3.1 Photosynthesis Flashcards
(29 cards)
Where does photosynthesis take place
In the chloroplasts
What are the adaptions of a leaf for photosynthesis
- large surface area
- the arrange plenty of leaves
- thin
- transparent cuticle and epidermis
- long, narrow upper mesophyll cells packed with chloroplasts
- numerous stomata
- stomata that open and close
- many air spaces
- a network of xylem
(Adaptations for ps) why do leaves have a large surface area
To collect as much sunlight as possible
(Adaptations for ps) what does the arrangement of the leaves minimise
Overlapping so avoids shadowing one leaf by another
(Adaptations for ps) why is a leaf thin
To keep the diffusion distance short and most light is absorbed by the first few mm
(Adaptations for ps) what does the transparent cuticle and epidermis ensure
That light is let through to the photosynthetic mesophyll cells beneath
(Adaptations for ps) why are the upper mesophyll cells long and narrow and packed with chloroplasts
To collect sunlight
(Adaptations for ps) why are there numerous stomata
For gaseous exchange
(Adaptations for ps) what is the importance of stomata that open and close
They can change in response to changes in light intensity
(Adaptations for ps) what is the importance of many air spaces in the lower mesophyll layer
To allow the diffusion of carbon dioxide and oxygen
(Adaptations for ps) what does the network of xylem do
Brings water to the leaf cells
(Adaptations for ps) what does the phloem do
Carries away the sugars produced in photosynthesis
What does photosynthesis produce
Oxygen by releasing it from water molecules
What is the equation for photosynthesis
6CO2 + 6H2O ——————–> C6H12O6 + 6O2
Light
What is the word equation for photosynthesis
Carbon dioxide + water ——————-> glucose + oxygen
Light
What are the 3 main stages of photosynthesis
1) capturing the light energy
2) the light-dependant reaction
3) the light-independent reaction
How is light energy captured during photosynthesis
By chloroplast pigments such as chlorophyll
What happens in the light-dependant reaction
Light energy is converted into chemical energy. During the process an electron flow is created by the effect of light on chlorophyll and this causes water to split (photolysis) into protons electrons and oxygen.
What are the products of the light-dependant reaction
Reduced NADP, ATP and oxygen
What happens on the light independent-reaction
These protons(hydrogen ions) are used to reduce carbon dioxide to produce sugars and other organic molecules
Chloroplast structure
- typically disk shaped
- 2-10 um long and 1 um in diameter
- surrounded by a double membrane
What are the 2 distinct regions found inside chloroplasts
The grana and the strong
Grana structure
Stacks of up to 100 disk like structures called thylakiods
Stroma structure
A fluid filled matrix where the light-independent stage of photosynthesis takes place. Filled with a number of other structures eg starch grains
