Relationship Between Photosynthesis, Respiration + Chloroplats & Photosynthetic Pigments Flashcards
What organisms use photosynthesis
-plants
-algae
-some types of bacteria
What is photosynthesis
-the conversion of light energy from the sunlight into chemical energy
What type of nutrition is photosynthesis an example of
-autotrophic nutrition
What are organisms that photosynthesise called and why?
-photoautotrophs
-because they use light energy as a source for autotrophic nutrition
Where in the food chain are photoautotrophs and what is their trophic level
-producers
-first trophic level
What is the general equation for photosynthesis
-6CO2 + 6H2O + energy ———> C6H12O6 + 6O2
What is the main product of photosynthesis
-monosaccharide sugars
Why is photosynthesis an example of carbon fixation
-because it is a process where carbon dioxide is converted into sugars
What are the 3 characteristics of carbon fixation
1) endothermic (needs energy)
2) needs electrons
Is respiration endothermic or exothermic and why?
-exothermic as it releases chemical energy
What is the equation for respiration
C6H12O6 + 6O2 ——> 6H2O + 6CO2 +energy
How do the processes of photosynthesis and respiration link together
-as they are both important in cycling CO2 and O2 in the atmosphere
-the products of one process are the raw material for the other process
When do plants respire
-all the time
When do plants photosynthesise
-only during daylight
What does the term compensation point mean
-where photosynthesis and respiration proceed at the same rate so that there is no net gain or loss of carbohydrate
What does the term compensation period mean
-the time a plant takes to reach its compensation point
What is the role of the chloroplast
-the site of photosynthesis
Describe the characteristics of chloroplast
-double membrane
-inter membrane space
-disc shaped
Describe the permeability of the outer membrane
-highly permeable
What are the 8 parts that make up the structure of a chloroplast
1) inner membrane
2) outer membrane
3) stroma
4) granum
5) thylakoids
6) lamellae
7) inter membrane compartment
8) chloroplast envelope
What is the granum (grana)
-inner part of the chloroplast made of stacks of thylakoid membrane
What stage of photosynthesis takes place at the granum
-the LIGHT-DEPENDENT stage
What is the stroma
-a fluid-filled matrix
What stage of photosynthesis takes place at the stroma
-LIGHT-INDEPENDENT stage
What are thylakoid membrane
-flattened membrane-bound sac found inside chloroplasts containing photosynthetic pigments/photosystems
What stage of photosynthesis takes place at the thylakoid membrane
-LIGHT-DEPENDENT stage
Describe the permeability of the thylakoid membrane
-less permeable
What are photosystems
-a system of photosynthetic pigments found in thylakoids
What is the shape of photosystems
-funnel-shaped
Where are photosystems found
-within the thylakoid membrane
What do photosystems contain
-photosynthetic pigments
What is the role of each photosynthetic pigment
-to absorb light of a particular wavelength and reflect other wavelengths of light
What colour do we see the pigment
-the colour of the wavelength of light that is being reflected
How does the photosystems work
-light is captures and is funnelled down to the primary pigment reaction centre at the base of the photosystem
Which chlorophyll is the primary pigment reaction centre always made of
-chlorophyll a
What are the two types of photosynthetic pigments
1) accessory pigments
2) primary pigment (reaction centre pigment)
What is the molecular structure of chlorophylls
-porphyrin group which is a magnesium atom and a long hydrocarbon chain
How many forms of chlorophyll a are there
2
What colour do both forms of chlorophyll a appear as
-blue-green
Where are both forms of chlorophyll a found
-at the centre of photosystems
What colour light do both forms of chlorophyll a absorbs
-red light
What are the names of the 2 forms of chlorophyll a
-P680
-P700
What is the difference between the 2 forms of chlorophyll a
-they have different absorption peaks
Describe the characteristics of P680
-found in photosystem II
-its peak of absorption is light of wavelength 680nm
Describe the characteristics of P700
-photosystem I
-peak of absorption is light of wavelength 700nm
Describe the characteristics of chlorophyll b
-absorbs light of wavelength 400-500nm and around 640nm
What colour does chlorophyll b appear and what does this mean
-appears yellow-green
-this means is reflects yellow-green light
How many accessory pigments are there
-2
What are the 2 types of accessory pigments called
1) carotenoids
2) xanthophylls
What light and wavelength do carotenoids absorb
- blue light of wavelength 400-500nm
What light do carotenoids reflect and what does this mean
-they reflect yellow and orange light so they appear to the eye as yellow-orange
What light and wavelength doxanthophylls absorb
-blue and green light of wavelengths 375-550nm
What light do xanthophylls reflect and what does this mean
-yellow light so they appear to the eyes as yellow
Why do we have we have two forms of chlorophyll a
-to absorb different wavelengths of light so the maximum amount of light is absorbed
What causes plants to become discoloured
-because chlorophyll a contains Mg the plant may become Mg deficient causing it to become discoloured
