Biochem Chapter 5 - Lipids Flashcards
(12 cards)
What are the four lipid soluble vitamins, and what are their functions?
1) Vitamine A (retinol) = used for vision, development, and immune function.
2) Vitamin D (cholecalciferol) = used to increase calcium absorption for increased bone development.
3) Vitamin E (tocopherols) = Antioxidants that prevent damage from oxidative stress.
4) Vitamin K = Used to produce prothrombin, a important clotting factor in the blood coagulation.
What is the fate of excess vitamin E?
1) Excretion through the urine.
2) Storage in glycogen granules.
3) Storage in adipose tissue.
4) Excretion through the feces.
Storage in adipose tissue - this is because vitamin E is a strictly lipid soluble vitamin, and cannot be going through urine as it has a lot of H2O.
glycogen granules store glucose only.
Feces do not excrete vitamins.
What kind of lipid is produced by almost all cells in the human body, and is crucial in the production of cAMP?
1) Glycolipids.
2) Sphingomyelins.
3) Steroid hormones.
4) Prostaglandins.
The answer is Prostaglandins - which are used to produce cAMP and regulate downstream signalling.
1) glycolipids are a definition for a wide array of lipids that contain a glycosidic bond from the backbone to a sugar.
2) Sphingomyelins are found in schwann cells and oligodendrocytes, and used to help maintain their membrane.
3) Steroid hormones will act on specific tissue receptors, and are produced by specific cells.
What is a primary precursor to prostaglandins?
1) Arachidonic acid.
2) Diterpenes.
3) Gangliosides.
4) Phospholipids.
1) Arachidonic acid.
Where is cholesterol located, and what is it’s function?
Cholesterol is found in the membrane of most cells, and is crucial to maintain proper membrane fluidity. Cholesterol may also act as a precursor to steroids, bile acids, and vitamin D.
What is the difference between a steroid and a steroid hormone?
A steroid is a definition for a molecular structure. A steroid hormone is a hormone that contains steroid structure, and travels through the blood to act on an effector tissue.
A 21 year old college student decides he wants to begin illegally taking anabolic steroids to improve his performance in bodybuilding. The student takes steroids for 6 months and begins to make a variety of negative consequences, such as poor skin, fatique, and emotional upset. He seeks medical attention from his primary care physician, who promptly orders a blood test. Which of the following molecular structures would be present in high amounts due to the student’s behavior?
1) Esters of long-chain fattys acids, which contain long-chain alcohol groups.
2) Phospholipids that contain a 3 carbon backbone.
3) Terpenes that contain 4 cycloalkane rings.
4) Lipids that contain a sphingosine backbone, and may or may not be a phospholipid.
The correct answer is 3) terpenes that contain 4 cycloalkane rings. Steroid structure can be defined as lipids containing 4 cycloalkane rings, with varrying functional groups.
1) describes the structure of waxes.
2) Describes the structure of glycerols - a general category of lipids.
4) describes the structure of a general sphingolipid.
Terpenes are a type of signalling lipid that can act as a precursor to steroids. These are built from isoprene (C5H8) units. A diterpene would contain:
1) 2 isoprene units.
2) 4 isoprene units.
3) 6 isoprene units.
4) 8 isoprene units.
2) 4 isoprene units - a common one is vitamin A
Terpenes contain building blocks that are each consisting of 2 isoprenes, so a diterpene = 2 terpene * 2 Isoprene/terpene = 4 isoprene.
A monoterpene contains how many isoprene groups?
2
A sesquitterpene contains how many isoprene groups?
3
A titerpene contains how many isoprene groups?
6
A tetraterpene contains how many isoprene groups?
8
