RED
Describe photosynthesis
The process by which plants synthesise carbohydrates from raw materials using energy from light
Outline the use of starch in plant
an energy store
Explain the importance of nitrate
to make amino acid which can be used to make protein for growth.
Outline the use of sucrose
transport in phloem. Plants do not transport glucose. they change it to sugar with larger molecules called sucrose. Sucrose is carried from one part of the plant to another inside tubes called phloem tubes
Explain the importants of magnesium ion
to make chlorophyll.Without chlorophyll, the plants leave will look yellow rather than green and will not be able to photosynthesis
State word equation for photosynthesis
carbon dioxide + water → glucose + oxygen
Why most leaves have large surface area and thin?
The larger the surface area, the more sunlight can be captured by the chlorophyll in the chloroplasts.
Leaf is thin so light can penetrate through the leaf and reach the chloroplasts in the cells efficiently.
State the function of Xylem?
Transport of water and mineral ions, and support
State the function of phloem?
Transport of sucrose and amino acids
State a structure of xylem vessels
thick walls with lignin
Complete this sentence: Chlorophyll is ________________
A green pigment that is found in chloroplasts
State TWO other structure of xylem vessels
a no cell contents
b cells joined end to end with no cross walls to
form a long continuous tube
Describe transpiration
loss of water vapour from leaves
State how water evaporates
Water evaporates from the surfaces of
the mesophyll cells into the air spaces and then
diffuses out of the leaves through the stomata as
water vapour
What is source and sink?
The part of a plant from which sucrose and amino acids are being translocated is called a source. The part of the plants to which they are being translocated is called a sink
Chlorophyll transfers energy__________
from light into energy in chemicals, for the synthesis of carbohydrates
What is transpiration pull?
A force produced by the loss of water vapour from a leaf, which reduces the pressure at the top of xylem vessels.
How water moves from xylem to the air, through a plant leaf
Water moves from the xylem vessels to mesophyll cell by osmosis. Water evaporates from the surface of the mesophyll cell walls. The air spaces contain water vapour. Water vapour diffuses out of the air spaces, through the stomata.
What is a control?
A standard sample that you use as a comparison, to find the effect of changing a variable.
What is the function of cellulose in plants?
To build cell wall
State the balanced chemical equation for photosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2
Explain how and why wilting occurs
If temperature is high, windy and very dry, transpiration happens very quickly. The plant lose water from its leaves faster than it can take it up from its roots. Individual cells in plants become flaccid. The tissues in the leaves are no longer supported by the turgid cells pushing outwards against one another.
Explain why some parts of a plant may act as a source and a sink at different times
Describe how water vapour loss is related to cell surfaces, air spaces and stomata.
Water evaporates from the cell surfaces of the leaf mesophyll cells, into the air spaces between as water vapour and out through the stomata. In order to control water vapour loss, the stomata close. This happens when the humidity of the air outside is too low, conditions are too windy/ hot, etc.
Explain the mechanism of water uptake and movement
The cohesion and adhesion of water in the vessel element helps water move up the vessel. Adhesion occurs when water molecules are attracted to the walls of the vessel, which has thick walls with lignin. Cohesion occurs when water molecules are attracted to each other.As some water molecules move up the vessel element, they pull other water molecules with them. Water molecules move up the xylem