lecture 26 stem cells

Question 1

what does totipotent mean

Answer 1

it means the cell has the ability to divide into any cell type, including the trophectoderm

Question 2

whats the trophectoderm

Answer 2

the embryonic part of the placenta

Question 3

what stage of embryonic development has the trophectoderm

Answer 3

this is the blastocyst

Question 4

embryonic cells are what, and what does the word mean

Answer 4

pluripotent, they can become any cell type except the trophectoderm

Question 5

what does terminally differentiated mean

Answer 5

the stem cells have become restricted in their roles and they can only divide into one type of cell or another stem cell.

Question 6

what dictates the type of cell a stem cell will turn into

Answer 6

What genes are turned on from the genome dictates what type of cell the stem cell will become.
Certain control genes which code for transcription factors become activated by random cell experience. These transcription factors control for transcription of specific genes, these genes dictating the cell differentiation.

Question 7

what is genomic equivalence

Answer 7

Differentiated cells contain all
the DNA required to build an
entirely new organism. so all cells have the same DNA, just different genes active

Question 8

what are embryonic stem cells

Answer 8

These are “harvested” from the inner cell mass (future embryo) of mammalian blastocyst embryos.
Human embryonic stem cells are pluripotent: they can develop into any of the 200 or so types of cell in our bodies, given the right conditions

Question 9

what are embryonic stem cells

Answer 9

These are “harvested” from the inner cell mass (future embryo) of mammalian blastocyst embryos.
Human embryonic stem cells are pluripotent: they can develop into any of the 200 or so types of cell in our bodies, given the right conditions

Question 10

what is iPS

Answer 10

induced pluripotent stem cells

Question 11

what happens in iPS

Answer 11

iPS cells are made by reprogramming adult skin cells.
iPS cells can be made from anyone, and are genetically identical to the source skin cells. As they are also pluripotent, they can generate any cell
type.

Question 12

describe adult tissue stem cells

Answer 12

Stem cells that divide without limit, these are the ones replacing tissue, so stem cells divide to replace skin tissue for example
Multipotent as they go onto make much more limited amounts of cell types as already reasonably specialised.
They can divide to give rise to more stem cells or divide into one or more types of functional tissue cells.

Question 13

why do stem cells divide asymmetrically

Answer 13

divide asymmetrically to give rise to a stem cell and a progenitor cell. The progenitor cell then divides to give rise to cells of a specific cell type. a stem cell needs to always be a result of the division so they can further replace cells in body.

Question 14

whats an umbilical cord stem cell

Answer 14

The stem cells are multipotent, as they are immature blood stem cells.
They are less restricted than blood stem cells from adults

Question 15

why can umbilical stem cells cure diseases

Answer 15

because they are from the embryo, so they have not developed any somatic mutation, so these stem cells can replace the leukemia damaged ones

Question 16

whats integrative gene therapy

Answer 16

Based on idea that for a monogenic gene disorder we can insert a functional copy of said gene.
A virus can deliver material to human cells, virus used to do this as they can target given cells.

Question 17

what else can be used for intergrative gene therpay

Answer 17

CRISPR cas-9

Question 18

whats regenerative medicine

Answer 18

the idea that pluripotent stem cells can be used to repair or replace damaged organs or tissues.

Question 19

how does regenerative medicine work

Answer 19

Pluripotent stem cells can be made from skin cells or blood cells
from a patient (genetically identical) or matched donors, or from embryos.
These stem cells can be encouraged to differentiate into specific cell types such as neurons, or retinal cells.
The differentiated cells can be transplanted into patients.

Question 20

whats an example of regenerative medicine

Answer 20

fixing retinal degeneration. in this the RPE is damaged, so photoreceptors die. putting iPS cells into the eyes and these should fix the RPE.