Section C: Plants Physiology Flashcards
Explain three ways the leaf is adapted to photosynthesis.
. The (waxy) cuticle has a large surface area so lots of light can be absorbed.
. The palisade cells are full of chloroplasts, which are at the top of the leaf so it can reach light.
. The upper epidermis is transparent, so light can pass through it and get to the palisade cells.
What do the root hairs do in the plant?
Take in/absorb water.
What is a xylem in terms of plants?
Tubes in the stem that transport water and minerals from the root up to the shoot, to the leaves in the transpiration stream.
What can be used to measure transpiration?
Potometer, it’s used to estimate the transpiration rate.
What is transpiration?
The loss of water from the leaves.
What are the four things that affect the transpiration rate in plants?
Humidity
Light intensity
Wind
Temperature
What do you have to boil the leaf in in the ‘test for starch’ experiment?
Ethanol.
How do nitrates help plants?
Cell growth. It it doesn’t get enough it will become ‘stunted’ and will have yellow older leaves.
How do phosphates help the plant?
Needed for respiration and growth. They also make the DNA and cell membranes. The leaves turn purple because of poor root growth.
How does potassium help the plant?
They help the enzymes needed for photosynthesis and respiration. This would make the leaves de-colour with dark splotches.
What are auxins?
Plant growth hormones.
What is phototropism?
When a shoot tip is exposed to light it needs more auxin on the side that’s in the shade than the side that’s in the light. This makes the cell elongate faster on the shaded part, so the shoot bends towards the light.
What is geotropism?
A root growing sideways will also have more auxin on its lower side, so the roots bend downwards.
