Plants Flashcards
What is the balanced photosynthesis equation
6CO2+6H2O=6O2+C6H12O6
Name the plant tissue where photosynthesis occurs
Palisade mesophyll tissue
What is the function of the air spaces in spongy mesophyll tissue?
They allow gases to diffuse in and out of cells
Why are the epidermal tissues covered with a waxy cuticle?
helps to reduce water loss by
evaporation
Why is the upper epidermis transparent?
so that light can pass through and reach the palisade layer
what is the guard cells purpose
Absorbs and loses water to open and close the stomata to allow carbon dioxide to diffuse in, oxygen to diffuse out
how are root hair cells specialised
Large surface area to absorb water by osmosis, extra mitochondria needed for active transport
what does lignin do in the xylem
waterproofs and ultimately kills the xylem cells, strengthens the walls, preventing them from collapsing and ensures that the vessels remain open even when the supply of water is low
what is the xylem vessel
end walls and the contents of the cell decay which creates a long column of dead cells with no contents
what is transpiration
The loss of water from leaves by evaporation through the stomata
why are water molecules in the xylem attracted to eachother
There is strong cohesion between the molecules because of hydrogen bonding. A continuous column of water is therefore pulled up the stem in the transpiration stream by evaporation from the leaves.
what are the transpiration systems functions
transporting mineral ions, providing water to keep cells turgid in order to support the plant, providing water to leaf cells for
photosynthesis, keeping the leaves cool by
evaporation
how can the rate of transpiration be investigated
the decrease in mass due to water loss or the volume of water absorbed.
what increases the rate of transpiration
bright light, higher temperatures, windy, dry
why do plants need glucose
for respiration, to make cellulose for strength, to store as starch, making amino acids, to make lipids
what two types of living cells do phloem contain and how do they work
Sieve tubes - specialised for transport and have no nuclei. Each sieve tube has a perforated end so its cytoplasm connects
one cell to the next.
Companion cells - transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy.
what is translocation
transports sucrose and amino acids
up and down the plant.
what are vitamins and minerals needed for
healthy growth, to make proteins
what does lack of nitrate ions look like and lead to
leads to insufficient protein production, leading to stunted growth, plants may be smaller and weaker
what does lack of magnesium ions look like and lead to
less chlorophyll so less photosynthesis, yellow leaves (chlorosis)
what is rose black spot and how can it be treated
Fungus spread by water and wind, Affects the growth of the plant as photosynthesis is reduced, Can be treated by using fungicides
what is tmv and how can it be treated
Virus spread by contact and vectors, Damages leaves and reduces photosynthesis, Spread is prevented by field
hygiene and pest control.
what are physical plant defences
Waxy cuticle – stop pathogen entering, Cell wall, Dead cells around stem e.g. bark
what are chemical plant defences
Antibacterial chemicals which kill bacteria, Poisons to deter herbivores
