Cloning

Part 2

Learning Objectives• To learn how asexual reproduction

takes place in plants.

• To learn about the advantages and disadvantages of cloned plants.

• To learn about plants cloned using tissue culture.

Success Criteria• I can explain how potato, strawberry

and spider plants reproduce asexually.

• I can explain the process of taking cuttings to clone plants.

• I can explain the process of tissue culturing to clone plants.

Starter• Write down 5 things you learnt about

cloning last lesson.

PLANT CLONES

Plant Clones

• The only natural clones in the animal kingdoms are twins.

• Many plants however, reproduce asexually.• In these cases, no fertilisation takes place – new

plants grow due to mitosis.

The part of a potato we eat is called the TUBER.

Left long enough, it will grow shoots and roots

and a new plant will grow.

1. Potato PlantsIf left long enough,

the eyes on a potato tuber will sprout

shoots and roots.

The tuber will grow in to a new plant, which is a genetic clone of the plant it grew on

itself.

2. Strawberry PlantsStrawberries grow on stems called runners.

The runners grow over the ground and have buds that grow into tiny strawberry plants called plantlets.

These plantlets put down roots and grow into adult plants.

Plantlet

3. Spider PlantsSpider plants grow plantlets on their stems.

If these are cut off the parent plant and placed in soil, they grow in to new adult plants.

Parent Plant

Plantlet

Worksheet 2

Complete parts a & b.

Cuttings

• Plants grown from cuttings or tissue culture are clones.

1. A short stem is cut off the parent plant with a sharp knife.

2. The end of the stem is dipped in rooting powder. The hormone helps roots grow.

3. The cutting is put into a pot of sandy soil.4. A bag is placed over the plant to keep in moisture.

Draw the diagram at the bottom of page 42 in your book.

Advantages and Disadvantages of Cloning Plants.

• Draw the following table in your books and complete it using the information on the top half of page 43.

Cloning Plants

Advantages Disadvantages

HIGHER

Tissue Culture

• Small sections of plant tissue can be cloned using tissue culture.

• Tissue culturing must be carried out using ASEPTIC TECHNIQUE (everything has to be sterile).

Tissue Culture

1. Plants with desired characteristics are chosen.2. A large number of small pieces of tissue are taken

from the parent plant.3. They are put in to sterile test tubes that contain

growth medium (agar and auxins).4. The tissue pieces are left in suitable conditions to

grow into plants.

Answer questions 16, 17 and 18 on page 43.

PLENARY

Plenary

Humans have been cloning plants for hundreds of years. Animals have only been cloned over the last few years.

Why is this?

Learning Objectives• To learn how asexual reproduction

takes place in plants.

• To learn about the advantages and disadvantages of cloned plants.

• To learn about plants cloned using tissue culture.

Success Criteria• I can explain how potato, strawberry

and spider plants reproduce asexually.

• I can explain the process of taking cuttings to clone plants.

• I can explain the process of tissue culturing to clone plants.