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Stem Cells and Cloning Study Guide
Complete the following on additional sheets of
paper.
U1.1.4 Multicellular organisms have properties
that emerge due to the interaction of their cellular
components.
1. Define and give examples of emergent
properties.
Emergent properties arise from the interaction of
the component parts of a structure.




Heart cell – characteristics of life
Heart tissue – can synchronize contractions
Heart organ – can pump blood
Cardiovascular system – can deliver blood
throughout the body
 Organism – can use blood for interconnected
functions
U1.1.5 Specialized tissues can develop by cell
differentiation in multicellular organisms.
2. Define tissue:
A group of cells that specialize in the same way to
perform the same function.
3. Outline the benefits of cell specialization in a
multicellular organism.
Cells can be more efficient in their role. They can
have a specialized structure and metabolism.
4. Define differentiation:
Development of specialized structures and
functions in cells.
U1.1.6 Differentiation involves the expression of
some genes and not others in a cell.
5. Describe the relationship between cell
differentiation and gene expression.
Differentiation in cells is due to different cell types.
All cells in a multicellular organism contain the same
genes, but different cells will express different
genes. To express a gene means to “switch it on” so
that the protein (or other gene product) is made.
U1.1.7 The capacity of stem cells to divide and
differentiate along different pathways is necessary
in embryonic development and also makes stem
cells suitable for therapeutic uses.
6. Define zygote and embryo
Zygote – the cell that results
from a sperm fertilizing an
egg cell.
Embryo: early stages of
development after the zygote
divides.
7. List 2 key properties of stem cells.
 Stem cells can divide repeatedly: useful for
treatment of tissues that need to replace cells
that have been killed or damaged.
 Stem cells are not differentiated: they haven’t
“turned off” genes so they can still differentiate
to produce different cell types.
8. Explain why stem cells are most prevalent in early
embryonic development.
The cells of the early embryo are the most versatile.
As the embryo develops, the cells gradually become
more differentiated.
9. Contrast the characteristics of embryonic,
umbilical and adult somatic stem cells.
Embryonic: can differentiate into any body cell
(pluripotent)
Umbilical: can only differentiate into blood cells
(multipotent)
Adult Somatic: found in bone marrow, skin and
liver; limited differentiation ability (multipotent)
10. Define totipotent, multipotent, and pluripotent.
Totipotent: can become any body cell plus
placenta. Zygote is totipotent
Pluripotent: Can become any body cell (but not
placenta). Blastocyst ICM is pluripotent.
Multipotent: have partially differentiated but
can still become multiple, related cell types
(umbilical cord stem cells and adult stem cells),
A1.1.3 Use of stem cells to treat Stargardt’s
disease and one other named condition.
11. Outline the cause and symptoms of Stargardt’s
disease.
Stargardt’s disease is a recessive genetic disease.
Light detection cells of the retina degenerate so
vision becomes progressively worse.
12. Explain how stem cells are used in the
treatment of Stargardt’s disease.
Retina cells derived from embryonic stem cells are
injected into the eyes. The cells attach to the retina
and improve vision without harmful side effects.
13. Outline the cause and symptoms of leukemia.
Leukemia is a cancer that results from an
accumulation of mutations leading to uncontrolled
division of the cells that create white blood cells.
14. Explain how stem cells are used in the
treatment of leukemia.
The person with leukemia is given chemotherapy,
which kills the cancer cells. Then, bone marrow
(with its adult stem cells) is transplanted from a
donor to the person with leukemia. The stem cells
establish themselves, divide, and start to produce
blood cells.
 Ideally, the stem cells from the person with
cancer can be harvested before chemotherapy
and then returned to their body.
A1.1.4 Ethics of therapeutic use of stem cells from
specially created embryos, from the umbilical cord
blood of a newborn baby and from an adult’s own
tissues.
15. List the source and mechanisms of obtaining
stem cells.
Embryonic: removed from a blastocyst inner cell
mass.
Cord blood: easily obtained from the umbilical cord.
Adult: buried deep in tissues, difficult to obtain.
16. Discuss the benefits and drawbacks of using
stem cells from different sources.
Embryonic:
Unlimited growth and differentiation potential
Cells won’t have genetic mutations that
accumulate with age.
Risk of becoming tumorous
Kills embryo
Cord blood:
Easy to obtain and store
Compatible with the adult that grows from the
baby (no immune rejection)
Multipotent, so limited cell types can be created
Adult:
Full compatible with adult donor, so no risk of
immune rejection
Hard to obtain in the body
Multipotent, so limited cell types can be created
Don’t have to kill embryo
NOS 1.1.2 Ethical implications of research –
research involving stem cells is growing in
importance and raises ethical issues.
17. Explain why biological research must take
ethical issues into consideration.
Biological research is a human endeavor and as
such will lead to people having different opinions
about what is ethical and should be permitted. The
opinions must be considered while deciding what is
best for the collective good.
U3.5.5 Clones are groups of genetically identified
organisms derived from a single original parent
cell.
18. Contrast sexual and asexual reproduction.
Sexual reproduction: offspring are genetically
different from the parents. Involves the fusion of a
male and female gamete.
Asexual reproduction: offspring are genetically
identical to the parent
19. Define clone and cloning:
Clone: a genetically identical organism
Cloning: the production of a clone
20. Describe different ways in which natural
clones can arise.
Zygote divides into two cells, each
developing into an embryo.
Embryo Splitting
Fission
Budding
U3.5.7 Animals can be cloned at the embryo stage
by breaking up the embryo into more than one
group of cells.
21. Describe the process of reproductive cloning via
embryo splitting.
A pluripotent embryo (usually at the 8 cell stage) is
separated into separate cells which can each
develop into separate indviduals.
22. Outline examples of cloning animal embryos via
natural & artificial embryo splitting.
In nature, embryo splitting results in identical twins
Artificially, can be performed in livestock embryos
(cows). But, rarely done. Use a squirt of saline
solution or a special micro-scale scalpel to split the
embryo.
U3.5.8 Methods have been developed for cloning
adult animals using differentiated stem cells.
23. Describe the process of cloning via somatic cell
nuclear transfer.
A3.5.4 Production of cloned embryos produced by
somatic cell nuclear transfer.
24. Outline the production of Dolly the sheep using
somatic cell nuclear transfer.
Dolly was the mammal to be cloned from an adult
somatic cell using the process of nuclear transfer in
1996 (U3.5.8).