Stem Cells

Question 1

What are the 4 types of stem cell?

Answer 1

totipotent
pluripotent
multipotent
unipotent

Question 2

What is differentiation?

Answer 2

the process by which stem cells become specialised

Question 3

What are stem cells?

Answer 3

undifferentiated cells which can continually divide and specialise to become different types of cells

Question 4

What are totipotent stem cells?

Answer 4

stem cells that can divide and produce any type of body cells

Question 5

Where can totipotent stem cells be found?

Answer 5

zygotes

Question 6

What results in totipotent stem cells becoming specialised?

Answer 6

some genes are expressed, whilst others are not

Question 7

What are pluripotent stem cells?

Answer 7

a type of embryonic stem cell that can divide to form ALMOST any type of cell

Question 8

What are pluripotent stem cells used for?

Answer 8

research into treating human disorders

Question 9

What are some potential applications of pluripotent stem cells?

Answer 9

• beta cells that produce insulin: diabetes
• neurones: Parkinson’s
• treating burns

Question 10

What are some issues with pluripotent stem cells?

Answer 10

• can continually divide to create tumours
• ethical issues: therapeutic cloning (making a zygote), destroying an embryo

Question 11

What are multipotent stem cells?

Answer 11

can divide to form a limited number of cell types

Question 12

Where can multipotent and unipotent stem cells be found?

Answer 12

bone marrow
umbilical cord
placenta

Question 13

What are unipotent stem cells?

Answer 13

can only differentiate into one type of cell

Question 14

What cells can the stem cells found in bone marrow differentiate into?

Answer 14

the different types of blood cell

Question 15

How can ethical issues of using pluripotent stem cells be overcome?

Answer 15

induced pluripotent stem cells (iPS cells)

Question 16

How are iPS cells produced?

Answer 16

• take somatic (body) cells from an adult
• use appropriate transcription factors to manipulate the DNA.
• If all genes are ‘switched on’ the cell is no longer specialised

Question 17

What is it called when all the genes are ‘turned on’?

Answer 17

returning to state of pluripotency

Question 18

What are the advantages of iPS cells?

Answer 18

• no ethical issues
• can divide indefinitely
• show self-renewal properties

Question 19

Where can stem cells be found in mammals?

Answer 19

• embryos
• the placenta
• the umbilical cord
• adult tissues

Question 20

What is one piece of evidence that shows all cells contain all genes, but some are turned off?

Answer 20

iPS - unipotent/somatic cells can be altered to act like pluripotent cells and produce the proteins of an embryonic stem cell

Question 21

What are 3 ways pluripotent cells can be used to treat human disorders?

Answer 21

• skin grafts for burns
• blood cells for leukaemia
• bone cells for osteoporosis

Question 22

What processes are regulated in order to control which genes are expressed?

Answer 22

transcription and translation