BIOL 3000 Botany - Lecture Exam #3: Plant Metabolites

Primary metabolites

Molecules found in all plant cells and are necessary for life

Secondary metabolites

Molecules found in some plants but not in others; important to the survival and propagation of plants with them; have many different functions

Describe alkaloids

Are alkaline nitrogenous compounds; usually occurr as heterocyclic rings; positively charged; especially important to the pharmaceutical industry

Characteristics of morphine

Derived from the fruits of the opium/ breadseed poppy (Papaver sonniferum); secondary metabolite; alkaloid; hallucinogenic; used to relieve pain

Characteristics of cocaine

Derived from the leaves of the coca plant (Erythroxylum coca) in the Andes of Bolivia and Peru; secondary metabolite; alkaloid; stimulant; insecticide

Characteristics of caffeine

Derived from the fruits/ seeds and leaves of coffee, cocoa, and tea plants; secondary metabolite; alkaloid; stimulant; allopathic (compound secretes into the soil and competes/ interacts with other plant species)

Characteristics of nicotine

Derived from the tobacco plant (Nicotiana tabacum); secondary metabolite; alkaloid; stimulant; insecticide; phytoalexin (antimicrobial and antioxidative)

Characteristics of theobromine

Derived from the cacao plant (Theobroma cacao); secondary metabolite; alkaloid; historically used to treat vascular diseases

Characteristics of theophylline

Derived from the leaves of the tea plant (Camellia sinensis); secondary metabolite; alkaloid; antioxidant; combats respiratory diseases/ illnesses; insecticide

Characteristics of atropine

Derived from the deadly nightshade (Atropa belladonna) and Egyptian henbane (Hyoscymus muticus) plants; secondary metabolite; alkaloid; stimulant; psychedelic; dilates the pupils

Characteristics of quinine

Derived from the bark of the Chinchona tree (Cinchona officinalis) in South America; secondary metabolite; alkaloid; protects against malaria

Characteristics of vinblasine

Derived from the Madagascar periwinkle (Vinca rosea); secondary metabolite; alkaloid; anti-cancerous against leukemia

Characteristics of reserpine

Derived from the roots of the Indian snakeroot plant (Rauwolfia serpentina); secondary metabolite; alkaloid; historically used to treat hypertension

Describe terpenoids "terpenes"

Are composed of isoprene units; are the largest class of compounds (> 22,000 compounds); categorized according to the number of units

What is isoprene gas? What two examples must you know?

Isoprene gas is emitted during the daytime in large quantities by some plants and is thought to cool down plants and slow their metabolic rates. Limonene and methanol are two examples of isoprene gas.

Characteristics of taxol

Derived from the bark of the Pacific yew (Taxus brevifolia); secondary metabolite; terpenoid; diterpenoid; anti-cancerous against ovarian and breast cancers; often made synthetically for the pharmaceutical industry

Characteristics of cardiac glycosides and digitoxin

Derived from toxic terpenoids in milkweed and the foxglove plant; secondary metabolite; terpenoid; used to treat cardiac diseases and heart arrhythmia

Characteristics of rubber

Derived from the the latex of the bark of the rubber tree (Hevea brasiliensis); secondary metabolite; terpenoid; comprised of 400 - 10,000 isoprene units; largest exported terpenoid compound

What are the three primary terpenoid functions you must know?

Carotenoids are orangey pigments which assist in light absorption and protect against sun damage. Plastoquinones are mobile, organic molecules which act as key electron and proton carriers (ATP transport) during photosynthesis. Plant hormones, such as gibberellins and ABA.

Describe phenolics

Phenolics are secondary compounds with a hydroxyl group (-OH) attached to an aromatic ring (6C ring with conjugated bonds)

Characteristics of flavonoids

Secondary metabolites; phenolic; are an important group of pigments for flower coloration

Characteristics of flavonols

Secondary metabolites; phenolic; a group of pigments which block far-UV light in leaves, protecting them

Characterisitcs of lignin

Secondary metabolite; phenolic; important to structure and defense

Characteristics of tannins

Secondary metabolites; phenolic; distrubuted throughout plant leaves, bark, fruits, etc.; protect against pests and UV raditation; block the formation of endothelin-1 (signaling molecule which causes blood vessel contraction; lowers blood pressure and reduces risk of heart disease

Characteristics of salicylic acid and acetylsalicylic acid (asprin)

Secondary metabolites; phenolics; derived from the bark of willow trees; development of SAR (systematic acquired resistance), creating long-lasting protection against pathogens after the plant is attacked/ damaged (boosts the immune system); airborne transmission signals to other plants; historically used by Native Americans for pain relief

Characteristics of aloin and chrysophanic acid

Secondary metabolite; phenolic; anthraquinone glycoside; derived from the sap of the aloe plant (Aloe vera); laxative; anti-inflammatory and soothing on the skin

What is a chromoplast?

A colored plastid responsible for the synthesis and storage of red, orange, and yellow carotenoid pigments; may contain oil bodies

What is an amyloplast?

A colorless plastid which synthesizes and stores starch

What is an etioplast?

A plastid exclusive to angiosperms which grow under low-light or lightless conditions; contain prolamellar bodies which store molecular building blocks and enzymes; turn into chloroplasts when exposed to light; prolamellar bodies turn into thylakoids when exposed to light

How do chloroplasts move?

Under dim-light conditions, chloroplasts move parallel to the leaf's surface to maximize light absorption. Under bright-light conditions, chloroplasts move perpendicular to the leaf's surface to minimize light absorption and to limit possible photodamage.