Models of Cell Differentiation + Stem Cells

Question 1

Skeletal muscle cells derive from the ___1.___

Answer 1

1. somites

Question 2

T or F: mouse myoblasts can be cloned to produce cell cultures derived from a single cell

Answer 2

TRUE

Question 3

MyoD, Mrf4, and Myf5 proteins can all activate the ___1.___ gene which is involved in muscle structural differentiation and functional maturation

Answer 3

1. myogenin

Question 4

T or F: myogenin is only expressed in proliferating undifferentiated myogenic cells, whereas MyoD, Mrf4, and Myf5 are expressed in non-dividing, differentiating cells

Answer 4

FALSE (switch myogenin with MyoD, Mrf4, and Myf5)

Question 5

Gene knock-out experiment: mice lacking ___1.___ make apparently normal skeletal muscle if ___2.___ is active … suggesting ___3.___ in the system. Mice lacking ___4.___ alone also make ___5.___, but with defects such as shortening of the ribs

Answer 5

1. myoD
2. myf5
3. redundancy
4. myf5
5. skeletal muscle

Question 6

Mice, in which both ___1.___ and ___2.___ are lacking, die before birth … even if such embryos express ___3.___ and make some muscle

Answer 6

1. myoD
2. myf5
3. mrf4

Question 7

If ___1.___ gene is knocked out, myoblasts are still formed but most ___2.___ is absent

Answer 7

1. myogenin

2. skeletal muscle

Question 8

Myogenin protein is thus considered to be a ____1.____ rather than a protein essential for muscle ___2.___

Answer 8

1. myogenic differentiation factor

2. determination

Question 9

The ___1.___ family of transcription factors activates transcription of muscle-specified genes by binding to a nucleotide sequence called the ___2.___, which is present in the ___3.___ regions of these genes

Answer 9

1. MyoD
2. E-box
3. regulator

Question 10

T or F: proliferation and differentiation are mutually exclusive

Answer 10

TRUE

Question 11

Proliferation and ___1.___ are mutually ___2.___

Answer 11

1. differentiation

2. exclusive

Question 12

Myoblasts that are multiplying in culture do not ___1.___ and only when ___2.___ ceases does ___3.___ begin

Answer 12

1. differentiate
2. proliferation
3. differentiation

Question 13

In the presence of growth factors, myoblasts that are expressing both ___1.___ and ___2.___ proteins continue to proliferate but do not ___3.___ into muscle

Answer 13

1. MyoD
2. Myf5
3. differentiate

Question 14

The removal of ___1.___ serves as a signal to differentiate and the myoblasts withdraw from the cell cycle and cell fusion occurs and ___2.___ takes place

Answer 14

1. growth factors

2. differentiation