Lecture 26

Question 1

What are the changes to cells from 8-cell stage to a blastocyst?

Answer 1

1. 8-cell stage
2. cell polarization
3. compaction
4. inner, apolar cells cut off
5. forms blastocyst, made of inner cell mass (ICM, formerly apolar) and trophectoderm (formally polar)

Question 2

How do the cells change as they develop in terms of specialization?

Answer 2

• starts off with totipotent cells
• embryonic stem cells gcan give rise to all cell types apart from trophectoderm (pluripotent)
• progressively more limited until terminally differentiated

Question 3

What makes an embryonic precursor cell non-differentiated + determined?

Answer 3

Master regulatory gene myoD is turned off as well as possible specializing genes.

Question 4

What makes a non-differentiated cell determined?

Answer 4

Master regulatory gene myoD is turned on, so can transcribe certain genes.

Question 5

What makes a cell terminally differentiated?

Answer 5

Master regulatory gene myoD and specialized genes are turned on

Question 6

What are embryonic stem cells (ESCs) and where are they found/harvested?

Answer 6

• pluripotent stem cells
• found in ICM of blastocyst embryos

Question 7

What are induced pluripotent stem cells (iPSCs) and where are they harvested from?

Answer 7

• pluripotent stem cells
• from adult skin cells but can be reprogrammed

Question 8

What are the most notable characteristics of adult stem cells?

Answer 8

• divide without limit
• undifferentiated, multipotent
• can either stay as stem cell or become another type of cell

Question 9

What makes umbilical cord stem cells different from adult stem cells?

Answer 9

• immature blood cells, so less restricted compared to adult stem cells

Question 10

What tissues are adult stem cells particularly important for renewing? Why?

Answer 10

Blood and skin as constantly need renewing

Question 11

Where are haematopoietic stem cells found?

Answer 11

Bone marrow

Question 12

What is the importance of stem cells in modern medicine?

Answer 12

• correcting single gene disorders
• gene therapy
• regenerative medicine

Question 13

How does regenerative medicine work?

Answer 13

• pluripotent stem cells made from blood or skin cells
• cells encouraged to differentiate
• differentiated cells can then be transplanted

Question 14

How do integrative gene therapies work?

Answer 14

• insert RNA version of normal allele into virus
• let virus infect bone marrow cells that have been removed from patient
• viral DNA carrying normal allele inserts into chromosome
• inject engineered cells into patient