Chapter 5.2 Flashcards
Describe terpenes. What are they precursors to. What are they built from
- terpenes are lipids
- precursors to steroids
- > other lipid signalling molecules as well
- > varied independent functions
- note terpenes are built from isoprene
- note terpenes are pungent chemicals
What are terpanoids? Refer to its relationship with the terpene class. Refer to similarities
- terpanoids are terpenes
- > that have undergone oxygenation or rearrangement of the carbon skeleton
- they both contribute to being biological precursors for steroids and also have similar aromatic properties
- > since they both are precursors for steroids, they both have a widespread role in biological function
Describe the general structure of steroids
- they are characterized by having four cycloalkane rings fused together
- > specifically, three cyclohexane and one cyclopentane
What is cholesterol? Why is it important? Is it amphipathic?
- it is a steroid of primary importance
- major component of the phospholipid bilayer
- > responsible for mediating membrane fluidity
-it is amphipathic
How does cholesterol work in the membrane during low temperatures and during high temperatures
Low temperatures
->it keeps the cell membrane from solidifying
High temperatures
- > it holds the membrane intact
- > and prevents it from becoming too permeable
What is cholesterol a precursor molecule for
-it is a precursor for VitaminD, bile acid and steroid hormones
Describe the general structure of prostaglandins
- produced by almost every cell in the body
- 20 carbon molecule
- > unsaturated carboxylic acids derived from arachidonic acid
- > contains one five carbon0ring
Describe the various functions of prostaglandins
1)paracrine or autocrine signalling molecules
2) regulate the synthesis of cAMP
- >downstream effects of this include: smooth muscle contraction, influence over the sleep-wake cycle and the elevation of body temperature associated with fevers
What enzyme helps in the production of prostaglnadins? What drug inhibits this enzyme
- cyclooxygenase helps in the production of prostaglandins
- >aspirin inhibits cyclooxygenase
What is a vitamin? What are the two different categories? How can these two different categories be excreted from the body?
- vitamin is an essential nutrient that cannot by adequately synthesized by the body
- > therefore, must be consumed in the diet
- the two types are
- > water-soluble and lipid-soluble
Excretion wise
->lipid-soluble accumulate in stored fats while water-soluble are excreted through urine
Describe the general structure of Vitamin A
- carotene
- >an unsaturated hydrocarbon
What is Vitamin A important for
-it is important for vision, growth and development and immune function
What is a metabolite of Vitamin A? What is the storage form of Vitamin A?
- retinal is a metabolite of Vitamin A
- > it is the aldehyde form
- > retinal is a component of the light-sensning molecular system in the human eye
- retinol is the storage form of vitamin A
- > it is oxidized to retinoic acid
- > retinoic acid is a hormone that regulates gene expression during epithelial development
What is the function of Vitamin D?
- cholecalciferol
- >absorbed or consumed by UV light-driven reaction in the skin
What does Vitamin D do when it is converted to calcitriol
- calcitriol increases calcium and phosphate uptake in the intestines
- > promoting bone production
