20.2 stem cells & totipotency

Question 1

what are totipotent stem cells?

Answer 1

divide & differentiate into any type of body cells

Question 2

where are totipotent stem cells found?

Answer 2

zygotes

Question 3

what are pluripotent stem cells?

Answer 3

could differentiate into almost any type of body cells

Question 4

where are pluripotent stem cells found?

Answer 4

embryos

Question 5

what are multipotent stem cells?

Answer 5

differentiate into a limited number of specialised cells

Question 6

where are multipotent stem cells found?

Answer 6

umbilical cord, bone marrow

Question 7

what are unipotent stem cells?

Answer 7

differentiate into a single type of cell only

Question 8

where are unipotent stem cells found?

Answer 8

adult tissues

Question 9

in which 2 ways are gene expression controlled by?

Answer 9

1- prevent transcription
2- prevent translation

Question 10

what are housekeeping genes?

Answer 10

codes for enzyme/proteins for respiration, transcription, translation, membrane synthesis, ribosomes, tRNA synthesis

Question 11

what is the exception cell that housekeeping genes are switched off?

Answer 11

red blood cells

Question 12

how do specialised cells express different genes?

Answer 12

genes are switched off for unneeded proteins

Question 13

how are stem cells self-renewal?

Answer 13

divide infinitely & provide more stem cells as they’re not immortal

Question 14

what are the 4 sources of stem cells?

Answer 14

1- embryonic
2- umbilical cord blood
3- placental
4- adult (body tissues)

Question 15

what are iPS cells?

Answer 15

induced pluripotent stem cells

Question 16

how are iPS cells produced?

Answer 16

unipotent stem cells are genetically altered
-> genes & transcription factors are switched on

Question 17

what are the 2 advantages/uses of iPS cells?

Answer 17

1- overcome ethical issues of using stem cells
2- could regrow tissue that’s been damaged due to accidents/diseases