Final deck Flashcards
How do plants fight gravity on land?
Lignin and evolution of vascular tissue
How do plants fight water loss on land (maintain water potential?)
stomatas with specialized walls. Cuticle
How do plants protect their gametes/zygotes from desiccation?
Sporopollenin polymer
What is the middle lamella and what does it contain (3)?
middle lamella is the apoplastic space inbetween primary walls that contains Mg2+, Ca2+ and pectins
What are the four ingredients in a primary cell wall?
Pectin, cellulose, hemicellulose, and proteins
Which is the hydrated and flexible one: primary or secondary cell wall?
Primary
What are the three differences between primary and secondary cell wall growth?
Primary: functions for cell growth and expansion, deposited during growth of cell, only withstands tensile forces
Secondary: functions for structural reinforcement, depostited after cell growth, and withstands tensile forces from gravity and hydrostatic pressure (keeps water inside)
When is the primary cell wall formed? When is the secondary wall formed?
Primary: formed during cell growth (cytokinesis)
secondary: formed after cell expansion is done
Where is extracellular cellulose made? Where is pectin made? Hemicellulose made?
Cellulose: made at the plasma membrane in cellulose synthase complexes.
Pectin: made at Golgi body
hemicellulose: made at the Golgi body
What hormone causes cell wall expansion? How does it do this?
Auxin promotes cell wall expansion by activating H+ pumps that acidify the matrix.
How does the acid-growth model work?
WHen the extracellular matrix is acidified, enzymes called expansins start breaking apart microfibrils. Increased water intake then expands the cell.
What is the difference between cellulose and amylose?
Cellulose is made by adding glucose monomers via an beta 1-4 bond, while amylose is made with an alpha 1-4 bond. This leads to a helical structure in amylose, and a pleated structure in cellulose
What is the difference between cellulose and hemicellulose?
Cellulose: made of only glucose beta 1-4 links
Hemicellulose: made of variable polysaccarides with 1-4 beta linkages
What is the difference between typical eudicot hemicellulose, and grass hemicellulose?
typical: GLC is main chain, and xylose chains allow for microfibril formation
Grasses: xylose main chain, while alt. sugars
What are pectins? where are they found?
Hydrophylic polysaccharides with acidic sugar residues. Found in primary cell wall
What is lignin made of? Where is it made?
Lignin is made of monolignols (phenylpropanoids) at the Cellulose-hemicellulose-lignin complex
What is the phenylalanine ammonia lyase and when is it used?
PAL deaminates phenylalanine to start down the path of lignin formation
What pathway is needed to create lignin?
the Shikimate pathway
What is cutin and what is it used for?
Cutin is a fatty acid wax that is deposited on leaves to prevent desiccation
what is suberin used for? WHere is it and what is it made of?
Suberin is a FA-derived polymer that is a major component of the casparian strip
Which ions can dissolve in water? Which can dissolve in soil?
Water: anions and highly polar/stable gasses (N2, O2, and CO2)
soil: cations, N, P, and S
How is calcium, phosphorous, and nitrogen obtained by plants?
Calcium: though cation exchange by the plant roots
phosphorous: symbioses with fungi
nitrogen: symbioses with bacteria
What is the difference between eurdicot roots and monocot roots? (3)
Eudicots: has a tap root that defines axis, lateral branch root develop off of tap root, adventitous root develop from non-root organs
monocots: No tap root, instead has crown roots at top that anchor plant, seminal roots follow underneeth. Adventitious roots anchor plant in place
What four factors determine root uptake effectiveness?
1) rate of nutrient removal from soil
2) rate of growth outside of depletion zone
3) rates of active/passive transport into root
4) microbial symbiosis
What is the nutrient depletion zone?
An area that forms when rate of nutrient uptake exceeds rate of replenishment
what two ways do nutrients move along the root surface?
bulk flow, and diffusion
What three ways can plants give photosynthate to roots (rhizodeposits)?
1) sloughed-off cells: cells that contain high amounts of carbon compounds to feed microbes
2) mucilage: both protects and feeds microbes
3) signaling molecules: signals to microbes to move towords plant
What are the two forms of fungal symbiosis? which one is the most common?
-Arbuscular mycorrhiza: fungi penetrates cortical cells and stays between cell wall and plasma membrane. Most common
-ectomycorrhiza: fungi do not penetrate root cells, but do penetrate the apoplast
What are the two types of arbuscular mycorrhizal infection?
aurum-type and Paris-type
What is a Hartig net?
A Hartig net is a network of mycorrhizal hyphae outside of the root
Who creates NH4+ in the soil? Who breaks it down to NO3?
NH4+ is created by decomposers. It is then assimilated into NO3 by a series of nitrite and then nitrate fixing bacteria
What enzyme is used for nitrate assimilation? what enzyme is used for nitrite assimilation?
Nitrate Reductase and Nitrite Reductase
How do plants fix nitrogen into amino acids?
From NO3-, it is converted back to NH4+, then added to a Glutamate to make glutamine, which then is added to a 2-OG to make 2 glu by GOGAT
What enzyme do microbes have that allow them to fix nitrogen in the air?
nitrogenase
What are the four major types of lipids?
TAGs, Glyceroplipids, Waxes, and other (hormones and signaling)
What is an oleosin and what is lipases
and oleosin is a ball of TAGs with their tails all inside. Lipases can then come in and cleave off a FA tail
What two enzymes regulate malate concentration in the TCA cycle? Why do they do it?
Malic enzyme: allows for the incorporation of a second malate to the first to conjugate it into pyruvate. Lowers organic acid levels (including citrate)
PEP carboxylate: allows for additional TCA intermediates by turning a PEP into a malate. This allows for the removal of other intermediates for N assimilation or GNG
What are the three steps in lignin biosynthesis
1)PAL deaminates Phe, which is then added to a CoA factor to designate it as a lignin precursor
2) precursor looses CoA, and is reduced to an aldehyde
3)Aldehyde is then reduced to an alcohol –> monolingnol
what four enzymes are involved in nitrogen fixation?
1)Nitrate reductase (reduces NO3 to NO2)
2) Nitrite reductase (reduces NO2 to NH4+)
3)Glutamine synthase (Fixes NH4+ to Glutamate to make a glutamine)
4)GOGAT (conjugates a Gln with a 2-OG to make two Glutamates)
What enzyme is needed in order to fix N2 from the air?
Nitrogenase (reduces an N2 to 2 NH3s)(only found in bacteria)
How many CesA subunits are there in a Cellulose synthase complex?
36 (6 per a rosette with 6 rosettes in a CSC)
Describe a nutrient in all four groups and what it does
Group 1: N, or S. Involved in AA, DNA, and RNA formation
Group 2: P, Si, and B. Involved in DNA and RNA formation
Group 3: K, Ca++, Mg ++. Critical cofactors and ions
Groups 4: Fe, Mn, Cu. Enzyme cofactors
Difference between Invertase, sucrose synthase, amylase, and startch phosphotase
Invertase: breaks sucrose into fructose and glucose
sucrose synthase: can transform UDP-GLc and fructose into sucrose, and visa versa
amylase: breakes amylopectin into maltose
startch phosphotase: uses phosphate to eat startch main frame
What does the shikimate pathway produce?
Lignin and auxin and salicyclic acid
What is the difference between phytoanticipins and phytoalexins?
Phytoalexins: inducible defense compounds
phytoanticipins: constitutive defense compounds
What are the five types of chemical defenses? Which two are widely avaliable?
Terpenoids and phenylpropanoids are the most common, but glucosinolates, alkaloids, and cyanogenic glycosides
Is lignin a terpenoid or a phenylpropanoid
phenylpropanoid
Which of the seven hormones are synthesized from isoprenoid metabolism, lipid metabolism, nucleotide metabolism, the shikimate pathway, and the yang cycle?
Isoprenoids: GA, ABA, and some CKs
Lipid metabolism: JA
Nucleotide metabolism: some CKs
shikimate pathway: IAA
yang cycle: ethylene
What does the Yang cycle do?
it recycles sulfur within the plant
Which go to the nucleus and which cause a kinase cascade? Photochrome, cryptochrome and phototropin?
photochrome and cryptochrome go to the nucleus. Phototropin goes starts a kinase cascade
Which experience phosphorylation during activation? Photochrome, cryptochrome and phototropin?
photochrome and phototropin are phosphorylated. Cryptochrome preforms a dimerization
Which absorbs blue light and which absorbs red light? Phytochrome, cryptochrome and phototropin?
phytochrome absorbs red. Cryptochrome and phototropin absorbs blue
Which have crown roots, seminal roots, and adventitious roots that can develop from root tissue?
Monocots
Which have tap roots, lateral roots, and adventitious roots that cannot develop from the root tissue?
dicots
What did Dr. Bloom’s CO2 enrichment study show?
That biomass at first went up, and then decreased with increased CO2. Believes that this is due to a cocurrent drop in NO3 assimilation
Which cofactor prefers photorespiration, and which prefers photosynthesis? (Mg++ and Mn++)
Mn: prefers photorespiration
Mg: prefers photosynthesis
What does the rubisco active site bind to?
Co2, O2, Me2+, RuBP, NADPH, and 6PG
Which hormones work via repressor degredation,
versus kinase cascade,
Repressor degreation: GA, Eth, JA, IAA
Kinase Cascade: CK, ABA
Where are receptors found for GA, IAA, ABA, Eth, JA, and CK found (3)?
ABA: plasma membrane
CK and Eth: ER membrane
JA, GA, and IAA: nucleus
Which hormone is involved in stomatal closure?
ABA
Which hormone is involved in wall acidification and cell expansion?
IAA
Which hormone is involved with rhizobial infection
CK
What do sieve elements do not have that other cells do?
No nuclei, vacuole, microfilaments, microtubules, golgi body, or ribosomes
What are the cells found in xylem, and what are the cells found in phloem?
xylem: tracheids, vessels, parencyma
phloem: sieve tube cells, companion cells, and parencyma
How many ATP and NADPHs made in photosynthesis per one CO2 fixed
3 ATPs and 2 NADPHs
Which photosystem is found in the lumen, and which is found in the grana
PSII: grana
PSI: thylakoid
