2_photosynthesis_notes

Equation of **Carbon dioxid**e and **Water** to form Oxygen, glucose, which helps sustain life of living things. Need sunlight light dependent/ light independent This shows us that the atmosphere gives us much more than air as it is also interrelated with growth and other survival needs Wood - what is it really? (actually a combination of factors e.g. air that create it -> air and fuel are linked) grow from factors??

Process where energy from the sun is converted into chemical energy that can be utilized by plants and also other organisms. Oxygen is released as a by product.
 * Definition:**

The two kinds of chlorophyll complement each other in absorbing sunlight. Plants can obtain all their energy requirements from the blue (less) and red parts of the spectrum. Spectrum of colours of leaves: over time different parts of pigments are being broken down. During autumn: to preserve as much energy as possible, the leaf extracts as much nutrients as possible, hence pigments slowly change. (being broken down)
 * Chlorophyll**

stacks - interconnected DNA stroma
 * Structure of choloroplasts**

mesophyll: palisade layer (longitudinal axis parallel to epidermis for more cell exposure?) mesophyll: spongy layer - irregular cells with large intercellular air space epidermis (upper and lower) Vascular bundle: xylem, phloem (xylem closer to upper epidermis as it started on the inside of the stem) Layer of cuticle above and below (see ppt slides on RAMBIO space for diagram)
 * Leaf: internal features**


 * REVISE: xylem, phloem**
 * HOMEWORK: create table to summarise info**

contains vacuoles, nucleus, choloroplasts choloroplasts - produce glucose, cause osmotic concentration to increase, water potential to decrease, hence water moves in (high to low potential net movement), becomes turgid cell wall prevents it from bursting cell wall thicker inside, when it explands, will bend inwards, opening the stomata to help transpire for the rest of the plant due to passive transport.
 * Stomata - guard cells**

GENERALISATION: structure and function: related structure is a way to make inferences on functions

Photosynthesis Light-splitting using sun's energy to split water molecule - electrolysis ENZYMES heat energy - causes faster photosynthesis (temp increases, photosynthesis increases. until saturation point where enzymes are denatured due to too high temp, then photosynthesis decreases) (forming oxygen) carbon forming stage -> joining individual carbon atoms together
 * Light dependent**


 * Photosynthesis summary [diagram]**

1. The light-dependent reactions in the thylakoids convert the energy of the sunlight into the chemical energy of ATP and NADPH 2. Part of the sunlight's energy is also used to split H2O forming O2 3. CO2 and H2O converted to glucose in light-independent reaction using chemical energy from stage 1

Opening in leaves that allow gas exchange - stomata Stomata found in underside of leaf - generally found on lower surface area (reduce water loss through transpiration) Therefore, the spongy mesophyll layer is nearer to the epidermis, containing much air space for the air to enter the plant Large surface area to volume ratio - thin but flat (to absorb sunlight better) Veins present so the leaf will not flop downwards due to gravity - Vascular bundle, bring in water and nutrients
 * Name some features of the plant that will enable more efficient photosynthesis**

- Concentration of CO2 - Amount of water - Amount of chlorophyll - Intensity of sunlight -> rate of photosynthesis increases with intensity until saturation point due to the presence of a limiting factor (to bring up saturation point, increase limiting factor.) E.g. limiting factor: amount of CO2,by pumping more CO2, photosynthesis-light graph will have higher saturation point.
 * Factors that affect photosynthesis**


 * Since plants respire and photosynthesize, what is the relationship between the CO2 release and uptake?

Watch the video "The Private Lives of Plants - Growing" and answer the following questions: o Why do young seedlings of climbers grow away from light? They need to find a host tree before they can climb up As young plants, they cannot grow upwards on their own Growing horizontal till they hit a vertical object with light above - signal changes and they grow upwards Factor - gravity Younger leaves - smaller Increasing volume to surface area ratio as height increases -> direct relationship

o What are the forces that cause the leaves to unfold during growth? Hydraulic pressure - water within the leaves spread

o Why are some of the leaves and leaf stalks “hairy”? Young leaves - roots are still very small Need more water - tender leaves (flaccid) adult leaves are turgid, glossy and firm because of the thicker cells, thicker wax layer and thicker transport tubes Trap water/moisture using the "fur", reduce water loss

o Name as many different types of leaf shape as possible. Different shapes of leaves - simple - heart - needle - palmed/lobed

o Name a few strategies that plants use to gather light. Grow upwards as much as possible Constantly changing position to gain as much light as possible Position leaves in mosaic way, every light space taken Underside red - reflect light, above - dark green, MORE chloroplasts to maximise light use Spikes - increase surface area to get light Focusing light - on surface of leaf using surface texture

**INDOOR plants **- grow well in shade (similar to those on forest floor)

DIFFERENT METHODS AND ADAPTATIONS o Why do roots have root hairs? What are their characteristics?

o How much water is loss through the stomata?

o How do trees “pump” water up its trunk to the leaves in the canopy layer?

o What are the properties of these “pipes”? What are they called?

o How do plants prevent the problem of having too much water accumulating on its large leaf surface especially in the tropics?

plants "attackers" - strong rain have "drains" or gutters along leaf surface so water can slide off when it rains - monkeys have bacteria in their stomachs to ferment/disgest the leaves (they are herbivores) to unlock nutrients from the leaves - insects caterpillars: cut along semi-circle of leaf, halfway through, start from the other side -> fold it inwards to form a tent and cut along the side to fold into cone shape. feed on surface of leaf inside safely

o Why do proboscis monkeys have to spend so many hours eating? Why do they have a large belly?

o How do you tell the difference between a leaf that has been eaten by a caterpillar and that of a grasshopper?

o What are the damages that are inflicted on plants? What strategies do these plants employ to protect themselves? Use the examples featured in the show to explain their strategies e.g. Acacia, Nettle, pebble plant, passion flowers, bracken, mimosa, Venus fly trap, marsh pitcher

- Acasia -> grow high up, umbrella shape, to prevent animals from eating/reaching leaves - thorns - sting and poison (nettle) - pebble plant - looks like a pebble, camouflage - mimicry: produce fake butterfly eggs (yellow spots), hence butterflies dont lay eggs there, thinking there are already eggs -> no caterpillars to destroy leaves - Bracken - mimosa: close up to prevent insects e.g. grasshoppers from eating it (steps: 1.leaves droop 2.stem bows down) - venus flytrap: hair triggers leaves to close, acid produced to digest - pitcher plant: looks like flower, has nectar to attract insects, insects fall into "trumpet"

Biofuel and Biomass - energy, parts, biomolecules, basically the MATTER of life - starts from SUN -> photosynthesis -> biofuel e.g. wood link to new topic (rambiowikispace)

video: corn grains -corn used in may ways diesel - alchohol (ethanol) as a fuel sugar (corn syrup) food (seed contains starch, carbohydrates and nutrients) feed for livestock (remaining nutrients) - soy, rape seeds, sunflower

asia uses oilpalm

are we addicted to oil? is technology the solution to the problem?

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