| what are Enzymes (involved in Chemical Digestion) | Enzymes are Biological Catalysts. They break down nutrients into small, soluble molecules that can be absorbed. |
| Where are the Digestive Enzymes Found? | 1) Proteases catalyse the breakdown of proteins into amino acids in the stomach and small intestine
2) Lipases catalyse the breakdown of fats and oils into fatty acids and glycerol in the small intestine
3) Amylase catalyses the breakdown of starch into maltose in the mouth and small intestine
4) Maltase catalyses the breakdown of maltose into glucose in the small intestine |
| What Factors effect Enzymes | - PH, different enzymes work best at different pH values
- Temperature (work best at 37°C) |
| What happens when a cell becomes cancerous? | When a cell becomes cancerous, it begins to grow and divide uncontrollably. New cells are produced – even if the body does not need them
- A group of cancerous cells produces a growth called a tumour.
- Cancer cells are undifferentiated – they do not carry out their normal function |
| Embryonic and Adult Stem cells | EMBRYONIC STEM CELLS:
1) An embryo develops from a fertilised egg (at the early stage of development the cells in the embryo are stem cells)
2) Cells are then removed from the embryo - Embryonic stem cells (they'll differentiate into any type of cell
3) Difficult to obtain and raise ethical challenges
ADULT STEM CELLS:
1) Found in: brain, eyes, blood, heart, liver, bone marrow, skin and muscle
2) Can only differentiate into related cell types (e.g. bone marrow cells can differentiate into blood cells and cells of the immune system)
(3) Use patients own stem cells, therefore they're genetically identical and less likely to get rejected |
| Plant Stem cells | 1) Found in the meristem region if the plant (mainly near the shoot tip and the root tip)
2) Can differentiate into any cell at anytime during the plants life
3) In a growing shoot new cells are being produced near the tip but as they become older and further away from the tip they become differentiated - and enlarge and develop vacuoles |
| Cloning in Plants | 1) Meristematic cells are removed from a plant and grown in a tissue culture
2) Cells are grown in a culture medium that contains agar - which provides support support and water for the growing cells - along with nutrients and plant hormones to stimulate growth and cell division.
- Plant cloning produces plants quickly and economically
- Its prevents plants from being endangered
- Clones will be genetically identical to the original plant. Its useful to provide desirable characteristics like disease resistance
Also Cloning in Plants also occurs naturally - e.g. in runners in strawberries (farmers take away cuttings) |
| Human Stem Cell Uses | 1) Adult/Embryonic Stem Cells: can be used to replace damaged or destroyed cells:
- in type 1 diabetes
- in cases of multiple sclerosis (which can lead to paralysis)
- in cases of spinal cord or brain injury (that have lead to paralysis)
3) Adult Stem cells: Differentiate in to a narrower range of cell types
- E.g. Bone marrow transplants are carried out: in case of blood cell cancer (like leukaemia and lymphoma) or when blood cells have been destroyed by cancer treatment |
| Give 7 Specialised cells in animals | 1)Circualtorty system - Transport substances, defend the body and regulate temperature
2)Excretory system - Remove waste products and unwanted substances and regulate water content
3)Muscular system - Bring about movement
4)Nervous system - Respond to external and internal stimuli and conditions, carry messages from the body work as a coordinated whole
5)Respiritory system - Deliver oxygen for respiration and remove waste
6)Reproductive system - Bring about firtilisation to produce new offspring
7)Skeletal system - Help bring about movement, support and protect internal structures, produce blood, store and release calcium |
| Give 4 specialised cells in plants. | 1)Leaf
- Palisade mesophyl - carry out photosynthesis
- Spongey mesophyll - Allows gases to circulate for gas exchange, carry some photosynthesis
- Guard cells - Open and close to control the exchange of gasses - Co2, H2O vapour, O2
2)Phloem
-Sieve tubes - Transport products of photosysnthesis, sugars and amino acids from leaf to where theyre needed
-Companion cells - Provide energy required for transporting substances in sieve tubes
3)Xylem - xylem vessels - Transport water and dissolved minerals from roots, up plant
4)Growing points - Merristem - Produce new cells as they divide |
| How does cloning in plants happen? | 1)Tissue sample is scraped from parent plant
2)Meristematic cells are removed and grown in tissue culture - the culture medium contains: agar to provide support and water for growing cells, nutrients and plant hormones to stimulate growth and cell division
3)Samples develop into plantlets to be transferred into compost
-A simpler way is to take cuttings |
| Why is plant cloning good? | 1)Identical plants quickly and economically, easier than sowing seeds
2)Increase production of disease resistant plant |
| Human Stem Cell Uses | 1) Adult/Embryonic Stem Cells: can be used to replace damaged or destroyed cells:
- in type 1 diabetes
- in cases of multiple sclerosis (which can lead to paralysis)
- in cases of spinal cord or brain injury (that have lead to paralysis)
3) Adult Stem cells: Differentiate in to a narrower range of cell types
- E.g. Bone marrow transplants are carried out: in case of blood cell cancer (like leukaemia and lymphoma) or when blood cells have been destroyed by cancer treatment |
| How does therapuetic cloning work? | 1)Human egg cell extracted from donor
2)Nucleus removed and discarded swapped with patients egg cell nucleus
3)The cell is stimulated to divide so developes into an embryo
4)After 4-5 days stem cells are removed
5)Stem cells from embryo are cultured for therapuric use |
| Benefits of Stem Cells in Medicine | Stem cells have great potential, in treating patients with currently untreatable conditions, growing organs for transplants, and research |
| CLINICAL ISSUES of Stem Cells in Medicine | - Difficult to find suitable donors
- Difficult to obtain & store
- Cultured stem cells could be contaminated with viruses |
| ETHICAL ISSUES of Stem Cells in Medicine | - Is it right to create embryos for therapy, and destroy them?
- Embryos can be viewed as commodities, and not as an embryo that could develop into a person
- At what stage of its development should an embryo be regarded as, and treated as a person |
| SOCIAL ISSUES of Stem Cells in Medicine | - Educating the public about what stem cells can, and can't do, is important
- Whether the benefits of stem cell use outweigh the objections
- Patients could be exploited by paying for expensive treatments and being given false hope of a cure as stem cell therapies are only in their developmental stages |
