Questions and Answers
What are the parts of a phospholipid? Are they polar or nonpolar?
Phospholipids consist of a glycerol molecule, two fatty acids, and a phosphate group; the phosphate group is polar (hydrophilic) and the fatty acid chains are nonpolar (hydrophobic).
How do phospholipids arrange themselves in groups around oil? Around water?
In water, phospholipids arrange with their hydrophobic tails facing each other and their hydrophilic heads facing out.
Where will polar molecules attach to the phospholipids?
Polar molecules attach to the hydrophilic regions of phospholipids that form hydrogen bonds with water.
Where will nonpolar molecules attach to the phospholipids?
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The ______ is attracted to water while the ______ is repelled by water.
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What are the differences between eukaryotic and prokaryotic cells?
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What similarities do eukaryotic and prokaryotic cells share?
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What is a unicellular organism?
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What is a multicellular organism?
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What is a virus?
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How does a virus compare to a cell?
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What parts do all cells have?
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What are cell membranes made of?
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What does 'aqueous' mean?
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What does 'intracellular' refer to?
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What is 'extracellular'?
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What is the fluid mosaic model?
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What do the different parts of cell membranes do?
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How do large, polar molecules cross the cell membrane?
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How do large nonpolar molecules cross the cell membrane?
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How do small, polar molecules cross the cell membrane?
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Study Notes
Phospholipids
- Composed of glycerol, two fatty acids, and a phosphate group modified by an alcohol.
- Phosphate group acts as a negatively-charged, polar hydrophilic head, while fatty acid chains represent uncharged, nonpolar hydrophobic tails.
Arrangement in Solutions
- In aqueous solutions, phospholipids arrange with hydrophobic tails facing inward and hydrophilic heads facing outward.
Polar Molecule Interactions
- Hydrophilic regions of phospholipids form hydrogen bonds with water and other polar molecules, present on both the exterior and interior of the cell.
Nonpolar Molecule Interactions
- Nonpolar molecules cluster together, interacting with each other while generally avoiding polar molecules. The hydrophilic heads maintain contact with water, ensuring cell membrane surfaces remain hydrophilic.
Hydrophobic and Hydrophilic Characteristics
- The “head” of the phospholipid is water-attracting (hydrophilic), whereas the “tail” is water-repelling (hydrophobic).
Eukaryotic Cells
- Feature larger ribosomes, possess membrane-bound nuclei, and can be unicellular or multicellular.
Prokaryotic Cells
- Lack a nucleus, contain smaller ribosomes, and are typically unicellular.
Similarities Between Eukaryotic and Prokaryotic Cells
- Both have a lipid bilayer and use DNA for genetic information.
Unicellular Organisms
- Composed of a single cell and include bacteria and protists.
Multicellular Organisms
- Includes plants, animals, and fungi.
Viruses
- Consist of genetic material (DNA or RNA) encased in a protein coat; cannot replicate independently and are significantly smaller than cells.
Comparison of Cells and Viruses
- Cells contain double-stranded DNA and multiple strands of RNA, while viruses may possess varied forms of genetic material.
Fundamental Parts of All Cells
- All cells consist of three main components: the cell membrane, nucleus, and cytoplasm.
Composition of Cell Membranes
- Made primarily of glycerophospholipids, which include glycerol, phosphate groups, and fatty acid chains.
Aquaeous Definition
- Refers to a water-based environment.
Intracellular vs. Extracellular
- Intracellular indicates the inside of the cell, while extracellular refers to the outside.
Fluid Mosaic Model
- Describes cell membrane structure as a fluid mix of phospholipids, cholesterol, and proteins with carbohydrates extending from surfaces.
Functions of Cell Membrane Components
- Protect intracellular contents, protect against the external environment, and regulate material entry and exit from the cell.
Transport of Large, Polar Molecules
- Due to their charge and size, large polar molecules require assistance to cross the nonpolar phospholipid bilayer.
Transport of Large Nonpolar Molecules
- Can slowly pass through the membrane, but the process is gradual.
Transport of Small, Polar Molecules
- Small polar molecules can typically cross membranes more readily, though specific details were not disclosed.
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Description
Test your knowledge on the structure and behavior of phospholipids with these flashcards. Learn how these molecules are composed and how they arrange themselves in various environments such as oil and water. This quiz is perfect for students studying cell biology or biochemistry.