mitosis, cancer, stem cells and monoclonal antibodies

why are new cells needed?

- growth + development 
- replacement of worn out damaged cells

what is an antibody

- a protein which will BIND to one binding site on one antigen
- complementary shape 

what does monoclonal mean?

-mono = one
- clonal = set of genetically identical cells (mitosis)

uses of monoclonal antibodies 

- diagnosis (pregnancy tests -> detects hcg)
- to treat diseases (cancer -> antibody can be bound with radiation/chemotherapy, targets specific cells)

therapeutic cloning uses the same...

- genes as patient
- not rejected by patient's body 

5 steps of producing monoclonal antibodies

1. inject mouse with target antigen

2. antigen stimulates mouse to produce lymphocytes, making antibodies

3. remove lymphocytes from mouse and fuse them with tumour cells to make hybridoma cells

4. screen hybridomas 
   find ones that produce correct antibody

5. hybridomas divide rapidly by mitosis + produce lots of monoclonal antibodies 

   
   

stem cell treatment can help conditions such as:

- paralysis
-diabetes

Stem cell definition

- an undifferentiated cell of an organism
- capable of giving rise to many cells through differentiation

3 stages of mitosis

1. interphase

   - cell DUPLICATES ITS CHROMOSOMES
   - forms 2 identical copies of each chromosome
   - cells get bigger + increase in mass 
   - cell increases the no. of sub cellular structures 

2. mitosis
   - one set of chromosomes is pulled to each end 
   - nucleus divides 

3. cell division
   - cytoplasm + cell membrane divide 
   - form 2 genetically identical daughter cells, identical set of chromosomes 

pros of embryonic stem cells

-can differentiate into any type of cell
-no risk of rejection
- can treat many types of human disease

pros of adult bone marrow stem cells 

-used to treat blood diseases
-more reliable 
-simple + safe operation
-quicker recovery
- no ethical/ religious objections
- cheapER

problems with monoclonal antibodies

- more side effects than expected (violent immune response)
- ethical issues

negatives/objections of stem cell treatments

- transfer of viral infections
- ethical/ religious objections

meristem cloning used for

- protecting rare species from extinction
- producing large numbrs of genetically identical crop plants

malignant

- cancers - invade healthy tissues 
- some cells may enter bloodstream + circulate to other parts of the body 

how do cancer cells divide 

- abnormal, uncontrolled division

gene

- small section of dna involved in producing a protein
- can have alternative forms - alleles 

embryo stem cells can be ....

any cell

cons of embryonic stem cells

-ethical/religious objections
-possible harm/death to embryo
- transfer of viral infections
-newer technology = less reliable 

cons adult bone marrow stem cells

- painful
- limitations on types of cell they can differentiate into 
- risk of infection during operations

bone marrow stem cells can be...

- blood cells

benign

- generally less fatal
- can be dangerous if growing in confined spaces (brain)

benefits of monoclonal antibodies

- highly specific to 1 type of antigen 
- very effective for diagnosis

4 causes of cancer

- genetic risk factors (breast / prostate)
- chemical carcinogens (tar)
- ionising radiation (uv light/x-rays)
- virus infections (HPV causing cervical cancer)

3 types of stem cell

- human embryos
- adult bone marrow
- Meristem tissue

2 main cancer treatment 

RADIATION - used to destroy cancer cells, stops mitosis 
CHEMOTHERAPY - chemicals are used to stop cancer cells dividing 
- target all rapidly dividing cells e.g. hair