3.2.4 - Cells - Cell recognition and the immune system Flashcards
1
Q
which cells identify the presence of pathogens and potentially harmful foreign substances in the body and to destroy or neutralise them to prevent harm?
A
lymphocytes
2
Q
what are antigens made from?
A
proteins
3
Q
what do different surface molecules enable them to identify?
A
pathogens (e.g. bacteria, fungi or viruses such as HIV)
cells from other organisms of the same species (harmful for those with organ transplants)
abnormal body cells (e.g. cancer cells)
toxins
4
Q
what can each different shape lymphocyte do?
A
each one can recognise a different shaped antigen
5
Q
when are lymphocytes made?
A
when you are a foetus
6
Q
what is the definition of an antigen?
A
foreign proteins that generate an immune response by lymphocyte cells when detected in the body
7
Q
where are antigens located?
A
on the surface of cells
8
Q
what happens if a mutation occurs in the gene which codes for the antigen?
A
the shape of the antigen will change
9
Q
what happens to the previous immunity to a pathogen if there is a mutation of the antigens?
A
any previous immunity to this pathogen (either naturally
through prior infection or artificially through vaccination) is
no longer effective, as all the memory cells in the blood will
have a memory of the old antigen shape
this is antigen variability
10
Q
what is an example of a chemical barrier that pathogens have to get past?
A
stomach acid
11
Q
what is an example of a physical barrier that pathogens have to get past?
A
skin
12
Q
what line of defence are the white blood cells?
A
if the pathogen enters the blood then the white blood cells are the second line of defence
13
Q
what type of white blood cells are responsible for the non-specific response?
A
phagocytes
14
Q
what type of white blood cells are responsible for the specific response?
A
lymphocytes
15
Q
what type of white blood cell is a phagocyte?
A
macrophage
16
Q
where are phagocytes found?
A
found in the blood and in tissues
17
Q
is phagocytosis a specific or non-specific response?
A
a non-specific response
18
Q
what is the process of phagocytosis?
A
phagocytes are in the blood and tissues and any chemicals
or debris released by pathogens or abnormal cells attract
the phagocytes and they will move towards these cells
there are many receptor binding points on the surface of phagocytes, they will attach to chemicals or antigens on the pathogen via these receptors
the phagocyte changes shape to move around and engulf the pathogen, once engulfed, the pathogen is contained with a phagosome vesicle
a lysosome within the phagocyte will fuse with the phagosome and release its contents, the lysozyme enzyme is released into the phagosome
this is a lytic enzyme which hydrolyses the pathogen, this destroys the pathogen, the soluble products are absorbed and used by the phagocyte
19
Q
where are all lymphocytes made?
A
made in the bone marrow
20
Q
where do T cells mature?
A
in the thymus
21
Q
which cells does the cell-mediated response involve?
A
T cells and body cells
22
Q
how is the cell mediated response specific?
A
because T cells respond to antigens on the surface of cells
23
Q
what are Antigen-Presenting Cells (APC)?
A
any cell that presents a non-self antigen on their surface
24
Q
what are examples of APC?
A
infected body cells presenting viral antigens on their surface
a macrophage which has engulfed and destroyed a pathogen presenting the antigens on their surface
25
why is cell mediated response described as ‘cell-mediated’?
because T cells only respond to antigens which are presented on cells (APC), and not antigens detached from cells and within body fluids, such as the blood
26
what is the process of cell mediated response?
1 - once a pathogen has been engulfed and destroyed by a phagocyte, the antigens are positioned on the cell surface, this is now called an antigen-presenting cell (APC)
2 - helper T cells have receptors on their surface which can attach to the antigens on APC
3 - once attached this activates the helper T cells to divide by mitosis to replicate and make large numbers of clones, cloned helper T cells differentiate into different cells
27
what are the different cells that cloned helper T cells differentiate into during cell mediated response?
some remain as helper T cells and activate B lymphocytes
some stimulate macrophages to perform more phagocytosis
some become memory cells for that shaped antigen
some become cytotoxic T cells (killer T cells)
28
what do cytotoxic T cells do?
destroy abnormal or infected cells
29
how do cytotoxic cells destroy abnormal or infected cells?
they release a protein, perforin, which embeds in the cell surface
membrane and makes a pore (a hole) so that any substances
can enter or leave the cell and this causes cell death
30
when are cytotoxic T cells most common?
in viral infections because viruses infect body cells, body cells are sacrificed to prevent viral replication
31
where do B cells mature?
in the bone marrow
32
what does the humoral response involve?
the response involving B cells and antibodies
33
how are antibodies transported around the body and are they soluble?
antibodies are soluble and transported in bodily fluids
34
what happens in the process of B cell activation?
antigens in the blood collide with their complementary antibody on a B cell
the B cell takes in the antigen by endocytosis and then presents it on its cell surface membrane
when this B cell collides with a helper T cell receptor, this activates the B cell to go through clonal expansion and differentiation (clonal selection)
B cells undergo mitosis to make large numbers of cells, these differentiate into plasma cells or memory B cells
35
do plasma cells make antibodies?
yes
36
how do B memory cells make antibodies?
divide rapidly into plasma cells when reinfected with the same pathogen to make large numbers of antibodies rapidly
37
how long can memory B cells live for in your body?
decades
38
how long do plasma cells live for?
short lived
39
what do memory B cells do instead of making antibodies?
they will divide by mitosis and make plasma cells rapidly if they collide with an antigen they have previously encountered
40
what is active immunity?
where large numbers of antibodies being produced so rapidly that the pathogen is destroyed before any symptoms can occur
41
what is the definition of an antibody?
quaternary structure proteins made up of four polypeptide chains
42
what does every antibody have that is different?
each different antibody has a different shaped binding site, which
is the variable region
the shape of the antigen-binding site is unique to the shape of a particular antigen
43
what is the process called that makes lots of antibodies clump together?
agglutination
44
why is agglutination important?
this makes it easier for phagocytes to locate and destroy the pathogens
45
what is passive immunity?
antibodies are introduced into the body
the pathogen doesn’t enter the body, so plasma cells and memory cells are not made
e.g. antibodies passed to a fetus through the placenta
or through breast milk to a baby
46
is passive immunity long term immunity?
no
47
what is active immunity?
active immunity is when immunity is created by your own immune system following exposure to the pathogen or its antigen
48
what are the two types of active immunity?
natural and artificial
49
what is natural active immunity?
following infection and the creation of the body's own antibodies and memory cells
50
what is artificial active immunity?
following the introduction of a weakened version of the pathogen or antigens via a vaccine
51
what are vaccines?
small amounts of weakened or dead pathogens or antigens are introduced in the mouth or by injection
52
how does having a vaccine cause your body to produce antibodies and become immune to that specific pathogen?
- exposure to the antigens activates the B cell to go through clonal expansion and differentiation (clonal selection)
- B cells undergo mitosis to make large numbers of cells, these differentiate into plasma cells or memory B cells
- plasma cells make antibodies
- B memory cells divide rapidly into plasma cells when re-infected with the same pathogen to make large numbers of antibodies rapidly
53
what is herd immunity?
if enough of the population is vaccinated the pathogen cannot spread easily amongst the population
54
who does herd immunity protect?
provides protection for those who are not vaccinated e.g those already too ill to have a vaccine or who have a lowered immunity, or those who are too young
55
what is a monoclonal antibody?
a monoclonal antibody is a single type of antibody that can be
isolated and cloned
56
what are antibodies made from?
proteins which have binding sites complementary in shape to certain antigens
57
what are some uses of monoclonal antibodies?
medical treatment
medical diagnosis
pregnancy tests
58
how can direct monoclonal antibody therapy be used to help deliver medication to cancer patients?
some cancers can be treated using monoclonal antibodies which are designed with a binding site complementary in shape to the antigens on the outside of cancer cells
the antibodies are given to the cancer patient and attach to the cancer cells, while the antibodies are bound to the cancer antigens,
this prevents chemicals from binding to the cancer cells which enables uncontrolled cell division
therefore, the monoclonal antibodies prevent the cancer cells from growing, and as they are designed to only attach to cancer cells they do not cause harm to other normal cells
59
how can indirect monoclonal antibody therapy be used to help deliver medication to cancer patients?
cancer can also be treated with monoclonal antibodies complementary in shape to the antigens on the outside of cancer cells which have drugs attached to them
these cancer drugs are therefore delivered directly to the cancer cells and kill them
this reduces the harmful side effects that traditional chemotherapy and radiotherapy can produce, this is often referred to as 'bullet drugs’
60
what can monoclonal antibodies be used to test for?
pregnancy
influenza
hepatitis
chlamydia
prostate cancer
61
how does an ELISA test use three different types of antibodies in a pregnancy test?
first mobile antibody, complementary to the antigen being tested for, and has a coloured dye attached
a second antibody complementary in shape to the antigen is immobilised in the test
a third antibody is immobilised and is complementary in shape to the first antibody
62
what are the ethical issues to do with monoclonal antibodies?
creating monoclonal antibodies requires mice to produce the antibodies and tumour cells, which leads to ethical debates
63
where do viruses replicate?
inside cells
64
why can viruses not be destroyed by antibiotics?
they have no cell wall
65
what is the core in HIVs structure?
genetic material (RNA) and the enzyme reverse transcriptase, which are needed for viral replication
66
what is the capsid in HIVs structure?
the outer protein coat
67
what is the envelope in HIVs structure?
extra outer layer, made out of lipids taken from the host’s cell membrane
68
what are the protein attachments in the HIV structure?
on the exterior of the envelope to enable the virus to attach to the host’s helper T cell
69
how is HIV transported through the body?
through the blood until it attaches to a CD4 protein on the helper T cells
70
during HIV replication what fuses with the helper T cell membrane?
the HIV protein capsule then fuses with the helper T
cell membrane, enabling the RNA and enzymes from HIV
to enter
71
what does the HIV enzyme reverse transcriptase do?
copies the viral RNA into a DNA copy and moves to the helper T cell
nucleus, this is why it is called a retrovirus
72
what do helper T create during HIV replication?
creates viral proteins to make new viral particles
73
how does AIDS occur from HIV?
AIDS is when the replicating viruses in the helper T cells interfere with the normal functioning of the immune system
74
what causes people to die from AIDS?
the destruction of the immune system that leads to death, rather than HIV directly
75
why are people with HIV more vulnerable to other diseases?
with the helper T cells being destroyed by the virus, the host is unable to produce an adequate immune response to other pathogens and is left vulnerable to infections and cancer
76
what are symptoms of AIDS?
skin - tumors
gastrointestinal - chronic diarrhea
central - meningitis
77
What is the function of reverse transcriptase?
It synthesizes DNA from an RNA template
## Footnote
This enzyme is crucial for retroviruses like HIV.
78
What are the components of a virus mentioned?
* Transmembrane glycoprotein
* Capsid
* Genetic material
## Footnote
These components are essential for the structure and function of viruses.
79
What does HIV target in the human body?
Helper T cells
## Footnote
HIV specifically infects and destroys these immune cells.
80
What is the normal range of helper T cells per mm³ in healthy humans?
800 - 1200 helper T cells
## Footnote
This range indicates a functioning immune system.
81
What T cell count indicates progression to AIDS?
Less than 200 helper T cells
## Footnote
This low count signifies a severely weakened immune system.
82
What is the consequence of HIV on B cells?
B cells cannot be stimulated to produce antibodies
## Footnote
This leads to impaired immune response.
83
What happens to cytotoxic T cells and memory cells during HIV infection?
They are sometimes infected and destroyed
## Footnote
This results in inadequate immune response.
84
What results from the destruction of helper T cells by HIV?
Inadequate immune response
## Footnote
This leaves the body vulnerable to infections and cancers.
85
In AIDS patients, what types of infections are they prone to?
* Infections of the lungs
* Infections of the intestines
* Infections of the brain
* Infections of the eyes
## Footnote
These infections are common due to the weakened immune system.
86
True or False: It is HIV that directly causes death in AIDS patients.
False
## Footnote
It is secondary infections and illnesses, not HIV, that lead to death.
87
What is the role of the protein capsid in HIV infection?
Fuses with the cell membrane
## Footnote
This process allows the HIV virus to enter the host cell.
88
What happens after HIV RNA and enzymes enter the T cell?
The mRNA leaves the nucleus of the host cell through nuclear pores
## Footnote
It utilizes the cell's protein synthesis mechanisms to create HIV particles.
89
Where is the new DNA from HIV moved after it is created?
Into the helper T cell's nucleus
## Footnote
This insertion is into the cell's DNA.
90
What does the HIV DNA in the nucleus create?
mRNA using the cell's enzymes
## Footnote
This mRNA contains instructions for making new viral proteins.
91
What are attachment proteins on HIV that bind to T helper lymphocytes?
gp120 molecules
## Footnote
These proteins specifically bind to CD4 receptor proteins.
92
What process occurs when HIV particles bud away from the helper T cell?
They form their lipid envelope
## Footnote
This occurs by taking a piece of the cell's cytoplasmic membrane.
93
What enzyme does HIV use to convert its RNA to DNA?
HIV reverse transcriptase
## Footnote
This is a critical step in the HIV replication process.
94
What are lymphocytes?
Lymphocytes are cells in the immune system that identify and destroy pathogens and harmful substances
## Footnote
Lymphocytes are crucial for the body's immune response.
95
What triggers a response to destroy a non-self cell?
The detection of a non-self cell triggers a response to destroy it
## Footnote
This is a key function of the immune system.
96
What types of entities can lymphocytes identify?
* Pathogens (e.g. bacteria, fungi, viruses)
* Cells from other organisms of the same species
* Abnormal body cells (e.g. cancer cells)
* Toxins
## Footnote
Recognition of these entities is vital for immune defense.
97
How many different types of lymphocytes does the human body have?
10 million different types of lymphocytes
## Footnote
Each type can recognize a different shaped antigen.
98
What happens to lymphocytes that are complementary to self-cells?
They die or production is suppressed to prevent attacking self-cells
## Footnote
This process occurs during fetal development and after birth.
99
Where are new lymphocytes made after birth?
In the bone marrow
## Footnote
New lymphocytes are produced throughout life.
100
What causes autoimmune diseases?
The production of lymphocytes that attack self-cells
## Footnote
This can occur if the process of lymphocyte selection fails.
101
Fill in the blank: Lymphocytes can recognize _______ which are unique to pathogens.
[antigens]
102
True or False: Lymphocytes are produced only during fetal development.
False
## Footnote
Lymphocytes are also produced in the bone marrow after birth.
103
What is the role of surface molecules on lymphocytes?
To identify different types of cells, including self and non-self cells
## Footnote
These molecules are usually proteins with unique 3D structures.
104
What are antigens?
Foreign proteins that generate an immune response by lymphocyte cells when detected in the body.
## Footnote
Antigens are located on the surface of cells.
105
What type of cell is a macrophage?
A type of immune cell that engulfs and digests foreign particles and pathogens.
106
What are the two types of B-cells mentioned?
* Effector B-Cell
* Memory B-Cell
107
What are lymphocytes?
A type of white blood cell that is part of the immune system.
108
What is antigen variability?
The phenomenon where pathogenic DNA mutates frequently, changing the shape of the antigen.
## Footnote
This can render previous immunity ineffective.
109
What happens if a mutation occurs in the gene coding for an antigen?
The shape of the antigen will change, making previous immunity ineffective.
110
Why does a new flu vaccine have to be created each year?
Because the influenza virus mutates and changes its antigens very quickly.
111
Fill in the blank: _______ are proteins produced by B-cells that help neutralize pathogens.
[Antibodies]
112
What type of T-cell is responsible for killing infected cells?
[Killer T-Cell]
113
What type of T-cell helps activate other immune cells?
[T Helper Cell]
114
What is the role of naive B-cells?
They are immature B-cells that have not yet encountered an antigen.
115
What is the second line of defence in the immune response?
White blood cells
## Footnote
They act after the initial chemical and physical barriers like skin and stomach acid are breached.
116
What are the two main types of white blood cells involved in the immune response?
* Phagocytes
* Lymphocytes
117
What is the function of phagocytes in the immune system?
Responsible for the non-specific response
118
What is the role of lymphocytes in the immune system?
Responsible for the specific response
119
What is phagocytosis?
A non-specific response where phagocytes engulf and destroy pathogens
120
What type of white blood cell is a macrophage?
A type of phagocyte
121
Where are phagocytes found in the body?
In the blood and in tissues
122
Fill in the blank: Phagocytosis is triggered by the detection of any _______ cell.
non-self
123
What happens to a non-self cell during phagocytosis?
It is engulfed and destroyed
124
What structures are involved in the process of phagocytosis?
* Phagosome
* Lysosome
* Phagolysosomes
125
What is the function of lymph nodes in the immune system?
They filter lymph and house immune cells
126
What organ is responsible for producing lymphocytes?
Thymus
127
Fill in the blank: The bone marrow is responsible for producing _______ blood cells.
white
128
True or False: Phagocytosis is a specific immune response.
False
129
What is the outcome of exocytosis in the context of phagocytosis?
Release of soluble debris from the phagocyte
130
What are phagocytes?
Cells in the blood and tissues that engulf pathogens and debris
## Footnote
Phagocytes play a crucial role in the immune response.
131
What attracts phagocytes to pathogens?
Chemicals or debris released by pathogens or abnormal cells
## Footnote
This attraction is part of the immune response.
132
What happens when a phagocyte detects a pathogen?
It changes shape to move around and engulf the pathogen
## Footnote
This process is essential for phagocytosis.
133
What is a phagosome?
A vesicle formed around an engulfed pathogen
## Footnote
The phagosome contains the pathogen for further processing.
134
What role do lysosomes play in phagocytosis?
They fuse with the phagosome and release digestive enzymes
## Footnote
Lysosomes are critical for breaking down pathogens.
135
What is lysozyme?
A lytic enzyme that hydrolyzes pathogens
## Footnote
Lysozyme is released into the phagosome to destroy the pathogen.
136
What are the end products after a pathogen is destroyed by a phagocyte?
Soluble products absorbed and used by the phagocyte
## Footnote
These products can be utilized for the phagocyte's own processes.
137
Fill in the blank: The process by which phagocytes engulf pathogens is called _______.
[phagocytosis]
138
True or False: Phagocytes have receptor binding points on their surface.
True
## Footnote
These receptors are essential for detecting and attaching to pathogens.
139
What happens to the pathogen after it is contained within a phagosome?
It is broken down by enzymes released from lysosomes
## Footnote
This breakdown is crucial for eliminating the pathogen.
140
What initiates the detection process of pathogens by phagocytes?
Receptors that detect viral proteins
## Footnote
These receptors are specific for recognizing pathogens.
141
What are lymphocytes?
White blood cells involved in the specific immune response
## Footnote
Lymphocytes are made in the bone marrow
142
Where do T cells mature?
Thymus
## Footnote
T cells are a type of lymphocyte
143
What is the cell-mediated response?
The response involving T cells and body cells
## Footnote
It is specific because T cells respond to antigens
144
List the organs of the immune system.
* Tonsils and Adenoids
* Thymus
* Lymph Nodes
* Appendix
* Bone Marrow
* Spleen
* Peyer's Patches
* Lymphatic Vessels
## Footnote
Lymph Nodes are mentioned multiple times
145
What are antigen-presenting cells (APC)?
Any cell that presents a non-self antigen on their surface
## Footnote
APCs include infected cells, macrophages, transplanted organ cells, and cancer cells
146
What types of cells can present viral antigens?
Infected body cells
## Footnote
These cells present antigens on their surface
147
What role do macrophages play in the immune response?
Engulf and destroy pathogens, presenting antigens on their surface
## Footnote
Macrophages are a type of antigen-presenting cell
148
True or False: T cells respond to self-antigens.
False
## Footnote
T cells respond to non-self antigens
149
Fill in the blank: T lymphocytes are made in the _______.
Bone marrow
## Footnote
This is where all lymphocytes are produced
150
What distinguishes cancer cells in the immune response?
They have abnormal-shaped self-antigens
## Footnote
This can trigger an immune response
151
What is the primary characteristic of a cell-mediated response?
T cells respond only to antigens presented on cells (APC)
## Footnote
This response does not involve antigens detached from cells and within body fluids.
152
Name four key terms associated with the immune system.
* Bone marrow
* Thymus
* Memory cells
* Antigen-presenting cells
* Cytotoxic T cells
153
What happens to a pathogen after it is engulfed by a phagocyte?
The antigens are positioned on the cell surface, forming an antigen-presenting cell (APC)
## Footnote
This process is crucial for the activation of T cells.
154
How do helper T cells become activated?
By attaching to antigens on antigen-presenting cells (APC)
## Footnote
This attachment triggers their division by mitosis.
155
What are the fates of cloned helper T cells?
* Some remain as helper T cells to activate B lymphocytes
* Some stimulate macrophages for phagocytosis
* Some become memory cells for that antigen
* Some become cytotoxic T cells
156
Fill in the blank: The cells that present antigens to T cells are called _______.
antigen-presenting cells (APC)
157
True or False: Cytotoxic T cells are also known as killer T cells.
True
158
Identify the type of T cell that helps activate B lymphocytes.
Helper T cells
159
What is the role of memory cells in the immune response?
To remember specific antigens for future responses
## Footnote
Memory cells enable a faster response upon re-exposure to the same antigen.
160
Which cells stimulate macrophages to perform more phagocytosis?
Cloned helper T cells
161
What do Cytotoxic T cells do?
Cytotoxic T cells destroy abnormal or infected cells
## Footnote
They are crucial in the immune response, particularly during viral infections.
162
What protein do Cytotoxic T cells release to induce cell death?
Perforin
## Footnote
Perforin creates pores in the target cell's membrane.
163
What is the role of perforin in the immune response?
Perforin embeds in the cell surface membrane and makes a pore
## Footnote
This allows substances to enter or leave the infected cell, leading to cell death.
164
Why are body cells sacrificed during viral infections?
To prevent viral replication
## Footnote
This is a protective mechanism to control the spread of the virus.
165
What symptom is associated with the action of Cytotoxic T cells during a cold?
Sore throat
## Footnote
The sore throat occurs because Cytotoxic T cells are destroying infected body cells in the throat.
166
Fill in the blank: Cytotoxic T cells are most commonly involved in _______ infections.
viral
## Footnote
They target cells that have been infected by viruses.
167
What do Granzymes do in the immune response?
Granzymes induce apoptosis in infected cells
## Footnote
They are serine proteases released by Cytotoxic T cells.
168
What is the TCR in the context of Cytotoxic T cells?
T-cell receptor
## Footnote
TCR is used by T cells to recognize antigens on infected cells.
169
True or False: Cytotoxic T cells only target cancerous cells.
False
## Footnote
Cytotoxic T cells primarily target infected cells, especially during viral infections.
170
What happens to a target cell after it is attacked by Cytotoxic T cells?
It undergoes cell death
## Footnote
This is a crucial step in eliminating infected or abnormal cells.
171
Where are all lymphocytes made?
Bone marrow
172
What is the primary function of B cells in the immune response?
Humoral response
173
What are antibodies?
Soluble proteins transported in bodily fluids
174
What does the term 'humoral' refer to?
Body fluids
175
What is clonal expansion?
The process of B cells undergoing mitosis to produce large numbers of cells
176
What do plasma cells produce?
Antibodies
177
What is the role of memory B cells?
To divide rapidly into plasma cells upon re-infection
178
How many different B cells are there approximately?
10 million
179
What is the mechanism by which a B cell takes in an antigen?
Endocytosis
180
What happens when a B cell collides with a helper T cell receptor?
The B cell is activated to undergo clonal expansion and differentiation
181
What are the two types of cells B cells can differentiate into?
* Plasma cells
* Memory B cells
182
Fill in the blank: The humoral response involves B cells and _______.
Antibodies
183
True or False: Antigens collide with antibodies on the surface of B cells.
True
184
What are memory B cells?
Memory B cells can live for decades in your body
185
How long do plasma cells typically last?
Plasma cells are short-lived
186
What do memory B cells do upon encountering a previously encountered antigen?
They will divide by mitosis and make plasma cells rapidly
187
What happens to antibody production during the secondary immune response?
Large numbers of antibodies are produced rapidly
188
What is active immunity?
This is when memory B cells produce antibodies rapidly upon re-exposure to an antigen
189
What is the primary immune response?
The response to the initial exposure to an antigen
190
What is the secondary immune response?
The response to a second exposure to the same antigen
191
Fill in the blank: Memory B cells do not make antibodies, rather they will divide by mitosis and make _______ if they collide with an antigen.
plasma cells
192
True or False: Memory B cells are responsible for the rapid production of antibodies during a secondary immune response.
True
193
What is the result of the rapid production of antibodies during the secondary immune response?
The pathogen is destroyed before any symptoms can occur
194
What is the term for the clones produced from memory B cells during an immune response?
Clone of ancestral cell
195
What does the concentration of antibodies indicate?
It indicates the strength of the immune response during primary and secondary exposures
196
What are antibodies?
Quaternary structure proteins made up of four polypeptide chains
## Footnote
Antibodies play a crucial role in the immune response.
197
What is the variable region of an antibody?
The part of the antibody with a different shaped binding site unique to a particular antigen
## Footnote
The variable region is shown in purple.
198
What is agglutination in the context of antibodies?
The process where antibodies bind to multiple antigens to clump them together
## Footnote
This facilitates easier identification and destruction of pathogens by phagocytes.
199
What are the main components of an antibody?
* Light chain
* Heavy chain
* Constant region
* Variable region
## Footnote
The constant region is shown in red.
200
True or False: Each antibody has the same shaped binding site.
False
## Footnote
Each antibody has a unique shape for its antigen-binding site.
201
Fill in the blank: Antibodies are _______ and can bind to multiple antigens.
flexible
## Footnote
This flexibility aids in the agglutination process.
202
What role do phagocytes play in relation to antibodies?
They locate and destroy pathogens that have been clumped together by antibodies
## Footnote
The clumping makes it easier for phagocytes to target pathogens.
203
What is passive immunity?
Antibodies are introduced into the body without pathogen entry, resulting in no long-term immunity.
## Footnote
Examples include antibodies passed to a fetus through the placenta or breast milk to a baby.
204
What are the key characteristics of passive immunity?
* Antibodies are introduced
* Pathogen does not enter the body
* No plasma or memory cells are made
* No long-term immunity
205
What is natural immunity?
Immunity developed through natural exposure to pathogens.
206
What is artificial immunity?
Immunity developed through medical intervention, such as vaccination.
207
What are antibodies?
Proteins produced by the immune system to identify and neutralize pathogens.
208
What is active immunity?
Immunity created by the body's own immune system following exposure to a pathogen or antigen.
209
What are the two types of active immunity?
* Natural active immunity
* Artificial active immunity
210
What is natural active immunity?
Immunity developed after infection, leading to the creation of the body's own antibodies and memory cells.
211
What is artificial active immunity?
Immunity developed after the introduction of a weakened pathogen or antigens via a vaccine.
212
What do vaccines introduce to the body?
Small amounts of weakened or dead pathogens or antigens
## Footnote
Vaccines can be administered orally or by injection.
213
What process do B cells undergo when exposed to antigens?
Clonal expansion and differentiation (clonal selection)
## Footnote
This process is crucial for the immune response.
214
What do B cells differentiate into after mitosis?
Plasma cells or memory B cells
## Footnote
Plasma cells are responsible for producing antibodies.
215
What is the role of plasma cells?
Make antibodies
## Footnote
Antibodies are crucial for identifying and neutralizing pathogens.
216
What happens to B memory cells during a secondary exposure?
They divide rapidly into plasma cells
## Footnote
This allows for a rapid production of antibodies.
217
Define herd immunity.
Protection for those who are not vaccinated when enough of the population is vaccinated
## Footnote
It prevents the spread of pathogens within a community.
218
What is the effect of herd immunity on disease spread?
It prevents the pathogen from spreading easily
## Footnote
This is especially important for vulnerable populations.
219
What happens when fewer people are immunized?
Disease spreads more easily
## Footnote
A lower immunization rate decreases herd immunity.
220
Fill in the blank: B cells undergo _______ to make large numbers of cells.
mitosis
## Footnote
Mitosis is essential for B cell proliferation.
221
True or False: Immunized people act as a barrier against infection.
True
## Footnote
Immunized individuals help protect the community from outbreaks.
222
What is the primary immune response?
The initial response to a pathogen upon first exposure
## Footnote
This response is typically slower than the secondary immune response.
223
What do initial exposures result in regarding antibodies?
A concentration of antibodies is produced
## Footnote
This concentration increases over time with exposure.
224
What is patient zero in the context of herd immunity?
The first person infected in an outbreak
## Footnote
Identifying patient zero can help trace the spread of disease.
225
What is a monoclonal antibody?
A single type of antibody that can be isolated and cloned
## Footnote
Monoclonal antibodies are created from identical immune cells that are all clones of a unique parent cell.
226
What are antibodies?
Proteins with binding sites complementary in shape to certain antigens
## Footnote
Antibodies play a crucial role in the immune response by recognizing and binding to specific antigens.
227
List three applications of monoclonal antibodies.
* Medical treatment
* Medical diagnosis
* Pregnancy tests
## Footnote
These applications leverage the specificity of monoclonal antibodies for targeted therapies and detection methods.
228
What is targeted medication in the context of monoclonal antibodies?
Direct monoclonal antibody therapy designed to bind to cancer cell antigens
## Footnote
This therapy prevents uncontrolled cell division by blocking chemicals from binding to cancer cells.
229
How do monoclonal antibodies prevent cancer cell growth?
By attaching to cancer cell antigens, preventing chemicals from binding
## Footnote
This mechanism disrupts the signaling pathways that promote cell division in cancer cells.
230
What is indirect monoclonal antibody therapy?
Monoclonal antibodies with drugs attached that target cancer cells
## Footnote
This method delivers cytotoxic drugs directly to cancer cells, minimizing side effects compared to traditional therapies.
231
What are 'bullet drugs'?
Monoclonal antibodies with attached drugs that kill cancer cells
## Footnote
The term emphasizes the precision of these therapies in targeting cancer cells directly.
232
What is the role of a cytotoxic drug in cancer treatment?
To kill cancer cells directly
## Footnote
Cytotoxic drugs are often used in conjunction with monoclonal antibodies to enhance the effectiveness of treatment.
233
What can monoclonal antibodies be used to test for?
* Pregnancy
* Influenza
* Hepatitis
* Chlamydia
* Prostate cancer
## Footnote
Examples include the Covid 19 antibody test.
234
What does ELISA stand for?
Enzyme-linked immunosorbent assay
## Footnote
ELISA is a common laboratory technique used for detecting and quantifying substances.
235
What is the role of the first mobile antibody in an ELISA test?
It is complementary to the antigen being tested for and has a coloured dye attached.
## Footnote
This helps in visualizing the presence of the antigen.
236
What is the function of the second antibody in an ELISA test?
It is immobilised in the test and complementary in shape to the antigen.
## Footnote
This helps in capturing the antigen for detection.
237
What does the third antibody do in an ELISA test?
It is immobilised and is complementary in shape to the first antibody.
## Footnote
This further aids in the detection process.
238
Fill in the blank: The test for pregnancy involves detecting _______.
hCG
## Footnote
hCG stands for human chorionic gonadotropin, a hormone produced during pregnancy.
239
True or False: A clear blue line in a pregnancy test indicates that the individual is pregnant.
True
## Footnote
This is a common result interpretation in home pregnancy tests.
240
What is the first step in the ELISA test procedure?
Add the test sample from a patient to the base of the beaker
## Footnote
This initiates the testing process to detect the presence of an antigen.
241
What is done after adding the test sample in the ELISA test?
Wash to remove any unbound test sample
## Footnote
This step ensures that only the bound antigens remain for further testing.
242
What type of antibody is added after washing the test sample in the ELISA test?
An antibody complementary in shape to the antigen you are testing
## Footnote
This antibody specifically binds to the antigen present in the sample.
243
What must be done after adding the first antibody in the ELISA test?
Wash to remove any unbound antibody
## Footnote
This step is crucial to ensure the specificity of the test.
244
What is the function of the second antibody in the ELISA test?
Binds to the first antibody and has an enzyme attached to it
## Footnote
This enzyme will later react with a substrate to produce a color change.
245
What is added to the ELISA test after the second antibody?
The substrate for the enzyme, which is colourless
## Footnote
The substrate reacts in the presence of the enzyme to produce a colored product.
246
What does the presence of color in the ELISA test indicate?
The presence of the antigen in the test sample
## Footnote
The intensity of the color indicates the quantity of the antigen present.
247
What ethical issues arise from the creation of monoclonal antibodies?
Use of mice to produce antibodies and tumor cells
## Footnote
This raises debates about the justification of animal use for human benefit.
248
What type of cells are involved in the fusion process to create hybridomas?
Myeloma cells and spleen cells
## Footnote
This fusion is essential for producing monoclonal antibodies.
249
What is the purpose of culturing hybridomas in HAT medium?
Select for positive cells
## Footnote
HAT medium allows only the desired hybridoma cells to grow.
250
What is the final step in the process of creating monoclonal antibodies?
Harvest monoclonal antibodies
## Footnote
This provides the antibodies needed for various applications, including cancer treatment.
251
What is the core structure of HIV?
Genetic material (RNA) and reverse transcriptase
## Footnote
These components are essential for viral replication.
252
What does the capsid of HIV refer to?
Outer protein coat
## Footnote
The capsid protects the viral RNA and enzymes.
253
What is the function of the envelope in HIV?
Extra outer layer made of lipids from the host's cell membrane
## Footnote
The envelope aids in the virus's ability to infect host cells.
254
What role do protein attachments play in HIV?
Enable the virus to attach to the host's helper T cell
## Footnote
This is crucial for the virus to initiate infection.
255
What is the primary target cell for HIV?
Helper T cells
## Footnote
HIV specifically targets these immune cells, which are vital for the immune response.
256
What happens when HIV attaches to a helper T cell?
The HIV protein capsule fuses with the helper T cell membrane
## Footnote
This fusion allows the virus's RNA and enzymes to enter the host cell.
257
What is reverse transcriptase's function in HIV?
Copies viral RNA into DNA
## Footnote
This process is essential for integrating viral material into the host's genome.
258
What is the term for HIV due to its replication process?
Retrovirus
## Footnote
This classification is based on the reverse transcription of RNA to DNA.
259
What occurs after reverse transcription in the HIV life cycle?
Viral DNA integrates into the host DNA
## Footnote
This integration allows the virus to hijack the host's cellular machinery.
260
How is a mature virion formed in HIV replication?
Viral protease cleaves new polyproteins
## Footnote
This process is necessary for the maturation of infectious virus particles.
261
What is the significance of new viral RNA in HIV?
Used as genomic RNA and to make viral proteins
## Footnote
This RNA is crucial for producing new viral particles.
262
Fill in the blank: HIV is transported around in the blood until it attaches to a _______.
CD4 protein
## Footnote
The attachment is a key step in the HIV infection process.
263
True or False: HIV can be destroyed by antibiotics.
False
## Footnote
Antibiotics are ineffective against viruses because they target bacterial cell walls.
