Unit 2.2 Cell Division and Stem Cells

What is a chromosome

A linear DNA molecules that are tightly coiled around proteins. Chromosomes contains genes

How many chromosome does human body cell contains

46 or 23 pairs

What are the sex chromosomes

It is a pair of chromosomes that determines sex, such as males have an x and Y chromosome while female has two X chromosome

What is mitosis

It is a form of cell division that produces two daughter cells, they are both genetically identical on the parent cell with the same number of chromosome (46)

What is mitosis used for in organisms [4]

• Asexual reproduction

• Growth

• Repair of damage cells

• Cell replacement

What is meiosis

It is a form of cell division involves in the formation of gametes, chromosome in meiosis is halved which mean it only has 23 chromosomes. There are two division in meiosis and produce total of 4 gametes

What is meiosis used for in organisms

• Increase genetic variation

• Ensures that the resultant zygote has a full set of chromosome

What is the difference between mitosis and meiosis

Mitosis

• Only occurs in non-reproductive cells

• Produce two daughter cells

• Daughter cells are genetically identical

• Have 46 chromosome

• Occurs for growth, repair and replacement of damaged cells

Meiosis

• Occurs only in reproductive cells

• Produces 4 daughter cells

• Daughter cells are genetically different

• Have 23 chromosomes

• Occurs for the formation of gametes during sexual reproduction

What is cancer

It is the results of uncontrolled mitosis which would forms primary tumour

What are stem cells

Cells that are unspecialised and capable of differentiating into a range of different cell types

Why is cell differentiation important

It gives higher efficiency as it enables the formation of specialised cells with specific functions

What are embryonic stem cells

Stem cells that are found in early embryos

What are the difference between adults and embryonic stem cells

Embryonic stem cells can differentiates into any type of cells while adult stem cell can only differentiates limited ranged of cells

What is the primary function of adult stem cells

To replace the dead cells

What are the potential use of stem cell in medicine

• Treat diseases like heart diseases

• Used to repair damaged tissues

• Used in scientific research

• Growing organs for transplant

What are the ethical issues related to the used of stem cells in medicine

• Catholics see embryos as a potential human life

• Could lead to farming of embryos for stem cells

• May lead to reproductive cloning of humans

Where are stem cells found in plants

Meristems (regions where cells are continuously dividing such as root tips)