Lipids 🛢️ Flashcards
Are lipids polar?
Non-polar molecules: electrons more evenly distributed.
No positive or negative areas in the molecules.
Lipids = insoluble.
Describe the structure of a fatty acid?
Contains a carboxyl group and a methyl group with a hydro carbon chain.
What is a saturated molecule?
Single C-C bond
Fatty acids tails = straight = tightly packed
Solid animal fats.
What is an unsaturated molecule?
Double C-C bond
Chain is ‘kinked’.
Lipids more fluid –> oils.
What is a triglyceride?
1 glycerol and 3 fatty acids.
Macromolecule as it is made up from different sub units.
Excellent energy storage molecule.
Why are triglycerides good energy storage molecules?
Glycerol can be converted into glucose.
Lots of chemical energy in the C=C and hydrogen bonds.
How are triglycerides formed?
Esterification
3 separate condensation reactions
Joined together by an ester bond.
3 H2O molecules are the end product.
What are lipoproteins?
Transport fat droplets throughout the body.
What are some functions of triglycerides?
Thermal insulation to reduce heat loss.
Cushioning to protect vital organs such as heart/kidneys.
Buoyancy for aquatic animals like whales.
Electrical insulation- myelin sheath.
What is a phospholipid?
Triglyceride:
Negative phosphate head = hydrophilic
Tail = hydrophobic (repels water)
Hydrophilic tail makes phospholipids arrange themselves in a bilayer.
Prevents water soluble substances from diffusing across the membrane.
What is cholesterol?
Hydrocarbon ring structure with a polar OH group.
What is the function of cholesterol?
How does its structure help carry out its function?
Strengthen cell membranes.
Small and flat shaped which allows it to pack between the phospholipid tail making the bilayer more/less rigid.
Decreases fluidity of the membrane.
Other functions of cholesterol?
Starting metabolite to form bile.
Synthesis of vitamin D.
Used in the formation of steroid hormones.
