Lipids Flashcards
What are the structural characteristics of lipids?
What are the functional characteristics of lipids?
Active:
-Pigments
-Hormones
What are fatty acids?
What is the nomenclature for fatty acids?
Describe fatty acid structure
What fatty acids are of nutritional importance?
What is triacylglycerol?
Why are fats key molecules for long term energy storage?
What is saponification?
What are waxes and their function?
Explain structural lipids in membranes
What are glycerophospholipids?
Draw the structure of Phosphatidylinositol and what is its function?
involved in intracellular signal transduction
What are galactolipids and sulpholipids?
What are sphingolipids?
Describe archaebacteria (extremophiles)
What are sterols?
What is cholesterol?
Draw the structure of DAG and IP3
How does Phophatidylinositol Act as an intracellular signal?
What are steroid hormones?
-Hydrohpobic oxidized sterol derivaties
-carried through bloodstream by carrier proteins
-pass through plasma membrane to bind receptors in the nucleus
-alter patters of gene expression and metabolism
-precurson to hormones (signalling)
What are characteristics of vitamins A,D,E,K
-All contain rings and long, aliphatic side chains
-All are highly hydrophobic
-differ widely in their functions
Describe vitamin D
-Regulates Ca2+ uptake and deposition
-Can be obtained from the diet or produced endogenously
-Endogenous production occurs in a series of reactions, one of which requires UV light
-Insufficient vitamin D is associated with skeletal defects (rickets)
-Excessive vitamin D can cause calcification of soft tissues
describe vitamin A
-Obtained from liver, egg yolks, and milk products
-Some animals have sufficient vitamin A in their livers to present a danger to humans if they were to consume them
-vitamin A exists in 3 forms: Alcoho (retinol), aldehyde and retinoic acid
-Retinal (aldehyde) is a light-sensitive compound with a role in vision. Deficiency causes night blindness
-“red eye” in photos results from retinal
Describe vitamin E (a-tocopherol)
-A reducing reagent that scavenges oxygen free radicals
-may prevent damage to fatty acids in membranes
-Often used as an additive in cosmetics
-deficiency causes scaly skin, muscular weakness and sterility
What are the common carbon chain lengths of fatty acids in plants and animals?
16-18 (most common)
20-22 (nutrients such as omegas)
What does unsaturated fatty acid mean?
1 or more double bonds
What are delta vs omega nomenclatures of unsaturated fatty acids?
Delta: COOH end
Omega: CH3 end
Are C=C double bonds commonly in cis or trans configuration? Why is it important?
Cis: Makes a structural kink change
Why do animal fat and plant oil look and feel so different while they are all tracylglycerols?
Cis double bonds found it plant oil make kinks that don’t allow for tight packing that makes the gel like structure in animal fats
Why are omega-3 fatty acids such as DHA branded as nutrional supplements?
-The body cannot make omega 3 or 6 fatty acids, must come from food
-Abundant in brain and spinal chord
To form micelles, do we need a polar group in addition to the hydrophobic tail?
Yes, need hydrophilic head to maintain structure of biological membranes
Which one has higher energy stored in one gram: sugar or fat, and why?
Fat, has a low oxidation state that burns more efficiently and a low hydration state that limit water interaction and are a more compact, dehydrated energy storage form
In biological membranes, how many long hydrophobic tails does a membrane-forming lipid molecule have?
Two hydrophobic tails per one hydrophilic head
How many backbones are commonly found in lipids? what are they?
Glycerol:
-Triacylglycerols
-Glycerophospholipids
-Galactolipids (sulfolipids)
Sphingosine:
-Sphingolipids
How many types of polar head groups are commonly found in lipids? What are they?
Phospho and glyco (sugars)
Which type of lipids are richest in oligosaccharide varieties?
Glycosphingolipids
Which type of lipids determines blood type?
Glycosphingolipids
Are biological membranes typically bi-layered or mono-layered? What organisms are the exception?
Typically bilayered, Archaebacteria (extremophiles) are the exception because they live under conditions of high temp, pH and ionic strength
Which type of lipid is often found to modulate the fluidity of biological membrane?
cholesterols
How does PIP2 processed to produce two signaling molecules? What are they?
Activation of PLC in response to extracellular signal triggers cleavage of PIP2 to produce IP3 which increases Ca2+ in which Ca and DAG activate specific intracellular pathways and processes
-IP3 and DAG
What type of compounds are sex hormones?
Steroid hormones (hydrophobic oxidized sterol derivatives)
