Transcript Sub-topic (a) Homeostasis

Learning Outcome

Describe the structure of viruses.
Three types of microorganism
fungi
bacteria
viruses
Parasite

Viruses are true parasites living off the cell
they have infected.

Some viruses enter a host and leave virtually
unnoticed.

Others cause disease and destroy the host.
Tiniest of Microbes



They are the tiniest and simplest of
microbes.
They can be 10,000 times smaller than
bacteria.
Viruses consist of a small collection of
genetic material (DNA or RNA) covered in a
protective protein coat called a capsid.
Take Over
Once inside a cell the
virus takes over.
 The virus gives the
host cell instructions.
 In other words the
host cell does all the
work and the virus gets
all the rewards.
 They persuade the host
cell to make new viral
particles.

Infection
The same virus can cause different reactions
in different hosts.
 For example, flu viruses infect birds, pigs and
humans.
 While some of these flu viruses will not harm
the birds they can overwhelm and kill humans.

Structure
protein coat
nucleic
acid
Success Criteria

I can describe can describe the structure of
viruses.
Learning Outcome

Give an outline of the stages of viral
replication.
Genetic material
(DNA)
Protein coat
Hollow tail
Fibre
Host Cell
Virus attaches to host cell
Virus attaches to host cell
Virus attaches to host cell
Virus attaches to host cell
Virus attaches to host cell
Virus puts tail through cell wall
Virus puts tail through cell wall
Virus pierces through cell wall
Virus pierces through cell wall
Virus pierces through cell wall
Virus pierces through cell wall
Virus pierces through cell wall
Viral DNA injected into host cell
Virus pierces through cell wall
Viral DNA injected into host cell
Virus pierces through cell wall
Viral DNA injected into host cell
Viral DNA replicates
Protein coats are synthesised
Each viral DNA becomes enclosed in a protein coat
Each viral DNA becomes enclosed in a protein coat
Each viral DNA becomes enclosed in a protein coat
Host cell bursts releasing many copies of virus
Host cell bursts releasing many copies of virus
To summarise....
 Attachment
 Insertion
 Replication
 Release
Remember
AIRR
Success Criteria

I can give an outline of the stages of viral
replication.
Learning Outcome

Give examples of viral infections and how
they are spread.
Group Activity
Complete the
viruses group
activity to find
out about viral
diseases and how
they are spread.
Complete the table in your booklet
Success Criteria

I can give example of viral diseases and how
the are spread.
Learning Outcome

Name the different parts of the blood and
their function.
The blood



The blood is extremely
important for the
body.
It carries substances
to all parts of the
body through the
circulatory system.
On average a person
has 5 litres of blood.
Blood

Plasma

Red Blood Cells

White Blood Cells

Platelets
Plasma


Blood may look like just a red liquid, however,
it is made up of a variety of different types
of cells all suspended in a fluid.
The main component of blood is a fluid called
plasma which is mainly water.
Components of blood

Suspended in the plasma
are:
 red blood cells and white
blood cells.
 dissolved substances such
as glucose, urea and amino
acids
 plasma proteins such as
antibodies and hormones
Red blood cells


There are around 5 million red blood cells per
mm3 of blood.
Their main function is to carry oxygen.
Red blood cells

Red blood cells have a biconcave shape.

This increases their surface area.

They contain a substance called haemoglobin,
a red oxygen carrying pigment which gives red
blood cells their colour.
Red blood cells


Red blood cells are very special animal cells
because they do not contain a nucleus.
This means they have a maximum amount of
space for haemoglobin.
Transport of respiratory
gases



Oxygen is carried in red blood cells.
It is attached to a haemoglobin, the red
pigment found in rbc.
The oxygen is carried around the body
attached to haemoglobin, it can then leave
the rbc and diffuse into the body cells.

haemoglobin + oxygen —> oxy-haemoglobin
White blood cells



There are many
different types of
white blood cell.
They are larger than
red blood cells and do
contain a nucleus but
no haemoglobin.
White blood cells are
involved in the immune
system.
Platelets



Platelets are tiny cells
found in the blood
They have no nucleus
and their job is to
make the blood clot.
If a blood vessel is
damages platelets rush
to the area and form a
clump to help stop
blood loss.
Success Criteria

I can name the different parts of the blood
and their function.
Learning Outcome


Name and recognise the two main types of
white blood cell involved in defence.
Describe the process of phagocytosis, as used
by white blood cells, stating the importance
of lysosomes in this process.
First-line defences


Before disease causing organisms can get into
the body and cause harm, they must pass
several barriers.
First-line defences are features of the body
that help to prevent the entry of harmful
organisms.
First Line of Defence
SKIN
TEARS
HAIR &
MUCUS
Second-line defences

White blood cells are the second-line defence.
Macrophage


A macrophage is a special
type of white blood cell
which can engulf and
digest bacteria.
It has a nucleus and
special structures called
lysosomes which contain
digestive enzymes.
Phagocytosis
Finding
Destroy
Engulf
Digest
Phagocytosis
lysosome
Bacterium being
engulfed
The enzymes digest the
bacterium so it is now harmless
Bacterium trapped
inside vacuole
Lysosome release digestive
enzymes into vacuole
Success Criteria


I can name and recognise the two main types
of white blood cell involved in defence.
I can describe the process of phagocytosis,
as used by white blood cells, stating the
importance of lysosomes in this process.
Learning Outcome

Explain the role of antibody production in
immunity.
Macrophage



Macrophages are a type
of non-specific
immunity.
This is because they
work against lots of
different pathogens.
Specific immunity
involves acting against
one particular pathogen.
Specific Immune Response



A specific immune response
is against one particular type
of virus.
The white blood cells
involved are called
LYMPHOCYTES.
These produce special
protein molecules called
ANTIBODIES.
Lymphocyte




If a child catches the chicken pox virus, a
specific lymphocyte is stimulated.
This lymphocyte then multiplies.
All these lymphocytes produce antibodies
specifically against the virus.
The virus is then destroyed eventually.
Antigens
antigen
cell
Antigens are your body’s way
of telling which cells are
your own, and which cells are
unwanted invaders.
Pathogens e.g. bacteria or
viruses, have different
shaped antigens from your
body cells, and your body can
tell that they don’t belong.
Antigens are a bit like an identity card.
Pathogens don’t carry the right identity
card, so your body attacks them.
red blood cell
Lymphocyte
Lymphocyte produces
antibodies specific to
the antigen
Lymphocyte
recognises antigen
as non-self
Antibodies
specifically attack
the antigen
The bacteria or
virus is rendered
harmless
Antibodies attach to the
viral antigens at receptor
sites. This causes the virus
to become harmless.
Specific immunity


Antibody production
is a type of specific
immunity.
This is because the
antibodies being
produced only work
against one type of
antigen.
Defence by antibodies
1. Viral particles
become attached to
____________ by
their antigens.
1. _______enters
body cell.
2. Lymphocytes
multiply and
produce large
numbers of
2. Virus
___________.
____________.
3. ___________ and
antibodies meet and
combine. This makes the
antigen ___________.
Antigens
antibodies
multiplies
Virus
lymphocyte
harmless
New pathogens you have never been
exposed to before attack the body and
multiply. This makes you feel ill
Lymphocytes detect the foreign
antigens on the pathogens
Lymphocytes make specific antibodies
for the antigen
The antibodies attach themselves to the
antigens on the pathogens and make
them harmless
Lymphocyte remembers the shape of the Pathogen you have previously come into
antigen
contact with enters your body again
Lymphocytes instantly recognise the
pathogens and make antibodies
immediately
The antibodies attach themselves to the
pathogens and kill them before the
pathogens have a chance to make you ill.
You now have immunity!!!
Make a model - The Immune Response
 Collect:
 10 cocktail sticks
 3 pipe cleaners
 2 colours of playdoh
 You have 10 minutes to design
and make a model showing the
immune response after exposure to
a pathogen
 Remember to include:
 pathogen
 antigen
 antibody
 phagocyte
Key part
Part of
structure
Explanation of what it is/
does?
Pathogen
A disease causing microbe
Antigen
Found on the outside of the
pathogen
Antibody
Is made by the white blood cells
to kill the pathogen
Phagocyte
A type of white blood which
engulfs and ingests the
pathogens
Phagocyte
Pathogen
Antigen
Antibody
What was good about your model?
How do you think it could have been
improved?
Success Criteria

I can explain the role of antibody production
in immunity.
Learning Outcome

Explain the importance of knowing blood
groups in organ donation.
Blood Grouping

A

B

AB

O
It is the type of
antigens on the surface
of your red blood cells
which decide your blood
group.
You will have the
opposite antibodies in
your plasma
Blood Group A


If you belong to the
blood group A, you have
A antigens on the
surface of your red
blood cells.
You have B antibodies
in your blood plasma.
Blood Group B


If you belong to the
blood group B, you
have B antigens on
the surface of your
red blood cells.
You have A
antibodies in your
blood plasma.
Blood Group AB


You have both A
and B antigens on
the surface of your
red blood cells.
No A or B
antibodies at all in
your blood plasma.
Blood Group O


You have neither A or
B antigens on the
surface of your red
blood cells.
You have both A and
B antibodies in your
blood plasma.
Who can donate to who?
RECIPIENT’S BLOOD GROUP
O
O
DONOR’S
BLOOD
GROUP
A
B
AB
A
B
AB
RECIPIENT’S BLOOD GROUP
O
No antigens
A
DONOR
BLOOD
GROUP
Antigen A
B
Antigen B
AB
Antigens
A& B
O
A
B
AB
Anti-A &
Anti-B
Anti-B
Anti-A
No
antibodies
√
√
√
√
√
√
√
√
√
Questions
1.
Who is the ‘universal donor’?
2.
Who is the ‘universal recipient’?
Success Criteria

I can explain the importance of knowing blood
groups in organ donation.
Earl’s Exit
A small pool of blood and a knife
were found near the bins. After
examining the area, the police
discovered a body and identified
him as Earnest “One Eyed” Earl.
The police have collected blood
samples from the pool of blood
and the weapon. The police need
to know their blood types to see
if it matches one of the 3
suspects they have identified or
if it belongs to the victim.
Suspects
1. Bobby “Baby” Brooks
2. “Slim” Jim Snoot
3. Barbie “Doll” Jones
Carry out the blood typing experiment to see if
you can identify who the blood on the weapon and
at the crime scene belong to:
Can you find Earl’s murderer?
Agglutination
+
X
+
X
X
+
+
X
Who Did It?!
Blood Samples
Blood group
Suspect 1
A
Suspect 2
B
Suspect 3
AB
Victim
O
Crime Scene
A
Weapon
O
The blood on the weapon must have belonged
to the victim.
But the blood left at the crime scene belongs
to suspect 1 so he must have killed Earl!