Biol 371 Samuel Flashcards
What is the highest cause of death in children?
Malnutrition
Whats the difference between animal and plant nutrition?
nutrition- plants do work to create energy, animals just eat them to get energy.
The start codon ATG codes for the amino acid methionine, can humans make methionine?
No, we need them from plants- we can’t even make the molecules that is coded from our start codon ATG.
How many essential elements do plants need?
17
What do the essential elements that plants need do?
Components of nucleic acids (N, P), amino acids (N, S)
Function as enzyme cofactors (Ca2+)
Role in photosynthesis (Mg2+, Fe2+, Fe3+) or regulation of osmotic potential (K+)- need magnesium and iron in chlorophyll
What the 17 essential elements seperated into?
macro and micro nutrients
What are the macronutrients and how do they become available for plants?
Theres non minerals (C, H, O), and theres minerals (N, P, K, S, Ca, Mg), these are only avaible to plants once dissolved in water as they’re ionic form.
What micronutrients are essential for plants (MUST KNOW)
Cu, Cl, Ni- needed in small amounts but are required for plants grow
Give an example of what happens when plants don’t have trace micronutrients
Potatoes will not grow w out micronutrients
Can nitrogen as it’s form in air be utilized by plants?
NO, Nitrogen has to be converted into plant available compounds through n fixing bacteria, bacterial ammonification, or bacterial nitrification.
N fixation- N fixing bacteria convert N2 gas to NH3 which then dissolves and becomes NH4.
Ammonification- Bacteria break decaying organic nitrogen compounds and convert it into NH4
Bacterial nitrification- oxidizes nh4 and makes it into no3, plants convert it back to nh3 in the plant and then transport it throughout plant.
What do plants prefer to take up? NO3, or NH4
NO3
If you continuously harvest plants what happens to the n fixation system?
If you continuously harvest plants, bacteria can’t fix nitrogen at the same rate which would lead to n deficient plants.
Describe the symbiosis between root nodules and plants?
roots have nodules - plant cells “infected” by N2-fixing Rhizobium bacteria
Gaseous form of nitrogen hard for plants to take up, ammonia easier, bacteria are given houses and plants are given a usuable form of nitrogen.
How did nitrogen depletion cause us to resort to fertilizer?
In the past we used to move lands and let the soil regain it’s nitrogen by itself through natural processes, but needing to do more and more farming made us use all the nitrogen in the land. Needed to resort to fertilizer in order to get nitrogen needed to grow crops at rate needed.
What problem did fertilizers pose to crops and how was it solved?
Plants grew tall due to fertilizer (artificial nitrogen) but because they grew so tall they collapsed. Need a solution to this problem as we need plants to grow but no collapse on themselves.
Dr. Norman borlaugh found a way to make a tall plant shorter (shutting down a hormonal pathway required for stem elongation creating a dwarf breed) and then use fertilizer to increase the yield of these plants.
What is a gmo?
a genetically modified organism, requires a piece of dna not native to the organism.
What was a negative effect of creating dwarf plants in terms of the hormonal pathway?
By breeding these crops he shut downa hormonal pathway that allowed elongation. Because this hormone was shut down it made it shorter but this hormone was needed to avoid drought, so it made the gmo plants more drought sensitive.
What is a negative side effect of using Nitrogen fertilizers?
The fertilizers runoff into water causing algal blooms which bacteria feed on and consequently deplete oxygen. Animal life at sea floors then die.
What is eutrophication?
Enrichment of an ecosystem with chemical nutrients such as compounds containing nitrogen and phosphorous
Example: nitrogen depletes into groundwater, groundwater runs off into a water body, forms algal blooms which shade plants hindering plant growth, and absorb more nutrients, when these blooms die their decomposition process takes up so much oxygen that oxygen levels fall and fish begin to die
What humus?
is the dark organic component of soil formed by decomposition of plants, holds water and nutrients. Has a negative charge so nutrients (ions) stick to it ex: ammonium
What properties does the size of soil particles determine?
Water availability, and mineral availability
What do micronutrients do in terms of reactions?
Act as catalysts
What solution is there to avoid negative effects of fertilizer but still have abundant plant growth?
Want to manipulate plants to make their own nitrates or make all crops have a symbiotic relationship with root nodules.
Define chlorosis and what causes it
yellowing of plant tissues due to lack of chlorophyll, happens when there’s a deficiency in plant nutrients so the plant can’t photosynthesize any more
What is a hydroponic culture, how can it be utilized?
Is when you grow plants in solution w out soil, can see what nutrients is important to plant using this as you can remove one nutrient in the water at a time. If plant grows bad you removed an essential element- one that is necessary for growth/reproduction, cannot be subbed, and has metabolic roles.
What is soil solution?
Is the combo of water and dissolved substances that coats soil particles and fills pore space. Is available for plant uptake after gravity drainage (in which water is drained and concentration of ions and nutrients is increased).
Why are water molecules attracted by clay particles and humus particles?
Because humus particles are neg charged so attracted to pos water molecules
Because clay is alkaline due to minerals, gives it a high ph (more basic and more neg charged) so it sticks to water molecule smore.
Describe how minerals are made available in soil
Minerals are dissolved in water and passively enter plant roots in their dissolved form, they are selectively absorbed by roots via ion-specific transport proteins
why are both cations (Na+, Ca++, Mg++) and anions (NO3-, SO42-, PO43- ) are present in soil solution, but not equally available to plants?
Because soil is negatively charged so it repulses the anions but binds tight to cations, makes it so anions enter soil solution and are uptook by plants easier. However, they’re also washed away because of this easier.
Describe the connection between root systems and soil solution
The solution moves in and out of roots, extensive root systems are adaptations to limited mineral nutrients, and they make up 20-50% of the plants mass
Explain how cation exchange works?
As dissolved cationic minerals are bound onto surface of clay particles (adsorbed), it’s hard to take them up, plan addresses this by pumping out H+ in order to replace the cations on the soil with H+ so the minerals can then be taken up by the roots. Plants also does cation exchange by respiration, in which it realses co2 that creates carbonic acid which dissociates into H+- displacing the minerals which will be uptook by plant.
What is a negative side effect of anions not binding to clay particles, whats a positive side effect?
Anions (NO3, SO4, AND PO4) are neg so they don’t bind to soil and go up plant roots readily, however this is also bad because water can leech them out of the soil and run off into groundwater and (NO3 and PO4) can cause eutrophication.
Although soils are usually basic, what happens to mineral content when they’re acidic due to events like acid rain caused by pollution?
Become acidic so the negative charges on the soil now become positive and cations are easily leeched out of the soil solution.
Whats passive transport?
solutes move down a concentration or electrochemical gradient. They diffuse over a semi permable membrane or they are released through transport proteins.
Whats active transport?
Is moving against an electrochemical or concentration gradient (ex transport pumps)
What mechanism are there to increase substance uptake in plants?
Root hairs, mycorrhizae.
How do root hairs increase substance uptake in plants? What substances do they help uptake?
They Greatly increase root surface area, absorb water and minerals
How do mycorrhizae help substance uptake in plants, what substances?
Mychorizzae increases plants supply of phosphate and plant gives the mychorizzae carbon, fungus interacts with root to mobilize phosphate
Why is there membrane transports in root cells?
Because charge particles require a channel or transport- can’t just diffuse.
Why do we want to reduce nitrogen fertilization?
Want to reduce nitrogen fertilization as each molecule of nitrogen is 300x more potent than CO2.
What are the different ways plant transport material?
Into and out of cells, cell to cell, and over long distances such as root to shoot.
What are the two mechanisms used transporting material in plants?
Passive and active transport
