BIOL380 Week 4 Cell Membranes

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What are Cell Membranes comprised of?

Phospholipids
What 3 things comprise Phospholipids?
- Glycerol Backbone
- Phosphate Head with or without other polar groups
- Two Fatty Acid Chains
What comprise the Polar (Hydrophilic) Head Group of the Phosphoilpid?
- Choline
- Phosphate
- Glycerol
What factors increase Fluidity of the Membrane?
- Short Fatty Acid Chains
- Double Bonds in Fatty Acid Chains
- High cholesterol that prevents Hydrocarbon Chains from interacting
- Cholesterol Present with Low temperatures
- Few Lipid Rafts
What are Lipid Rafts also known as?

Microdomains
Lipid Rafts have high concentrations of what?

Cholesterol
What is special about the Fatty Acid Chains of the Lipid Rafts?

Lipid Raft Fatty Acid Chains are longer and straighter than in other parts of the membrane.
Rafts are thicker or thinner than other parts of the membrane?

Thicker
What are the Phospholipids that are primarily expressd on extracellular face of the membrane?
- Phosphatidychoine
- Sphingomyelin
What are the Phospholipids primarily expressed on the intracellular face of the membrane?
- Phosphatidylethanolamine
- Phosphatidylserine
What are the two types of Proteins within the Membrane?
- Integral Proteins
- Peripheral Proteins
Which of the Protein types (Integral or Peripheral) cannot easily be separated from the membrane? Which can?

Integral cannot be separated easily; Peripheral can.
What are the functions of Carbohydrates in the membrane?
- Protects the cell surface from chemical & mechanical damage
- Gives the cell a lubricated surface for migrating cells
- Cell Recognition
- Cell Adhesion
What are the two types of Cell Walls?
- Primary Cell Wall
- Secondary Cell Wall
When is the Secondary Cell Wall present?

When Cell Growth stops
The composition of the Secondary Cell Wall is similar to the primary Cell Wall but what can be different?

The Secondary Cell Wall may have additional components such as LIGNIN (network of phenol compounds)
What is the Secondary Cell Wall primarily made up of and what is the significance?

Carbohydrates; the significance of this is because Carbohydrates are typically found on the extracellular membrane of most cells.
What are 3 Cell Wall components?
- Cellulose Microfibrils
- Cross-Linked Glycans
- Pectins
What are Cellulose Microfibrils, what do they provide, and how are they arranged?
- Linear chains of Glucose molecules
- Provide tensile strength (comparable to steel)
- Sets of microfibrils are arranged in layers
What are Cross-Linking Glycans and what do they do?
- Branched polysaccharides; linear backbone of one type sugar with short chains of other sugars.
- Connects cellulose microfibrils to each other.
What are Pectins and what do they do?
- Pectins are gelatin-like substance that could be either more fluid or more solid.
- They resist compression or smushing.
What is Turgor Pressure?

The force that constantly pushes against the inside of the Cell Wall

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Geo

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BIOL380 Week 4 Cell Membranes

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BIOL380 Week 4 Cell Membranes

Updated

2011-09-29T04:36:53Z

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