Genetic variation and its control Flashcards
Why do plants and animals have similar characteristics to their parents?
The information that results herein is carried by genes, which pass on in the sex cells (gametes) that develop into the offspring
What are chromosomes? Where are they found?
Bundles of genes that control the characteristics of the body. Found in the nucleus of a cell
What might the reason be for a difference in a characteristic between different individuals?
The genes they have inherited (genetic causes)
The conditions they have grown up in (environmental causes)
A combination of both
Define the two forms of reproduction
Sexual reproduction - fusion of male and female gametes, which leads to variety in the offspring due to the mixture of genetic info from the two parents
Asexual reproduction - no gametes and only one parent is needed, so no mixing of genetic info. No genetic variation in offspring so they are clones
How can new plants be produced quickly and cheaply?
What characteristics does this produce in the offspring?
Taking cuttings from older plants
They are identical to their parent
What are the modern cloning techniques?
Tissue culture - using small groups of cells from part of a plant
Embryo transplants
Adult cell cloning
Describe the process of embryo transplants
Splitting apart cells from a developing embryo before they specialise, then transplanting the identical embryos into host mothers
Describe the process of adult cell cloning
The nucleus is removed from an unfertilised egg cell. A nucleus from an adult body cell, such as a skin cell, which is inserted into the egg cell. The egg cell takes an electric shock that causes it to divide to form embryo cells, which contain the same genetic info as the adult skin cell. When the embryo develops into a ball of cells, it is inserted into the womb of an adult female to develop fully.
How does genetic engineering work?
Genes from the chromosomes of organisms can be ‘cut out’ using enzymes and transferred to cells of other organisms. This is done at the early stage of the organism’s development so that they develop with the desired characteristics
How is genetic engineering used mainly at the moment?
Genes are transferred to crop plants that might make them resistant to insect attacks or to herbicides, for instance. These are called genetically modified (GM) crops, and often give an increased yield
What concerns do some people have about GM crops?
They might affect the populations of wild flowers and insects
We don’t know what health effects they might have by us eating them
