1.1 division and differentiation in human cells Flashcards
Define the term stem cells
Stem cells can divide to self-renew and can differentiate into specialised cells. They are present in both somatic and germline tissue
State the difference between somatic and germline stem cells.
A somatic cell is any type of cell in the human body other than cells involved in reproduction where as germline cells are gametes
Identify the two types of cell division
Mitosis- Cell division
Meiosis- Form of nuclear division which produces gametes
State the types of cell division involved in the production of stem cells and haploid gametes
Somatic cells divide during growth and tissue repair (mitosis)
Diploid germline cells first divide by mitosis then by meiosis which further doubles the genetic material. The first round seperates the homolougus chromosomes and the second seperated the chromatids. The result is 4 haploid gametes
Define the term cell differentiation
The process by which a cell expresses certain genes to produce proteins that are characteristic for that type of cell
Explain how cell differentiation gives rise to specialised cells with particular functions
A human blood cell switches on the genes for the production of haemoglobin and a muscle cell switches on the genes for specific muscle proteins. This is called selective gene expression
What do all differentiated cells originate from?
All differentiated cells with originate from unspecialised stem cells
The two different types of stem cells are called
Embryonic, tissue
Describe the role of embryonic stem cells
Embryonic stem cells have the ability to differentiate into all of the cell types that make up an organism
What are embryonic stem cells described as
Pluripotent
Describe the role of tissue cells
These cells replenish differentiated cells that need replaced in the tissues in which they are found.
What do the tissue cells give rise too
These cells give rise to a much more limited range of cell types and will tend to develop into cell types that are closely related to the tissue in which they are found.
What are tissue cells described as?
Multipotent
Give examples of therapeutic uses of stem cells
Skin grafts- Used to treat people who are badly burnt
Bone marrow transplant- Used to treat people with blood related cancers, leukaemia or sickle cell anaemia
Cornea repair- Multipotent stem cells are removed from the healthy eye and transplanted into the damaged eye
what does stem cell research involve
stem cell research involvs stem cells being used as model cells to study,
How diseases develop
How cells react when being tested with a variety of drugs
State the difference between therapeutic and research uses of stem cells
The aim or research uses is to ensure that the quality of stem cells used and the safety procedures carried out are of the highest order and abuses of the system are prevented.
Therapeutic uses foucses on the medical potential and are in special interest of repair of diseased or damaged organs
Identify some of the ethical issues of using embryonic stem cells
- Embryos need to be destroyed in order to gain access to them
-Poses a moral dilemma between the duty to respect life and the duty to alleviate suffering by being able to treat disease and injury
Explain why cancer cells divide excessively
A cancer is uncontrolled growth of cells. Cancer cells do not respond to regulatory signals
State the term used t describe an abnormal mass of cells resulting from a cancerous cell
Tumour
What can tumours be classified as?
Benign or malignant
What is a benign tumour
A benign tumour is a discrete group of abnormal cells in one place within an otherwise normal tissue. For example warts which do not cause issues if removed
What is a malignant tumour
Malignant is cancerous tumour. When some of its cells lose the surface molecules that keep them attached to the og group, enter the circulatory system and spread through the body.
This enables them to inade other tissues and do harm by producing new tumours in other parts of the body. This is how secondary cancer develops
Explain why cancer cells may spread through the body
the surface molecules that keep them attached to the og group, enter the circulatory system and spread through the body.
This enables them to inade other tissues and do harm by producing new tumours in other parts of the body.
Explain the difference between a primary and secondary tumour
Primary cancer is where a cancer starts. When cancer cells break away from the primary cancer and settel and grow in other parts of the body is when its then called seconary cancer
what is a tissue
A living tissue is made from a group of cells witha similar structure and function which all work together to do a particular job
Name the four basic types of human tissue
Epithelium
Connective tissue
Muscle tissue
Nervous tissue
Epithelium
Covers the skin in an inner lining of digestive tract. Forms a physical barrier to damage and infection
Connective tissue
Covers outer layers arteries, veins. Their elastic fibres give flexibility to blood vessels
Muscle tissue
Skeletal muscles include fast and slow twitch fibres responsible for movement
Nervous tissue
Involved in processing and communication within the body
what do cancer cells originate from
Most cancers originate from a cell that has undergone a succession of mutations to the genes involved in the control of cell division.
As the genetic errors
