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Questions and Answers
What feature of alveoli contributes to efficient gas exchange?
What feature of alveoli contributes to efficient gas exchange?
How do fish gills enhance the efficiency of gas exchange?
How do fish gills enhance the efficiency of gas exchange?
What characteristic of the diffusion pathway across an exchange surface aids in efficient transport?
What characteristic of the diffusion pathway across an exchange surface aids in efficient transport?
What is the role of the circulatory system related to gas exchange in mammals?
What is the role of the circulatory system related to gas exchange in mammals?
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What happens to the surface area : volume ratio as body size increases?
What happens to the surface area : volume ratio as body size increases?
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What characteristic of the fluid mosaic model allows phospholipids to move within the bilayer?
What characteristic of the fluid mosaic model allows phospholipids to move within the bilayer?
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Which of the following statements accurately describes the movement of phospholipids in the membrane?
Which of the following statements accurately describes the movement of phospholipids in the membrane?
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What type of molecules can pass through the phospholipid bilayer without needing assistance?
What type of molecules can pass through the phospholipid bilayer without needing assistance?
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What was one major flaw in the Gorter and Grendel model of membrane structure?
What was one major flaw in the Gorter and Grendel model of membrane structure?
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What significant contribution did Singer and Nicolson make to cell membrane understanding?
What significant contribution did Singer and Nicolson make to cell membrane understanding?
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Why did the Davson and Danielli model of the membrane face criticism?
Why did the Davson and Danielli model of the membrane face criticism?
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What does the phrase 'partially permeable' imply about the cell membrane?
What does the phrase 'partially permeable' imply about the cell membrane?
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What do the terms 'peripheral' and 'integral' refer to in the context of membrane proteins?
What do the terms 'peripheral' and 'integral' refer to in the context of membrane proteins?
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What evidence supported the fluid mosaic model as the best representation of membrane structure?
What evidence supported the fluid mosaic model as the best representation of membrane structure?
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The main role of channel and carrier proteins in the cell membrane is to:
The main role of channel and carrier proteins in the cell membrane is to:
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What is the primary method by which gas exchange occurs?
What is the primary method by which gas exchange occurs?
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As an organism increases in size, what happens to its surface area to volume ratio?
As an organism increases in size, what happens to its surface area to volume ratio?
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Why do single-celled organisms effectively exchange gases?
Why do single-celled organisms effectively exchange gases?
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What is the consequence of having a lower surface area to volume ratio in larger organisms?
What is the consequence of having a lower surface area to volume ratio in larger organisms?
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Which adaptation helps large multicellular organisms facilitate gas exchange?
Which adaptation helps large multicellular organisms facilitate gas exchange?
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What is the relationship between diffusion distance and cell size in larger organisms?
What is the relationship between diffusion distance and cell size in larger organisms?
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How does aerobic respiration affect gas exchange requirements?
How does aerobic respiration affect gas exchange requirements?
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What defines an organism's surface area to volume ratio?
What defines an organism's surface area to volume ratio?
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What component forms the hydrophilic part of a phospholipid?
What component forms the hydrophilic part of a phospholipid?
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What is the primary role of cholesterol in cell membranes?
What is the primary role of cholesterol in cell membranes?
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Which type of protein is embedded within the phospholipid bilayer?
Which type of protein is embedded within the phospholipid bilayer?
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What characterizes the tails of a phospholipid?
What characterizes the tails of a phospholipid?
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What is the term for the double-layered structure formed by phospholipids?
What is the term for the double-layered structure formed by phospholipids?
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What function do glycolipids and glycoproteins serve on the cell surface?
What function do glycolipids and glycoproteins serve on the cell surface?
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How do intrinsic proteins differ from extrinsic proteins?
How do intrinsic proteins differ from extrinsic proteins?
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Why are membranes without cholesterol likely to break down?
Why are membranes without cholesterol likely to break down?
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What happens to the rate of diffusion if the thickness of the membrane is halved?
What happens to the rate of diffusion if the thickness of the membrane is halved?
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Which component of Fick's Law represents the difference in concentration between two areas?
Which component of Fick's Law represents the difference in concentration between two areas?
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What is the primary role of the lungs in gas exchange?
What is the primary role of the lungs in gas exchange?
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Which feature of the trachea helps prevent airflow obstruction?
Which feature of the trachea helps prevent airflow obstruction?
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What type of epithelium forms the walls of the alveoli?
What type of epithelium forms the walls of the alveoli?
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The bronchi have a structural difference compared to the trachea, what is it?
The bronchi have a structural difference compared to the trachea, what is it?
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What is the purpose of the layer of moisture lining the alveoli?
What is the purpose of the layer of moisture lining the alveoli?
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Which of the following statements about bronchioles is false?
Which of the following statements about bronchioles is false?
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How do alveoli contribute to the efficiency of gas exchange?
How do alveoli contribute to the efficiency of gas exchange?
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Study Notes
Gas Exchange Surfaces
- Organisms exchange gases for aerobic respiration (O₂ intake, CO₂ output) and photosynthesis (CO₂ intake, O₂ output).
- Gas exchange occurs via diffusion across exchange surfaces.
- Exchange surfaces have high SA:V ratios for efficient exchange.
- SA:V ratio decreases with increasing organism size.
- Single-celled organisms have high SA:V, allowing efficient diffusion-based exchange.
- Multicellular organisms have adaptations like alveoli (lungs), lamellae (fish gills), and spongy mesophyll (leaves) to increase surface area.
- Diffusion pathway is minimized by a single layer of flattened epithelial cells.
- Diffusion rate depends on the concentration gradient between exchange surfaces and environment.
- Maintaining a concentration gradient relies on movement of substances, e.g. ventilation systems, blood flow in alveoli.
- Fick's Law of Diffusion: Rate ∝ (SA x ΔC) / thickness.
Fick's Law of Diffusion Equation
- Rate = P x A x ((C₁ - C₂) / T)
- P = permeability constant
- A = surface area
- C₁ - C₂ = concentration difference
- T = thickness of membrane
Lungs and Gas Exchange
- Lungs maximize gas exchange, minimizing water loss in air-breathing animals.
- Located in the thorax (chest cavity).
- Air enters trachea, branching into bronchi & bronchioles, ending in alveoli.
- Trachea has C-shaped cartilage rings to prevent collapse and for flexibility during swallowing.
- Trachea and bronchi have mucus and cilia to trap and remove dust & pathogens.
- Bronchioles have smooth muscle for adjusting airflow.
- Alveoli have a single layer of squamous epithelium for rapid diffusion.
- Alveoli surrounded by capillaries for efficient gas exchange (O₂ in, CO₂ out).
- Moist surface in alveoli allows gas exchange in solution.
Cell Membranes
- Membranes are vital for all cells.
- The cell surface membrane separates the interior from exterior.
- Membranes control substance exchange.
- Phospholipid bilayer forms the basic membrane structure.
- Phospholipid composed of glycerol, phosphate head (hydrophilic), and fatty acid tails (hydrophobic).
- Bilayer forms due to hydrophilic/hydrophobic interactions with water.
- Membrane proteins (intrinsic/extrinsic): transport & communication.
- Cholesterol regulates membrane fluidity and stability.
- Glycolipids and glycoproteins aid cell-to-cell communication and recognition (e.g. blood groups).
- The fluid mosaic model describes the dynamic nature of membrane components.
- Membranes are selectively permeable, allowing some molecules to pass more readily than others.
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Description
This quiz covers the mechanisms of gas exchange in organisms, including the role of diffusion and the significance of surface area to volume ratios. Explore the adaptations of multicellular organisms and the application of Fick's Law of Diffusion in understanding respiratory efficiency. Test your knowledge on how different structures facilitate gas exchange in various organisms.
