Micropropagation

Plants can be cloned and propagated in horticulture and agriculture.

Describe how artificial clones of plants are produced using micropropagation.

Potato plants can be naturally cloned from tubers.

Many diseases can infect potato plants.

State one disease that can infect potato plants and state the type of pathogen that causes the disease.

The diagram shows a lily plant and a peppermint plant.

Lily plant
Peppermint plant

State the name of structure X and outline how a gardener could produce many cloned plants from structure X.

State the name of structure Y and describe the process by which a new plant can form naturally from structure Y.

Many organisms undergo asexual reproduction by mitosis.

State two other roles of mitosis in organisms.

Plants reproduce asexually by mitosis.

Explain why mitosis, and not meiosis, is used for asexual reproduction in plants.

Bacteria reproduce asexually by a process called binary fission.

Suggest why bacteria are unable to reproduce asexually by mitosis.

During meiosis, the independent assortment of chromosomes leads to the formation of genetically different gametes.

Gametes of the western clawed frog contain 10 chromosomes.

Calculate the number of genetically different gametes resulting from the independent assortment of chromosomes that would be produced by an individual frog.

Plant cloning is often used by farmers to produce new plants.

A plant that is often cloned by taking cuttings is lavender, Lavandula angustifolia.

A farmer had two fertiliser solutions, solution A and solution B, and wanted to investigate which one to use on lavender plants. In order to ensure the investigation would be valid, two cuttings were needed from the same parent plant.

Describe how to clone a plant by taking a cutting.

Cloning plants is also known as vegetative propagation.

Identify three advantages of vegetative propagation in agriculture.

Temperature and light intensity are two factors that affect the rate of photosynthesis.

A student investigated how temperature and light intensity affected the rate of photosynthesis in the aquatic plant Elodea canadensis. The rate of photosynthesis was measured by counting the number of bubbles produced by the plant per minute.

The student’s results are shown in Table 3.

Identify the anomalous result in Table 3 and explain how this result could be confirmed as an anomaly.

* Describe how the student could improve their experimental method and the presentation of their data.

Photosynthesis occurs in two stages: the light-dependent stage and the light-independent stage. The light-independent stage is affected by temperature more than the light-dependent stage.

Explain why temperature has a greater effect on the rate of the light-independent stage.

Scientists are able to clone desirable plants that show a high rate of photosynthesis. The following passage describes how plants are cloned.

Complete the passage using the most appropriate words or phrases.

Cells are removed from the meristem tissue in axial buds or........

tips. The tissue sample that is removed is called the........ Ethanol can

be used to........ the plant tissue. Hormones are used to stimulate mitosis,

which produces a mass of cells called a........

The potato plant, Solanum tuberosum, is a staple food plant in many parts of the world.

Potatoes are susceptible to infection by a pathogen called Phytophthora infestans, which causes a disease known as potato late blight. The most visible sign of the disease is a brown discolouration of the leaves.

Some varieties of potato are resistant to infection by P. infestans.

State two ways in which an individual S. tuberosum plant could respond to infection by infestans.

Suggest why it is important to use clones in an investigation such as this.

State how a clone of potatoes could be produced for this investigation and explain why it is important to carry out this procedure under aseptic conditions.

asepsis is important because........

The extent of infection is estimated by comparing the area under the curve from the graph. The area under the curve for clone B is 1250. (Units can be ignored in this instance.)

Using Fig. 18, calculate the approximate area under the curve, between day 35 and day 98, for clone C.

Calculate the area under the curve for clone C as a proportion of the area under the curve for clone B.

Using Fig. 18, suggest why the area under the curve is used as a measure of infection rather than the area of leaf that is visibly affected on a given day.

The clones were planted in adjacent fields in order to control variables such as temperature, wind speed and rainfall.

Suggest two other abiotic variables that this precaution was intended to control.