12.1 Flashcards
funtion of leaf stalk
holds leaf blade away from stem so that lead blade can obtain sufficient light energy
adaptations of leaf blade
large flat surface compared to its volume to obtain maximum light energy for photosynthesis, large thin blade so carbon dioxide can rapidly reach inner cells of leaf
what are the network of veins in leaf made out of
xylem vessels and phloem tissue
function if xylem
transport water and mineral salts from roots to leaf cells
function of phloem
transports sucrose and amino acids from leaf cells to all parts of plant
how does leaf arrangement help plant
so that leafs are not blocking each other from light energy and each leaf receives sufficient light energy
properties of cuticle
waxy and transparent
why is cuticle waxy
reduce water loss through evaporation
why is cuticle transparent
allows sunlight to penetrate leaf
what is upper epidermis
a single layer of closely packed cells with no chloroplasy
what is palisade mesophyll tissue
closely packed, long and cylindrical cells specialised for photosynthesis
what is spongy mesophyll tissue
numerous large intercellular air spaces among loosely packed cells for rapid diffusion of oxygen and carbon dioxide
what are the adaptations of leaf for photosynthesis (6 points)
waxy cuticle on upper lower epidermis, stomata present in epidermal layers, chloroplast containing chlorophyll in all mesophyll cells, more chloroplast in palisade mesophyll cells, large intercellular air spaces in spongy mesophyll tissue, veins containing xylem and phloem situated close to mesophyll cells
function of guard cells
control the movement of oxygen, carbon dioxide and water vapour between leaf and surrounding atmospheric air
how does stoma open
in sunlight, when guard cells are turgid
how does stoma close
on a hot sunny day, when guard cells are flaccid
