Cell Differentiation

Question 1

Stem cells

2

Answer 1

unspecialised cells
capable of proliferation and differentiation

Question 2

Proliferation

2

Answer 2

• division by mitosis for indefinite periods
• different genes become activated by internal signals (other genes) or external signals (e.g. chemicals, certain molecules)** leading to differentiation**

Question 3

Totipotent Stem Cells

definition + example

Answer 3

have potential to specialise into any type of cell necessary for embryonic development (embryo, embryonic membranes)
e.g. zygote after it’s fertilised

Question 4

Pluripotent Stem Cells

definition + example

Answer 4

can give rise to many, but not all, cell types necessary for foetal development (foetal tissues but not placental tissues)
e.g. inner mass of blastocyst

Question 5

Multipotent Stem Cells

3

Answer 5

• pluripotent stem cells undergo further specialisation to become multipotent
• can give rise to cells that have a particular function
• e.g. muscle cells, blood stem cells

Question 6

3 sources of stem cells

Answer 6

• embryonic stem cells
• adult stem cells
• induced pluripotent stem cells

Question 7

Embryonic stem cells

Answer 7

totipotent or pluripotent
cultured from unused frozen embryos at blastocyst stage obtained from IVF clinics

Question 8

Embryonic stem cells uses

2

Answer 8

• build new tissue (e.g. spray-on skin for skin cancer)
• stimulated to become replacement cells (e.g. pancreatic cells needed to secrete insulin for diabetes)

Question 9

Adult stem cells

1

Answer 9

multipotent
include umbilical cord/placental and tissue

Question 10

Umbilical cord and placental

1

Adult stem cell

Answer 10

extracted from discarded tissue at birth

Question 11

Tissue

example

Adult stem cell

Answer 11

e.g. bone marrow transplant

Question 12

Adult stem cell uses

3

Answer 12

treat range of blood disorders and immune system conditions
e.g. leukemia, anaemia, autoimmune diseases
patient’s own cells could be used for treatments

Question 13

Induced pluripotent stem cells

3

Answer 13

• Derived from adult cells (skin/blood) which are reprogrammed back into embryonic-like pluripotent state
• can be grown indefinitely in culture in an undifferentiated state
• provides an unlimited source of any type of human cell needed for therapeutic purposes