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303 Cards in this Set
- Front
- Back
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Compare what happens to Carbon in photosynthesis vs. cellular respiration
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C is fixed in photosynthesis
C is burned in cellular respiration |
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What are the 4 resevoirs for C in the carbon cycle?
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atmosphere
biomass sediment fossil fuel |
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photoautotrophs
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nourish themselves via sunlight
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relate the overall reactions of photosynthesis and cellular respiration
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they are the inverse math equations of each other
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What is the purpose of photosynthesis
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to take light energy and convert it into sugars and organic molecules
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autotrophs are the producers or consumers of the biosphere?
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producers
take CO2 and other inorganic materials and make organic molecules |
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heterotrophs are the producers of consumers of the biosphere?
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consumers
they live on the compounds produced by other organisms |
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What are examples of photoautotrophs?
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plants
alage cyanobacteria unicellular protists |
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is glucose a direct output of photosynthesis?
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no
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What is the function of chloroplasts?
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they are organelles of photosynthesis
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What is chlorophyll and what is its function?
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Chlorophyll is a green pigment in chloroplasts.
They absorb light energy and transfer it |
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Why is chlorophyll green?
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because it cannot absorb green light
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What is the structure of chloropyhll and how does it affect its funcitonal ability?
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Hydrophobic tail (allows for permeability in the membrane)
Ring of excitation--the many double bonds allow for it to easily capture energy |
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Our atmosphere is mostly made up of what element?
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N
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Relate photosynthesis, the early earth, and oxygen
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The early earth did not have oxygen in its atmosphere, but as photosynthetic organisms developed, photosynthesis created the presence of O2
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What is ozone and what is important about it?
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O3 and it blocks UV light
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A wave can be thought of as
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a wave or particle of energy
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Does purple have high or low energy?
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high
short wavelength and high frequency |
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Does red have high or low energy?
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low
long wavelength and low frequency |
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What is an example of a wave with high energy?
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gamma ray
high frequency |
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what is an example of a wave that has low energy
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radio waves
low frequency |
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Relate wavelength and energy
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wavelength is inversely related to energy
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Explain pigments and light absorption
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Pigments are selective in the wavelength of light that they can absorb. When they do absorb the right wavelength, the valence electrons will jump to an excited state of energy. However, all electrons want to exist at their ground energy state, so it will give off its energy in the form of light and heat
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Where is cholorphyll located?
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in the thylakoid membrane
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Stomata
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the regulating pores of a leaf that let in carbon dioxide and try to minimize water loss
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Stroma
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the dense fluid within the chloroplast
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thylakoids
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membrane sacs that house chlorophyll
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granum
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stack of thylakoids
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What is good about granum?
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it increases the reaction surface area
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What are the two stages of photosynthesis
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Light reaction and calvin cycle
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photosynthesis is exergonic or endergonic?
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endergonic
it creates sugars |
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photosynthesis is what kind of process?
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a redox process
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What is reduced in photosynthesis?
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carbon dioxide
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In general, what does the light reaction part of photosynthesis do?
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take light energy and convert it into NADPH and ATP
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In general, what does the calvin cycle do?
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makes sugars, but relies on fuel (energy) from the light reaction
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What is the difference between NAD and NADP
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NAD with an extra phosphate group
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where in the process of photosynthesis is oxygen released?
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in the light reaction when water is split
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Compare and contrast chlorophyll a and b
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chlorophyll a is a pigment involved in the light reaction. It can absorb violet/blue and red light.
chlorophyll b is a secondary pigment that helps absorb light that chlorophyll a cannot absorb This can happen due to the slight structural differences between the two |
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carotenoids
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hydrocarbons that help absorb light that cannot be absorbed by the chlorophyll and helps in photoprotection
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The light reaction begins with photosystem I or II?
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II
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where are photosystems found?
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in the thylakoid membrane
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What is the structure of a photosystem?
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a reaction center complex that contains special chlorophyll a that is surrounded by the light harvesting complex
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explain the reaction center complex
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it is a protein complex that houses special chlorophll a and a primary electron acceptor
it is the place where electrons are transferred to the primary electron acceptor |
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expalin the light harvesting complex
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acts as the antennae for the reaction center complex
surrounds the reaction cetner contains pigment molecules (a, b, carotenoids) that are bound to proteins where light is received and then transferred |
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What is the difference between PSI and PSII
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PS II's cholorphyll
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What is special about special chlorophyll a
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it will lose its electrons and donate them in a redox reaction to the primary electron acceptor
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Explain the light reaction steps that occur in PS II
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PS II begins the light reaction
A photon excites a pigment molecule and when it goes back to ground state it excites another pigment molecule (ie. transfer of shaking energy) This shaking energy transfers all the way to the special chlorophyll a. Special chlorophyll a will then donate their electrons to the primary electron acceptor via a redox reaction Water is then split in order to replace the missing electrons in the primary electron acceptors |
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What is the purpose of water in the light reaction
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to reduce the special chlorophyll a
water is split to form 2 e- 2 H+ and O2 |
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Explain the first electron transport chain of the light reaction
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The primary electron acceptor from PSII will its electrons to PSI via an ETC
First plastoquinone accepts the e-, pumping 2H+ across into the thylakoid space The e- is passed to cytochrome complex, pumping 2H+ more Plastocyanin (Pc) is the final e- acceptor before it is passed to PSI |
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When is ATP made in the light reaction?
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When e- are passed to cytochrome complex in the 1st ETC
The proton gradient that is created drives the making of ATP via ATP synthase |
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What parts of the first ETC are mobile e- carriers
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plastoquinone and plastocyanin
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What happens in PSI in the light reaction
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When PSII is getting some energy, PSI also absorbs a photon of light which will excite a pigment, which eventually via the transfer of shaking energy from pigment to pigment will lead to the E being transferred to special chlorophyll a PS700.
The special chlorophyll a will then give their e- to the primary electron acceptor. To fill the missing e- the e- from the ETC which originally came from PSII is used to reduce the special chlorophyll |
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What happens in the 2nd ETC of the light reaction
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The e- acceptor of PSI passes its energy to feredoxin (Fd) which is a protein
Fd is then oxidized to reduce NADP to NADPH via the transfer of 2 electrons uses NADP reductase as the enzyme to catalyze the reaction |
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Where is NADPH made?
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in the stroma
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Where is ATP made in the light reaction?
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in the stroma
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what is the purpose of cyclic electron flow
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producing ATP because that non cyclic can't produce enough of
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explain cyclic electron flow
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Electrons from the primary electron acceptor of PSI go to Fd to Cytochrome C (ATP synthesis) to Pc and back to PSI
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What two things does cyclic electron flow not include?
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NADPH creation and PSII
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What is the carbon source for the calvin cycle?
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CO2
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What are the three phases of the calving cycle?
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carbon fixation
reduction regeneration |
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Explain the first phase of the calvin cycle--carbon fixation
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carbon dioxide is attached to a 5 C molecule ribulose bisphosphate, which is catalyzed by rubisco
3 co2 to 1 molecule |
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what is special about rubisco
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it is the most abundant (because its super slow) and most important protein
it is responsible for giving us our carbon source (sugar) |
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explain the reduction phase of the calvin cycle
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rearrangement of the double bond on RuBP in order to create more potential energy
Uses: 6 ATP and 6 NADPH Product: 6 G3P 1 G3P leaves and 5 stay |
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expalin the regeneration phase of the calving cycle
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5 G3P are phosphorylated by 3 ATP and rearranged to make 3 RuBP
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Make the connection between oxygenase activity in Rubisco and why is it bad?
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When Co2 is present rubisco will lead to the greation of G3P in the calvin cycle, which is the desired outcome.
When rubisco uses O2 in the calvin cycle it creates 2 phosphoglycate which is not able to be processed by the rest of the calvin cycle. BAD! |
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In what conditions will oxygenase activity worse and why?
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In hot and dry conditions because stomata will close to prevent water loss
When they are closed, O2 is unable to escape, which leads to a build up while CO2 keeps being consumed this leads to an increase in oxygenase activity |
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What is photorespiration and why is it needed?
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It is needed in order to keep the calvin cycle going and reverse the effects of oxygenase activity.
2 phosphoglycate + o2 + atp --> g3p + co2 + adp +pi A very wasteful process |
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what 3 organelles are required for photorespiration?
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chloroplasts
mitochondria perixosomes |
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what are peixosomes
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they transfer H to O2 to create H2O2
they help detoxify and breakdown fats as well |
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How do C4 plants minimize photorespiration
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they have a 4C intermediate that happens before the cavlin cycle
it occurs in the mesophyll cells and uses PEP carboxylase, which doesn't have any oxygenase activity The calvin cycle occurs in the bundle sheath cells |
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CAM plants
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They store CO2 in a 4C intermediate at night and during the day they release the molecule to undergo photosynthesis
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what two plant categories are seed bearing
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gymnosperms
angiosperms |
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what categories of plants are nonvascular
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liverworts
hornworts mosses |
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what are the categories of plants that are vascular
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gymnosperms
angiosperms pterophytes lycophytes |
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monocots and dicots are found in what category of plants
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angiosperms
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what is a primary difference between monocots and dicots
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the seed leaves
1 monocot 2 dicot |
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compare the veins in monocot vs. dicots
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monocot- parallell
dicot- netlike |
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compare the stem vascular tissue in a monocot vs. a dicot
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monocot- scattered
dicot- patterned ring |
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compare the root system in a monocot vs. a dicot
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monocot- fibrous
dicot- taproot |
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compare the pollen grain in a monocot vs. a dicot
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monocot- 1 opening
dicot - 3 openings |
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compare the floral organs of a monocot vs. a dicot
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monocot- multiple of 3
dicot- multiple of 4 or 5 |
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What are the 3 levels of plant organization?
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plant cells
tissues organs |
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tissue
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group of cells with a common function, structure, or both
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organ
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consists of several types of tissues that together carry out a particular function
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What are 3 organs of plants
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roots
stems leaves |
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What is the purpose of roots
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to anchor, absorb h2o and minerals, and store carbohydrates
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what is the structure of roots
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taproot
lateral root fibrous root |
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root hairs
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are an extension of the cell and increase the surface area for water and mineral absorption
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what is the function of stems
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support
transport storage |
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node
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where a leaf attaches to the stem
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internode
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the distance on the plant between nodes
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axillary bud
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found where the leaf and stem meet -- "armpit"
responsible for lateral growth |
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apical bud
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found at the shoot of the plant
responsible for vertical growth |
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leaf function
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photosynthesis
storage support |
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structure of a leaf
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blade- flat part
petiole- stalk which joins the leaf and stem at the node veins |
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what are the 3 types of plant tissue
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dermal
vascular ground |
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What is dermal tissue and what is its function?
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it is the tissue that forms outer protective coverings
function: protection and preventing water loss |
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Trichomes
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dermal tissue that is specialized to reduce water loss and reflect excess light. it will also deter insects from biting the plant by forming a barrier or secreting toxins
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epidermis
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found in nonwoody plants and is a single layer of tightly packed cells that is an outer dermal tissue
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cuticle
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dermal tissue that forms a wax coating in plants that helps prevent water loss
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periderm
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dermal tissue found in woody plants that will replce the epidermis in older parts of the plant
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Vascular tissue function
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long distance transport between root and shoot system
composed of xylem and phloem |
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xylem
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vertical transport of h2o and dissolved minerals
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phloem
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doesn't transport in a specific direction; it's main function is to transport sugars from where they are made to where they are needed
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Stele
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giant column of vascular tissue in the root or stem
xylem + phloem + pericycle |
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ground tissue function
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photosynthesis
storage support it is basically all other tissue that can't be classified as vascular or dermal |
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pith
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ground tissue that is internal to vascular
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cortex
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ground tissue that is external to vascular
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pericycle
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the first layer in the stele
it is a layer of parenchyma cells in dicots they assist in lateral root development |
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Draw a picture of a dicot root and monocot root. Label the following: epidermis, cortex, endodermis, stele, pericycle, xylem, and phloem
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Done
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Explain the difference in the arrangement of vascular bundles in the stems of monocots and dicots
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dicots are organized in a cylinder fashion where phloem is on the outside and vascular is pointing towards the inside
monocots- the vascular bundles are not arranged in a specific pattern |
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What are the 5 types of plant cells
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parenchyma
collenchyma schlerenchyma trachieds and vessel elements sieve-tube elements |
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What are 4 things that are found in the plant cell that aren't found in an animal cell
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plasmodesmata
cell wall chloroplasts vacuole |
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vacuole
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Storage is its key function.
Stores protein reserve/seeds, stash toxic products, store salts/minerals |
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How does the vacuole cause the plant to swell
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When it stores salts/minerals, water will rush into the vacuole which will cause it to swell
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Tonoplast
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wall around the vacuole
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What is the function of the cell wall?
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to provide structure and support
it pushes back against the pressure of the vacuole when it swells |
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What is the basic blueprint for the cell wall in terms of structure?
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cellulose
middle lamella primary cell wall hemicellulose pectin plasma membrane |
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middle lamella
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thin layer of sticky polysaccharides called pectin that is between the primary walls of adjacent cells
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hemi cellulose and the cell wall
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mess of polysaccharides that cross link cellulose
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pectin
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a matrix of polysaccharides that attract water
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protoplast
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plant cell minus the cell wall
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seconday cell wall
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develops between the plasma membrane and the primary cell wall
adds additional cell protection and support has lignin to create more hardness |
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plasmodesmata
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way that plant cells communicate
penetrates the cell wall |
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Lignin
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heterogenous phenolic polymer, cell wall filler that x-links polysacchariades, hydrophobic
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totipotency
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cells that can differentiate
ie stem cells |
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parenchyma
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generic plant cells
they have primary walls that are thin and flexible no secondary wall ALIVE |
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what is the function of parenchyma
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metabolism and storage
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collenchyma
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Living
they are grouped in strands or cylinders and have uneven thickened primary walls lack seconday walls |
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function of collenchyma
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flexible support
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sclerenchyma
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dead
thick secondary walls with lignin |
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function of sclerenchyma
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rigid support
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two types of sclerenchyma
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schlereids and fibers
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tracheids and vessel elements function
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transport and support
they form non living conduits for water to flow through 2ndary wall with lignin |
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tracheids
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dead at maturity and are foudn in all plants
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vessel
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dead
found mostly in angiosperms |
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seive tube elements function
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transport
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sieve tube elements
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found mainly in the phloem of angiosperms
lack many organelles so they use companion cells to help out use sieve plates that have pores that facilitate the flow of fluid |
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name 3 specialized dermal cells
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guard cells
root hairs bark |
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name 2 specialized ground tissue cells
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fibers and sclerids
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name 3 specialized vascular cells
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sieve tube elements
tracheid vessel |
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what are 2 types of cells that make up dermal tissue
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epidermal
periderm |
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what are 3 types of cells that make up ground tissue
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collenchyma
parenchyma sclerenchyma |
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what are 2 types of cells that make up vascular tissue
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xylem and phloem
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indeterminate growth
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growth that occurs continuously throughout the life of a plant
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determinate growth
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growth that stops at maturity
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Meristem
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areas of embryonic tissues where perpetual plant growth occurs
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two types of meristems
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lateral and apical
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apical meristems are found where? what is their function?
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Found at the roots and shoots (tips)
Function: primary growth |
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lateral meristems are found where? what is their function?
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Two types: cork and vascular cambium
function: to assist in secondary growth (increasing girth) |
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two types of lateral meristems
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vascular and cork cambium
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lateral meristems are only found in what types of plants?
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woody plants
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cork cambium
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replaces teh epidermis with a thicker periderm (2nd layer of tissue, right beneath the periderm/epidermis)
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vascular cambium
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adds layers of vascular tissue called secondary xylem and phloem
located between phloem and xylem |
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contrast primary growth in herbaceous and woody plants
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herbaceous- occurs throughout the entire plant body
woody plants- only occurs in young parts that haven't become woody yet |
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What are the four zones of root primary growth development?
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1.Root cap- tip of the root that provides a protective barrier between the apical meristem and the soil that it is trying to push through
2.Zone of cell division- where the apical meristem is and its derivative cells 3.Zone of elongation- root cells elongate and push the root down 4.Zone of maturation- cells become specialized |
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primordia
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where leaves develop in the shoot apical meristem
provides protection as well |
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axillary buds
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site of meristematic cells that are responsible for lateral growth
located at the "Armpits" of the plant where the stem meets the petiole |
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What is the structure of the vascular cambium? where is it located?
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it is cylinder of meristematic cells, that is 1 cell thick
found between primary xylem and phloem |
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What happens in the vascular cambium
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it expands the interior w/ xylem and exterior with phloem
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the cork cambium forms where?
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outside of the primary phloem
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what does the cork cambium form from?
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parenchyma cells in the cortex
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What are the two tissues of the cork cambium and where are they located?
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phelloderm-inside
cork-outside |
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What happens to cork cells?
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they eventually die and secrete a waxy material called suberin
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what is the function of cork cambium
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for protection of roots and stem
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Explain the formation of the cork cambium
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A) Primary growth will occur and the vascular cambium is formed, which leads to the formation of secondary xylem and phloem
B) Girth will increase. the cells that are external to the vascular cambium can't keep up with this increase in growth leading to rupturing of the epidermis. At this point, the cork cambium is formed from parenchyma cells in the cortex C) Girth will continue to increase leading to more rupturing and the reformation of the cork cambium. Happens in later growth |
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What does the periderm include
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the cork cambium and cork cells
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What does bark include
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everything external to the vascular cambium
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plane cell division determines what?
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the shape of a cell
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What are the two types of plane cell division?
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symmetrical
1 plane --> line 2 plane --> cube asymmetrical |
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what is an example of asymmetrical plane cell division?
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guard cells
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Explain plant cell expansion
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Vacuoles will swell with water uptake
Cellulose will act as a belt to restrict growth Microtubules will direct growth by their orientation affecting where cellulose microfibrils are |
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What is water potential? what does it depend on? how does it flow?
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direction of water movement
high concentration to low concentration depends on solutes and pressure water potential = osmotic potential (solutes) + pressure potential |
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What does solute potential depend upon and why
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the number of solutes in solution
solutes interact with water and bind to it, which decrease the available water molecules that can move freely and perform work |
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what sign ( + or - ) is solute potential
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-
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what is pressure potential and what are its two types?
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the physical pressure on a solution
Positive (+) - added pressure, like pushing water Negative (tension)- taking away pressure, like pulling water |
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what water potential relationship between the environment and the cell causes the cell to swell
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water potential of the cell is less than that of the environemtn
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what water potential relationship between the environment and the cell causes teh cell to shrink
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water potential of the cell is greater than the environment
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What are 3 compartments that water travels through in the cell and how does it occur?
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cytosol
cell wall vacuole happens via diffusion and active transport |
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What are 3 types of short distance movement?
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symplast
apoplast transmembrane |
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Symplast
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movement of water and minerals through the cytosol from cell to cell
connected by plasmodesmata |
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apoplast
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transport of minerals and water through the cell wall of plant cells
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transmembrane
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movement of water and nutrients through the cell into the cell wall of another cell and back into the cell
(combo of symplast and apoplast) |
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endodermis
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the innermost layer of the cortex, the last level before reaching the xylem
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what are casparian strips? what are they made of? what is their function?
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Function: to act as a barrier before the xylem
Made of: suberin, wax They are located on the endodermis they force water and nutrients that are traveling apoplastically to move symplastically |
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transpiration
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the loss of water vapor from the leaves and aerial parts of the plant
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Explain how root pressure moves water as a form of short distance transport
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solutes that are in the xylem will build up because casparian strips won't let them through
this build up will cause a negative water potential, which will lead to water flowing in and pushing water up |
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guttation: what is it and what is its purpose?
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purpose: alleviate root pressure
hydrathodes release water in the morning |
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what are the three types of long distance transport
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water
transpiration pressure flow hypothesis |
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Cohesion and how does it help with the transport of water
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H-bonding between water molecules
helps hold together the column of water that is being pulled up the xylem. when water evaporates, the H-bonds tub on molecules from further down |
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Adhesion and how does it help with the transport of water
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water H-Bonding with a surface
counters the downward force of gravity |
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Surface tension
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how difficult to stretch of break the surface of a liquid
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how does transpiration affect the following: surface tension, evaporation, and pressure potential
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increase in transpiration leads to
increase in surface tension increase in evaporation decrease in pressure potential |
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Explain the transpiration cohesion tension mechanism and water transport
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Main idea: water potential gradient drives the movement of water
The air outside of leaves is drier than the air inside of a leaf. Therefore the water potential outside the leaf is less than the water potential inside the leaf. Water therefore wants to move out of the leaf and does so through stomata's opening and closing (transpiration) and evaporation through air spaces The evaporation and loss of water causes a greater surface tension within the cell, which decreases its pressure potential. A decrease in the pressure potential leads to a decrease in water potential Because water moves from a high potential to low potential, water is then drawn to move towards the area with the lowest water potential, at the leaves. The movement upward is facilitated by the adhesion of water molecules to trachieds and vessels to combat the force of gravity and cohesion between molecules to pull each other up the xylem |
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Explain how stomata's guard cells open and close
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Hydrogen ions are pumped out of guard cells, creating a gradient, and as they are coming back in K+ is cotransported into the cell. Because of the solute build up, water rushes in, causing the cell to swell which leads to opening
The closing of the cell happens in result to the potassium being pumped out |
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Explain cavitation and ways the plant overcomes it
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the formation of gas bubbles in the water column that impedes its movement
Ways to avoid: tracheary elements divert it new tracheary elements are formed root pressure refills the blocked vessels (only in small plants) |
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Explain the pressure flow hypothesis in relation to phloem and the transport of sugars
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Basic idea: low pressure at the "sink" and high pressure at the "source" Water potential always moves from high to low
Phloem is "loaded" using a H+ gradient created by a pump and ATP between compainion cells and sieve tube elements. H+ will then be transported back in and cotransport sucrose This increased in solute concentration causes water to be drawn into the seive tube, which causes the pressure to increase and the water potential to increase. Because the sinks are at a low pressure, the phloem will move towards that area. The pressure in the phloem is then released (phloem unloading) by unloading sugars down their concentration gradient via passive transport |
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Guard cells are what kind of cell?
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specialized epidermal cell
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The mesophyll in a leaf is made up of what type of cells
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parenchyma
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Where is the mesophyll located
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between the two layers of the epidermis on the leaf
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Where do you typically find parenchyma cells?
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Root- where ground tissue is found, in the pith and cortex regions
Leaf- in the mesophyll Stem- cortex and pith regions |
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Where do you typically find collenchyma cells
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in the outer part of the cortex region of a stem
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Sclerenchyma cells are found in what vascular tissue?
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phloem
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The endodermis can be defined as
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the innermost layer of cells of the cortex
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Where do you find the endodermis?
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ONLY IN ROOTS
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Where do you find the pericycle?
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ONLY IN ROOTS
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meristematic cells is synonymous with what?
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embryonic cells or undifferentiated cells--haven't gotten its specialized function yet
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The cork cambium, vascular cambium, and apical meristems are all made up of what type of cells
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meristematic, or undifferentiated cells
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The vascular cambium is only found in
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the stem
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the cork cambium is found in
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the stem of woody dicots
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the pericycle is composed of what types of cells
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parenchyma
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What is the outermost part of the stele?
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the pericycle
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In woody plants, seconday phloem cells differentiate into what?
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sclerenchyma fiber cells, sieve-tube members, and companion cells
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In woody plants, secondary xylem cells differentiate into what?
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tracheids and vessel elements
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Xylem and phloem rays produced by the vascular cambium are made up of what cells?
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parenchyma
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Annual rings in a tree are made up of what kind of cells?
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xylem cells
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Wood is primarily made up of what kind of cells
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secondary xylem
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photosynthesis occurs in what kind of cells?
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parenchyma
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veins are composed of
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vascular bundles
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how many essential nutrients are there?
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17
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how many macronutrients are there?
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9
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how many micronutrients are there?
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8
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what is the wet weight of a plant?
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what is inside of the plant
80-90 percent water |
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turgor pressure
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pressure of the cell contents against the cell wall of a plant
this is determined by the water uptake of the vacuole |
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how does turgor pressure benefit nonwoody plants
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it provides rigidity so that the plants can vertically grow towards the sun
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What are functions of water within the plant
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transpiration
turgor pressure cell wall growth-cell elongation electron donor in photosynthesis acts as a nutrient of H and O |
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What is the dry weight of the plant?
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96% organic material
this om is carbs--cellulose 4% is inorganic material |
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what does essential mean? (in context of being an essential nutrient)
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needed for the completion of the life cycle of a plant
life cycle = seed to seed |
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Why are the essential nutrients essential?
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build monomers
necessary for cellular processes |
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What elements provide for organic material
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C H O N S
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what elements provide for energy transfer
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P and B
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What elements provide for chlorophyll, electrochemical gradients, and enzymes
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K, Na, Mg, Ca, Mn, Cl, Mo
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What elements provide for electron transfer
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Fe, Cu, Zn
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What are the 3 sources of nutrients in plants
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Air
Water Soil |
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What provides 96% of dry weight of soil?
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Air
C and O |
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What source provides the wet weight
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water
H and O |
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What charged ions lead to leaching in soil?
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negatively charged because clay is a negatively charged particle
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what charged ions are retained in the soil
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typically positive ions because they are attracted to the negative charged particle in soil
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Explain cation exchange between roots
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Because the soil holds onto positively charged particles, the soil can't directly take them up.
The root will then exchange ions with the particles of the soil. CO2 reacts w/ water to form carbonic acid, which then forms bicarbonate which releases a proton to be exchanged w/ a cation from the soil |
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how does pH affect nutrient availability
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can alter the presence of microogranisms
change retention of ions can increase or decrease solubility forms complexes that plants can't absorb |
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what are resevoirs for nitrogen
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atmosphere (big one)
biomass dissolved in water bound to soil |
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how many atps are required to break the triple bond of n2
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16
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What do N fixing bacteria do
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That atm N2 and make ammonia
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what do ammonifying bacteria do
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take OM (humus) and make ammonia
Decomposers |
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what do nitrifying bacteria do
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take ammonium and turn it into nitrate
they oxidize it for energy |
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what do denitrifying bacteria do
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exist in anaerobic environments
take nitrate and turn it into atmospheric nitrogen |
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what form of N do plants like most
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nitrate
although they will absorb ammonium |
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mutualism
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both benefit
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parasitism
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one benefits the other doestn'
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examples of mutualism
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legumes and rhizobia
plants and fungi |
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examples of parasitism
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plant competition
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what is the 2nd most important class of crops
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legumes
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green manure
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a cover crop that is grown for its nutrients and organic matter that it adds to the soil
it eventually gets plowed under and into the soil |
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intercropping
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a legume is grown between a primary crop like wheat
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What are the two chemicals that are used to form mutualism? who emits them?
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Flavonoids- emitted by plant
Nod- emitted by bacteria or rhizobia |
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Explain the process of forming mutualism
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The roots and bacteria will emit flavonoids and nods.
Upon the receival of the nod, the roots will deform, elongating, and will make an infection thread that the bacteria enters. Cortex and pericycle cells will begin to divide and the bacteria is lead by infection thread to that spot. A nodule is formed out of the dividing cells and a bacteriod is found in the center. At this point N2 can be fixed. Maturation of the nodule occurs, where vascular tissue is developed to allow for the exchange of sugars and nitrate |
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what enzyme helps nitrogen fixation
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nitrogenase
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what kind of environment do the N fixing bacteria need to live in. Why is it a problem
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anaerobic
that means no O2 for the plant |
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How do plants overcome the oxygen problem with n fixing bacteria
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they have leghemoglobin
this acts as an oxygen buffer |
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explain what benefits the host and symbiont get out of plant and mycorhhizae mutualism
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plant- gets more water and P
mycorrhizae- get carbs |
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ectomycorrhizae
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found externally on tree roots
increases the surface area to pick up water never penetrates the cell but has hyphae that chill between cortical cells |
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endomycorrhizae
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mycorrhizae that will penetrate the cell wall of the plant root cells
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the periderm is made up of what material? and what does it do?
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suberin
it blocks anything from coming in or out |
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Why doesn't the cork cambium block water and mineral uptake in the roots
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Primary and secondary growth occurs at the same time but in different locations in the plant.
In the case of the roots, secondary growth occurs in older parts of the roots where growth isn't occuring anymore. Water and mineral uptake occurs at the root apical meristem |
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what are the 3 basic steps in signaling
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reception
transduction response |
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Explain reception in plant signaling
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A protein will receive a stimuli (light or hormone) which will causes a change in the protein conformation.
proteins are specifically designed to receive a specific stimuli |
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explain the transduction phase in plant signaling
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The stimulus message is sent by relay proteins and 2nd messagers to activate cell response
it is amplified so that the message is sure to be received |
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Explain the process of etiolation and de etiolation
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Etiolation occurs when a plant is growing underground. It will keep its leaves unexpanded and protected by the apical hook in order to prevent leaf damage and using unncessary cholorphyll.
When the plant reaches the surface and receives light, it triggers a response that leads to the opening of the plant leaves and undergoing photosyntheis (de-etiolation) |
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Explain an example of stimuli and response in relation to seed germination
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Light triggers germination in plants
Dark = no germination Light = germination Specifically Red light = germination Far red light = no germination When phytochrome Pr absorbs red light it will turn to phytochrome Pfr which turns on seed germination |
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What is a phytochrome and a chromophore?
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Phytochrome is a protein subunit that absorbs red light
Chromophores and the light absorbing subunit of phytochromes |
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What are the two forms of phytochrome?
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Pr and Pfr
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what are hormones and how do they affect a plant?
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the are small chemical signal molecules
they affect cell growth and cell differentiation |
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phototrophism
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the growth of a plant shoot either towards ( + ) or away ( - ) from light
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Auxins and who discovered them
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class of hormones that promote growth of the plant through cell elongation
charles darwin and his son discovered it |
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Explain the process of auxin being discovered and how it affected plant growth.
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Charles Darwin and son made observations that a plant would grow in different directions in response to light. They hypothesized that they coleoptile was responsible for it. Through different tests messing with the coleoptile they discovered that it was responsible for the plants response to light.
Another scientist (Boysen-Jensen) then discovered that there was a mobile chemical signal that was promoting the growth. He did so by separating the tip from the rest of the plant. Lastly, another scientist (Went), discovered that the coleoptile sent this chemical down the plant to encourage growth. He captured the chemical in an agar block. Cut off all the coleoptiles of the plants and put the plants in the dark. He placed the agar on different places on the plant and it encouraged different bending. |
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Explain the transport of auxin, why is it polar?
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Auxin will travel in one direction-downward
The proteins for auxin transport are located at the bottom (basal) end of the cell |
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Explain the acid growth hypothesis
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Axin stimulates a proton pump which will create an electrochemical gradient
The increased acidity will acidify the cell wall causing the cellulose fibers to loosen. Enzymes will also be activated by the low pH. Enzyme 1 will loosen hemicellulose Enzyme 2 will cleave the hemicellulose The cellulose will slide and the cell wall will expand in response to the increased swelling of the vacuole. (The increase voltage bring in K+ which bring water into the vacuole) |
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Relate auxin and phototrophism
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Auxin concentration is greater on the darker side of the plant, which causes more growth. Auxin concentration is lower on the light side so it doesn't grow as much which causes bending
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Gravitrophism
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plant growth in response to gravity
+ with gravity - away from gravity |
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Explain auxin in relation to roots and gravitrophism
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Roots will "droop" due to gravity which special organelles called statoliths will recognize. This leads auxin being sent to the statoliths at the "drooping" area to stimulate linear growth
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which cells can be totipotent?
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parenchyma
they can be kept in an undifferentiated state in the right conditions |
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cytokinins
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hormone that is involved in cell division and differentiation
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auxin, cytokinins, and root and shoot growth
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auxin and cytokinin ratio affects which part of the plant grows
low amount of cytokinin = root growth high amount of cytokinin = shoot growth |
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Explain apical dominance
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The regulation of the suppression of auxillary bud development by the ratio of auxin and cytokinin
increased auxin coming down from the SAM --> no auxillary bud increased cytokinin coming up from the root --> auxillary bud RATIO IS KEY |
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Gibberellins
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hormone that stimulates leaf and stem growth
involved with fruit growth |
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Gibberellins and seed germinatino
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gibberellins stimulate the hydrolisis of alpha amlyase in order to make disaccharides to help with seed germination and growth
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abscisic acid: what is it and what are some examples where it is found?
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The anti hormone that slows growth
associated with seed dormancy and water stress (opens K+ channels to close guard cells) |
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Ethylene: what is it? and how does it help fruit ripening?
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It is a gaseous hormone
in fruit ripening it activates enzymes hydrolase and pectinase to break down the cell wall which leads to the softening of fruit and creating sweet sugars |
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what are qualities of model organisms for biotechnology
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short life cycle
small available easy to manipulate biologically relevant to other organisms small genome to sequence |
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Arabidopsis thaliana
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the first plant that had its genome sequenced
the most studied plant 125 million bases |
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In how many years has genome sequencing rapidly changed?
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20 years
from doing it by hand and maybe getting 2400 nucleotides a day, to getting 1,000,000,000 nucleotides |
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Rice as a model genetic modification plant
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2nd genome sequenced
Pro: agriculturally relevant Con: hard to grow and has a longer life cycle |
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what is the benefit of brachypodium distachyon as a genetic model plant?
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it is related to many grasses and grains
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artificial selection
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humans selecting the desirable traits of plants and breeding them for them
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seedless watermelon
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are sterile w/ an odd number
treated with colchincine to deplymerize microtubules which help in chromosome segregation |
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bananas
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propogated asexually
seedless no genetic variation |
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transgene modification
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transferred gene into genome
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transgenic modification
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genome is modified through recombint dna technology that carries genes from other organisms
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how was golden rice created
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2 genes of a daffodil and 1 gene from a bacteria were incorporated into the genome of the rice to increase its yield of beta carotine to decrease vitamin a deficiency
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bacillus thuringiensis
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used against insects
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agrobacterium tumefaciens
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a naturally occuring genetically modifying bacteria that is associated with the plant disease crown gall
it modifies the plant genome of the inflected plant by injects a segment of DNA into the plant cell |
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selectable marker
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a gene that is introduced into the cell to serve as an indicator of whether or not successful genetic modification has occured
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rainbow papaya
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is resistant to the ringspot virus
buffers the non gmo papaya from getting it, but can cross breed with it to continue to make gma papaya |
