lecture 26 - cellular differentiation & stem cells

Question 1

How does an embryo begin?

Answer 1

As a small number of equivalent/identical naïve totipotent cells that have the potential to give rise to any type of cell.

Question 2

What is cell polarisation in terms of embryonic development?

Answer 2

When the nuclei of the cells move to one side of the cell and layer of micro vili forms on the outer sides of the cells , facing the inter uterine environment

Question 3

What is the result of cell compaction in embryonic development?

Answer 3

The outer and inner cells begin to differentiate into the ICM (inner cell mass), and trophectoderm

Question 4

What is the ICM, in terms of embryonic development?

Answer 4

Inner Cell Mass

Question 5

What does the ICM (inner cell mass) give rise to?

Answer 5

Embryonic stem cells

Question 6

What types of cells can embryonic stem cells give rise to?

Answer 6

All cell types except trophectoderm

Question 7

What are trophectoderm cells?

Answer 7

Cells that give rise to the placenta during embryonic development.

Question 8

How can the potency of embryonic stem cells be described?

Answer 8

Pluripotent

Question 9

What does pluripotent mean, in terms of cell development?

Answer 9

Can give rise to a wide range of cells

Question 10

In embryonic development, the progressive restriction of cell fate leads to?

Answer 10

The terminal differentiation of cells, so that individual cells can only form replicas of themselves and can opt change their fate.

Question 11

How is the ‘fate’ of a pluripotent precursor embryonic cell decided?

Answer 11

Based on the genes that are turned on or off - certain genes code for certain transcription factors that allow specific proteins relevant to cell function to be manufactured.

Question 12

What is the regulatory gene that controls the differentiation of an embryonic cell into a muscle cell component/myoblast?

Answer 12

myoD

Question 13

What is the function of MyoD protein?

Answer 13

It is a transcription factor that allows a myoblast to develop into a muscle fibre by acting as a transcription factor to turn on genes that are relevant for muscle development (e.g. mysoin)

Question 14

Where can human embryonic stem cells be harvested from?

Answer 14

The ICM of blastocyst embryos

Question 15

What are induced pluripotent stem cells?

Answer 15

Cells made by reprogramming adult skin cells to become pluripotent - to mimic stem cells.

Question 16

How can adult tissue stem cells be described, in terms of differentiation and potency?

Answer 16

Undifferentiated, multipotent

Question 17

What does totipotent mean, in terms of cells?

Answer 17

A cell found in an early embryo that can give rise to all cell types.

Question 18

What does multipotent mean in terms of cells?

Answer 18

Can give rise to one or a few different cell types

Question 19

Are adult stem cells multi potent or pluripotent?

Answer 19

Multipotent

Question 20

What is asymmetric division?

Answer 20

The division of a stem cell into a stem cell and progenitor cell (less specialised but still capable of differentiation) - two non-identical daughter cells

Question 21

What is a progenitor cell?

Answer 21

A descendant of a stem cell that is specialised to a specific type of tissue, but can further differentiate into specific cell types

Question 22

How can stem cells be used to correct single gene disorders?

Answer 22

By inserting a normal allele into a stem cell, a wide variety of functioning cells can be produced when they enter the body.

Question 23

What 2 types of cells do not become differentiated during embryonic development?

Answer 23

Stem cells and Germ cells