2A: Assemblies of molecules, cells and groups of cells within single cellular and multicellular organisms Flashcards Preview

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Flashcards in 2A: Assemblies of molecules, cells and groups of cells within single cellular and multicellular organisms Deck (82)
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Plasma Membrane

Functions to contain the cell structures and protects them from the environment

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Plasma Membrane

Functions to contain the cell structures and protects them from the environment

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Composition of Plasma Membrane

Phospholipid Bilayer that can reseal and repair itself if a small portion is removed;
Interior = hydrophobic, nonpolar molecules like CO2 or O2 or Steroid Hormones can easily cross
Exterior = hydrophilic

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How does water cross the plasma membrane?

Water passes through aquaporins in order to get through the membrane since its polar

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How do ions, carbohydrates and amino acids get through the membrane?

They utilize special channels or transport proteins

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Channel Proteins

Selective to certain ions/molecules that need to cross the membrane

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How do ions, carbohydrates and amino acids get through the membrane?

They utilize special channels or transport proteins

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Fluid Mosaic Model

Accounts for the presence of lipids, proteins and carbohydrates in a dynamic, semisolid plasma membrane that surrounds cells

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Phospholipid Bilayer

Contains proteins embedded within the plasma membrane

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Phospholipid Bilayer

Contains proteins embedded within the plasma membrane

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Membrane Dynamics

The free movement of lipids forming lipid rafts, Flippases that maintain bidirectional transport of lipids between the two layers of the phospholipid bilayer

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Movement of Protein & Carbohydrates

Move within the membrane but are slowed by their relatively large size

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Movement of Protein & Carbohydrates

Move within the membrane but are slowed by their relatively large size

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Movement of Protein & Carbohydrates

Move within the membrane but are slowed by their relatively large size

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Membrane Components [Lipids]

Triacylglycerols & Free Fatty Acids
Glycerophospholipids
Cholesterol
Waxes

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TAG & FFA

Act as phospholipid precursors and are found in low levels in the membrane

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Cholesterol

Present in large amounts and contributes to membrane fluidity and stability

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Waxes

They function in waterproofing and defense

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Waxes

They function in waterproofing and defense

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Function of Proteins in the Cell Membrane

Transports, Cell Adhesion Molecules and Enzymes

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Transmembrane Proteins

Can have one or more hydrophobic domains and are most likely to function as receptors or channels

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Embedded Proteins

Usually part of a catalytic complex or involved in cellular communication

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Embedded Proteins

Usually part of a catalytic complex or involved in cellular communication

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Membrane-Associated Proteins

Act as recognition molecules or enzymes

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Glycoprotein Coat

Carbohydrates that form a protective coat and functions in cell recognition

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Glycoprotein Coat

Carbohydrates that form a protective coat and functions in cell recognition

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Cell-Cell Junctions

Regulate transport intracellularly and intercellularly;

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Types of Cell-Cell Junctions

Gap Junctions, Tight Junctions, Desmosomes and Hemidesmosomes

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Types of Cell-Cell Junctions

Gap Junctions, Tight Junctions, Desmosomes and Hemidesmosomes

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Dominance of Biomolecules in the Lipid Membrane

Lipids > Proteins > Carbohydrates > Nucleic Acids