stem cells

Question 1

what is a stem cell called because it can diffrentiate into almost any type of cell

Answer 1

pluripotent

Question 2

what is a stem cell called because it can diffrentiate into any type of cell

Answer 2

totipotent

Question 3

what is a stem cell called when it can divide into multiple but not all cell types

Answer 3

multipotent

Question 4

what do stem cells have ability to do

Answer 4

self renew (reproduce themselves many times over)

Question 5

when is an embryo totipotent

Answer 5

-first cell formed when sperm fertilizes egg (zygote)
-and after the first few cell divisions (blastomeres)

Question 6

when is an embryo pluripotent

Answer 6

-when it developed into a blastocyst (ball of cells formed from blastomeres)

Question 7

why is a blastocyst pluripotent

Answer 7

because:
-the inner cell mass can become nearly any but not all cells (cant become placenta and umbilica)

Question 8

parts of a blastocyst

Question 9

sources of embryonic stem cells

Answer 9

-embryonic stem cells (early embyro when zygote begins divisions)
-stem cells in umbilical cord blood (multipotent)
-adult stem cells found in developed tissues like bone marrow
-induced pluripotent stem cells

Question 10

how do induced pluripotent cells form

Answer 10

-reprogramming diffrentiated cells to become undiffrentiated when they respecialise
-to switch on certain genes and become undiffrentiated

Question 11

how are stem cells used in bone marrow transplant

Answer 11

-treat disease of the blood (lukemia) and immune system
-restore blood system after treatment for specific types of cancer (bone marrow cells obtained, stored, then put back)

Question 12

uses of stem cells in drug research

Answer 12

-stem cells develop into human tissue
-new drugs can be tested on this rather than animal cells

Question 13

how to get embryonic stem cells

Answer 13

(1) after IVF, donation of unused embryos for stem cell research
(2) through embryonic cloning

Question 14

what is embryonic cloning

Answer 14

-nucleus removed from egg cell
-nucleus inserted into egg cell
-electrically stimulated
-develops into embryo

Question 15

stem cell research in developmental biology

Answer 15

-can understand how multicellular organisms develop
-make particular cell types to see how they function and what goes wrong when diseased

Question 16

uses of embryo to repair damaged tissue and replace lost tissue

Answer 16

-treat mice with type 1 diabetes by programming stem cells to become pancreatic beta cells
-bone marrow cells to treat liver disease
-directed to become nerve tisue to treat alhzhimers or repair spinal cord injuries

Question 17

difficulties of stem cells

Answer 17

-need to find out which cytokine cell signalling molecule needed to direct the differentiation of stem cells into particular type of cells
-difficult to culture in a lab

Question 18

use of stem cells for organs (regenerative medicine)

Answer 18

-can populate a bioscaffold of an organ then directed to develop and grow into specific organs for transplanting
-patients cells are obtained, reprogrammed into iPS cells, then used to make organs
-no need for immunosuppressant drugs

Question 19

what are adult stem cells

Answer 19

-can become specialised to repair and replace surrounding differentiated cells
-multi-potent

Question 20

example of adult stem cells

Answer 20

hematopoietic
-stem cell found in bone marrow which can differentiate into various blood cells (red, lymphocytes, platelets)

Question 21

how to grow stem cells

Answer 21

-remove from blastocyst and culture in petridish
-stem cells divide several times and scientists divide the population into other dishes
-after several months, there are millions of stem cells
-stem cell line occurs potentially
-cell lines can be frozen and shared between labs for developing therapies

Question 22

whats a cell line

Answer 22

-if stem cells continue to grow without differentiating