extra B1 monoclonal antibodies therapeutic cloning

• Chromosome

  A structure made up of large molecules of DNA. They carry genes which control the characteristics of the body. There are 46 of these in a normal human body cell, found in 23 pairs.

  
• DNA

  A molecule made of very long strands twisted to form a double helix, which contain 4 different compounds called bases.

  
• Gene

  A small section of DNA on a chromosome. Each codes for a particular sequence of amino acids to make a specific protein (eg colour of iris)

  
• Mitosis

  When a cell divides into two to make two identical cells. This type of cell division is needed for growth, replacing worn out cells and repairing damage.

  
• Stem Cells

  An undifferentiated cell of an organism from which certain other cells can arise from differentiation, or is capable of giving rise to more stem cells. (self renewal or differentiation) These can be obtained from embryos, adults and meristems in plants.

  
• Undifferentiated


  When a cell has not been differentiated into a specific type of cell. Stem cells are described as this.

  
• Embryonic stem cells

  Differentiate to form all the specialised cells in your body. These can be cloned and made to differentiate into most different types of human cells.

  
• Therapeutic Cloning

  Where an embryo is produced with the same genes as a patient and then used to get stem cells which can be used for medical treatment as they are not rejected by the patient's body.

  
• Clone

  A genetically identical copy of something

  
• Where are chromosomes found?

  The nucleus of the cell
• What are the functions of mitosis? (2)

  1. Growth and development of an organism

  2. Repair of tissues by replacing cells
• What happens during mitosis? (4)

  1. Cell grows and replicates DNA

  2. One set of chromosomes is pulled to each end of cell

  3. Nucleus divides (this part is mitosis)

  4. Cytoplasm and cell membranes divide to form two genetically identical daughter cells (this part is cytokinesis)
• What are the 3 stages of the cell cycle?

  Interphase, mitosis and cytokinesis
• Interphase

  Longest part of cell cycle, cell grows and develops and function parts in our body. Almost at the end of interphase, DNA and chromosomes double.
• Cytokinesis

  When the cell cytoplasm divides to form the daughter cells
• What are 3 sources of embryonic stem cells?

  1. aborted embryos

  2. spare embryos from IVF

  3. umbilical cord/placental donation
• Where can we find adult stem cells and what is a disadvantage of this?

  Bone marrow and some other tissues BUT these only develop into a limited range of cells (eg those found in bone marrow develop into blood cells)
• Meristem tissue

  This can differentiate into any type of plant cell throughout the life of the plant.
• What are 2 uses of stem cells from meristems?

  1. Rare species can be clones to protect from extinction as clones can be produced quickly and economically

  2. Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers
• What conditions might stem cells be able to treat? (2)

  1. Diabetes - grow new pancreatic tissue

  2. Paralysis - grow/replace damaged neurones
• What are downsides to use of stem cells?

  1. Potential risks such as transfer of viral infection

  2. Ethical or religious objections

  (3. Can be rejected by the immune system - not on spec but still relevant)
• Monoclonal antibodies

  Antibodies produced from a single clone of cells. They are specific to one binding site on one antigen and so target a specific chemical or cell in the body.
• How are monoclonal antibodies produced? (4)

  1. Stimulate mouse lymphocytes to make particular antibody

  2. Lymphocytes combined with tumour cell to form hybridoma

  3. Mitosis of hybridoma (to produce clones that all produce desired antibody)

  4. Large quantity of antibody collected and purified
• What are 3 uses of monoclonal antibodies?

  1. For diagnosis in pregnancy testing - detection of hCG in urine, bind to hormone and produce colour change

  2. In labs to measure hormone levels, other blood chemicals or pathogens e.g. HIV

  3. In research to locate/identify specific molecules in a cell by binding to them with a fluorescent dye
• How can monoclonal antibodies be used to treat diseases such as cancer? (3)

  - monoclonal antibody can be bound to a radioactive substance, toxic drug or chemical

  - this stops cells growing and dividing

  - delivers substance to cancer cells without harming other healthy cells
• Disadvantages of monoclonal antibodies

  1. Create more side effects than expected

  2. Producing the right monoclonal antibodies and attaching them to other compounds is more difficult than expected