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54 Cards in this Set
- Front
- Back
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Characteristics of Animals |
-Chemoheterotrophic -Energy & C source- acquisition of energy rich organic substances as food -Consumer -Limited Growth -Free moving -Most cells without rigid extracellular matrix -No chlorophyll |
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Characteristics of Plants |
-Photoautotrophic -Direct use of sun's energy CO2 as C source -Producer -Unlimited growth -rooted to substrate -Rigid Cell Walls -Chlorophyll |
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Endodermis |
-Living cylinder of cells that acts as a barrier to apoplastic fluids |
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Eudicot Root |
-Root with xylem and phloem in the centre |
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Monocot Root |
Root with parenchyma in the centre |
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Shoot system |
Made up of stem and leaves |
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Axillary Bud |
-Grow into new branches -Found wedged between the stem and a branch. |
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Rhizomes |
-under the ground (not root- modified stem) -vertical shoots grow from axillary buds on the rhizome |
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Bulbs |
-bulbs are vertical underground -shoots consisting mostly of the enlarged bases of leaves that store food -many layers of modified leaves (ex. onion) |
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Meristems |
-located at shoot -a tissue in most plants containing undifferentiated cells -keeps plant growing |
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Formation of branches |
-Different because roots grow from everywhere to keep plant stable whereas branches grow out of certain places |
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Leaf |
-Made of blade and petiole -Simple Leaf- single undivided blade (some of deeply lobbed -Compound Leaf- Blade consists of multiple leaflets (leaflets have no axillary buds at base) -Doubly Compound Leaf- divided into smaller leaflets -Parallel veins or branched veins |
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Types of Leaves |
-Spines- cacti -Storage Leaves-adapted for storing water- ice plant -Bracts-attract pollinators- red poinsettia leaves -Reproductive Leaves- create adventitious plantlets (fall off the leaf and take root in the soil)- Kalanchoe daigremontiana |
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Advantages of Living In Water |
-No need for massive support -No shortage of water -release of gametes into the water -surrounded by water, nutrients, and gases |
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Disadvantages of Living In Water |
-Light drops very quickly in clear water- reduces photosynthesis -Big shortages of CO2 and Oxygen |
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Disadvantages of Living on Land |
-Gravity has to be overcome- early plants only contained cellulose and lacked lignin -Water less plentiful -Water/nutrients at different locations than gases -dispersal of gametes |
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Adaptions to life on Land |
-Larger leaves to increase photosynthesis -Water transport systems- from soil to leaves -Support of plant body- thicker cell walls & lignin |
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Cause of Upward Growth |
-Due to "new" lignified xylem tissue -Not due to increased photosynthetic surface |
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Photosynthesis |
-largest biosynthetic activity on the planet -160 billion tons of carbohydrates per year -produces oxygen (O2) |
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Leaf Cross Section |
-photosynthesis is performed in green plant tissues(chloroplasts) -in cyanobacteria: in thylakoid membranes |
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Process of Photosynthesis |
-H2O + CO2 + Light --> Glucose (C6H12O6) +6O2 -Light is from the sun which provides electromagnetic energy -energy (glucose) is stored in chemical bonds within carbohydrates -photosynthesis is about energy capture in bonds **Page 12 of Topic3** |
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Energy Needed for Photosynthesis |
-8 photons= 1408 KJ mol^-1 -only 2526 KJ mol^-1 - 2072 KJ mol^-1 = 479 KJ mol^-1 of energy used for the reaction 479/1408 *100= 34% efficiency (old LCD light bulbs had 3% efficiency) |
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3 Steps of Photosynthesis |
1.) Photochemistry (light reaction) 2.) electron transfer (and production of NADPH &ATP (Light reaction)) -located in thylakoid membrane and thylakoid space (lumen) 3.) incorporation of CO2 into carbohydrate (and production of O2 (dark reaction/calvin cycle)) - located in stroma |
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Light |
-electromagnetic radiation. we characterize it by its energy (wavelength = (upside down y)) -short upside down y- high energy level (UV rays) -high upside down y- lower in its energy (red) |
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Three classes of light- absorbing compounds |
PIGMENTS -chlorophylls (chl) :chl a and chl b -carotenoids -phycobilins (only found in red algae and cyanobacteria which have chl a and chl c) -pigments absorb certain wavelengths of the visible light. each pigment has its own absorption spectrum |
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Chlorophyll Colour |
-absorbs approximately 70% of the red and blue wavelength light -unabsorbed green light bounces back to eye -chloroplast looks green - chloroplast does NOT absorb green |
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Wavelengths that Drive Photosynthesis |
-400-700nm -Blue and red light |
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Excitation Energy Exploited in the Chloroplast |
i. the pigments are linked together in 'light harvesting complexes' - chl a, chl b, carotenoids ii. These are connected to 'reaction centres' - transfer of electrons to primary electron acceptor -light harvesting complexes & reaction centre - photosystem |
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Excitation Energy Steps |
1.) Light excites pigment in PSII-excited electron- this e falls to ground state another e in nearby pigment is excited- e in pigment P680 is excited 2.) Transfer of e from chlorophyll a pair (P680) to primary electron acceptor (now P680+ missing e) 3.) e hole in P680+ must be filled:P680+ is the strongest biological oxidizing agent known- pulls e from water |
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ATP and NADPH |
-ratio is 1:1 - oxygen is a byproduct (waste product) -photophosphorylation- is the process of turning ADP to ATP using sunlight - When ATP is needed more than NADPH e recycling occurs- cyclic electron flow within PS I! |
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Photosynthesis in Darkness |
-All light reactions (photochemistry, electron transport, splitting water, production of protons) stop -Dark reactions continue as long as substrates are available (calvin cycle) |
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Compounds to Transfer Energy |
1.) photochemistry (light reaction) - pigments transfer radiant energy to chemical bonds 2.) electron transfer (and production of NADPH & ATP light reaction) - enzymes transfer chemical energy 3.) incorporation of CO2 into carbohydrate (and production of O2 dark or calvin reaction)- enzymes transfer chemical energy |
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RuBisCO |
-Ribulose bis phosphate carboxylase/ oxygenase -over millions of years plants changed the atmospheric gas composition- [O2] from 2-20% -plants paid a price- O2 went up and RuBisCO became increasingly inefficient |
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RuBisCO Formula |
Normally-RuBP + CO2 --> 2 x 3C G3P Occasionally- RuBP +O2--> 3C G3P +2C compound -useless compound- transformed into G3P (involves chloroplast peroxisome and mitochondria)- produces CO2( called photorespiration) |
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Grapes |
-Filled with glucose and water -Cell wall can stop the diffusion of water into the cell -Cell vacuole regulates water intake |
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Plastid |
-Proplastid is undifferentiated and can turn into chloroplast -upon light- proplastid matures into chloroplast -dark- proplastid differentiates into etioplasts -plastids with high concentrations of carotenoid pigments (chloroplast can convert to chromoplasts- fruit starts off green then converts (strawberry)) |
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Change of Colour in Fruit |
-chloroplasts die off when fruit ripens revealing the underlying pigment that existed all along |
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Non-Pigmented Plastids |
-amyloplasts- starch storage in shoots, roots and seeds -Elaioplast- fats and oil storage (seeds) -proteinoplast- protein storage (seeds) |
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Metabolites |
-human body has 3000-4000 -plants have 10000 - 100000 -plastids contribute substantially to the biosynthetic capacity -plastids produce terpenes (largest group of natural products in the world |
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Flower Scent |
-from flowers-beta ocimene -leaves- 3-hexenyl acetate -plants give off scent at peak times of 2 in the afternoon to 2 at night. - evolved to only open at times when reproduction potential is higher |
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Light as Information |
-length of day -direction of the light -light intensity -wave length of the light -chloroplasts obtain the information and passes it to the nucleus |
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Movement of Plants With Light |
-Heliotropism-follows the sun -Phototropism- follows the light -Negative phototropism- (roots) try and get away from the light |
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Germination |
-some seeds need light to grow, some need none and some don't care -the light to germinate can be as little as moon light. -the weaker the light the longer the exposure time -Very Low Fluence Response (VLFR) 0.1 μmol/m^2–1μmol/m^2 -Low Fluence Response (LFR) -High Irradiance Response (HIR) >1000μmol/m^2 |
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Plant Growth of Shaded vs Non-shaded Plants |
-no light grows tall -light- plants grow more branches and leaves |
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Light Receptors |
-Blue-light photoreceptors (350-500 nm) -cryptochromes- plant morphogenesis -phototropin- phototropism-chloroplast movement- stomatal opening -zeitlupe-day length perception -circadian rhythms -Phytochromes- red light (600-750 nm) -seed germination- shade avoidance
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Phytochrome |
-two identical subunits- each has two domains -photoreceptor- protein bound covalently to non-protein pigment= chromophore which undergoes cis-trans isomerization-> rearrangement of secondary structure in protein -Kinase activity in bacterial phytochromes, but in higher plants kinase related domain (no functional kinase -Types (PHYA, PHYB, PHYC, PHYD, PHYE) |
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Phytochrome- Inactive vs. Active Forms |
-synthesis in the dark is inactive form -Pr- inactive form (sagging)- far red light -Pfr- active form (straight)- red light -part of signalling cascade in the cell- transport to nucleus to activate gene expression -Response- seed germination and control of flowering |
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GFP |
-green florescent protein |
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PhyA and PhyB-E |
-PhyA- type I (light labile) : most abundant in dark grown seedlings -PhyB-E- type II (light stable): PhyB most abundant in light grown plants |
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Absorption of Red Vs Far-Red |
sunlight: -red and far red 1:1 ratio -conversion to Pfr is faster -branching stimulated, vertical growth inhibited shade:-Red light absorbed by canopy, far-red passes canopy -Shift in favour of more Pr -shade avoidance: growing tall and thin |
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Circadian Rhythms |
-Function in around a 24 hour clock (can be 21-27) -Plants follow environmental conditions (light, temperature, relative humidity) -Many continue in continuous light or darkness -Processes follow a daily rhythm |
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Jet Leg for Plants |
-plants with a shorter or longer inner clock can desynchronize when put in darkness for days. -Example: bean plant has a clock of 26 hours. Put in darkness for 3 days, taken out and it is off from the sun by 6 hours. -Most organisms are prone to jet lag -Increase in Pfr each day at dawn resets clock |
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Photoperiodism |
-plants are able to detect change of temperature, light, day, night and change in season (photoperiod) -A physiological response to photoperiod is known as photoperiodism -3 types: i. neutral (day length sensitive) ii. long day type iii. short day type |
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Neutral Vs Long day Vs Short Day |
-neutral plants aren't influenced to flower by day length - will flower at any latitude-dandelions flower all season -Long day plants only flower if the number of hours of daylight exceeds certain threshold -Short day plants only flower if the number of daylight hours is less than a certain number- late summer |
