Higher human biology
Unit 1 – human cells
• 1 Division and differentiation in human cells
• Cellular differentiation is the process by which a cell
develops more specialised functions by expressing the
genes characteristic for that type of cell.
• (a) Stem cells — embryonic and tissue (adult) stem cells.
• Stem cells are relatively unspecialised cells that can
continue to divide and can differentiate into specialised
cells of one or more types. During embryological
development the unspecialised cells of the early embryo
differentiate into cells with specialised functions. Tissue
(adult) stem cells replenish differentiated cells that need
to be replaced and give rise to a more limited range of
cell types.
Some questions to think about
•
•
•
•
•
What is a cell?
What varieties of cell exist?
What is a tissue? Give some examples.
What is an organ? Give some examples.
What is a system? Give some examples.
Bozeman biology
• https://www.youtube.com/watch?v=jp6L5e
mD8rw
Specialised cells
• The human body is made up of many specialised cells
that have specific structural, functional and
biochemical properties
• Specialised cells arise from the differentiation of
unspecialised cells during embryo development.
• Specialised cells with similar functions are grouped
into tissues. Similar tissues are grouped into organs
and similar organs are grouped into systems.
Specialised cells
• https://www.twigonglow.com/films/different
-types-of-cell-1042/
• Differentiation short film
Why have specialised cells?
• Division of Labour
• Multicellular organisms
have millions of cells
• To ensure all process
carried out – division of
labour where cells
become differentiated
and specialised to carry
out 1 specific function
•
• Cell differentiation is under genetic
control and involves cell signalling
processes.
• During differentiation, genes that
express proteins important for the
function of that cell remain ‘switched
on’.
• Once a cell becomes specialised, it stops
dividing and only expresses the genes
are characteristic for that type of cell.
Differentiation
• During differentiation, certain genes
that express proteins important for the
function of a specific cell are ‘switched
on’. This allows it to develop a more
specialised structure to carry out a
specific function.
• Once a cell becomes differentiated it
only expresses the genes that produce
the proteins characteristic for that
type of cell.
Stem cells
Some questions to think about…
•What is a stem cell?
•What are some different types of stem cells?
•What is the purpose of stem cell research?
•What are some ways that stem cells have been
successfully used in medicine?
•What are some of the issues in stem cell
research?
•What are some of the misconceptions that
people have about stem cell research?
Stem cells film
• http://www.educationscotland.gov.uk/video
/h/video_tcm4664297.asp?strReferringCh
annel=highersciences&strReferringPageID
=tcm:4-66593264&class=l3+d142456+d143862
What is a stem cell?
Stem cell
SELF-RENEWAL
(copying)
Identical stem cells
Stem cell
DIFFERENTIATION
(specializing)
Specialized cells
Why self-renew AND differentiate?
1 stem cell
1 stem cell
Self renewal - maintains
the stem cell pool
4 specialized cells
Differentiation - replaces dead or damaged
cells throughout your life
Stem cell development
animation
What are stem cells?
Stem cells are unspecialised cells that have the ability
to reproduce to make more stem cells or differentiate
into specialised cells of one or more types.
Stem cell jargon/definitions
Potency
A measure of how many types of specialized cell a stem
cell can make
Stem cell
type
Description
Totipotent
Each cell can develop into
a new individual
Pluripotent
Cells can form any (over
200) cell types
Examples
Cells from early (1-3
days) embryos
(zygote)
Some cells of
blastocyst (5 to 14
days)
Cells differentiated, but can Fetal tissue, cord
Multipotent form a number of other
blood, and adult stem
tissues
cells
Unipotent
????
Spermatogonial cells
in testicles only make
Types of stem cells
Embryonic
Adult
Embryonic stem cells
Embryonic stem cells
• Embryonic stem cells are derived from
unspecialised cells found within an embryo.
• They have the ability to differentiate into
all cell types that make up an organism.
Where are stem cells found?
zygote stem cells
Totipotent can diffrerentiate into all cells and
placenta/ umbilical cord etc.
embryonic stem cells
blastocyst - a very early
embryo about 50-100 cells
tissue stem cells
fetus, baby and throughout life
Adult (tissue) stem cells
• Do adult vs embryo stem cell card sort!
Adult (tissue) stem cells
• Adult or tissue stem cells are found in various tissues of
adults and children, including the brain, bone marrow,
skeletal muscle and skin.
• These cells replenish differentiated cells that need
replaced through age or damage in the tissues in which
they are found. They are able to differentiate into a
much more limited range of cell types and will tend to
develop into cell types that are closely related to the
tissue in which they are found.
• Eg adult stem cells in bone marrow will produce red blood
cells, platelets, phagocytes and lymphocytes.
Other types of stem cells
• Stem cells can also
be taken from the
umbilical cord of new
babies.
• Like adult stem cells,
these cells can
differentiate into a
limited range of
specialised cells.
Induced pluripotent stem cells
- the exception to the rule!
Induced pluripotent stem (iPS) cells are adult
cells that have had their nucleus genetically
reprogrammed to an embryonic stem cell-like
state.
• (b) Somatic cells divide by mitosis to form
more somatic cells. These differentiate to
form different body tissue types: epithelial,
connective, muscle and nerve.
What do you think somatic cells
are? Look at the pictures…..
B Lymphocyte
Smooth muscle
cartilage
Somatic cells
neutrophil
Ciliated epithelial cell
Red blood cell
platelets
Somatic cells
Cardiac muscle
Squamous epithelial
cells
Nerve cells
T lymphocyte
Somatic cells
All body cells (except gametes and the cells which
make them) are called somatic cells. They divide
by mitosis and differentiate to form more cells of
that tissue.
Mutations that occur in somatic cells aren’t passed
onto offspring.
• Do somatic cell passport activity
Tissues and organs
Body organs are formed from a variety of
tissues made from somatic cells. E.g.
1. Epithelial cells which cover the body surface
and line body cavities (E.g bladder,
respiratory etc)
2. Connective tissue includes blood, bone and
cartilage cells
3. Muscle cells form muscle tissue
4. Nerve cells form nervous tissue
Give an account, with examples, of
the different body tissue types and
their functions. (8 marks)
1.
Body tissue cells derive from somatic stem cells …
2.
3.
4.
5.
6.
7.
8.
9.
10.
by repeated mitosis.
Epithelial tissue - covers the organ surfaces.
Protection - skin / secretion - intestinal glands / absorption - villi.
Connective tissue - gives shape to organs and supports them.
Protection - skull bones / structural framework - ribs / storage of energy adipose tissue / connecting body organs - blood / connecting epithelial to
muscle tissue - cartilage (in tendons)
Muscle tissue - which causes locomotion or movement within organs.
Skeletal muscle - locomotion / smooth muscle - in arterioles control of
access to capillary bed / cardiac muscle - contraction of the heart.
Nervous tissue - which transmits messages between the central nervous
system and the rest of the body (and within the central nervous system).
Neurons - conduct impulses / glial cells - maintain a constant
environment for neurons.
• (c) Germline cells divide by mitosis to
produce more germline cells or by meiosis
to produce haploid gametes. Mutations in
germline cells are passed to offspring.
Mutations in somatic cells are not passed
to offspring.
What do you think germline cells
are?
Division of germline cells
• Germline cells can
divide by mitosis to
produce more
germline cells.
• Germline cells can
divide by meiosis to
produce gametes.
Germline cells
Gametes and the cells that produce the
gametes are called germline cells. They divide
either by mitosis to produce more germline cells
or by meiosis to produce gametes.
Mutations that occur in germline cells are
passed onto offspring
• Stage 1 – chromosomes copy themselves
• Stage 4 – homologous pairs of chromosomes
line up at equator
• Stage 5- chromosomes pulled apart by spindle
fibres
• Stage 6 – 2 cells formed
• Stage 8 – individual chromosomes line up at
equator
• Stage 9 – chromosomes pulled apart by
spindle fibres
• Stage 10 – gamete cells formed with half a
chromosome complement
Give an account of cell
differentiation under the following
headings:
stem cells
somatic cells
germline cells
• (d) Research and therapeutic uses of stem
cells by reference to the repair of
damaged or diseased organs or tissues.
Stem cells can also be used as model
cells to study how diseases develop or for
drug testing. The ethical issues of stem
cell use and the regulation of their use.
Stem cell research
• http://www.educationscotland.gov.uk/video
/h/video_tcm4664297.asp?strReferringCh
annel=highersciences&strReferringPageID
=tcm:4-66593264&class=l3+d142456+d143862
Therapeutic stem cells
• https://www.twigonglow.com/films/therape
utic-stem-cells-1066/
TED talk Anthony Atala Growing
new organs
• http://www.ted.com/talks/anthony_atala_gr
owing_organs_engineering_tissue?langua
ge=en
Stem cell research
Stem cell research provides us with a
wealth of information and can be studied
in a variety of ways, including:
•how cell processes such as growth,
differentiation and gene regulation work
•the study of diseases and their
development
•drug testing
•therapeutic uses in the treatment of
diseases such as leukaemia (bone marrow
transplant), Hunter’s disease and heart
disease
•therapeutic uses in medicine, including
skin grafts for burns and stem cell grafts
for cornea repair.
For example, stem cells
could be turned into
new bone cells and then
injected into weak or
broken bones to speed
up healing time.
Windpipe Transplant
• http://www.bbc.co.uk/learningzone/clips/w
oman-gets-windpipe-transplant/5857.html
Or they could become
nerve cells that
could heal spinal
cord injuries.
Skin cells could replace
burnt skin, and brain
cells could help people
who have suffered brain
damage.
Stem cells could be taken from
someone with heart disease and
be turned into heart cells,
which can gather in a dish and
throb! They could then be
injected back into the patient
to rebuild their heart tissue
and combat heart disease.
• Beating heart cells in a dish!
http://www.youtube.com/watch?v
=RO4pAc21M24
• Symptoms: mask-like
face, stiffness and
tremors until sufferers
eventually become
immobile.
• Replacing the affected
brain cells seems more
hopeful than finding
better drugs. Many
people think that stem
cells could be grown into
new brain cells that
could help to treat or
even cure Parkinson's.
Therapeutic stem cell cloning
Stem cell uses
• Model cells to study how diseases
develop
• Drug testing
• Tissue replacement
–
–
–
–
–
e.g. skin grafting for burn patients
heart tissue for heart disease patients
brain nerve cells for Parkinson’s sufferers
blood for transfusion
nerve cells for spinal cord injuries
• Do stem cell newspaper report activity
Corneal stem cell transplant
• https://www.youtube.com/watch?v=nHK0L
p1jJnw 2 mins
• https://www.youtube.com/watch?v=PJbdb
APXA7c 2 mins
• https://www.youtube.com/watch?v=eM9Izl
K0uv8 25 mins
Corneal stem cell therapy
• Stem cells extracted from healthy eye,
cultured (grown) and transplanted back
into the damaged eye
• Repairs cornea
• Shorter waiting time than traditional
donation
• Reduced chance of rejection as
patient’s own cells transplanted
Describe how stem cells have contributed to
corneal transplants and skin grafts.
•
Corneal transplants
1.
2.
3.
4.
5.
•
stem cells isolated from the patient's healthy eye
new tissue can be cultured/grown
transplanted back into the damaged eye,
repair the damaged cornea.
Shorter waiting time than corneal donation
Skin grafts
6.
7.
8.
9.
10.
Stem cells isolated from healthy skin
New tissue grown / cultured
dehydration and infection are risks until graft done.
Produces skin cells much more quickly.
reduces the time patient at risk.
Presentation task
Using what you have learned already and adding further
research, create a presentation that covers the following
aspects of stem cells:
•the biology of stem cells – what is a stem cell, types of
stem cells
•the potential of stem cells – details of one or two research
projects involving stem cells that you have found
particularly interesting, details of potential therapies
•stem cell dilemmas – explore the moral and ethical issues
surrounding stem cell research (personal points of view can
be expressed if desired).
You will be assessed using all three of the above criteria as
well as on the overall quality of your presentation.
•
•
•
•
www.sscn.co.uk
www.allthingsstemcell.com
www.hypeandhope.com
www.abpischools.org.uk click interactive, 14-16,
biology, then stem cell research
• http://www.hhmi.org/biointeractive/click/index.ht
ml
• http://learn.genetics.utah.edu/content/stemcells/
• www.cells4life.co.uk
Criteria
4
3
2
1
The biology of stem cells
Covers the topic in depth
with details and
examples. All key
terms and words
have been defined.
Subject knowledge
is excellent.
Includes essential
knowledge about
the topic. Subject
knowledge is good.
Includes most information
about the topic but
there are some
factual
errors/omissions.
Content is minimal and
there are several
factual
errors/omissions.
The potential of stem cells
More than one example of
stem cell research
has been covered in
depth. More than
one example of
potential stem cell
therapies has been
explored.
At least one example of
stem cell research
has been covered in
depth. Potential
stem cell therapies
have been covered.
An example(s) has been
covered but is
lacking in depth
and detail of
information.
Examples are minimal.
Very few details
given.
Stem cell dilemmas
The moral and ethical
issues surrounding
stem cell research
have been explored
in detail. More than
one perspective has
been given for
many issues.
The moral and ethical
issues surrounding
stem cell research
have been covered
well. More than
one perspective has
been given for
some issues.
Some moral and ethical
issues have been
mentioned but lack
detail. Arguments
detailed not
balanced/only one
perspective given.
Very little detail given in
this area.
Quality of presentation
Interesting, well
rehearsed, all
members of group
involved, word
content of slide
minimal, good eye
contact with
audience, smooth
delivery.
Relatively interesting,
fairly smooth
delivery. Eye
contact mainly
good and most
members of group
involved at some
stage.
Able to maintain interest
of audience but
delivery not
smooth. Failed to
make eye contact
on some occasions.
Some group
members not
involved.
Poor eye contact, not able
to maintain interest
of audience.
Reading from
slides, delivery not
smooth.
The ethical issues of stem cell
use
http://www.playbackschools.org.uk/progra
mme/3144/stem-cell-research-theissue
(15min)
Stem cell views
• http://www.pbslearningmedia.org/resource/
tdc02.sci.life.cell.stemcellvid/stem-cellsseeds-of-hope/#
Watch the clip on stem cell research and answer
the following questions
http://www.pbslearningmedia.org/resource/tdc02.sci.lif
e.cell.stemcellvid/stem-cells-seeds-of-hope/ (7min)
1.
What does Dr Snyder mean when he says stem cells
are "flexible and plastic?"
2. In this video what evidence convinces you that stem
cells can be used to cure spinal cord injury?
3. Dr Snyder points out that there are ethical
concerns, and that there is no single answer that will
please everyone. Who do you think should be the
ones to decide where to obtain stem cells for
medical research?
• Do stem cell card sort for and against
Not in our back yard!
Should a business license be issued to ESC lifeworks Inc. by the city of
Dundee?
Debate the issue- use the hand out to help organise the structure of the debate
Some useful Video Clips – Stem Cells and Ethics
• http://www.educationscotland.gov.uk/video/h/video_tcm4664297.asp?
strReferringChannel=highersciences&strReferringPageID=tcm:4658424-64&class=l3+d142456+d143862
• http://www.bbc.co.uk/learningzone/clips/stem-cell-research-andmedicine/6013.html
• http://www.bbc.co.uk/learningzone/clips/ethics-of-using-foetal-stemcells-for-stroke-treatment/5888.html
• http://www.bbc.co.uk/learningzone/clips/alternative-to-embryo-stemcells-developed-by-researchers/6581.html
• http://www.bbc.co.uk/programmes/p00k7j7w
• http://www.bbc.co.uk/learningzone/clips/stem-cellresearch/14287.html
Ethical issues surrounding stem cells
• Practices using adult (tissue) stem cells remain
fairly uncontroversial.
• Many pro-life and religious groups argue that
embryos have human rights, should not be
destroyed and should not be created simply for
scientific research.
• Opposing arguments include the potential to
discover cures for diseases for which there are
currently none and improved treatment of a
range of medical conditions.
Regulation of stem cell use
• The laws surrounding embryonic stem
cells and adult stem cells differ because
while both have similar capacities in
differentiation, their modes of
derivation are not.
• While embryonic stem cells are taken
from embryos, adult cells can be taken
from consenting adults.
Regulations surrounding the use of
embryonic stem cells
– The research must be licensed by the Human
Fertilisation and Embryology Authority
(HFEA).
– Researchers must justify that the creation
of an embryo is necessary and that the work
could not be carried out in another way.
– Embryos over the development stage of 14
days cannot be used as this is the stage at
which there is some primitive development of
the nervous system.
• The use of stem cells in therapeutic
treatments in the UK is currently
restricted to adult stem cells.
• Whether or not embryonic stem cells
can be used in the future remains to be
seen.
Cloning
Cloning
• Human reproductive cloning is illegal in
the UK. As a result of the Human
Reproductive Cloning Act (2001) nobody
in the UK is allowed to use cell nuclear
transfer, or any other technique, to
create a child.
Regulations surrounding stem cell
use
• Research must be licensed by the Human
Fertilisation and Embryology Authority
(HFEA).
• Researchers must justify that the creation
of an embryo is necessary and that the
work could not be carried out in another
way.
• Embryos must be under 14 days old.
• Human cloning is illegal in the UK
Compare the location and functions
of embryonic and tissue (adult)
stem cells. (7 marks)
•
Stem cells are undifferentiated cells capable of repeated division to both
•
•
•
•
•
•
•
•
more stem cells and cells that will later differentiate to form specialised
cells.
Embryonic stem cells (ESCs) are found in the inner cell mass of the
blastocyst.
ESCs are capable of repeated division…
…to form more ESCs and other cell types.
ESCs are: capable of forming all the other cell types of the body /
pluripotent
Tissue stem cells (TSCs) are found throughout the juvenile and adult
body.
TSCs are capable of repeated division to form more TSCs and other cell
types.
TSCs: can only form cells of the organ to which they belong / are
multipotent.
e.g. bone marrow tissue cells can only give rise to bone marrow cells, red
blood cells, platelets, phagocytes and lymphocytes.
• (e) Cancer cells divide excessively to
produce a mass of abnormal cells (a
tumour) that do not respond to regulatory
signals and may fail to attach to each
other. If the cancer cells fail to attach to
each other they can spread through the
body to form secondary tumours.
Stuart brown –
stooibrown@yahoo.com
• Cancer. I worked for ten years in the Dept of Surgical &
Molecular Oncology at Ninewells so I can speak a bit
about how cancer is researched and treated although
there's not a lot I can say about pharmaceutical
therapies - that stuff just went way over my
head. However, I can talk about the bowel cancer
screening programme, for example and that might fit not
just with this module but also with the public health bit
later in the syllabus. I also worked on x-ray ablation of
breast cancer, cryogenic and thermal ablation of solidorgan cancers and a lot on colon cancer
surgery. Another thing I'm quite familiar with is the use of
nanoparticles and microbubbles to pursue novel cancer
therapies;
What is cancer?
• https://www.twigonglow.com/films/what-iscancer-1580/
TED talk
• http://www.ted.com/talks/deborah_gordon_
what_ants_teach_us_about_the_brain_ca
ncer_and_the_internet
Reverse the odds app
• http://www.mavericktv.co.uk/news/emmynomination-for-reverse-the-odds/
Cancer cells
•Cancer cells continue to
reproduce to produce a
mass of abnormal cells (a
benign tumour).
•They do not respond to
normal regulatory signals
that would instruct them to
stop dividing when
necessary.
•They lose the molecules on
their surface that would
normally hold them in place
and can therefore be
detached from their
neighbours, causing the
cells to spread (malignant
tumour).
Skin cancer cells (melanoma)
• It is thought that 90–95% of cancers
are caused by environmental and
lifestyle factors such as obesity and
tobacco.
• It is estimated that 5–10% are due to
genetics.
HPV – environmental factors
• Certain strains of the
human papilloma virus
(HPV) have been shown
to cause cervical cancer.
• The routine immunisation
programme in Scotland is
for girls aged 12 and 13
(S2). There is also a oneoff, three-year catch-up
programme for older girls.
• Watch melanoma film
UV sensitive yeast
• UV sensitive strain of yeast: Baker’s yeast solution
(saccharomyces cerevisiae) kept covered in foil.
• Yeast glucose agar dish divided into 3 sections: sun with
sunscreen / sun with no sunscreen / no sun
• Use aseptic techniques
• Expose to sunlight for 15 mins on bright day or longer on
less bright day (or UV light)
• Incubate 3-4 days at room temp 1-2 days at 30 degrees.
• Count the number of colonies
Cancer
• Cancer cells divide excessively to produce a
mass of abnormal cells (called a tumour).
• They do not respond to regulatory signals
that would instruct them to stop dividing
when necessary.
• They may fail to attach to each other, called
malignant tumours. This means they can
spread throughout the body, forming
secondary tumours.
Super Science: Nanotechnology
• https://www.youtube.com/watch?v=a8FM9
umJXvo
• Imagine a tiny robot the size of a human
cell, injected by the millions into your
bloodstream on a search and destroy
mission: to locate cancer cells, and kill
them. Welcome to the scientific frontier of
nanotechnology.
Your task
Produce an information leaflet designed to
answer the questions of a patient recently
diagnosed with cancer. Points to consider:
•How are cancer cells different from other
cells?
•What is a tumour?
•How will I know if my cancer has spread?
•What is the difference between a malignant
tumour and a benign tumour?
•How will my cancer be treated?