NAME THE VASCULAR TISSUE THAT TRANSPORTS THE PRODUCTS OF PHOTOSYNTHESIS?
Phloem
GIVE 2 STRUCTURAL FEATURES OF THIS TISSUE
- Phloem consists of long, tubular sieve tubes.
- Phloem consists of companion cells.
DRAW A DIAGRAM OF A TRANSVERSE SECTION OF A DICOT STEM SEEN UNDER A MICROSCOPE
WHICH OF THE ABOVE TISSUE TYPES HAVE A DIFFERENT LOCATION IN THE ROOT
Vascular
WHERE PRECISELY IS THE TISSUE FOUND IN THE ROOT
In the centre
GIVE ONE FUNCTION OF GROUND TISSUE
Storage
WHICH OF THE TISSUES IS COMPOSED OF LIVING CELLS?
Phloem
WHAT IS THE FUNCTION OF MERISTEMATIC TISSUE
Growth of new cells by mitosis
EXPLAIN HOW ROOT HAIRS ENTER AND THE PASSES TO THE VASCULAR TISSUE
water enters the roots by osmosis
GIVE 2 FEATURES OF XYLEM THAT FACILITATE THE UPWARD MOVEMENT OF WATER
Lignin for thickened walls for support. This stops the xylem from collasping.
Pits to allow the sideways movement of water and minerals
Tapered ends / narrow
NAME AND BRIEFLY EXPLAIN 2 PROCESSES INVOLVED IN THE UPWARD MOVEMENT OF WATER
Root Pressure
As water moves into the root by osmosis it builds up a pressure that pushes the water up the xylem
Transpiration
As water evaporates from the leaf by transpiration, more water is pulled upwards through the xylem and into the leaf
WHAT IS MEANT BY MONOCOTYLEDONOUS
One seed leaf
GIVE AN EXAMPLE
Grass / daffodils
HOW ARE THE VEINS ARRANGED IN THE LEAVES OF A MONOCOT
Parallel
HOW DOES THE VEIN ARRANGEMENT DIFFER IN A DICOT?
They are netted
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EXPERIMENT QUESTION IN 2009
DRAW A LABELLED DIAGRAM OF A TRANSVERSE ROOT
WATER ENTERS THE OUTERMOST CELLS BY OSMOSIS. WHAT DOES THIS TELL YOU ABOUT THE CELL SAP OF THE OUTERMOST CELLS?
It has a high solute concentration
DESCRIBE THE RELATIONSHIP BETWEEN TRANSPIRATION AND WATER UPTAKE (FROM THE GRAPH). SUGGEST A REASON
As the rate of transpiration increases, the rate of water uptake also increases. The cohesion tension model explains how when water is lost in transpiration, each water molecule pulls the one behind it (due to the extreme cohesive nature of water). If there is a continuous column of water in the xylem, the ‘pull’ is transmitted all the way down to the roots and more water enters the roots.
NAME THE STRUCTURE FOUND IN STEMS EQUIVALENT TO STOMATA
Lenticels
NAME 2 COMPOUNDS THAT LEAVE THROUGH THIS STRUCTURE
Water and CO2
DESCRIBE THE PRINCIPLE FEATURES OF THE COHESION TENSION MODEL
Water evaporates from the cells of the leaf through transpiration. These cells then become less turgid.
This causes water from the xylem vessels to move into the leaf cells by osmosis.
The loss of water from the leaves is controlled by the waxy cuticle and the opening and closing of the stomata.
Transpiration causes more water to be pulled in a continuous column of water up the xylem vessels to replace it.
Water molecules are attracted to each other and this cohesive property means that a column of water can move up the xylem vessels without breaking.
The tension caused by transpiration from the leaves pulls the colun upwards.
The flow of water inside the plant is called the transpiration stream’.
OUTLINE HOW WATER FROM THE SOIL REACHES THE LEAF. (18MARKS)
- Water enters the root hair by Osmosis, this is because the cell sap on the outermost layers have a higher solute concentration creating a concentration gradient.
- Water moves by diffusion then from root hairs to ground tissue reaches the xylem.
- Cohesion tension model (explain)b