PLANT STRUCTURE AND FUNCTIONS Flashcards
What is photosynthesis?
The process where plants produce energy from Carbon Dioxide and Water.
What is the word equation for photosynthesis?
CARBON DIOXIDE + WATER —> GLUCOSE + OXYGEN
What is the balanced equation for photosynthesis?
6CO2 + 6H2O —> C6H12O6 + 6O2
Photosynthesis is the opposite of what?
Aerobic Respiration
What kind of reaction is photosynthesis?
Endothermic - It takes in light energy from the sun.
How is light energy absorbed?
Through green chlorophyll inside chloroplasts.
How is CO2 absorbed?
Through stomata, small holes in the epidermis (skin) of a leaf which open and close.
How is Water absorbed?
It enters through the roots and is transported to the leaves via the xylem.
What is un-respirated glucose used for in plants?
- can form Cellulose, used to build and strengthen cell walls
- can form starch, which is insoluble and is the storage for carbohydrates
- lipids (fats and oils) stored in seeds
- combining with nitrates from soil, amino acids can form. If there are enough amino acids, protein is formed.
What factors affect photosynthesis?
Light intensity, Carbon dioxide concentration, Temperature.
How can photosynthesis be investigated? (PRACTICAL)
Water plants such as pond weed release bubbles of oxygen which can be counted.
METHOD
An LED lamp is set up at different distances from the plant in the beaker. LEDS are used to prevent a change in temperature.
Sodium Hydrogen Carbonate is placed into the tube to provide a controlled supply of carbon dioxide.
Using a bung (stopper), delivery tube and syringe, measure oxygen output in the syringe every minute. Repeat this a few times for consistency.
Change the distance of the light and repeat.
(The boiling tube may be placed in a water bath to easily check temp)
What is the independent variable in the photosynthesis practical?
Light intensity (lamp distance)
What is the dependent variable in the practical?
Oxygen output
What is the control variable in the practical?
Pondweed used, or amount of sodium hydrogen carbonate
What is used to provide a controlled amount of CO2 for the practical?
Sodium hydrogen carbonate
What equipment is needed for the photosynthesis practical?
(optional: water bath), Bung, delivery tube, pondweed sample, boiling tube, syringe, thermometer, LED lamp, ruler, DISTILLED WATER
List leaf adaptations:
Large surface area for photosynthesis
Thin structure for quicker diffusion of CO2
Chlorophyll to absorb sunlight
Network of veins for more efficient transportation
Stomata for diffusion of CO2 and O2
What is the Xylem
The transportation system that moves water and mineral ions from the roots to the leaves
What is the Phloem
The transportation system moving food substances and amino acids from the leaves to every other place in the plant. This food transportation is called TRANSLOCATION
What do root hair cells do?
They transport mineral ions and water into the plant through osmosis and active transport. They contain lots of mitochondria to release energy needed for active transport.
What do guard cells do?
In high light levels, they absorb water and become turgid (stiff) which opens the stomata and allows for diffusion to occur. In low light levels, they become flaccid and this closes the stomata.
What is lignin?
A carbohydrate material that strengthens the xylem.
What is a sieve tube?
A tunnel where translocation takes place. Each sieve tube is perforated at the end so connects seamlessly with cytoplasm. They each have companion cells that provide energy for active transport.
What is transpiration?
When water that is on the tissue on the inside of a leaf evaporates and diffuses out of the stomata. This lost water is replaced by water from the xylem, which is replaced by water from the roots.
What factors affect transpiration?
Temperature
Humidity
Air movement
Light intensity
How can the rate of transpiration be measured?
By using a potometer connected to a plant that measures water uptake. The water uptake is measured by the time it takes for a water bubble to move a set distance in the tube.
What structure is used for translocation within the phloem?
Sieve tubes.
