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Introducing Plants
The Sun is the source of all energy on Earth. Green plants are the link between man and
the Sun. Without green plants most life on Earth would not exist.
Give examples of advantages of there being a wide variety of plants
There is an enormous range of plants on Earth. This variety has many advantages:
 There is a large range of characteristics for breeding from
 There is a greater choice for use as raw materials
 They provide different sources of food for many animals
 They provide a variety of habitats for many animals
 They maintain the gas balance of the atmosphere
Green plants take in carbon dioxide and produce oxygen
 They make homes, gardens and all ecosystems more beautiful
Describe 3 specialised uses of plants
There are countless ways in which man uses plants.
Here are three:
Food
Raw materials
Medicines
Growing Plants
All living things must reproduce to ensure that they do not become extinct.
In order to reproduce, flowering plants produce seeds.
Describe the functions of the three main parts of the seed of a dicotyledon, i.e. seed
coat, embryo, food store
Structure of a seed
A seed is made up of
an embryo - small undeveloped plant
a food store - food supply until the plant can make its own
a seed coat/testa - tough protective coat
Describe the effect of temperature and the availability of water and oxygen on
germination
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Germination is the development of a plant embryo into an independent plant with green
leaves. During germination the food store present is used to give the young plant energy
for growth. Seeds need certain conditions in order to germinate.
To germinate seeds need: Water, Oxygen, Warmth
Describe the functions of the parts of flowers, i.e. sepal, petal, stamen, anther, stigma,
ovary, nectary
Structure
Sepal
Petal
Stamen
Function
Protects the unopened flower bud
Brightly coloured to attract insects
Male part of the flower, contains anther and
filament
Produces male gametes (pollen)
Top of the female part which collects the pollen
Produces female sex cells (ovules)
Produce sugary nectar which attracts insects
Anther
Stigma
Ovary
Nectary
Describe the methods of pollination
Pollination is the transfer of pollen from the anther to the stigma.
self-pollination
Pollen is transferred from the anther of one flower to the stigma of the same flower
or another flower on the same plant
cross-pollination
Pollen is transferred from the anther of one flower to the stigma of a flower on a
different plant
There are 2 methods of pollination:
 Insect
 Wind
Insect pollination
Pollen is brushed onto the insect’s body when it sucks
nectar from a flower. Pollen is carried by the insect.
When the insect goes to another flower the pollen
grains stick to the stigma.
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Wind pollination
Pollen is blown by the wind from the anther hanging
outside of the flower. Pollen is carried by the wind.
Pollen sticks to stigmas hanging outside of the flower.
Describe fertilisation and fruit formation
After fertilisation ovules become seeds each contains an embryo, a seed coat and a
food store. The ovary becomes a fruit this is often fleshy and succulent (e.g. plums
etc) but can also be very tough and dry (e.g. nuts)
Describe ways of propagating flowering plants artificially by cuttings and grafting
Man can produce new plants by artificial methods that would not take place naturally.
The most common methods are:
 Cuttings
 Graftings
Cuttings
A piece of stem with some leaves is taken from the
parent plant. It is then placed in a suitable compost to
allow it to form roots.
Grafting
A bud or shoot of a valuable plant is taken and
joined to the developed root stock of a hardy plant.
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Describe asexual reproduction by runners and tubers
Some plants can reproduce asexually (without flowers or fertilisation). Asexual
reproduction involves only one parent. Many plants have special structures that allow
them to reproduce sexually.
Runners
Side shoots grow out from the parent plant.
Buds form along the runner. These obtain
food and water from the parent until they
grow their own roots. Eventually they
become detached from the parent. e.g
strawberry, spider plant
runner
Tubers
Underground food store that stores enough food over winter to start the
growth of a new plant. Each new plant can then make its own food and form
several tubers for the next winter. A shoot grows from an eye. Shoot
forms leaves. food made by leaves is sent down to make new tubers. plant
withers but tubers stay in soil until next year e.g. potato, dahlias, crocus.
Making Food
Explain the need for transport systems in a plant
Plants need transport systems as all parts of the plant need water (taken in through
the roots) and food (made in the green parts of the plant). Plants therefore need
transport systems to move these substances around.
Describe the pathways of movement of water and food in xylem and phloem
Xylem vessels carry water which is absorbed from the soil by the roots and is carried
up to all parts of the plant.
Phloem vessels carried dissolved food (sugars) from the leaves down to all parts of the
plant that cannot make their own food e.g. roots, flower
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State that plants take in carbon dioxide from the air through stomata which can open
and close
Plants take in carbon dioxide from the air through tiny pores on
the surface of the leaves. These pores are called stomata.
State that water vapour is lost through stomata
Stomata open during the day and close at night
State that green plants make their own food which may be stored as starch
Green plants make food in the form of sugar. This sugar can be used straight away or
converted into the storage carbohydrate, starch.
When a plant is left in the dark it uses up its stored food, this is called destarching.
State that green plants convert light energy to chemical energy using chlorophyll
Chlorophyll captures light from the Sun and converts it into chemical energy which is
used to make glucose
Describe the process of photosynthesis in terms of raw materials and products
Photosynthesis is the process by which green plants use light energy to make food.
Carbon dioxide + water
raw materials
light energy
glucose + oxygen
products

chlorophyll
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