provides rapid responses via electrical signals to effectors.
- Endocrine system: Provides slower but longer-lasting responses by releasing hormones into the bloodstream.
- Effectors: Organs, tissues, or cells that carry out the response to restore homeostasis.
- Negative feedback: The key mechanism that restores homeostasis. Any deviation from the normal condition triggers a response that opposes or negates the initial change.
Urea production
- Urea is produced in the liver from the deamination of excess amino acids.
The structure of the human kidney
- The kidney is composed of the cortex, medulla, and pelvis.
- The functional unit of the kidney is the nephron.
Parts of a nephron
- Renal corpuscle: Bowman's capsule and glomerulus
- Proximal convoluted tubule (PCT): reabsorption of water, glucose, amino acids, and salts
- Loop of Henle: establishes a concentration gradient in the medulla
- Distal convoluted tubule (DCT): further reabsorption of water and salts, secretion of waste products
- Collecting duct: reabsorption of water, final concentration of urine
The formation of urine in the nephron
- Ultrafiltration: Filtration of small molecules from blood into Bowman's capsule, forming filtrate.
- Reabsorption: Selective reabsorption of useful substances from the filtrate back into the blood.
- Secretion: Active transport of waste products from the blood into the nephron.
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Description
Explore the vital role of energy in living organisms, focusing on ATP as the universal energy currency. This quiz covers the mechanisms of ATP synthesis, including substrate-level phosphorylation and chemiosmosis, essential for various biological functions. Test your understanding of how energy supports movement, active transport, and anabolic reactions.
