B6 PLANTS Flashcards
Photosynthesis
How plants produce glucose using the energy from the light
Photosynthesis
Equation
Carbon dioxide + water -> glucose + oxygen
Chloroplasts
Part of plant cell where photosynthesis happens
Chlorophyll
A green pigment that enables photosynthesis by trapping the enters in light
Forming starch
As soon as they are made glucose molecules are joined together into long chains to form starch
At night
Starch is converted into sugar called sucrose which is easy to move around the plant
Uses if sucrose
Sucrose is converted into
Glucose for respiration
Starch for storage
Other molecules for growth
Biomass
the total mass of materials in an organism (except water)
Photosynthesis is the main source of biomass
Job of leaves
To conduct as much photosynthesis as possible as quickly as possible
Leaf adaptations
To do more photosynthesis leaves have a : large surface area of waxy Cuticle palisade cells a sponge layer stomata
Large surface area
Allows the leaf to absorb more light
Waxy cuticle
A waxy coating that stops water evaporating from the leaf
Palisade
Cells two cells in a leaf with many chloroplasts lots of photosynthesis
Spongy later
A layer of cells with lots of gaps that allow gases to move around inside the leaf
Stomata
Singular stoma
Holes in the bottom of the leaf that allow carbon dioxide in an oxygen and water vapour out
Stomata structure
Each stoma
Is surrounded by two cells called guard cells that can swell to open it or shrink to close it
How stomata work
During the day the stomata Open to allow gas exchange at night the stomata
Close stomata close during dry spells to stop water loss
Limiting factor
A factor that holds back the rate of photosynthesis when in short supply
The limiting factors
Carbon dioxide concentration light intensity temperature
Limiting factor graphs
The lion sleeps up when the factor is limiting the line levels out when the factor is not limiting
Carbon Dioxide and light intensity
To start with increasing them will increase the rate of photosynthesis because they are limiting eventually increasing them further has no effect as they are no longer limiting
Temperature and photosynthesis
Increasing temperature towards the optimum increases the rate as particles move faster and collide more increasing past the Optimum decreases rate as enzymes denatured
Inverse square law
1new =
1oringinal x d2 Original / d2 new
Roll of roots
To absorb water and nutrients from the soil
Root hair cells
Their role is to quickly absorb water and minerals from the soil
The adaptions are long hair with increases the surface area thin cell walls to ease water absorption
Movement of water
Water enters roots by diffusion and osmosis and travels to the xylem in the centre
Diffusion in toots
Water defuses along the cell walls around the outside of each cell until it reaches the xylem
Osmosis in roots
Water travels from cell to cell across cell membranes by osmosis and it reaches the xylem
Minerals in the soil
Plants absorb minerals from the soil such as nitrates
Phosphates and potassium
Absorbing minerals
Plants absorb minerals by active transport because their concentration is low
Transportation
The movement of water into a plant roots up its stem and evaporating out of the leaves
Xylem
Hollow tubes that carry water from the roots up the stem to the leaves
Xylem cells
Their role is to carry water from the roots to the leaves
There adaptions hollow to let water past no walls between neighbours to allow water through rings of ligin in to make some strong
Factors increased greatly transpiration
air movement dryer air higher temperatures
Translocation
The movement of sucrose sugar around the plant through the phloem
Phloem
Tissue that transports sucrose around plants made of sieve tubes and companion cell
Siege tubes
Cells in phloem with A large channel running through them to carry sucrose solution
Companion cells
Cells in phloem that sit next to the sieve tubes and pump sucrose into the sieve tubes
