B4 - It's a green world

Who planted that there ?

• Which type of leaf cell contains the most choloplasts?
• Explain why there are air spaces between mesophyll cells.
• Explain why a plant leaf is broad.
• What is the purpose of stomata?

Recycling

• Name the process that removes carbon from the atmosphere.
• Explain how carbon is released from limestone.
• Name the type of organism that converts proteins into nitrates.
• Describe one way in which nitrogen can be "fixed."

Who planted that there?

• Palisade cells
• They allow gases to diffuses easily and reach all the cells.
• So it has a large surface are to absorb light.
• To allow gas exchange

Recycling

• Photosynthesis
• Limestone reacts with acid rain to release carbon dioxide.
• A decomposer
• Nitrogen fixing bacteria convert it into ammonia

Water, water everywhere

• What name is given to the movement of water in and out of cells?
• Describe the change you would see using a microscope if onion cells were placed in strong salt solution.
• Explain how osmosis is used to close the guard cell.
• Explain why stomata are mainly found on the underside of the leaf.

Transport in plants

• Name the vessels that carry water and minearls in the stem
• Explain why xylm vessels are strong enough to support a tree
• name two things that increase the rate of transpiration
• Explain how increased light intensity increases transpiration rate.

Water, water everywhere

• Osmosis.
• Water leaves the cells, which become plasmolysed.
• Less sugar is made, water leaves the guard cell, the guard cell becomes plasmolysed, the stoma closes.
• To reduce water loss.

Transport in plants

• Xylem vessels.
• They conatin lignin
• Increased light intensity; increased temperatue; decreased humidty; increased air movement.
• When light intensity increases the stomata open. This allows more water to escape.

Plants need minerals too

• Name two minerals needed for photosynthesis.
• Which mineral would you give a plant with poor root growth?
• Which mineral is used to make chlorophyll?
• Describe two differences between diffusion and active transport.

Energy Flow

• Describe the difference between a pyramind of numbers and a pyramin of biomass.
• Calculate the efficeny if there's 2000Kj of energy in grass and 40Kj is used for growth of a cow.
• Explain how sugar cane can be used to fuel a car.
• Explain why biofuels are renewable energy sources.

Plants need minerals too

• Potassium and magnesium
• Phosporus.
• Magnesium
• Active transport requires energy and is against the concentration gradient; it also uses carrier molecules.

Energy Flow

• A pyramid of numbers shows the number of organisms, a pyramind of biomass shows the mass of organisms.
• 40/2000 = 0.02 or 2%
• Sugar cane is fermented using yeast to make alcohol. The alcohol is miced with petrol to make Gasohol, a fuel for cars.
• Plants used can be replaced by growing more.

Farming

• Suggest one way in which intensive farming is cruel to animals.
• Suggest one advantage of hydroponics.
• Write down one way organic farrmers can replcae nitrogen from lost soil.
• Sugges one disadvantage of organic farming.

Decay

• Name three detrivores
• What is meant by the term "optimum temperature?"
• Explain what's meant by the term "saprophyte."
• Explain why drying prevents food decay.

Farming

• Enclosed in very small spaces, given harmful drugs. etc.
• The mineral  supply is controlled and unused minerals are recycled, reducing costs. There is better control of external conditions and disease.
• Grow nitrogen-fixing plants, use manure, use compost.
• High costs and a small yield.

Decay

• Earthworms, maggots and woodlice.
• The temperature at which enzymes work best.
• An organism that feeds off dead and decaying material.
• It removes the moisture that bacteria needs to grow.