Photosynthesis A- Level Biology Flashcards
Why is photosynthesis so important to us as humans?
They produce the oxygen we breathe by releasing it from the water molecules
Photoautotrophic organisms carry out photosynthesis
Light energy is absorbed by chlorophyll and converted into chemical energy
Biological molecules stored in plants and algae may be consumed by hetertrophs
What does life depend on?
Continous transfers of energy
What does this energy that eneters the organism depend on?
The type of nutrition
In plants, energy in light is absorbed by chlorophyll and then transferred into chemical energy of the molecules formed during photosynthesis. These molecules are used by the plant to produce ATP during respiration
Non-photosynthetic organisms feed on the molecules produced by plants and then use them to make ATP during respiration
Where is the site of photosynthesis?
Leaf is the main photosynthetic structure in the eukaryotic plants
Chloroplasts are the cellular organelles within the leaf where photosynthesis takes place
Why are leaves adapted to bring and remove waste products?
- Leave bring: (Raw materials of photosynthesis
- Water
- Carbon dioxide
- Light
- Leaves remove its products
- Oxygen
- Glucose
Why is it important that leaves have a large surface area?
- Absorbs as much sunlight as possible
Why is it important with the arrangement of leaves on a plant?
- Minimises overlapping and avoids the shadowing of one leaf by another
Why is it important that leaves are thin?
- As most light is absorbed in the first few micrometres of the leaf
- Keeps the diffusion distance for gases short
Why is it important a leaf has a transparent cuticle and an epidermis?
Let the light through to the photosynthetic mesophyll cells beneath
Why is it important that leaf has long, narrow upper mesophyll cells packed with chloroplasts?
They can collect sunlight
Why is it important that the leaves have numerous amount of stomata for gas exchange?
- So that all mesophyll cells are only a short diffusion pathway from one
What do stomata open and close to?
In response to changes of light intensity
Why do leaves have many air spaces in the lower mesophyll layer?
Allow rapid diffusion in the gas phase of carbon dioxide and oxygen
Why do leaves have a network of xylem and phloem?
Brings water to the leaf cells - xylem
carries away the sugars produced during photosynthesis - phloem
What is the chemical equation of photosynthesis?
6CO2 + 6H2O -> (light) C6H12O6 + 6O2