Plant Biology Exam 3 (Ch.11-13)

absorption spectrum

a graph of the relative ability of a pigment to absorb different wavelengths of light

action spectrum

a graph of the relative rates of reaction of a process as influenced by different wavelengths of light

anabolic reactions

a reaction that produces larger compounds from smaller precursors, for example, the synthesis of glucose from molecules of acetlyCoA

ATP synthase

C3 or Calvin Cycle

One type of stroma reaction

c4 metabolism / c4 photosynthesis

a set of metabolic reactions in which carbon dioxide is fixed temporarily into organic acids that are transported to bundle sheaths, where they release the carbon dioxide and C3 photosynthesis occurs

chemiosmotic phosphorylation

the synthesis of ATP and ADP and phosphate using the energy of an osmotic gradient and a gradient of electrical charge occurs in chloroplasts and mitochondria.

CAM metabolism

cyclic electron transport

the flow of electrons from P700 back to plastoquinone in photosynthesis, such that there is proton pumping but no synthesis of NADPH

cytochromes

small electron carriers that contain iron

electron transport chain

a series of electron carriers that transfer electrons from a donor which becomes oxidized to a receptor which becomes reduce.

grana

a set of flat vesicles in chloroplasts involved in chemiosmotic phosphorylation

light compensation point

the level of illumination at which photosynthetic fixation of carbon dioxide just matches respiratory loss. 

light-dependent reactions

in photosynthesis, the set of reactions directly driven by light

noncyclic electron transport

the flow of electrons from water to NADPH during the light-dependent reactions of photosynthesis

photon

a particle of light energy, also called a quantum

photorespiration

the oxidation of phosphoglycolate produced when RuBP carboxylase adds oxygen, not CO2 to RuBP

photosystem I

the pigments and electron carriers that transfer electrons from P700 to NADPH

photosystem II

the pigments and electron carriers that transfer electrons from water to P700 in photosystem I

pigment

any chemical that absorbs light. in botany, they are important either because they light they absorb initiates a reaction (like photosynthesis) or it produces colors that make flowers and fruits visible to animals. 

plastocyanin

a copper containing electron carrier

plastoglobuli

a droplet of lipid located within a plastid

plastoquinone

a class of lipid-soluble electron carriers 

reaction center

a special chlorophyll a molecule actually involved in the transfer of electrons in photosynthesis.

RuBP carboxylase / RUBSICO

the enzyme in photosynthesis that carboxylates RuBP thus bringing carbon into the plants metabolism

stroma

in chloroplasts, the fluid material located between thylakoids

stroma reactions / dark reactions

in plant photosynthesis, the set of reactions that occur in the stroma are not directly powered by the light

thylakoid lumen

the photosynthetic membrane of the chloroplasts

respiration

the breakdown of molecules such that part of their energy is used to make ATP id oxygen is required as an electron acceptor, the process is aerobic respiration, if not it is anaerobic respiration.

pentose phosphate pathway

a type of respiration in which glucose is converted either to ribose or erythrose

obligate aerobes / strict aerobes

an organism that must have oxygen to survive

obligate anaerobe / strict anaerobe

an organism that is killed by exposure to oxygen

lactic acid fermentation

Krebs cycle / citric acid cycle 

metabolic pathway in which acetly-CoA is oxidized to carbon dioxide as reduced electron carriers are generated

glycolysis

the metabolic pathway by which glucose is broken down to pyruvic acid

fermentation / anaerobic respiration

respiration that uses any substance other than oxygen (plants and fungi typically use pyruvate or acetaldehyde) as the ultimate electron acceptor.

facultative aerobe

an organism that can use oxygen in present or survive without it 

alcohol fermentation

cytochrome oxidase

cyanide-resistant respiration / thermogenic respiration 

respiration in which electron transport is uncoupled from ATP synthesis so heat is generated.

Acetyl-CoA

a small molecule containing two carbons attached to a carrier molecule named CoA, this carries two carbon units from one metabolic pathway to another

aerobic respiration  

respiration that used oxygen as the ultimate electron acceptor.

active transport

the forced pumping of molecules from one side of a membrane to the other by means of molecular pumps located in the membrane

adhesive

in water transport, water is described as this because water molecules stick or adhere to other water molecules

apoplast

the intercellular spaces and cell walls of a plant all the volume of a plant that is not occupied by the protoplasm

aquaporin

a membrane protein that permits water to cross the membrane rapidly

callose

a long-chain carbohydrate polymer that seals certain regions, such as damages sieve elements or growing pollen tubes

cavitation

in xylem, the breaking of a water column when tension overcomes the cohesive nature of water; an embolism forms

cohesion-tension hypothesis

hypothesis that as water is pulled upward by transpiration, its molecules cohere sufficiently to withstand the tension

cohesive

in water transport, water is described as this because water molecules stick to or cohere to any molecules capable of forming hydrogen bonds

diffusion

the random motion of particles from regions of higher concentration to regions of lower concentration

eutrophication 

the process that occurs as rivers and lakes receive too many mineral nutrients (usually as pollution from fertilized fields) they develop an overabundance of algae, much of which dies and decays, depleting the oxygen in the water and harming the fish. 

incipient plasmolysis

as a plant cell is losing water and shrinking, the point at which the protoplast just begins no longer to exert pressure against the wall

long-distance transport

in movement within a plant, long-distance transport involves distances greater than a few cells, typically either xylem or phloem or both are involved

megapascal (MPa)

a unit for quantifying pressure; 1 MPa is about 10 bars or 10 atm of pressure

molecular pump

an integral membrane protein that forces molecules from one side of a membrane to the other, using energy in the process called active transport.

osmosis

diffusion through a membrane

osmotic potential!

a component of water potential; a measure of the effect of solute particles on a substance’s ability to absorb or release water

plasmolyze

the shrinking of a cell due to loss of water, not to confused with lysis

pressure flow hypothesis

the hypothesis that flow in phloem is due to active loading in sources and active unloading in sinks.

pressure potential

a component of water potential, a measure of the effect of pressure or tension on a substance’s ability to absorb or release water.

selectively permeable membrane

a membrane that is relatively permeable to some substances and relatively impermeable to others

short-distance transport

in movement of material within a plant, this transport involves distances of only a few cells; xylem and phloem are not involved.

sinks

in phloem transport any organ or tissue that receives material transported by the phloem

sources

in phloem transport, any organ or tissue that supplies material to be transported

symplast

the protoplasm of all the cells in a plant are interconnected by plasmodesmata; the entire mass is this

water potential

the chemical potential of water; a measure of the ability of a substance to absorb or release water relative to another substance.