SB6 - Plant structures and their functions

What are plants and algae in terms of a food chain and what does this mean?

They are the main producers and are therefore the primary producers of biomass?

What is the formula of photosynthesis?

6CO₂ + 6H₂O → C₆H₁₂O₆ +O₂

How does temperature, light intensity and carbon dioxide concentration affect the rate of photosynthesis?

With an increase in temperature, rate of photosynthesis will increase, this will increase until a certain point (optimum), after this point, enzymes will denature and the rate will decrease.

The higher the light intensity the faster the rate of photosynthesis until it plateaus, once it isn’t the limiting factor anymore. 

CO₂ concentration is the same as light intensity.

What is the light intensity practical?

Algae balls of the same size and weight are placed in a test tube full of water which is then sealed.

A lamp is placed at a certain distance from the test tube.

As photosynthesis occurs, oxygen is produced and bubbles form, count the bubbles and record and compare with other distances.

Must use water bath in front of the light bulb so temperature doesn’t change the observation.

What is the relationship between rate of photosynthesis, light intensity and distance from light source?

Light intensity is measured in lux.

Light intensity is directly proportional to rate of photosynthesis.

Light intensity is inversely proportional to the square of the distance from the lamp.

How are root hair cells adapted for absorbing mineral ions?

Large surface area to volume

Large permanent vacuole to store water and increase movement of water from the soil to cell.

How are root hair cells adapted for absorbing water?

Lots of mitochondria to provide energy for active transport of minerals into the root hair cell.

What are the adaptations of xylem cells for their functions?

Once formed, lignin is released which causes the cells to die and causes the cell to become stronger to withstand the pressure of the movement of water.

Their cell walls at the top and bottom are destroyed so it can form a long, continuous, hollow chain, to increase the flow of water.

What are adaptations of the phloem for its functions?

Cell walls of each cell form structures called sieve plates, allowing the movement of substances from cell to cell.

They are alive.

They contain lots of mitochondria in the companion cell allowing for active transport to occur.

How are water and mineral ions transported through the plant through transpiration?

How is sucrose transported around the plant by translocation?

How is the structure of the leaf adapted for photosynthesis and gaseous exchange?

What are the factors that effect the rate of transpiration?

How is a cactus adapted to survive in the desert?

How do auxins control and coordinate plant growth?

Why are auxins used in agriculture?

Why are gibberellins used in agriculture?

Why is ethene used in agriculture?