B2 - Cell Division

Question 1

what is cell division

Answer 1

mitosis, the process of making new cells. Meiosis is the type of cell division that creates egg and sperm cells. Mitosis is a fundamental process for life.

Question 2

when do animal cell differenciate

Answer 2

animal cells can differenciate at an early stage to form different types of cells

Question 3

when can plant cells differenciate

Answer 3

have the ability to differenciate throughout their life

Question 4

what is cell division mainly used for

Answer 4

• used for repair and replacement of cells
• as a cell differentiates it acquires different subcellular structures to enable it to carry out a certain function. It has become a specialised cell.

Question 5

what does the nuclues of a cell contain

Answer 5

chromosomes made of DNA molecules, each chromosome carries a large number of genes.

Question 6

how are chromosones normally found in the body

Answer 6

in pairs
- normal adult body contains 46 chromosones and 23 pairs

Question 7

what is mitosis

Answer 7

the process by which a cell replicates its chromosomes and then seperates them, producing two identical nuclei in preparation for cell division

Question 8

what are the stages of the cell cycle

Answer 8

1. Before a cell can divide it needs to grow and increase the number of sub-cellular structures such as ribosomes and mitochondria. The DNA replicates to form two copies of each chromosome.
2. In mitosis one set of chromosomes is pulled to each end of the cell and the nucleus divides.
3. Finally the cytoplasm and cell membranes divide to form two identical cells.

Question 9

why is the cell cycle important for

Answer 9

the growth and development of multicellular organisms

Question 10

what are stem cells

Answer 10

they are undifferenciated cells that can develop into specialised cells and more stem cells

Question 11

what is the function of stem cells in embryos, in adult animals and in meristems plants

Answer 11

• Stem cells from human embryos can be cloned and made to differentiate into most different types of human cells.
• Stem cells from adult bone marrow can form many types of cells including blood cells.
• Meristem tissue in plants can differentiate into any type of plant cell, throughout the life of the plant.

Question 12

what treatment is able to be helped with stem cells

Answer 12

diabetes and paralysis

Question 13

what are the disadvantages of stem cells

Answer 13

• potential risks of rejection
• transfer of viral infection
• some people have ethical and religious objections

Question 14

what are the advantages of stem cells

Answer 14

• they can differenciate into any cell
• can treat a wide range of diseases and injuries
• can replace damaged cells

Question 15

what can stem cells from meristems in plants be used for

Answer 15

to produce clones of plants quickly and economically
- Rare species can be cloned to protect from extinction.
- Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.