stem cells

Question 1

A. What are Stem Cells?

Answer 1

A cell that has the ability to continuously divide and
differentiate (develop) into other cell/tissue types.

This ability allows them to replace cells that have died and
replace defective cells/tissues in patients who have certain
diseases or defects.

Question 2

Adult Stem Cells v embryonic stem cells

Answer 2

They have different self-renewal capabilities
- Embryonic stem cells: near indefinite self-renewal
- Adult stem cells: limited self-renewal

They have different differentiation potentials
- Embryonic stem cells: differentiate into ALL cell types in an
organism

• Adult stem cells: differentiate into restricted cells types.

They differ in how they respond to external stimuli

Embryonic stem cells readily change upon stimulation

Adult cells need to be activated by cues, e.g. injuries.

Question 3

2 properties of a stem cell

Answer 3

potency
self renewal

Question 4

potency

Answer 4

are undifferentiated (have no specialized role) but have the

potential to give rise to differentiated cells with a specialized function.

Question 5

self renewal

Answer 5

capacity to replicate themselves and produce both a copy and also a differentiated cell.

Question 6

zygote

Answer 6

totipotent

Question 7

blastocyst

Answer 7

pluripotent

Question 8

multipotent

Answer 8

ectoderm,
mesoderm,
endoderm

Question 9

stages of embryo development 1.

Answer 9

1. zygote, first cell after fertilization of egg and sperm

Question 10

stages of embryo development 2.

Answer 10

Morula, 3-4 days old with 16 cells arrives in the uterus

Question 11

stages of embryo development 3.

Answer 11

blastocyst, consists of
the inner cell mass
(will become foetus) and the
trophoblast ( will form the
placenta). Blastocyst
implants into the
endometrium lining of
uterus.

Question 12

Stages of embryo development 4.

Answer 12

GASTRULA : Day 16 (3 weeks)

The blastocyst folds in to form
three germ layers ..

Innermost (endoderm

Middle (mesoderm)

Outer (ectoderm)

Question 13

Stages of embryo development 5.

Answer 13

FOETUS : 9 weeks

Most organs and systems have
formed. Continues to grow to 38 weeks and then it is born ( a baby)

Question 14

ectoderm

Answer 14

nueron
skin cells
pigment cells

Question 15

mesoderm

Answer 15

skeletal muscle
smooth muscle
cardiac muscle
red blood cells
bone cells

Question 16

endoderm

Answer 16

stomach cells
pancreatic cells
liver cells
( specialised cells 0 )

Question 17

the potential uses of stem cells for treating disease or damaged organs

Answer 17

Turn into different types of cells (like blood, skin, or muscle cells).

Repair or replace damaged cells.

Question 18

issues associated with the use of embryonic stem cells for research and medicine.

Answer 18

To get these stem cells, scientists have to destroy the embryo.

Some people believe that an embryo is the very beginning of a human life, so destroying it is morally wrong.

Others believe that it’s okay if it helps save lives or treat serious diseases.