Cells Flashcards
How are palisade leaf cells specialised?
1) Packed with chloroplasts for photosynthesis. 2) Crammed at the top of leaf (nearer light). 3) Tall shape, so more surface area for absorbing more CO2.
How are guard cells adapted ?
1) when inflated with water it becomes turgid and opens stomata. 2) When deflated it becomes flaccid and closes stomata. 3) sensitive to light so close at night to save water.
what is differentiation?
when a cell changes to become specialised for a function.
what is a tissue?
group of similar cells working together to perform a particular function.
what is an organ?
group of different tissues working together to perform a certain job.
organ system
group of organs working together to perform particular function.
examples of organ system
digestive, respiratory, reproductive.
photosynthesis
Carbon dioxide + water -> glucose + oxygen
green substance in plants is..
chlorophyll
plant structure (starting from top)
waxy layer, upper epidermis, palisade layer, spongy mesophyll, lower epidermis with guard cells.
limiting factors of photosynthesis..
1) light intensity 2) CO2 concentration 3) Temperature
why is light a limiting factor?
as light intensity is raised, rate of photosynthesis increases until certain point. it will make no difference so there is another limiting factor.
why CO2 is a limiting factor?
increases rate of photosynthesis up to a point. there is another limiting factor.
why temperature is a limiting factor?
increase in temp. means faster rate of photosynthesis until it gets too hot. enzymes get damaged at 45°C
how plants use glucose…
1) respiration 2) making cell walls(convert to cellulose) 3) stored as starch. 4) making proteins.