Photosynthesis Flashcards
What is the word equation for:
Photosynthesis
light intensity
Water + carbon dioxide –> glucose + oxygen
What is the chemical equation for:
photosynthesis
6H2O + 6CO2 –> 6O2 + C6h12O6
Where does:
photosynthesis take place
Chloroplasts
What are in:
Chloroplasts
Chlorophyll
What is the purpose of:
Chlorophyll
To absorb light energy
What are the reactants for:
Photosynthesis
- Carbon dioxide
- Water
What are the products of:
Photosynthesis
- Glucose
- Oxygen
What is the:
Energy Transfer in Photosynthesis
Light energy –> Chemical energy
How does:
Oxygen enter the leaf
- Diffusion
- through the stomata
- from high concentration outside the leaf
- to low concentration in the leaf
How is:
Water absorbed by the Plant
- Osmosis
- Root hair cell
How are:
Mineral ions absorbed
- By the roots
- Active transport and diffusion
What are the:
Main limiting factors of photosynthesis
- Light intensity
- Carbon dioxide concentration
- Temperature
(Water is a limiting factor but is not a main one, usually not the case)
What is the worst:
Colour of Light for photosynthesis
- Green
- Chloropyll cannot absorp green light
- Light intensity will become the main limiting factor
(leafs are green because chlorophyll reflects green light)
What are the best:
Colours of Light for photosynthesis
- Red and blue
- Chlorophyll abosrbs these colours best
What is a:
Limiting Factor
(When it comes to photoshynthesis)
A factor which limits the rate of photosynthesis.
How is Photosynthesis affected by:
Temperature
- ↓ temperature –> ↓ kinetic energy –> ↓ collisions
- Optimum temperature –> ↑ kinetic –> ↑ collisions
- ↑ temperature –> enzymes denature –> enzyme-substrate complexes cannot form anymore
What are the different:
Structures in a Leaf
- Waxy Cuticle
- Upper Epidermis
- Palisade Mesophyll
- Spongy Mesophyll
- Lower epidermis
- Guard cells
- Stomata
What is the purpose of the:
Waxy Cuticle
- Water-proof layer to prevent water loss to keep plants turgid
- otherwise they would be flaccid as water would evaporate
- This would lead to the shrinking of the cell vacuole leading to the plant being weak and soft
What is the purpose of the:
Upper Epidermis
Transparant layer to allow light to go through to the palisade layer, where the chloroplasts are
What is the purpose of the:
Palisade Mesophyll
- Contains chlorophyll needed for Photosynthesis
- Chloroplasts are site of photosynthesis
What is the purpose of the:
Spongy Mesophyll
Cells are not tightly packed creating lots of air spaces. Air spaces increase the surface area to volume ratio of the leaf and reduce the diastance of the diffusion pathway increasing the number of cells in contract with the gases exchanged
What is the purpose of the:
Guard cells
Control the opening and colsing of the stomata. They open during the day and close at night when photosynthesis is not needed to redcue water loss.
What is the purpose of the:
Stomata
Allow for the diffuison of gases in and out of the leaf. Present only on the lower side of the leaf and so as to reduce water loss.
(top of leaf would have high levels of evaporation as it is usually warmer)
Why are:
Leaves broad?
So that there is a large surface area to be exposed to higher volumes of light
What are the uses of:
Glucose in a Plant
- Sucrose for fruits
- respiration
- active transport, more nitrogen, proteins
- celluose for cell wall
- starch food store
- fats and oils can be stored or used for growth
How do you:
Destarch a leaf
keep it in the dark for 2 days
What are:
Variegated leaves
Leaves that have chlorophyll in only certain parts of the leaf
How to:
Test a leaf for starch
- Boil water with a bunsen burner
- Put the leaf in the boiling water for 1 minute
- Turn bunsen burner off
- put leaf in test tube full of ethanol in boiling water for 10 minutes for the leaf to decolorise
- Test for starch using iodine
What is:
Nitrate used for
(in plants)
- Contains nitrogen for amino acids and proteins which is needed for growth
- If there is not enough, leaves will turn yellow
What are:
Phosphates used for
(in plants)
- For making DNA, membranes, respiration and growth
- If there is not enough, poor root growth and purple leaves
What is:
Magnesium used for
(in plants)
- Needed to make chlorophyll
- If there is not enough, leaves will turn yellow
What is:
Potassium used for
(in plants)
- To help enzymes which are needed for both photosynthesis and respiration
- If there is not enough, there will be poor flower and fruit growth and discoloured leaves
Why do:
Plants die in waterlogged areas?
If the roots are waterlogged there is less oxygen, anaerobic respiration happens…
What is the:
Vascular bundle made out of
Xylem and Phloem
Xylem characteristics
- Hollow, dead cells to form a continuos tube
- Transports water and minerals up the plant
- Is held together by rings of strong waterproof lignin
- Is in the centre of the vascular bundle
Phloem characteristics
- Transports sugars and food molecules around the plant
- movement of these molecuels is called transolocation
- can move either up or down
- made of living cells
- companion cells provide the ATP for the phloem sieve tube cells
- The end walls of the tube cells have pores through which food is transported from cell to cell - this is called the sieve plate
Why do Multicelluar organisms like plants need a transport system?
Complex Multicelluar organisms need to transport nutrients and gases over a large distance
