Practice Questions

1.Give two uses of gibberellins in agriculture.

Any two from:

-end seed dormancy

-promote flowering

-increase fruit size

2.Auxins are used as selective weed killers. Explain how using selective weed killers can affect biodiversity in an area. 

Auxins used as selective weed killers kill many broad-leaved plants (weeds). When these plants are removed, there are fewer plant species growing in the area, so plant diversity decreases.

With fewer types of plants, there may also be less food and habitat for insects and other animals. This can lead to a reduction in the number of different organisms living in the ecosystem, so biodiversity decreases.

3.Plant hormones are widely used in agriculture and the food industry.

Describe three different ways plant hormones are used by humans to control plant growth.

Any three from 

1. Auxins

Selective weed killers: Kill broad-leaved weeds without harming grasses or cereal crops.

Rooting powders: Stimulate root growth in plant cuttings, helping gardeners and farmers produce new plants more quickly.

Tissue culture: Promote growth of plant cells in laboratories, allowing large numbers of identical plants to be cloned.

2. Ethene

Controlling fruit ripening: Fruit can be picked when unripe (so it doesn’t get damaged during transport) and then exposed to ethene to ripen at the right time. This is widely used in the food industry for bananas, tomatoes, and other fruits.

3. Gibberellins

Ending seed dormancy: Makes seeds germinate when desired, useful for farming.

Promoting flowering: Encourages plants to flower earlier or under conditions they normally wouldn’t, useful for commercial flowers.

Increasing fruit size: Stimulates growth to produce larger fruits, e.g., bigger grapes.