Transpiration And Photosynthesis Flashcards
Give the equation for photosynthesis
Carbon dioxide+ water —> Glucose + Oxygen
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Explain why chlorophyll is needed in photosynthesis
Chlorophyll absorbs the light energy needed
to convert carbon dioxide and water into
glucose (chemical energy)
What are the three limiting factors in
plants?
Light intensity, carbon dioxide
concentration, temperature
What is the glucose used for from
photosynthesis?
1 - to release immediate energy through
respiration in all plant cells
2 – store as insoluble starch
3 – to make proteins for growth
4 – to make cellulose fibres to
strengthen the cell wall
5 – to produce fat/oils for storage in
seeds
What is the term for a leaf where chlorophyll is only present in part of it?
Variegated
Explain why, when the iodine test is done on a variegated leaf, only part of the leaf turns black
The green chlorophyll is needed to absorb the light energy to convert carbon dioxide and water into glucose which is stored as Starch in these green parts of the leaf
How do plants produce proteins for
growth?
To produce proteins, plants also use
nitrate ions that are absorbed from the soil
to make amino acids that are then joined
to make proteins.
How could you increase the rate of
photosynthesis in a greenhouse?
Light bulbs
Parrafin heater
What are the limiting factors on a graph showing how light intensity affects rate of photosynthesis?
On the slope = light
intensity
On the flat = temperature
or carbon dioxide
concentration
What are the limiting factors on a graph showing how temperature affects rate of photosynthesis?
On the slope up and
down = temperature.
On the peak = carbon
dioxide concentration
or light intensity
What are the limiting factors on a graph showing how carbon dioxide concentration affects rate of photosynthesis?
On the slope = carbon
dioxide.
On the flat = temperature
or light intensity
Describe the shape of a light
intensity graph.
As the light intensity increases the
rate of photosynthesis increases up
to a peak point. After this point any
further increase in light intensity
does not increase the rate of
photosynthesis.
Explain the shape of a light
intensity graph.
When the line is diagonal at the
start light intensity is limiting the
rate of photosynthesis. At the
peak point light is no longer
limiting photosynthesis, something
else is e.g. temperature or carbon
dioxide concentration.
What is the function of a stoma?
Open/close to control gas exchange in the leaf
How do stoma open?
Guard cells fill with water by osmosis
Thicker inner wall does not stretch as
much as the thinner outer wall
Results in guard cell bending -
banana shaped
Stoma opens between guard cells.
Identify features of Xylem
Not made of living cells, hollow, continuous tubes, direction of flow is upwards, main substances transported are water and mineral ions, name of process is transpiration (transpiration stream)
Identify features of phloem
Made of living cells, are not hollow, are not continuous tubes (sieve plates), direction of flow is upwards and downwards, main substances transported are sucrose and amino acids, name of process is translocation.
How is xylem and phloem stored?
In a vascular bundle
Explain how water
moves from the soil
to the xylem.
From a high concentration of
water (high water potential) to
a low water concentration
(low water potential) – down
a concentration gradient via
osmosis
Explain how you would use a potometer to
measure he rate of transpiration in a plant.
Set up underwater to prevent
introduction of air bubbles other than the
one used for measuring.
Water is drawn up via the transpiration
stream and lost out of the leaves via
transpiration. This will be visible by the
moving of the air bubble along the scale.
You could measure the distance the air
bubble moves
Remember: not a perfect measure as
some water will be used in
photosynthesis
What is a
source?
Place where
something (in this
case, sugar) is made
What is a
sink?
Place where
something is used or
stored
What is a mineral deficiency?
The situation where a plant cannot get enough of a particular mineral from the soil for healthy growth.
Different minerals are needed for different reasons, so each one causes different symptoms of mineral deficiency.
What are the symptoms of nitrate deficiency?
Poor growth, yellow leaves
