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Photosynthesis. 6.1 Chloroplasts and Photosynthetic Pigments. Dependent on LIGHT. Photosynthesis: process that converts energy from the Sun into chemical energy to be used by living cells. Light: type of EMR occurring in individual packets of energy called photons
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Photosynthesis 6.1 Chloroplasts and Photosynthetic Pigments
Dependent on LIGHT • Photosynthesis: process that converts energy from the Sun into chemical energy to be used by living cells. • Light: type of EMR occurring in individual packets of energy called photons • Photons: corresponds to particular wavelengths- short wavelengths = high energy- long wavelengths = low energy • Light a mixture of wavelengths (ie. Separate through prisms)
Photosynthesis & Cellular Respiration • Plants only living organisms capable of producing own food (glucose). • Photosynthetic organisms capture energy and store it in bonds of glucose- energy passed on to other organisms in food web • ALL organisms release energy stored in glucose by cellular respiration.- fuels cellular activities Carbon dioxide + water + energy glucose + oxygen 6 CO2(g) + 6 H2O(l) + energy C6H12O6(s) + 6 O2(g)
Pigments • Special pigments in photosynthetic organisms capture photons from solar energy- begin reactions of photosynthesis • Chlorophyll: absorbs photons from solar energy- types of chlorophyll: a & b- chlorophyll a primary light-absorbing pigment • Accessory pigments: absorb photons poorly- chlorophyll b: absorbs photons chlorophyll a does not or does poorly- carotenoids: transfer energy absorbed into a molecule of chlorophyll a
Chlorophyll • Both a & b absorb photons with energies in blue-violet and red regions • Reflect (transmit) those with wavelengths of 500 nm to 600 nm. - we see this as GREEN light • Chlorophyll a only pigment that can transfer energy from sunlight to the reactions of photosynthesis.
Chloroplasts • Photosynthesis occurs in the leaves - must contain chlorophyll- must obtain CO2 and H20- must capture solar energy • chlorophyll found in membranes of chloroplasts- chloroplasts located in stems and leaves
Chloroplasts • Approximately 3 – 8 m in length, 2 – 3 m in diameter • Enclosed by inner and outer membranes • Stroma: interior of chloroplast • Thylakoids: connected and stacked sacs within stroma • Grana: columns of thylakoids • Lamellae: single thylakoids that connect grana • Thylakoid membrane: where photosynthesis occurs- contains pigments and electron transport chains • Structure of thylakoid system:- increases surface area of thylakoid membrane- increases efficiency of photosynthesis