Plants 🌱 Flashcards
Word equation for photosynthesis
Carbon dioxide + water ————> glucose + oxygen
Symbol equation for photosynthesis
6CO_2 + 6H_2O ————> C_6H_12O_6 + 6O_2
What is the glucose produced in photosynthesis used for
To make starch
What happens when photosynthesis stops
Starch is broken down into simpler substances which are moved into the cytoplasm and used to make SUCROSE
What is sucrose used to make
Starch
Other molecules for the plant (eg. Cellulose lipids or proteins)
glucose for respiration (to release energy)
Is photosynthesis endothermic or exothermic
Endothermic
What are the 4 key features in the structure of a leaf
Wide and flat
Lots of veins
Stomata on the underside
Thin
How does leaves being adapted to be THIN help the plant
Gases can reach cells easily
How does leaves being adapted to have STOMATA on the underside help the plant
Allows gas exchange 
How does leaves being adapted to be WIDE AND FLAT help the plant
Large surface area and absorbs as much light as possible
How does leaves being adapted to have many VIENS help the plant
Carry water to the cells and carry glucose away
What is the waxy cuticle
The covering on plant leaves to help to plant retain water (water proof)
What is the epidermis
Provides a protective layer against injury water loss & infection
Also thin & transparent to allow light to enter
What is the Palaside layer
Tightly packed layer of cells beneath the cuticle and upper epidermis
Contains the majority of chloroplasts which use chlorophyll to perform photosynthesis
What is the spongy Mesophyll
They are covered by a thin layer of water.
Gases dissolve in this water as they move in and out of cells
What is the vascular bundle
Network of veins (xylem and phloem) which support the structure of the leaf and transport substances to and from the cells
What are the stomata and guard cells
Stomata are pores in the epidermis that function as gateways linking internal and external gases. Guard cells control wether the stomata are opened or closed
What happens to guard cells in the daytime
Stomata are open to enable gas exchange as the guard cells have taken in water by osmosis and are TURGID
What happens to the guard cells at night
Stomata are closed to prevent water loss. This is because the guard cells have lost water by osmosis and are FLACCID
How does increasing light intensity affect the rate of photosynthesis
It increases the rate of photosynthesis until a limiting factor becomes short in supply
How does the amount of CO2 concentration affect the rate of photosynthesis
If the rate of CO2 increases the rate of photosynthesis will also increase
How does temperature affect the rate of photosynthesis
Chemical reactions involved in photosynthesis are controlled by enzymes.
As the temperature increases collisions between enzyme and a substrate increase and therefore so does the rate of photosynthesis.
At high temperatures enzymes become DENATURED and this will decrease the rate of photosynthesis
Light intensity is measured as 600 Lux at a distance of 20 cm from a lamp
Calculate the light intensity at a point 40cm away from the lamp
So you are doubling (x2) the distance…
Therefore the light intensity is 1/4 (1/2^2) the original
New light intensity = 600÷4 = 150 lux
What is the function of the xylem vessel
Carries water and minerals