Questions and Answers
What is diffusion?
What is osmosis?
What happens to your fingers after sitting in the bathtub for hours?
They start to look like prunes
What is the primary function of a phospholipid bilayer?
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The cell membrane is ____ permeable.
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What does 'semi-permeable' mean?
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Diffusion causes particles to move from ____ to ____ concentration.
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Does a cell use energy when molecules diffuse in or out of the cell down the concentration gradient?
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_____ requires energy to transport molecules against a concentration gradient.
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In ____ and ______ no energy is used.
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What needs a helper to get things across?
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What does concentration refer to?
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What does diffusion do?
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What does osmosis do?
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What type of membrane allows some substances through?
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Study Notes
Diffusion
- Process where particles move from an area of high concentration to an area of low concentration.
- Examples include odors traveling in the air and oxygen diffusing from lungs into the blood.
- Occurs without the use of energy, following the concentration gradient.
Osmosis
- Special case of diffusion focused on water molecules.
- Water moves across a semi-permeable membrane from an area of lower solute concentration to higher solute concentration.
- Examples include the wrinkling of fingers after prolonged water exposure and the effects of salt on slugs and swollen throat cells.
Phospholipid Bilayer
- The fundamental structure of the cell membrane, composed of two layers of phospholipids.
- Functions as a barrier to control substance entry and exit.
Semi-permeable Membrane
- Cell membranes are selectively permeable, allowing certain substances to pass while blocking others.
- This characteristic is vital for maintaining cellular homeostasis.
Concentration Gradient
- Diffusion is guided by the concentration gradient, moving from areas of high concentration to low concentration.
- Facilitated diffusion also applies to particles needing assistance for transport across the membrane.
Active Transport
- Requires energy to move molecules against their concentration gradient.
- Critical for maintaining necessary concentrations of ions and nutrients within cells.
Key Definitions
- Facilitated Diffusion: Requires assistance (like transport proteins) to move substances across the membrane.
- Concentration: Refers to the amount of a substance within a given area.
Functions
- Diffusion: Essential for moving critical substances, such as oxygen, into cells.
- Osmosis: Vital for regulating water levels and maintaining cell integrity.
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Test your understanding of diffusion and osmosis with these flashcards designed to illustrate key concepts through relatable scenarios. Each card presents a term followed by a definition that connects the scientific principle to everyday experiences.
