Cards to help revise with all the 3 and 4's for Science.

  • Created by: dannielle
  • Created on: 04-05-11 09:17


What is the green stuff called in plants?

What is the equation for photosynthesis?

6 ways in which leaves are adapted for photosynthesis and how?

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Chlorophyll or Chloroplasts

Carbon dixoide + water - Glucose + Oxygen

Leaves are broad so that theres a large surface exposed to light.

They're also thin which means carbon dioxide and water vapour only have to travel a short distance.                                                                                                   The upper epidermis is transparent so that light can pass through.                        Leaves contain lots of chlorophyll which is the pigment that absorbs light energy for photosynthesis.                                                                                                 The lower surface is full  of little holes called stomata. They're there to let gases in and out and to allow water to escape. This is transpiration.                  

Leaves have a network of veins. These deliver water and other nutrients to every part of the leaf and take away the food produced by the leaf.

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Write out the definition of Osomosis

Explain how and why a plant cell becomes turgid.

Explain how and why a plant cell becomes flaccid.

Explain how and why a plant becomes plasmolysed.

Describe how plants are adapted to reduce water loses

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Osomosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower concentration.

When a plant is well watered all its cell will draw water in by osmosis and become plump and swollen. When the cells are like this they're said to be turgid. Turgor pressure helps support the plant tissues.

If there's no water in the soil a plant starts to wilt. This is because the cells start to lose water and so they lose turgor pressure. The cells are then said to be flaccid.

If the plant is really short of water, the cytoplasm inside its cell starts to shrink and the membrane pulls away from the cell wall. The cell is now said to be plasmolysed.

Because the stomata close automatically when supplies of water dry up and the stomata are sensitive to light and close at night to conserve warer without losing out on photosynthesis.

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What is transported in the xylem?

What is transported in the pholem?

What is translocation?

What is transpiration?

Describe the structure of pholem and xylem?

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Water and minerals are transported in the xylem.

Food substances (mainly sugars) are transported in the pholem.

Translocation is the movement of food substances around a plant.

Transpiration is the water loss in a plant, it is caused by evaporation and diffusion.

The structure of an xylem tube is that they are made of dead cells and have no end walls or plates. The thick side walls are strong and stiff which gives the plant support.

The structure of pholem tubes are that they are made of living cells with end plates to allow stuff to flow through. They transport food going in both directions.

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Plants need three main minerals

Nitrates are needed by the plant because?

Phosphrates are needed by the plant because?

Potassium are needed by the plant because?

Magenisum is needed in small amounts because?

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Nitrates are needed to make proteins and amino acids. They are needed for cell growth. If they do not get enough they will get yellow older leaves.

Phosphates are needed for making DNA and cell membranes and they're needed for respiration and growth. Plants with not enough will have poor root growth and purple older leaves.

Potassium helps enzymes that are needed for photosynthesis and respiration. If there's not enough potassium in the soil then the plants have poor flower and fruit growth. Also discoloured leaves.

Magnesium is required for making chlorophyll needed for photosynthesis. Without magnesium plants have yellow leaves.


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