Year 9 Term 3 Flashcards
(52 cards)
What is the usual condition in the stomach
Acidic
What is the usual condition in the small intestine
Alkaline
What is the relationship between temperature and rate of digestion
As the temp increases, so does the rate of digestion until it reaches an optimum temp. Then the enzymes denature and the rate drops
Organs of a plant
Roots
Stem
Leaf
Tissues of a plant
Xylem
Phloem
Epidermal tissue
Mesophyll
What’s the epidermal tissue
It covers the plant
What is mesophyll
Carries out photosynthesis
What is the phloem
Transports dissolved sugars from the leaves (where they are made in photosynthesis) to the rest of the plant for immediate use or storage. The phloem form continuous tubes from the stem to the roots
What is the xylem
Xylem tissue transports water and mineral ions from the roots to the stems and leaves. Composed of hollow tubes strengthened by lignin, adapted for transport of water in the transpiration stream
What is the cambium
Where new xylem and phloem are grown
What is transpiration
The process of water moving up a plant against gravity through the xylem. Water evaporates through the stoma and moves out the leaf. The water is drawn through the xylem like a straw and produces a flow of water
How can transpiration be measured
Can be measured using a potometer which can be used to show how the uptake of water changes in different conditions. It gives you a good idea of how much water the plant loses.
How does temperature affect the rate of transpiration
It increases because by increasing the temp it increases the kinetic energy of molecules which makes diffusion, osmosis and evaporation happen faster
How does humidity affect the rate of transpiration
Decreases because when the air is humid there is more water vapour in it and so is less able to accept more water molecules by evaporation
How does wind affect the rate of transpiration
Increases because the wind blows water vapour away from the stoma keeping the concentration gradient high
How does light intensity affect the rate of transpiration
Increases because light causes the stoma to open. Wider stoma allow faster diffusion of water vapour out of the leaf
How has the leaf adapted to transpiration
The leaf is thin and has a large surface area and has stomata mainly on the lower surface and spongy mesophyll cells
What does the waxy layer do
The waxy layer is a waterproof layer on the upper epidermis. This prevents water loss
What does the spongy do
The spongy layer has rounded cells which are not tightly packed so have a large surface area for gas-exchange
What do the guard cells do
They open and close the stomata to control water loss (also allows gases to move I a mad out)
What do the arrangement of cells do
It means there is a short diffusion distance
What is translocation
The movement of food molecules through the phloem
How are sugars used in respiration
To release energy
How are sugars used in meristems
At the tips of roots and shoots where cells are dividing by mitosis for growth
