biology 3.3 Flashcards
Why do Plants need water?
-Photosynthesis
-Structure and support-turgidity
-Transport dissolved nutrients
-Cooling
Why do plants need transport systems?
-Plants grow throughout their lives so need effective tranport systems to transport nutrients
-Surface area to volume ratio
-Non green plants can’t photosynthesis so need glucose and oxygen transported to them
What is transpiration and translocation?
-Transpiration is where water and mineral ions are transported in the xylem upwards, the process is passive
-Translocation is where sugar and amino acids are transported in the phloem bidirectionally and the process is active
What is found in the vascular bundles?
Xylem, Phloem, Sclerenchyma, Collenchyma, and Parenchyma
What are the functions of Sclerenchyma, Parenchyma and Collenchyma?
-Sclerenchyma provide support and structure
-Collenchyma are involved in growth and strength
-Parenchyma is a soft packing tissue
What are the adaptations of the xylem vessels?
-Cell walls decay and don’t contain cytoplasm or organelles
-The end plates break down leaving a long hollow tube
-Cell walls are thicker than usual to withstand pressure of water
-Cell walls are lignified which makes the cells waterproof, strong and keeps the vessel open but kills the cells
What are bordered pits?
-Non-lignified regions of the xylem vessel that allow water and mineral ions to move laterally between xylem vessels
What are the adaptations of the phloem vessel? and why do they need companion cells?
-Elongated, no nucleus, very little cytoplasm
-The end walls form perforated plates
-Sieve tube elements can’t keep themselves alive so need companion cells to carry out their metabolic function
What are the adaptations of companion cells?
-Large nucleus
-Dense cytoplasm
-Many mittochondria for ATP for active transport
-Infoldings on the cell surface membrane to increase surface area for active transport
