Plants and gm

Meristem tissue in plants contains the cells that divide as the plant grows. It is found at the growing tips of shoots and roots.

Plant cells differentiate into different types of plant cell depending on where they are in the plant.

Stem cells from meristems can be used to produce clones of plants quickly and economically. 

The loss of water vapour from the surface of plant leaves is known as transpiration.

Water evaporates in the leaves and the water vapour escapes through the stomata by diffusion.

The stomata can open or close as conditions change because the guard cells can gain or lose water by osmosis.

Factors that increase the rate of photosynthesis or increase stomatal opening will increase the rate of transpiration.

We measure water uptake, not transpiration.

The rate of transpiration varies with:

Light intestity, which affects the opening of the stomata 

Air movements, which affect the concentration of water vapour in the air around the leaves

Temperature, which affects the rate at which water evaporates.

Genetic engineering is a process that involves modifying the genome of an organism to introduce desirable characteristics.

Genes can be transferred to the cells of animals and plants at an early stage of their development so that they develop desired characteristics. This is genetic engineering.

In genetic engineering, genes from the chromosones of humans and other organiams can be cut out using enzymes and transfered to the cells of bacteria and other organisms using a vector, which is usually a bacterial plasmid or a virus.

Crops that have had their genes modified are known as genetically modified (GM) crops. GM crops often have improved resistance to insect attack or herbicides and generally produce a higher yeild or increased nutritional content.