Biology Chp 6
Terms
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- Wavelengths of light between ___ and ___ are part of the ___ ___ and are used for photosynthesis.
- 380-750...visible light
- What is a photon?
- individual packet of electromagnetic energy traveling in waves
- Photons with short wavelengths have (high/low) energy
- high
- Define pigment
- class of molecules that absorb photons with particular wavelengths
- What happens to photons that are not absorbed by a pigment?
- They are reflected or transmitted
- The most abundant pigment in green plants is ___
- Chlorophyll a
- Why is chlorophyll b called an accessory pigment?
- It enhances efficiency of photosynth reactions by capturing additional wavelengths
- What are the most important colors in photosynth?
- purple/red
- What is an absporption spectra?
- It gives us a picture of how such photosynthetic pigments absorb diff. wavelengths of visible light
- What color do xanthophylls reflect?
- yellow, brown, purple, or blue
- What color do phycobilins reflect?
- red or blue-green
- What color do anthocyanins reflect?
- red-purple
- Why are leaves green in summer and red/orange/yellow in fall?
- The chlorophyll content declines in autumn & lets the other colors show thru
- NADP transports ___ & ___
- electrons & hydrogen
- Where do light reactions take place?
- thylakoid
- What do light reactions use and make?
- They use water & sunlight to make ATP & NADPH.
- Where do D.R. take place?
- stroma
- What do the D.R. use from the L.R.?
- NADPH & ATP
- What do dark reactions use and make?
- uses NADPH & ATP from L.R. along w/ CO2 to make glucose
- What happens in P.S. II?
- 1. energy from sunlight is used to split water 2. Energy from ETC is used to make ATP
- What happens in P.S. I?
- 1. Sunlight causes chlorophyll to lose electrons 2. H+ & e- comb. w/ NADP to make NADPH
- What is made when the water splits?
- H+, e-, & O2 Oxygen = waste product
- How is the ATP made in L.R.?
- - hydrogen ions form water builds up inside the thylajoid - e- reach ATP synthase & H+ rush thru - energy is used to make ATP * remember ATP synthase dam! when last e- hits the ATP synthase dam it opens and the H+ rush out
- What is the enzyme used in D.R.?
- Rubisco
- What is the chemical equation for photosynthesis?
- 6CO2 + 6H2O --> 6O2 + C6 H12 O6
- Cuticle
- waxy coating that protects leaf, prevents water loss
- epidermis
- outside layer of cells ~ protection
- palisade mesophyll
- tightly packed cells w/ chloroplasts, used solely for photosynth
- spongy mesophyll
- scattered cells, lots of air space - CO2 & O2 exchange
- stomata & guard cells
- control CO2, O2, & water in/out of leaf
- vein
- transport water & glucose
- bundle-sheath cells
- specialized cells, C4 plants only adaptation to hot, dry climates adds new enzyme so it won't bond to O2
- The guard cells control the opening of the stomata. When water leaves the guard cell the stomata are (open/closed). When water enters the guard cells the stomata is (open/closed)
- closed...open
- The purpose the stomata is to _______
- control water loss & gas exchange
- Describe the adaptation C4 pathways provide.
- Adds a step to fix CO2 into a 4 Carbon compound with a diff. enzyme (that will not bond with O2) Later releases CO2 to normal cycle in bundle-sheath Adaptation to hot, dry climates