Unit 1 - Immunity and Viruses Flashcards
Membranes have a combination of _________ that are unique to an individual
surface proteins
The only exception of unique surface proteins are in
identical twins
The immune system can recognize the combination of membrane antigenic molecules as ______ antigens
‘self’
Foreign antigens are recognized as being _______ and are ________
non-self, destroyed
Safe blood transfusion depends on giving blood to a patient which the immune system will
recognize as self
Blood from group O donors do not have any
antigens
Blood group O can be given to
anybody
Group O are what type of donor?
universal donors
What blood group doesn’t have any antigens?
Group O
Blood group A can be given what blood groups?
Blood group A and AB
Blood group A can’t be given to blood group O or blood group B because blood group A has
anti-A antibodies
Blood group B can be given to what blood groups?
Blood groups B and AB
Blood group B can’t be given to blood groups A or O because they have
Anti-B antibodies
Blood group AB patients do not have any blood group antibodies so therefore can
receive blood from anyone
Blood group AB can receive blood from anyone so are known as
universal recipients
If the wrong blood was given to a person, what would happen?
The donated blood cells would stick together and block blood vessels and the patient would die
Antibodies are what?
Proteins synthesized by lymphocytes in response to the presence of foreign antigens
Antibodies are synthesised by
lymphocytes of the immune system
Antibodies are produced when?
there are foreign ‘non-self’ antigens detected
Antibodies are what shape?
Y
Antibodies have a receptor for a specific
antigen
Antibodies have receptors on the end of each
arm of the Y
The receptors in an antibody are for a
specific antigen
Antibodies bind to antigens causing the foreign cells to
clump together
By causing the foreign cells to clump together the antibodies render the foreign cells
harmless
Once rendered harmless by the antibodies, the foreign cells are
destroyed by the macrophages
In the presence of an antigen B-lymphocytes
multiply
What lymphocyte multiplies in the presence of an antigen ?
B-lymphocyte
When b-lymphocytes multiply in the presence of an antigen this is called a
cellular response
Some b-lymphocytes become
memory cells
Some b-lymphocytes become memory cells so that they are ready to respond to the
same antigen in the future
Most b-lymphocytes produce antibodies specific to that antigen and this is known as the
humoral response
B-lymphocytes produce antibodies specific to
a specific antigen
A humoral response is when
B-lymphocytes produce an antibody specific to an specific antigen
T-lymphocytes are also known as
Killer T Cells
T-lymphocytes role is to
attack and kill infected cells
T-lymphocytes kill body cells that signal they have been invaded this is called a
cell mediated response
T-lymphocytes kill infected cells by
injecting a chemical which perforates the cell membrane destroying the cell.
Macrophages engulf cells marked by antibodies in a process known as
phagocytosis
Cells marked by antibodies are engulfed in phagocytosis by
macrophages
A vacuole enclosing the invading cells merges with
lysosomes
lysosomes contain
protein digestive enzymes
The term innate immunity describes
the natural barriers we are born with
Innate immunity prevents
disease organisms entering the body
An example of innate immunity we are born with is
our skin
The immune system responds to a second infection ______ than the first
faster
The body responds quicker to a second infection because it has
natural immunity
Active immunity is stimulated artificially by a
vaccination
A vaccine has a disease or virus that has been
killed, weakened or attenuated
A vaccine is active immunity because a _________ is triggered in response to it
full immune response
An example of artificial active immunity is
a vaccine
In response to a vaccine the body produces
its own memory cells
A short term natural passive immunity is
mothers passing antibodies through the placenta or in breast milk
An artificial passive immunity is when a person is
injected with antibodies made by another animal
Autoimmunity is when lymphocytes attack the bodies
own cells
An example of an autoimmune disease is
rheumatoid arthritis or multiple sclerosis.
An allergy is a hypersensitive immune system response of
memory lymphocytes to the antigens in harmless substances.
Phagocytosis has 3 steps to it, step 1:
A phagocyte’s cytoplasm contains a rich supply of organelles called lysosomes which contain digestive enxymes.
Phagocytosis Step 2:
Some of the lysosomes fuse with the vacuole and release their enzymes into it.
Phagocytosis Step 3:
The bacterium becomes digested and the breakdown products are absorbed
An example of natural active immunity is
infection by pathogen leading to a full immune response
An obligate parasite is a
virus
Viruses are not
cells
Viruses contain:
one type of nucleic acid (either DNA or RNA) surrounded by a protein coat
If a virus contains RNA then it is an
retrovirus
Invasion of a cell by a virus: Stage 1 -
A virus attaches itself to a host cell and thrusts tail through cell wall
Invasion of a cell by a virus: Stage 2 -
The virus injects its DNA into a host cell
Invasion of a cell by a virus: Stage 3 -
Viral DNA replicates using bacterial nucleotides
Invasion of a cell by a virus: Stage 4 -
Viral DNA is transcribed into viral mRNA which directs formation of protein coats using bacterial amino acids
Invasion of a cell by a virus: Stage 5 -
Each viral DNA becomes enclosed in a protein coat
Invasion of a cell by a virus: Stage 6 -
Host cell bursts releasing many copies of virus
