paper 1

• translocation is the movement dissolved sugar from the leaves to the rest of the plant through the phloem
• the importance of translocation is it allows the plant to grow and respiration and glucose storage
• in a phloem cell the substances can be transported in both directions
• in a phloem cell the cells have end walls with small holes in them to allow the movement of substances
• tranpiration is the evaporation of water from the roots of a plant and it pulls water up the plant through the xylem
• the importance of transpiration is it provides water to cells to keep them turgid, provides water for photosynthesis and transports dissolved minerals
• a stoma is an opening on the underside of a leaf that lets gases pass into or out of the leaf
• stomata are controlled by guard cells which open when they become turgid and close when they lose their turgor pressure
• in a xylem cell water and minerals can only be transported up the cell
• a xylem cell is made of dead cells joined together with no end walls between them
• in a xylem cell there are thick walls stiffened with lignin
• measels is a virus spread by sneezing a coughing that can cause a fever and rash, it can be treated by painkillers and vaccines
• HIV is a virus spread by the exchange of bodily fluids which can cause flu-like symptoms and can lead to AIDs, it can be treated by antiretroviral drugs and cotraception