bio 162 midterm 2

essential nutrient

An element or compound that is required for normal growth and reproduction. cannot be synthesized by the organism.

What happened in the van Helmont experiment.

Hypothesis: The mass of a growing plant comes from the soil. Plant a sapling in the soil and wait 5 years. The plant had a 3700% increase in mass, and the soil had a 0.066% increase in mass. Unaware that gases have mass, he thought the mass came from water. Most of the added mass came from carbon dioxide in the atmosphere. 60g of soil removed was the vital nutrients.

limiting nutrients (macro)

nitrogen, phosphorus, and potassium. Availability limits plant growth.

micronutrients

cofactors for specific enzymes- substances that are required for normal enzyme function.

mobile nutrients

readily transported from older leaves to younger leaves when in short supply, so older leaves deteriorate first. N,P,K, Mg

immobile nutrients

stay tied up in older leaves. Younger leaves are first to show deficiency symptoms. iron or calcium.

hydroponic growth

growth of plants in liquid cultures rather than soil

humus

decayed organic matter in soils. depending on size and composition of these particles, can be called gravel, sand, clay, silt. first ingredient in soil.

leaching

loss of nutrients via the movement of water through soil. sandy soils are more prone to this.

cation exchange

protons or other soluble cations bind to negative charges on soil particles and cause bound cations (Mg, Ca) to be released from the soil.

what stays in solution in soil water, readily available to plants but may wash away easily.

anions

what tends to bind to soil particles but can be released by cation exchange.

positive ions

zone of maturation

most nutrient uptake occurs just above the growing tip

electrochemical gradient

combined effect of an ions concentration gradient and electrical (charge) gradient across a membrane that affects the diffusion of ions.

membrane potential

difference in electrical charge across a cell membrane.

passive exclusion

ions move through roots following the same routes that water follows.

metallothioneins

small plant proteins that bind to and prevent excess metal ions from acting as toxins.

antiporter

carrier protein that allows an ion to diffuse down an electrochemical gradient, using energy of that process to transport a different substance in the opposite direction against its concentration gradient.

nitrogen fixation

incorporation of atmospheric nitrogen (N2) into ammonia (NH3), which can be used to make many organic compounds.

Nod factors

molecules produced by nitrogen-fixing bacteria that help them recognize and bind to roots of legumes.

autotroph

organism that can synthesize their own food

heterotrophs

organisms that obtain food by consuming other organisms.

epiphytes

grow on the trunks or branches of trees, not soil or a host plant.

primary benefit of why some plant are carnivorous

to obtain nitrogen in low nitrogen enviornments

where do parasitic plants get nutrients

through photosynthesis, but all obtain water and nutrients by penetrating the xylem of host plants.

vitamins

organic or carbon-containing compounds that are vital for health. required in minute amounts.

minerals

Inorganic substances used as compounds of enzyme cofactors or structural materials.

suspension feeders

sponges and tubeworms. filter small organisms or bits of organic debris from water by cilia, mucus-lined nets, or other structures.

deposit feeders

earthworms and sea cucumbers. swallow sediments and other types of deposited material rich in organic matter

fluid feeders

suck or lap up blood, nectar, or other fluids

mass feeders

The majority of animals. seize and manipulate chunks of food.

adaptive radiation

diversification of a single ancestral lineage into many species, each of which lives in a different habitat or exhibits a distinct form.

incomplete digestive tracts

single opening, the mouth, through which the animal both ingests food and eliminates wastes. mouth opens into a chamber called the gastrovascular cavity, where digestion takes place.

complete digestive tracts

two openings. start at the mouth and end at the anus. The interior of this tube communicates directly with the external environment via these openings.

chemical digestions in the body

1. mouth. Salivary amylase begins the breakdown of carbs and lipids

2. stomach begins protein breakdown. lipids continue to be digested. carbs not.

3. small intestine completes processing of three major macromolecules: carbs, proteins, lipids.

4. small molecules resulted from the digestions of these macromolecules are absorbed in the small intestine, along with water, vitamins, and ions.