Biology Chapter 789 Questions Flashcards
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Questions and Answers

Discuss the importance of electrons in the transfer of energy in living systems.

The transfer of energy in the form of electrons allows the cell to transfer and use energy in an incremental fashion.

Explain how ATP is used by cells as an energy source.

ATP is able to power cellular processes by transferring a phosphate group to another molecule (a process called phosphorylation).

Describe the overall result in terms of molecules produced during the chemical breakdown of glucose by glycolysis.

There is a net gain of two ATP molecules during glycolysis.

Compare the output of glycolysis in terms of ATP molecules and NADH molecules produced.

<p>2 ATP, 2 NADH, and 2 pyruvates.</p> Signup and view all the answers

Explain how a circular pathway, such as the citric acid cycle, fundamentally differs from a linear biochemical pathway, such as glycolysis.

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Describe how pyruvate, the product of glycolysis, is prepared for entry into the citric acid cycle.

<p>Pyruvate is modified by removal of a carboxyl group followed by oxidation, and then attached to Coenzyme A.</p> Signup and view all the answers

Describe how electrons move through the electron transport chain and explain what happens to their energy levels during this process.

<p>Electrons go from a higher to a lower energy level and are ultimately passed to oxygen, forming water.</p> Signup and view all the answers

Explain how a proton (H+) gradient is established and maintained by the electron transport chain.

<p>There is a higher concentration of H+ ions in the inter-membrane space, maintaining a proton gradient.</p> Signup and view all the answers

Discuss the fundamental difference between anaerobic cellular respiration and fermentation.

<p>Fermentation uses glycolysis only, while anaerobic respiration uses all parts of cellular respiration, including the citric acid cycle.</p> Signup and view all the answers

Describe the type of fermentation that readily occurs in animal cells and the conditions that initiate that fermentation.

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Discuss the ways in which carbohydrate metabolic pathways, glycolysis, and the citric acid cycle interrelate with protein and lipid metabolic pathways.

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Explain why metabolic pathways are not considered closed systems.

<p>Many of the substrates, intermediates, and products are reactants in other pathways.</p> Signup and view all the answers

Describe how feedback inhibition would affect the production of an intermediate or product in a pathway.

<p>Binding of the end product to the allosteric site slows down or stops the enzyme's activity.</p> Signup and view all the answers

Identify the mechanism that controls the rate of the transport of electrons through the electron transport chain.

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Explain the significance of photosynthesis to other living organisms.

<p>Photosynthesis captures sunlight and converts it into chemical compounds that are essential for life.</p> Signup and view all the answers

Describe the main structures involved in photosynthesis.

<p>Photosynthesis takes place in chloroplasts, which contain chlorophyll.</p> Signup and view all the answers

Identify the substrates and products of photosynthesis.

<p>Photosynthesis requires sunlight, carbon dioxide, and water as substrates and produces oxygen and G3P.</p> Signup and view all the answers

Explain how plants absorb energy from sunlight.

<p>Plants use chlorophyll to capture light energy, converting water and carbon dioxide into glucose.</p> Signup and view all the answers

Describe short and long wavelengths of light.

<p>Short wavelengths are high energy, while long wavelengths are low energy.</p> Signup and view all the answers

Describe how and where photosynthesis takes place within a plant.

<p>Photosynthesis takes place in the mesophyll of the leaves inside the chloroplasts.</p> Signup and view all the answers

Describe the Calvin cycle.

<p>The Calvin cycle incorporates CO2 into organic molecules and converts it into carbohydrates.</p> Signup and view all the answers

Define carbon fixation.

<p>Carbon fixation is the incorporation of carbon dioxide into organic compounds.</p> Signup and view all the answers

Explain how photosynthesis works in the energy cycle of all living organisms.

<p>Photosynthesis combines sunlight, water, and carbon dioxide to produce sugar and oxygen.</p> Signup and view all the answers

Describe four types of signaling mechanisms found in multicellular organisms.

<p>Paracrine, endocrine, autocrine, and direct signaling across gap junctions.</p> Signup and view all the answers

Compare internal receptors with cell-surface receptors.

<p>Cell-surface receptors transmit a signal from outside the cell to the cytoplasm.</p> Signup and view all the answers

Recognize the relationship between a ligand's structure and its mechanism of action.

<p>When a ligand binds to the extracellular domain, it activates the enzyme.</p> Signup and view all the answers

Explain how the binding of a ligand initiates signal transduction throughout a cell.

<p>The activation of the receptor's intracellular components sets off a signaling pathway.</p> Signup and view all the answers

Recognize the role of phosphorylation in the transmission of intracellular signals.

<p>Phosphorylation regulates protein function and transmits signals throughout the cell.</p> Signup and view all the answers

Evaluate the role of second messengers in signal transmission.

<p>Second messengers help to spread a signal through the cytoplasm by altering the behavior of cellular proteins.</p> Signup and view all the answers

Describe how signaling pathways direct protein expression, cellular metabolism, and cell growth.

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Identify the function of PKC in signal transduction pathways.

<p>PKC mediates the cells' response to a stimulus from the plasma membrane to the nucleus.</p> Signup and view all the answers

Recognize the role of apoptosis in the development and maintenance of a healthy organism.

<p>Apoptosis removes cells during development and eliminates potentially harmful cells.</p> Signup and view all the answers

Describe how single-celled yeasts use cell signaling to communicate with one another.

<p>Yeast cells secrete a signal molecule called mating factor that attracts them to their mates.</p> Signup and view all the answers

Relate the role of quorum sensing to the ability of some bacteria to form biofilms.

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Study Notes

Energy Transfer in Living Systems

  • Electrons are crucial for energy transfer, enabling cells to utilize energy incrementally.
  • ATP provides energy through phosphorylation, transferring a phosphate group to molecules.

Glycolysis Overview

  • Glycolysis uses 2 ATP to split glucose, resulting in a net gain of 2 ATP after producing 4 ATP.
  • Produces 2 ATP, 2 NADH, and 2 pyruvate molecules.

Citric Acid Cycle vs. Glycolysis

  • The citric acid cycle operates as a circular pathway, while glycolysis is linear.
  • Pyruvate is transformed to enter the citric acid cycle by removing a carboxyl group and attaching Coenzyme A.

Electron Transport Chain Dynamics

  • Electrons descend energy levels in the electron transport chain, ultimately reducing oxygen to water.
  • Energy released creates a proton gradient across the inner mitochondrial membrane, driving ATP production via ATP synthase.
  • The inner mitochondrial membrane's impermeability to protons helps establish and maintain this gradient.

Cellular Respiration Types

  • Fermentation utilizes glycolysis only, while anaerobic respiration includes glycolysis, the citric acid cycle, and an alternative electron acceptor.

Metabolism Interconnectivity

  • Carbohydrate, protein, and lipid metabolic pathways are interconnected, sharing substrates and products across various reactions.
  • Metabolic pathways aren't closed systems; substrates and products are involved in multiple pathways.

Feedback Inhibition and Regulation

  • Feedback inhibition occurs when an end product binds to an enzyme’s allosteric site, reducing its activity to control production levels.

Photosynthesis and Its Importance

  • Photosynthesis is vital for all life forms; it converts sunlight into chemical energy stored in carbohydrates.
  • Chloroplasts, containing chlorophyll, are the sites of photosynthesis, using water and carbon dioxide to produce oxygen and energy-rich compounds like G3P.

Light and Photosynthesis

  • Chlorophyll A and B absorb light energy, converting it into a glucose synthesis process.
  • Short wavelengths = high energy (e.g., gamma rays); long wavelengths = low energy (e.g., radio waves).

Calvin Cycle and Carbon Fixation

  • The Calvin cycle occurs in the stroma, fixing CO2 into organic compounds with the aid of ATP and NADPH.
  • Carbon fixation literally refers to incorporating CO2 into organic materials.

Signaling Mechanisms in Multicellular Organisms

  • Types of signaling include paracrine, endocrine, autocrine, and direct signaling across gap junctions.
  • Internal receptors interact with ligands inside cells, whereas cell-surface receptors transmit signals from the exterior to the cytoplasm.

Signal Transduction and Cellular Response

  • Binding of a ligand activates intracellular signaling pathways, initiating a cascade of cellular reactions.
  • Phosphorylation regulates protein functions and signal transmission within the cell.
  • Second messengers amplify signals throughout the cytoplasm, modifying cellular responses.

Roles of Signal Pathways

  • Signal pathways regulate processes such as protein expression, metabolism, and cellular growth.
  • Protein Kinase C (PKC) facilitates cellular responses by conveying signals from the plasma membrane to the nucleus.

Apoptosis and Health Maintenance

  • Apoptosis eliminates unnecessary or harmful cells, supporting development and maintaining organismal health.

Yeast Cell Communication

  • Yeast utilize mating factors as signaling molecules to attract mates, showcasing simple yet effective cell signaling mechanisms.

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Description

Test your knowledge on the role of electrons and ATP in energy transfer within living systems. This quiz includes essential concepts surrounding cellular processes and energy usage. Perfect for biology students looking to reinforce their understanding of cellular energy dynamics.

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