Unit 4 Photosynthesis Flashcards
Define Photosynthesis
solar energy used to convert CO2 and H2O into sugar and O2
Define Autotrophs
Organisms that make their own food
“self-feeders”
Define Photoautotrophs
Autotrophs that use energy from light
Define heterotrophs
the consumers of the Biosphere
-cannot make own food
-consume animals and plants
Define Chlorophyl
Light absorbing pigment in the Chloroplasts
how many chloroplasts does s mesophyll cell have
30-40 Chloroplasts
Define Stomata
Pores that allow CO2 in the leaf and O2 out of the leaf
Define veins
deliver water, minerals, sugars to all part of the plants
Define a wavelength
the distance between the crests of the electromagnetic waves
Define the Electromagnetic Spectrum
full range of wavelengths
Define a Photon
Discreet packet of light energy
Which wavelengths have more energy Longer or shorter
Shorter wavelengths have more energy
Define Pigments
light absorbing molecules
Where are pigments located?
build into the Thylakoid membranes
How do Pigments work
absorb some wavelengths and reflect others
Define Chlorophyll a
Absorbs blue-violet and red light
What pigment participates directly in photosynthesis
pigment Chlorophyll a
Define Chlorophyll b
Absorbs blue and orange light
which pigment transfers energy to another pigment
Chlorophyll b
Define Carotenoids
reflect shades of yellow and orange
Define Photoprotection
protection from excessive light energy
some Carotenoids capture and dissipate excessive light energy
What is the opposite of Cellular respiration
Photosynthesis
What are the stages of Photosynthesis
- Light reactions
- Calvin cycle
where do light reactions happen
In the Thylakoids
where does the Calvin Cycle happen
in the Stoma
-carbon fixation
What is the first stage of Light reactions
- Light energy is absorbed by chlorophyll
- H2O is split and O2 is released
- the electrons from H2O are transferred to NADP+ to reduce it to NADPH
- ATP is produced
how is solar energy gotten
a pigment molecule absorbs a photon which makes an electron jump to another energy level
as the electron drops back down it releases energy in the form of heat or light
Define Reaction Centre
pair of specialized chlorophyll a molecules bound to proteins
which photosystem works first 1 or 2
Photosystem 2 works first
Define Carbon Fixation
the incorporation of inorganic CO2 into Organic molecules which are reduced to form sugars
what are the reactants of the Calvin Cycle
CO2 from air
ATP and NADPH from light reactions
What are the products of the Calvin Cycle
G3P
How many main steps in the Calvin Cycle
4 main steps
What is the first step of the Calvin Cycle
- Carbon Fixation
- starts with a 5-carbon sugar (RuBP)
cycle turns 3 times to generate 1 molecules of G3P
what is the second step of the Calvin cycle
- Reduction
- ATP and NADPH are used to reduce the 3-carbon Molecules to G3P
what is the third step of the Calvin cycle
- Release of G3P
-every 3CO2 molecules, 1 molecule is released as a product
what is the fourth step of the Calvin cycle
- Regeneration of RuBP
- 5 G3P molecules rearranged to make RuBP
What are C3 Plants
start plants the use CO2 directly from the air
due to hot/dry conditions the plants close their stomata to reduce loss of water
when that id done the leaf also cannot get any CO2 in and O2 out
what are C4 Plants
Fix carbon into a 4-carbon intermediate compound
Storing the CO2 in one type of cell then releasing it into another cell to perform Photosynthesis
What are CAM plants
adaptive to very dry climates
-conserve water by only opening its Stomata at night
then the CO2 is released during the day so the Calvin cycle can proceed
