4 mistakes learners make with transport in cells, each one named and explained.
Water travels up the xylem and sugars travel in the phloem, and both depend on surfaces built to let things through.
You say a leaf has the same number of stomata on the top as on the bottom.
Nothing on the outside of a leaf suggests the two sides are built differently.
Question. Where are most of the stomata on a typical leaf?
A common answer. equally on both surfaces
The answer. on the lower surface
Why. Keeping them underneath, out of direct sun, loses the plant less water.
Ask what the plant gains. Fewer stomata in the sun means less water lost.
You answer that the root hair cell is long and thin, and stop there.
The shape is the visible fact, and naming it feels like the whole answer.
Question. Why is a root hair cell long and narrow?
A common answer. so it can reach further into the soil
The answer. because the long extension gives a much larger surface area for absorbing water
Why. Marks are for the consequence of the shape, not the shape itself.
Every adaptation answer needs the word so, followed by what it achieves.
You explain transpiration as water coming in at the leaves and passing down through the plant.
Rain lands on leaves, and watering a plant looks like wetting the whole of it.
Question. Where does the water in a plant get in?
A common answer. through the leaves, where the rain lands
The answer. through the root hair cells
Why. Water is taken in at the roots by osmosis and lost at the leaves, so the flow is upwards.
Transpiration is a loss at the top that pulls the column up from below.
You say sugars travel up the xylem, or that the phloem carries water from the roots.
Both are tubes running the length of the plant, and the names give no clue which is which.
Question. Which tissue carries sugars made in the leaves?
A common answer. the xylem
The answer. the phloem
Why. Phloem carries dissolved sugars, in both directions. Xylem carries water and minerals upwards only.
Tie phloem to food. Both words start with the same sound as the thing they carry.
WAJD spots these patterns in your child's answers and names the one behind their wrong answers, instead of just marking them wrong.