chapter 4 Ph photosynthesis
chapter 4 Photosynthesis
Introduction Co2+H2O光绿色物(cH2O)+O2(1)
Introduction ❑ Strategies for getting energy ➢ Photoautotrophic & Chemoautotrophic: • Make it (e.g. photosynthesis) ➢ Heterotrophic. • Eat it CO２+ H２O 光 绿色植物 (CH２O)＋O２ (1)
Introduction
Introduction ❑ Sunlight = energy & information for plants. ➢ Radiant energy (SUNLIGHT) • Maintains planetary temperature suitable for life • Ultimate source of energy to sustain life (Photosynthesis). ➢ Provides information about the environment • Photomorphogenisis (光形态发生作用） – light quality. • Photoperiodism-- day/night length
ignificance of photos
Significance of photosynthesis ➢ Photosynthesis – Essential for animal survival. • Captures energy from the sun. • Makes complex organic molecules from CO2, water and minerals. • Releases O2 required for cellular respiration. ➢ ~ 250 Billion metric tons of sugar produced each year via photosynthesis
Photosynthesis
Photosynthesis light 6 CO2 + 6 H2O C6H12O6 + 6 O2 Consists of both Light & Carbon-fixation Reactions
Light- Properties Visible light comprises a small portion of the electromagnetic spectrum(光谱) Wavelength, A(nm) 10310 10 10 10 1010110310 Frequency. V(Hz) 10201018101610141012101010310510102 Gamm Ultra Radio radiation r X-ray violet Infrared Microwave wave 400 Visible spectrum 700 Hgh energy Low energy
Light – Properties ➢ Visible light comprises a small portion of the electromagnetic spectrum (光谱）
Light Properties Ultraviolet(uv light => 100-400 nm
Light Properties ➢ Ultraviolet (UV) light => 100 - 400 nm ➢ Photosynthetically Active Radiation (PAR) => 400 -- 700 nm • Violet => ~380 -- 455 nm • Blue => ~455– 500 nm • Green => ~500– 580 nm • Yellow => ~580– 595 nm • Orange => ~595– 620 nm • Red => ~620– 700 nm • Far Red => ~700– 775 nm ➢ Infrared => ~775– 100,000 nm
operties
Light Properties ➢ The particle aspect of light is described as a photon（光子）. • Each photon contains specific amount of energy called a quantum (量子) (plural quanta). • The energy of a photon (a quantum of light) is inversely proportional to its wavelength (λ). • Violet light (short λ) has almost twice the energy of red light (long λ)
Light -Properties Photons can be absorbed by atoms to excite electrons(e)into higher energy states, or dislodge e from atoms Photon ucleus Electron Ground state Excited state
3 Ways to Describe Light
3 Ways to Describe Light ➢ Light quantity-- how much? ➢ Light quality --composition with respect to wavelength. ➢ Timing - duration and periodicity