Bio260 Unit 4 Resource 1 - Plant & Animal Nutrient Acquisition

ask abt 14, 30, 36-37

Nutrients

• provides energy, contributes to body structure, and/or reg chem processes in body

• non-essential can be made by animals

• essential cannot be made, supplied from food

4 classes of essential nutrients

• amino acids

• fatty acids

• vitamins

• minerals

General info about AA

• we req 20 AA and can make all but 8

• plants make all 20

• used for immediate metabolism (plants) & protein synthesis (animals)

General info about fatty acids

• lipids are req for membranes and energy storage

  • use for energy, as membrane component, and as signaling molecules

General info about Vitamins

• org compounds req in small amounts

• 13 are essentail for humans

• plants make all essential vit

General info about Minerals

• inorg compounds req in trace amounts

• inorganic substances that help satisfy essential metabolic and structural functions in organisms

• sometimes categorized as macrominerals or microminerals/trace elements

• all plant essential nutrients are minerals

AA in Plants

• plants can also take AA directly from soil

• made from intermed of glycolysis, Citric Acid cycle, and assimilated inorg N (nitrate and ammonium)

• most plants are incomplete in AA composition

  • ppl who eat plant proteins need to eat specific plant combos to get all essential AAs

• stored in central vac

• transported in phloem to dvlping vegetative reproductive sink tissues

  • transport of AA from plant cells is mediated by transport proteins in plants

AA biosynthesis in animals

• non-essential AA made from intermed of glycolysis and citric acid cycle

What happens to AA in animal bodies?

• AA not stored in animal bodies, they circulate in blood and are taken up by cells to make proteins

• liver removes excess AA + detoxifies it by removing amino group

  • highly toxic ammonia forms during

  • remaining C chain of AA can be used to make carbohydrates or lipids

Lipids in Plants vs Animals

• plants

  • store fats and oils in forms of triglycerides

  • use lipids as carbon storage

• animals

  • store excess sugars as fats in adipose tissue

  • store excess glucose as glycogen in liver and muscles

• insulin is used to inhibit production of glucose

  • used for high blood sugar

• glucagon is used to increase blood glucose

• used for low blood sugar

What happens to dietary fat?

• packaged into chylomicrons in the intestine initially and then delivered to muscle and adipose tissue

• remaining lipids in chylomicron remnants are routed to the liver as triglycerides

What is triacylglycerol?

• most common lipid in plants and animals

What are fatty acids?

• 3 families based on presence of DB in the hydrocarbon chain

  • saturated: H or straight chains w/ no DB

  • monounsaturated: has 1 DB b/w adjacent C atoms

  • polyunsaturated aka PUFA: has more than one DB b/w adj C atoms

    • omega-6 (n-6)

    • omega-3 (n-3)

Fatty acids in plants

• usually straight chain, unsat-carbocyclic acids w/ even # of C

• syn in plastids and assembled in endoplasmic reticulum

• only plants can make omega-3 and omega-6

Essential fatty acids in animals

• can make most of the fatty acids needed

• 98% of ingested fatty acids are in the form of triacylglycerol

• essential polyunsat fatty acids: linoleic, linolenic, and arachidonic acids

• deficiencies in fatty acids are rare

Vitamins in animals

• organic molec reg in diet in small amounts

• 13 vitamins are essential to humans

• vit E: protects fatty molec

Vitamins in plants

• B vitamins may be converted into enzyme cofactors in plants

• reduce oxidative stress

• water soluble vitamins

  • B1: thiamine

  • B2: riboflavin

  • B3: niacin

  • B6: key role in nitrogen metabolism

  • B8: biotin

  • Vit C: antioxidant

• fat soluble vitamins

  • pro-vit A: cartenoid vit A doesn’t exist in plants

  • vit E: important in nutrient transport

  • vit K1: electron carrier supp photosyn

  • vit D: not found in plants but is in fungi and yeast

Where is Vit D acquired?

• synthesized in the skin upon exposure to sunlight & other forms of DVB radiation

• additional sources are from supplements, w/ small amounts coming from food like protein and dairy.

Adaptations of vasc plants

• adaptations for acquiring resources were key steps in evolution of vasc plants

  • plants grew taller and had flat broad appendages

    • more cells and needed more water, nutrients, and improved anchoring system

  • evol of xylem and phloem made it possible to dvlp roots and shoots

    • made long-distance transport (from bottom to top) of water, minerals and products of syn possible

  • more roots = better anchor

    • root sys formed symbiotic relationships w/ bacteria, cyanobac, or fungi

  • increase shoot length = more distance b/w roots-water and nutrients-leaves-sources of sugar

How does nitrogen pass thru in biochem cycle?

• atmosphere has 78% of nitrogen

• acquiring N req breaking stable triple covalent bond b/w 2 N atoms to make ammonia or nitrate

  • aka nitrogen fixation

• plants provides sugar from photosyn that are used by nitrogen-fixing microorg for energy

  • in exchange for C sources, microbe provides fixed N to host plant for growth

Biological nitrogen fixation

• NH3 + H20 → NH4+ + HO-

• done by bac or cyanobac

  • N fixing bac forms symbiotic assoc

  • req anaerobic conditions, host makes root nodules in legumes

• ammonia (NH3) dissolves in water to make ammonium (NH4+)

• ammonium is absorbed and then stored in vac (b/c toxic) then converted to AA

  • Convert nitrate (NO3) to nitrite (NO2) in cystol

  • transport NO2 into chloro → red to ammonium (NH4+)

• nitrate is the most important b/c plants and animals consume it

What is mycorrhizal?

• a fungi that helps nutrient uptake by roots or broad range of angisperms

• mycorrhizal fungi form a mycorrhiza

• the tiny hyphae of mycorrizal fungi extend reach of roots into surr soil and start acquiring nutrients (esp. Phosphorus)

  • in return, plants provide carbohydrates to fungi

Other mineral absorption

• plants take in sulfur from sulfates in the soil or as sulfur dioxide thru stomata

  • used in AA, proteins, and oils

• root hairs take in phosphates from soil by symporter; made into sugar, phospholipids, and nucleotides

• ferric iron is taken from soil and then is used as a comp. in many enzymes (cytochromes in e-transport)

  • also involved in syn of chlorophyll