Lipids and membranes Flashcards
Describe a significant structural component of membrane lipds
AMPHIPHILIC
hydrophilic and hydrophobic- fatty acids elements
What is the morphology of lipid in aqueous media?
Closed sheets (spheres)
What are saturated and unsaturated fatty acids?
Saturated- No double bond in chain
Unsaturated- double bond in chain
What are essential and non essential fatty acids?
Give examples
Functions in the body?
Essential- Body needs them for homeostasis- we can not make them- no desaturase enzymes
- alpha-linolenic acid (an omega-3 fatty acid)
- linoleic acid (an omega-6 fatty acid)
Non essential- Made in body from food, e.g. Oleic acid- fats and oils
Both are needed for of cell membranes integrity, nervous system function, vision, cognition and memory
Difference beween cis and trans fatty acids? How are fatty acids stored?
Cis- cis-double bonds place a kink in the linear structure of the fatty acid chain- lowes melting point
Stored as triglycerides
Use of fatty acids for paracrines?
Essentail fatty acids, using the enzyme elongases dehydrogenases -produces arachoid acid and eicosapentaenoic acid
These are auto and paracrine molecules used for inflamation, pain and fever
Lipid membrane formation- Describe the structure
Polar heads- like water
Hydrophobic tails- hate water
- Lipid bilayers tend to close in on themselves.
- ## Lipid bilayers are self-sealing because a hole in a bilayer is energetically unfavourable.
What is Cholesterol?
A steroid built from four linked hydrocarbon rings. A hydrocarbon tail is linked to the steroid at one end and a hydroxyl group at the other.
Function of Cholesterol in the membrane
key regulator of membrane fluidity
The different shape of cholesterol compared with that of phospholipids disrupts the regular interactions between fatty acid chains. Cholesterol acts as a buffer and maintains the fluidity of cell membranes depending on the lipid it interacts with.
What is Cholesterol a precursor for?
steroid hormones (cortisol and aldosterone), sex hormones (progesterone, oestrogen and testosterone), vitamin D (for skin), and the bile acids (for gall bladder and liver
