Photosynthesis - Introduction Flashcards
Structure of plant leaf + adaptations
Cuticle - colourless, no light reflection, allow all wave lengths
Upper epidermis
Palisade mesophyll - many chloroplast with pigment stacked
Spongy mesophyll- lots of air space for gas
Stoma - gas exchange + water evaporation
Xylem - transport water
Phloem - transport organic substance
Diagram of plant leaf
https://resource.download.wjec.co.uk/vtc/2020-21/el20-21_1-14/downloads/image_6.jpg
Structure of chloroplast
Thylakoid - contain pigment for light dependent reaction, inner membrane
Lumen - space inside thylakoid
Granum - stacks of thylakoid
Stroma- light independent reaction
Diagram of chloroplast
http://resource.download.wjec.co.uk/vtc/2020-21/el20-21_1-14/downloads/image_7.png
What is pigment + types
Molecule that absorbs light energy for photosynthesis
Primary pigment - Chlorophyll A
Accessory pigment - Chlorophyll B + Carotenoids
(There’s more)
How to separate pigment of a plant + rf value
Use chromatography paper and apply pigment on it
-dip tip in solution, and pigment dissolves and move with solution up paper
-smaller molecule travel far, larger not far
rf = how far a pigment can travel if dissolved in solution. Over the distance the solution travel
Distance move by pigment/ distance by solution
http://resource.download.wjec.co.uk/vtc/2020-21/el20-21_1-14/downloads/image_8.png
What is wave length
Different colours of light reflected by a prism and measured in nano meters
Purple -> blue -> Green -> yellow -> red
https://as2.ftcdn.net/v2/jpg/05/10/99/55/1000_F_510995535_T19g8wqKFC5mMh5HTiVJeuidNFKUHtKl.jpg
Absorption spectrum
-Shows the optimum wavelength that allow for each pigment light absorption to be optimum
https://ib.bioninja.com.au/img/absorbance%20mobile.jpg
Action spectrum
-Shows the rate of photosynthesis and show which wavelength is the most useful for photosynthesis
https://old-ib.bioninja.com.au/_Media/absorption-and-action-spect_med.jpeg
Theodore Englemann graph
-A bimodal distribution of aerobic bacteria (2 peaks)
-most gather at the area of leaf under the light wave length of blue (400nm to 500nm) and red (650-700)
-since more lights from this wave length is being absorbed and undergo photosynthesis for o2.
-so bacteria move to these area to respire
-less at green wavelength as not much O2 available
https://scienceviola.weebly.com/uploads/9/2/8/3/92839492/3333653-orig_orig.jpg
Why does chloroplast have multiple pigment
-Each pigment have their own optimum light absorption at different wavelengths
-so photosynthesis can undergo in variety of wavelength
- so photosynthesis more likely to be carried out
How does absorption spectrum + action spectrum relate to photosynthesis rate
More light absorbed = more photosynthesis
Why does most leave have green colour
-Green wave length not absorbed
-No potential for photosynthesis, not useful = reflected
Why does leafs change colour
If certain wavelength of light not available to leaf, some pigment that is optimal with that wavelength is deactivated
Adaptations of sun plant + shaded plant
Sun plant:
-large palisade cells, small chloroplast
-low chlorophyll content
-small, thick leaves
Shaded plant:
-small palisade cell, big chloroplast
-high chlorophyll content
-large, think leaves
