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114 Cards in this Set
- Front
- Back
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a stolon is a modified (stem/root/leaf)? |
stem
above ground stems with indeterminate growth that allows a plant explore surrounding territory. If ground is suitable it made adventitiously roots at the nodes |
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a tendril is a modified (stem/root/leaf)?
How is it modified? |
stem OR leaf!!
elongated twining stems (axillary buds) or leaves. Wrap around other objects to support itself. |
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a cladode is a modified (stem/root/leaf)?
How is it modified? |
Stem
Flattened green stems that function as leaves. Often succulent, as in Christmas cactus. |
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a thorn is a modified (stem/root/leaf)?
How is it modified? |
Stem
hard and sharp pointed- can be large spikes. |
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a bulb is a modified (stem/root/leaf)?
How is it modified? |
stem & leaves
A composite of a highly compressed stem surrounded by numerous storage leaves (store carbs and starch for plant use- shrivel during vegetative growth) |
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a rhizome is a modified (stem/root/leaf)?
How is it modified? |
stems
like stolons (explore surrounding habitat) but UNDERGROUND. sometimes swollen for food storage |
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a corm is a modified (stem/root/leaf)?
How is it modified? |
stem
short vertical stems, much like bulbs, but with no leaf tissue. Corms are entirely stem tissue. Dense and woody. |
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a tuber is a modified (stem/root/leaf)?
How is it modified? |
stem OR root!!
function is storage during vegetative dormancy. Determinate growth. Stem tuber eg: potato Root tuber eg: carrot, sweet potato |
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Spines are modified ________.
example? |
LEAVES
eg. catcus |
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Modified leaves which act as petals are called _______.
example? |
Floral Bracts.
eg: poinsettia |
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leaves of an onion bulb, or an individual clove of garlic are examples of what?
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storage leaves
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carnivorous plants display modified ______.
examples? |
leaves.
eg: snap trap in venus fly trap, sticky fly-paper leaves in the sundew, and pitchers. |
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Plants with leaves modified for asexual reproduction are called _________. How do they accomplish asexual reproduction?
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Maternity Plants.
Leaves bear "Plantlets" (clones of mother that detach and root adventitiously.) |
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roots that allow for gas exchange in stagnant areas?
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Pneumatophores
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sweet potatoes are an example of....?
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storage roots (root tubers)
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close to ____% of water taken up by plants in a day is lost through the stomata.
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99%!!
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How many stomata per squared cm?
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10,0000-100,000 stomata/ cm2!!!
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Water that is lost from the surface of a plant is called…
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transpiration.
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tendency of water molecules to escape at the leaf surface?
(relatively high or low?) |
"enormous"
a person would have to drink 40 L of water a day to scale with a corn plant. |
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speed of water inside a plant?
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up to about 75 cm per minute
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How does water move in the plant?
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cohesion and adhesion...no pump, no metabolic energy required!
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The force that pulls water (and even the mercury) up from the reservoir is called_____.
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tension
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tension is _____ pressure.
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negative
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Three forces that enable water movement in the xylem?
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tension, adhesion, cohesion
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What causes the wave of tension in the water column that runs from the leaf all the way down to the soil?
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transpriration
release of water molecules tugs on the "chain" |
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What is a tension wave?
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When transpiration causes the tension/stretching of the water in the xylem from the stomata, all the way down to the root hairs!
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define diffusion
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net movement of molecules from an area of higher concentration to an area of lower concentration.
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define osmosis
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diffusion of water across a differentially permeable membrane… aka semi-permeable membrane.
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An area of high osmotic pressure in plants is called...?
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turgor pressure
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Explain Mass Flow in plants.
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Sugars & nutrients move down phloem to roots and other parts of plant (to lower concentrations), while water moves up xylem to leaves (to lower concentrations of water).
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osmostic "sinks" for sugars and nutrients?
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roots
meristems actively growing areas storage tubers stobili flowers/ fruits *At night chloroplasts become a sink! |
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osmostic sources for sugars and nutrients?
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leaves
storage tubers Photosynthetic stems |
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While movement of water and minerals through the xylem is driven by _________ most of the time, movement through the phloem is driven by __________.
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negative pressures (tension)
Positive hydrostatic pressures |
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__________results from higher relative osmotic potential in the roots at night (root pressure) because transpiration in the shoots has virtually stopped
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guttation
(the appearance of drops of xylem sap on the tips or edges of leaves of some vascular plants) |
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What is guttation?
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the appearance of drops of xylem sap on the tips or edges of leaves of some vascular plants
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Non-woody plants have _____ to keep them from wilting.
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turgid cells
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_____have a secondary cell wall which keeps them from wilting without woody tissue or turgid cells.
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collenchyma
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What is a type of secretory tissue in leaves that secretes water through pores in the epidermis or margin of leaves (typically at the tip of a serration.)
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a hydathode
"pressure relief valve" |
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How do stomates open and close?
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It requires active transport of K+.
When the cells fill up with water and k+, they buckle and open., when pressure is released, stomata close. |
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What is an organic compound made in one part of the plant, transported to another part of the same plant, where it elicits a response.
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hormone
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define plant hormone?
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organic compound made in one part of the plant, transported to another part of the same plant, where it elicits a response.
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Name the 5 families of plant hormones.
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1. Auxins
2. Gibberellins 3. Cytokinins 4. Ethylene 5. Abscisic Acid |
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Jobs done by AUXINS?
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Cell wall plasticity (stretchability)
Apical dominance Abscission of leaves and fruit Vascular tissue differentiation Fruit development (auxin from seeds!) Phototropism Gravitropism the production of ethylene |
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_____is a common synthetic auxin
that kills broad-leaved plants at the recommended dose but not grasses. |
2,4-D
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the most common auxin is ....?
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indole-3-acetic acid (IAA)
aka rooting solution |
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Jobs done by Gibberillins?
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Growth: cell division and elongation
Seed germination: breaks dormancy Juvenility: apply GA to adult branch results in juvenile leaves! Flowering: e.g. biennial plants/ bolting Fruit growth and artificial enlargement ( e.g. grapes) |
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cytokinins are related to Which nucleotide?
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adenine
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Jobs done by Cytokinins?
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Cell division
Organogenesis (interactions with auxins) Delay of senescence in leaves –prolongs greenness Delay of senescence in flowers (cut flowers!) |
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the airborne plant hormone, synthesized from the amino acid methionine?
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Ethylene
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Which hormone explains the contagion effect?
“one bad apple spoils the whole batch!” |
Ethylene
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Jobs ETHYLENE does?
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Fruit ripening
Synchronized flowering (e.g. mangos, pineapples) Flower senescense/aging (e.g. orchids) Leaf abscission (breakdown of the middle lamella) Sex expression Stem elongation/ thigmomorphogenesis (strong stout plants) rooting/ moisture content of soil/ waterlogging effect on the development of root hairs Wounding/ freezing and contagious effects (e.g. abscission of damaged parts)… tree-to-tree warning of insect threat! |
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What is thigmomorphogenesis?
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When a plant exposed to touch/wind becomes strong and short (compact)
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What is the main job of Abscisic Acid ?
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to counter other hormones' jobs.
Makes things go dormant |
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What is Phototropism?
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movement toward light orchestrated by auxins in the apical meristem.
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Darwin's experimanet with oats found _____in the Coleoptiles( the pointed protective sheath covering the emerging shoot in monocots).
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Auxins
(when tips/coleoptiles were covered, no phototropism!) |
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What hormone(s) involved in thigmomorphogenesis?
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auxins and ethylene
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define pulvinus/pulvini
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a joint-like thickening at the base of a plant leaf or leaflet that facilitates (nyctinastic and thigmonastic) movement.
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What is circumnutation?
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the “questing” behavior of plants such as vines.
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Tern for when plants move parts of their bodies (leaves and/or stems and /or flowers) in response to the movement of the sun.
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solar tracking
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What is Seismonasty?
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response to vibration
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How does Seismonasty, response to vibration, work?
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Leaf or leaflet is held up by the petiole when flexor cells are turgid and extensor cells are flaccid, K+ water rushes out of flexor cells and sugar water rushes into extensor cells, dropping the leaf
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What is nyctinasty?
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noctural “sleep’ response – due to leaf pulvini
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What is a photoperiod?
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the ratio of length
of day to the length of night |
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Absorption of red light by Pr (phytochrome red) converts it into...?
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Pfr
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Absorption of far red light by Pfr (phytochrome far red) converts it into
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Pr
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In the dark, Pfr (phytochrome far red) spontaneously converts to
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Pr
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Give examples of each:
day-neutral plants short-day plants long-day plants intermediate day plants |
day-neutral plants dandelion
short-day plants potatoes long-day plants radishes intermediate day plants sugarcane (subtropical) |
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When does each flower? :
day-neutral plants short-day plants long-day plants intermediate day plants |
day-neutral plants flower anytime
short-day plants Flower in the fall long-day plants Flower in the spring/summer intermediate day plants only flower if day length is 12 hr |
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5 things phytochrome is involved in?
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Flowering (previous slide)
Etiolation (response to shade) Competitive growth (response to light quality and filtering of light by competitors) Seed germination (detection of appropriate conditions i.e. near enough to surface?) Leaf senescence (preparation for the cold or dry season) |
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what is etiolation?
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a process in flowering plants grown in partial or complete absence of light characterized by long, weak stems; smaller, sparser leaves, etc
** "quest" for light and don't green up until they find light. |
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What are circadian rhythms?
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daily rhythms: Mysterious “hardwired” phenomena that occur regardless of conditions (even temperature).
Eg flowers that open and close on a daily schedule leaves that fold and unfold on a daily schedule |
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A method of plant propogation in which stems still attached to their parent plants may form roots where they touch a rooting medium. Severed from the parent plant, the rooted stem becomes a new plant.
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Layering
layering can be done in the air- mid branch using sphagnum moss! |
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What is a scion?
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a detached shoot or twig containing buds from a woody plant which is grafted onto the stock
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what does facultatively autotrophic mean?
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Can be an autotroph or heterotroph,
like euglena! |
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What is photosynthesis?
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…the conversion of energy contained in light (photons) into energy contained in the chemical bonds of reduced biomolecules (e.g. ATP, NADH, NADPH, glucose, etc.).
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Oxidation is ...
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loss of electrons – oxidized molecules have been de-energized. (energy has been released).
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reduction is...
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gain of electrons – reduced molecules have been energized. (this requires energy input).
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is photosynthesis net oxidation or reduction?
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reduction
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chemical equation for Photosynthesis?
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Light + ATP + CO2 + Water + NADPH --------> ADP + NADP + O2 + GLUCOSE
(net reduction) |
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structure of ATP?
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An adenine, a sugar and 3 phosphates...this is a nucelotide!
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What is the function of Nicotinamide?
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It's the electron carrier-
NAD+ when oxidized, NADH when reduced! |
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NADPH is similar to NADH; the difference is ______________.
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a mono-phosphate group
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the most important electron carriers in photosynthesis are _______ & _________.
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ATP and NADPH
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What goes into the calvin cycle (in the chloroplast) and what come out?
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In: ATP, NADPH, CO2
Out: NADP+, ADP, Glucose and other carbon molecules (some glucose is broken into pyruvate and ATP) |
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What are the dark reactions?
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Reactions that occur in the stroma, aka, the calvin cycle
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What comes out of photosystems II and I?
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(first) photosystem II: ATP, O2
Photosystem I: ATP, O2, NADPH |
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What goes into and out of the KREBS cycle (in mitochondria)?
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In: NAD+, pyruvate
Out: ATP, CO2 and NADH |
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What goes into and out of the electron transport system?
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In :O2, NADH, electrons
Out: NAD+, H2O, ATP |
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Helibacterium
(chlorophyll c) are ancetors of .... |
chloroplasts
of “brown plants” |
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cyanobacterium
(phycobilins) are ancestral to.... |
the red plants
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Chloroxybacterium
(chlorophyll b) are ancestral to.... |
chloroplasts
of “green plants” |
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What is a pigment?
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a molecule that absorbs light and consequently reaches a higher energy level
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3 things can happen when light hits a pigment- what are they?
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secured as chemical energy and/or
re-emitted as light of a different wavelength and/or dissipated as heat |
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What happens if pigments are disorganized?
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fluorescence
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To secure light energy as chemical energy, photosynthetic pigments must be organized in the context of photosystems that are embedded on the ___________.
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thylakoid membranes
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the most important photosynthetic pigment?
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Chlorophyll a- the most abundant & ancestral pigment!
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oxidized carotenoids are called...
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xanthophylls
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What is the purpose of Carotenoids and xanthophylls?
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They extend the range of photosynthesis by absorbing light that is not absorbed by chlorophylls
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beta carotene, lycopene are examples of .....?
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Carotenoids
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What is photo-oxidation?
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a process that occurs when excited chlorophyll transforms oxygen into high-energy radicals..
Carotenoids protect against this |
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Problem with "free radicals"?
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can attract hydrogen away from adjacent molecules – this can disable or destroy the molecule – or cause mutation to DNA
(carotenoids protect against free radicals) |
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what are the photochemical and biochemical reactions?
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photochemical- light reactions (photosystems)
biochemical- dark reactions (Calvin) |
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Most photosynthetic cells contain _____ chloroplasts; about _______ chloroplasts per square millimeter of leaf surface is normal.
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40-200
500,000 |
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Photolysis: where does it occur, what does it produce?
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Breaks up water in photosystem II.
H2O gives off protons for ATP and electrons for the Electron transport system |
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cells that contain chlorophyll?
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palisade parenchyma
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The photochemical reactions use ______ to produce ______.
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light
ATP & NADPH |
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The biochemical reactions use _____ to produce _____.
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ATP and NADPH (from light rxns)
sugars (reduced CO2) |
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stroma?
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gelatinous-fluid
matrix in which Dark (biochemical) reactions (Calvin Cycle) occur! |
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What happens in photosystem I?
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reduces NADP* to NADPH
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pH is chloroplast stroma?
Thylakoid space? How does this help photosynthesis? |
stoma: 8
thylakoid: 5 (1000X that of stroma!) the proton gradient supplies the “power” for the reduction of NADPH from NADP+ |
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Chemical summary of photosynthesis.
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2H2O + 2NADP+ + 3ADP + 3 Pi (photochemical)
+ 8 photons ----> O2 +2NADPH + 3ATP + 4e- +2H+ (biochemical) |
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C4 plants utilize _________ of the light and dark reactions
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spatial separation
(sectioned off) |
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CAM plants utilize _________ of the light and dark reactions.
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temporal separation
(night and day) |
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Thigmonasty?
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response to movement, such as in the Venus fly trap.
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