Paper 2- cell structure

• What is cell differentiation?

  Cell differentiation is the process by which a cell changes to become specialised.
• Define the term specialised cell.


  Specialised cells are cells that have developed specific characteristics that allow them to perform particular functions.
• What determines the features of specialised cells?


  The features of specialised cells are determined by the expression of genes in the nucleus.
• How are red blood cells specialised to carry out their function?


  Red blood cells have a large surface area to increase diffusion of oxygen and contain haemoglobin which binds to and transports oxygen. They have no nucleus to allow more space for haemoglobin.
• example of a specialised plant cell.

  Examples of specialised plant cells include:

  • Root hair cell
  • Palisade mesophyll cell
  • Xylem vessel
• Root hair cells 


  Root hair cells have an increased surface area to allow increased absorption of water and mineral ions from the soil.
• example of a specialised animal cell.

  • Red blood cells
  • Nerve cells
  • Ciliated epithelial cells
  • Sperm / egg cells
  • Muscle cells
• Define the term stem cell.


  A stem cell is an undifferentiated cell that can differentiate to form other cell types and that can divide an unlimited number of times.
• Embryonic stem cells 


  Embryonic stem cells can differentiate into most, or in some cases all, cell types. This enables them to form the tissues and organs needed during development.
• What are the potential applications of stem cells in medicine?


  Stem cells could potentially cure diseases such as diabetes and paralysis, and repair or replace damaged organs.
• Risk from infection/mutation when transferring lab-cultured stem cells into a patient 


  Stem cells cultured in a lab could become infected, or could accumulate mutations. These could be passed to the patient during therapy.
• What is the potential benefit of being able to use a patient's own stem cells in medical treatment?


  potential benefit of being able to use a patient's own stem cells in medical treatment is that stem cells from the same patient would not be rejected by the patient's immune system.
• ethical issues associated with use of embryonic stem cells in medicine

  Many have ethical concerns around the use of embryonic stem cells in medicine. These concerns are related to whether or not embryos should have human rights. Concerns include:

  • Destruction of embryos
  • Embryos cannot give consent
  • Embryos are treated as a commodity
• adult cells limited capacity 


  Adult stem cells have a limited ability to differentiate; they can only give rise to a few cell types.