Photosynthesis Flashcards
What is an autotrophic and heterotrophic organism?
- Autotrophic
- organism that photosynthesise
- use sunlight to build complex organic molecules
- heterotropic
- obtain complex organic molc by eating other organisms
Why do chloroplasts contain a netowrk of membranes?
- provide a large SA to maximise the absorbtion of light
- essential in the first step of photosyntheises
What features do the membranes form?
- membrane form flattened sacs called thylakoids
- thylakoids are stacked to form grana
- the grana are joined by membranous channels called lamellae
Where is light absorbed?
- complexes of pigments
- such as chlorophull
- embedded within thylakoid membranes
What is the fluid enclosed in the chloroplast and what is its function?
- site of many chemical reactions
- resulting in the formation of complex organic molecules
What do pigment molecules do?
- absorb specific wavelengths of light and reflect other
- different pigments absorb and reflect different wavelength
- why they have differences in colour
What is the primary pigment in photosynthesis and what does it absorb and reflect?
- chlorophyll a
- absorbs
- red
- blue
- reflects
- green
- reason for green plants
What are the accessory pigments and what is their function?
- chlorophyll b
- xanthophylls
- cartenoids
- absorbs different wavelengths of light than those absorbed by chlorophyll a
- causes different shades of leaves
What is the antennae complex
- accessory pigments embeeded in thylakoid membrane of the chlorplast
- these and other proteins and pigments form a light harvesting system
- aka antennae complex
What is the role of the antennae complex?
- role of the system is to absorb light energy of different wavelengths and transfer this energy quickly and efficiently to the reaction centre
What is the reaction centre?
- chlorophull a is located in the reaction centre
- which is where the reaction involved in photosynthesis takes place
- contains the primary pigment only
How are photosynthetic pigments investigated?
- chromotography
- seperate pigments in a plant extract
- mobile phase would be the soln containing the mixture of pigments
- stationary phase a thin layer of silica of gel applied to glass
- different interaction with the stationary phase and different solubilities in mobile phase lead to moving at different rates
What is the retention value?
- Rf value cna be calculated using the formula
- distance travalled by component / distance travelled by solvents
Explain shape of both curves
- photosynthwaia
- increased photosynthetic activity during the day
- increase activity of LDR
- respiration
- slihg increase during day because enzyme controlled reaction are temp dependant
What is the chlroplast envelope
double membrane of the chloroplast
What happens to the carbodhydreates produced by photosyntehsis?
stored as starch grains in teh stroma
