B2 retrieval practise Flashcards
Biology Paper 1
What has to happen for growth in animals?
Cell division and differentiation in animals
What has to happen for growth in plants?
Cell division, elongation and differentiation
What are stem cells?
Cells that can divide to form many types of cell
Give three examples of stem cells
Embryonic stem cells, adult stems cells, meristems
Give 2 advantages of embryonic stem cells
Easy to extract from embryo, produce any type of cell
Give a disadvantage of embryonic stem cells
The embryo is destroyed when the cells are removed
Give a risk involved with all sorts of stem cells
They may not stop dividing and so could cause cancer
Give an advantage of stem cell treatment
Faulty cells are replaced with healthy cells
Give 2 advantages of using adult stem cells
No embryo is destroyed, if taken from the person to be treated will not cause rejection by the body
Give a disadvantage of adult stem cells
Produce only a few types of cell
Where do embryonic stem cells come from?
Embryos at a very early stage of division (8 cells)
Where do adult stem cells come from?
Bone marrow
Where are meristems found?
In rapidly growing parts of a plant e.g. tips of roots and shoots
Name the three types of neurone in a reflex arc
Sensory, relay, motor
Which part of a neurone insulates it?
myelin sheath
