Lipids - 3.5 - (4) Flashcards
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What are sterols or steroid alcohols?
they are another type of lipid found in cells
What are sterols not like?
fats and oils and they have little in common with them structurally
What kind of molecules are sterols?
they are complex alcohol molecules which are based on a four carbon ring structure with a hydroxyl group at one end
Like phospholipids, what do sterols have?
they have dual hydrophilic/hydrophobic characteristics
In sterols, what is the hydroxyl group?
polar and so it is therefore hydrophilic and the rest of the molecule is hydrophobic
What is cholestrol?
it is a sterol
Where in the body is cholesterol manufactured?
primarily in the liver and intestines
What does cholesterol have an important role in?
in the formation of cell membranes, becoming positioned between the phospholipids with the hydroxyl group at the periphery of the membrane
What does cholesterol add stability to?
cell membranes and it regulates their fluidity by keeping membranes fluid at low temperatures and stopping them becoming too fluid at high temperatures
What is vitamin D, steroid hormones, and bile all manufactured using?
cholesterol
Due to their non-polar nature, what do lipids have?
many biological roles
What are some of the biological roles of lipids?
- membrane formation and the creation of hydrophobic barriers
- hormone production
- electrical insulation necessary for impulse transmission
- waterproofing, for example in birds feathers and on plant leaves
What do lipids, in particular triglycerides, have an important role in?
long-term energy storage
Where are lipids, triglycerides, stored under?
the skin and around vital organs
What does lipids, triglycerides, provide under the skin?
thermal insulation to reduce heat loss, for example in penguins
