Cell Division part 1 Flashcards
What is differentiation?
The process in which a cell changes to become specialised to its job
Where are stem cells found? and what is the difference between the two stem cells which are found?
One is found in a human embryo this can specialise to be whatever it wants
The other is found in the adult bone marrow and can specialise only into a few
What are stem cells useful for?
Replacing and growing cells naturally
Scientists use them for:
Transferring and replacing faulty cells
Replacing nerve or spinal injuries
What is different between nerves found in the perifial nervous system and nerves found in the central nervous system?
Nerves found in the perifial nervous system can re-grow and heal themselves whereas nerves found in the central nervous system cannot and therefore need stem cells.
What are the risks of stem cells?
and what do scientists do to avoid this?
When transplanting a stem cell to the new patient viruses (that live inside stem cells) might get transplanted and make the patient sicker.
To avoid this we use a technique called theurapeutic cloning
Why are some people against stem cell research?
1) They feel that human embryos shouldn’t be used for experiments since each one is a potential human life whereas others think curing existing patients who are suffering is more important than the rights of embryos
2) Embryos used in research are usually unwanted ones fro m fertility clinics which, if they weren’t used for research would eventually be destroyed.
3) Campaigners feel that scientists should concentrate more on finding other sources of stem cells so that they can help people without using stem cells from embryos
Explain the process of therapeutic cloning
Human egg cell from donor, nucleus removed and discarded
The nucleus from the patients cell is removed and transferred to the donor of the egg cell
The cell is stimulated to divide which then develops into an embryo
After 4-5 days the stem cells are removed
The stem cells from the embryo are cultured for therapeutic cloning
Where are stem cells in plants found?
What can they differentiate into and for how many times?
In the meristem which is close to the tip of the shoot and the tip of the root
They can differentiate into any cell and throughout the whole time of the plants life
What can stem cells in plants be used for? 2 reasons
Stopping a rare plant from going extinct and making more plants with are resistant to disease
What is the function of a SPERM CELL and what are its adaptations to its function?
function- travel towards and fertilise the egg
adaptations- Tail to swim towards the egg
Many mitochondria to transfer energy to the tail
Acrosome contains enzymes to break through the outer layer of the egg cell
Streamline to help it swim
What is the function of a NERVE CELL and what are its adaptations to its function?
function- to carry electrical signals from one part of the body to another
adaptations- long to cover more distance
myelin sheath to insulate the impulses
dendrites to connect with other nerve cells to create a nervous tissue
What is the function of a MUSCLE CELL and what are its adaptations to its function?
function- to contract quickly
adaptations-special proteins that slide past each other to make muscle fibres contract
many mitochondria to transfer energy for these contractions
What is the function of a ROOT HAIR CELL and what are its adaptations to its function?
function- to absorb water and minerals from the soil
adaptations- Long hair like extensions to increase SA for absorption
many mitochondria to fuel the active transport of minerals into the cell
large vacuole for water to move in by osmosis
What is the function of a XYLEM CELL and what are its adaptations to its function?
function- transport water and mineral ions from the roots to the leaves
adaptations- hollow in the centre so that stuff can flow through them
hollow tubes are strengthened by lignin
extra info- made from dead cells
What is the function of a PHLOEM CELL and what are its adaptations to its function?
function- transports the products of photosynthesis from the leaves to the rest of the plant
adaptations- very few sub cellular structures so stuff can flow through them by translocation
extra info- made from living cells
