Stem cells

Question 1

what gives rise to every cell type and tissue in the body?

Answer 1

a fertilised egg

Question 2

what happens to a fertilised egg cell during development?

Answer 2

divides repeatedly to produce different cell types

Question 3

what is totipotency?

Answer 3

the ability to produce a fully formed, complex multicellular organism

Question 4

what has totipotency?

Answer 4

fertilised egg

Question 5

what does the genome inside a fertilised egg do?

Answer 5

has a series of instructions that directs the production of different cell types, expressing different sets of genes at different times

Question 6

what do stem cells and proliferating precursor cells do?

Answer 6

generate a continuous supply of terminally differentiated cells

Question 7

where abouts do terminally differentiated cells lie in the development pathway?

Answer 7

at the dead end

Question 8

where are the cells that replace terminally differentiated cells generated from?

Answer 8

a stock of proliferating precursor cells

Question 9

where do proliferating precursor cells derive from?

Answer 9

a small number of self renewing stem cells

Question 10

what can each daughter cell become when a stem cell divides?

Answer 10

remain a stem cell or go on to become terminally differentiated

Question 11

what is self-renewal?

Answer 11

when a stem cell divides into another stem cell

Question 12

what does the stem cell control system do?

Answer 12

ensures that differentiated cells are generated in the appropriate places and in the right numbers

Question 13

what does the stem cell control system depend on?

Answer 13

extracellular signals exchanged between the stem cells, their progeny and other cell types

Question 14

how do induced pluripotent stem (iPS) cells work?

Answer 14

genes encoding a combination of transcription regulators can be used to reprogram skin fibroblasts harvested from an individual with a genetic disorder
causes them to form iPS cells that contain disease-causing mutation
patient specific iPS cells can be induced to differentiate into type of cell affected by disorder
studies can be made on disease mechanism
enables search for potential treatments

Question 15

what causes cells to differentiate?

Answer 15

signalling molecules

Question 16

what do totipotent cells do?

Answer 16

can become any cell type in the body