biology B1 (6)
- Created by: haidee
- Created on: 30-04-12 20:04
Fullscreen
Inheritance
- Offspring look like their parents because of genetic information passed on to them in the gametes (sex cells) from which they developed
- The information is contained it the chromosomes which are found in the nucleus of a cell
- The information is carried by the genes DNA is a molecule from which chromosomes are made
- Chromosomes found in pairs one inherited from my father and one from your mother
- Each chromosomes in a pair carries genes which code for the same characteristics
- Everybody is different even identical twins
- Some of the differences are caused by our genes
- Some differences are caused by the conditions in which we have developed many differences are caused by a combination of both
Plant tissue culture or micropropagation
- A small number of cells is taken from a parent plant
- The cells are transferred to a sterile jelly or liquid rich in nutrients and plant growth hormones
- The cluster of cells will divide rapidly and develop roots and shoots
- The tiny plantlets are transferred into plotting trays where they develop into plants
- Cloning of plants has many important commercial implications
- Successful varieties of plants can be produced commercially on a massive scale in a relatively short tome, enabling scientists to develop:
- -fast growing crops that give more than one harvest in a year
- -or crops with better disease-resistant qualities
- Advantages of tissue culture:
- -you can grow many plants in a small amount of time
- -all the plants have the same genetic information so inherit the same desirable characteristics
- -little space is needed and the conditions can be precisely controlled
- Disadvantages to tissue culture:
- -because they all have the same genetic information they are susceptible to disease or pests
- -No variation means there is danger of reducing the gene pool
- -No possibility of new beneficial characteristics by chance
Embryo cloning
- At this very early stage of development every cell of the embryo can still form all of the cells needed for a new cow
- They have not become specialised
- Divide each embryo into several individual cells
- Each cell grows into an identical embryos in the lab
- Transfer embryos into their host mothers, which have been given hormones to get them ready for pregnancy
- Identical cloned calves are born
- They are not biologically related to their mothers
Adult cell cloning
- A cell from the udder of one sheep is taken and the egg cell from another sheep
- The egg…
Comments
No comments have yet been made