chapter 12- communicable DISEASES Flashcards
what are the two types of lymphocytes
b and t lymphocytes
where are b and t lymphocytes both produced
in the bone marrow
where do b lymphocytes mature
in the bone marrow
where do t lymphocytes mature
in the thymus
what is a naive b lymphocyte
one that has never encountered the pathogen it has complementary receptors /is specific to
what stimulates the clonal expansion of b cells
interleukins
many of the cloned b cells differentiate into what
plasma cells that secrete the same antibody
what do antibodies in the blood do
circulate in the blood and lymph where they bind to the foreign antigens at the site of invasion
outline the processes that lead to the production of antibodies against an unfamiliar bacterium (3)
b cells/lymphocytes have antigen receptor/complementary to only one antigen (1)
selected/activated b cell clones/divides by mitosis (1)
forms/differentiates into plasma/effector cells (1) which secrete antibodies specific/complementary to antigen (1)
not all of the clones differentiate into plasma cells some….
remain as memory cells within the lymphatic system
what is antigen presentation
when the macrophage presents the foreign antigens on their surface membrane to the b lymphocytes in the lymph nodes
what is an immune response
the process of destroying a non self cell
what is a self cell
one that is from the body
what is a non self cell
a foreign cell
what is a pathogen
any microorganism that causes communicable disease
what is a lymphocyte
a type of white blood cell that identifies non self cells based on their antigens
lymphocytes form part of the ..
specific immune response
what is an antigen
a protein in the cell surface membrane that triggers an immune response
how are lymphocytes able to recognise antigens
they have receptors that are complementary to antigens on non self cells
each lymphocyte has receptors that can recognise …
one specific anigen
the shape of rhe antigen binding site is a result of its…
tertiary structure
four examples of passive physical barriers which help plants prevent the entry of pathogens
bark, waxy cuticles, closing stomata, cellulose in cell walls
How is a plant’s response to attack by pathogens triggered?
By cell signalling involving the release of signalling molecules. This is triggered by molecules associated with cell damage or pathogen entry attaching to receptors.
Name two materials actively produced by plants in response to infection.
Callose and lignin.
Where is callose deposited to help prevent the spread of a pathogen in a plant? (3 things)
Where is callose deposited to help prevent the spread of a pathogen in a plant?
Give five types of defence chemicals in plants.
Give five types of defence chemicals in plants.
Name two barrier defences which help prevent entry of pathogens in animals and an additional one for humans
skin and mucous membranes
and expulsive reflexes (coughing and sneezing)
What is the name of the cells in the mucous membranes that secrete mucus?
goblet cell
How does mucus help prevent pathogens entering the body? it traps… and it contains
Mucus traps pathogens and contains white blood cells and enzymes that kill bacteria.
Name three defence mechanisms, other than barrier defences, which help prevent entry of pathogens in animals.
blood clotting, wound repair, expulsive reflexes
Name two chemical secretions which help prevent entry of pathogens in animals
lysozymes and stomach (HCl) acid
In the inflammatory response, which two chemicals are released by mast cells?
cytokines and histamines
Explain how the site of a wound becomes inflamed. (4/5 things)
First, the blood vessels around the wound dilate. This increases their permeability, which allows fluid to enter the tissue. This leads to swelling. It also allows the entry of white blood cells to kill pathogens
What are the effects of histamine on tissues?
dilation of blood vessels causing heat, redness and increased formation of tissue fluid causing swelling (oedema)
Name two non-specific defence mechanisms which act in response to the entry of pathogens in animals.
fever, phagocytosis
name 2 human diseases caused by bacteria
tuberculosis and bacterial emingitis
Name the disease caused by bacteria that kills potatoes and tomatoes.
ring rot
Name two human diseases caused by viruses.
AIDS and influenza.
Name one human and one plant disease caused by a protoctist.
hat protoctists cause malaria in humans and late blight in plants.
Name the virus which causes mosaic disease in the leaves of some plants.
tobacco mosaic virus
Which type of pathogen causes athlete’s foot and ringworm in animals
fungus
what is a phagocyte
a white blood cell that forms part of the nonspecific immune response that destroy pathogens in a process called phagocytosis
1st step of phagocytosis: the phagocyte is attracted to ….. and so moves …
chemicals released by the pathogen and so moves along a concentration gradient
2nd step of phagocytosis: receptors on the …
phagocyte bind to pathogen, recognising it as nonself
3rd step of phagocytosis: the phagocyte …. the pathogen to form
engulfs to form a phagosome
4th step of phagocytosis: …. in the phagocyte fuse with the … forming…
lysosomes fuse with the phagosome forming a phagolysosome
5th step of phagocytosis: the lysosomes release … which ..
lysozymes which hydrolyse the pathogen
describe the process of phagocytosis (5)
phagocyte attracted by a substance (1)
receptors on csm of phagocyte recognise and attach to antigens on surface of pathogen (1)
pathogen engulfed (1)
enclosed in phagosome/vacuole (1)
phagosome/vacuole fuses with lysosome (1)
lysosome contains enzymes (1)
pathogen is hydrolysed/destroyed.
what is a phagosome
the vacuole/vesicle which encloses a pathogen after it has been engulfed by a phagocyte.
What is a phagolysosome?
the structure formed when a phagosome combines with a lysosome
Which two types of white blood cells are involved in phagocytosis?
neutrophils and macrophages
Which type of phagocyte is involved in both the non-specific and specific immune response?
macrophage
what are antigen presenting cells
cells that present foreign antigens on their cell surface membrane
What is the term for immunity in which T lymphocytes respond to a foreign antigen?
cell-mediated immunity
what is the role of t helper cells
to produce cytokines called interleukins, these stimulate B cells to increase antibody prodcution, phagocytes/neutrophils to ingest pathogens and the production of other t cells
explain how t helper cells act to speed up these processes (2) (processes being production of antibodies)`
stimulated by antigen-presenting cells (1) release cytokines/interleukin (1)
stimulating b cell > mitosis/clonal expansion (1)
What are interleukins and what is their function?
Which type of T cells live a long time after an initial infection and allow a faster immune response if there is a subsequent infection?
t memory cells
What is the role of T regulator cells?
To suppress the immune response to prevent an autoimmune response.
What term is used for the type of immune response in which B lymphocytes respond to a foreign antigen?
humoral immune response
Which type of B cell produces antibodies in response to a foreign antigen?
plasma cells
What are the steps involved in the humoral immune response? (2)
the response of b lymphocytes to a foreign antigen, clonal selection and the release of antibodies
How does the secondary immune response differ from the primary immune response?
In the secondary immune response, plasma cells and antibodies are produced at higher speed and concentration due to the presence of memory cells produced during the primary immune response
explain how memory cells caused the differences between 2 lines on the graph (primary and secondary response) (2)
memory cells not acting in the first line/primary response
memory cells remained in blood after primary response
so not wait/faster clonal selection
what are cytokines and what is their function
they are cell signalling molecules released by the immune cells to help regulate the immune response
they are produced released by phagocytes that have engulfed a pathogen and they attract other phagocytes to the site of infection
what are opsonins and what is ther function
they are proteins which bind to the pathogens antigens and make them more recognisable to phagocytes
and prevent the pathogen from repelling phagocytes
complementary receptors on the phagocyte then bind to opsonin allowing the phagocyte to engulf and destroy the pathogen
What are agglutinins and what is their function?
Substances, including antibodies, that cause particles to clump together.
What are anti-toxins and what is their function?
an antibody which is able to neutralise a toxin
What are interleukins and what is their function?
a type of cytokine produced by the t helper cells which stimulate other immune cells
what is agglutination
when pathogens are clump together, this enables phagocytes to engulf multiple pathogens
Describe active immunity.
resistance that arises as a result of exposure to an antigen which causes b lymphocytes to produce antibodies
define passive immunity
resistance that arises when antibodies introduced into the body either from injection or by breastfeeding bind to an destroy specific toxins/venoms/antigens
what IS a vaccine
a suspension containing an antigen or antibody used to prevent disease
what is the definition of a vaccine
to prevent disease by injecting antibodies or stimulating the immune system to produce antiboides in response to a specific antigen
what is herd immunity
when large numbers of the population are vaccinated meaning very few people carry the pathogen so vunerbale,susceptible people are less likely to make contact with infected people
4 possible sources of medicine
microorganisms, plants, animals and chemical synthesis
Name the plants which are the source of the drugs aspirin and digoxin.
the yew tree is the source of aspirin and foxglove is the source of digoxin
The fungus Penicillium chrysogenum is the source of which drug?
the antibiotic, penicillin
What is meant by the term ‘‘personalised medicine’’?
Using information about a person’s genometo choose treatment which will work best for the individual.
What is meant by the term “pharmacogenomics”?
The study of how a person’s genes affect their response to particular drugs/ pharmaceuticals/medicine
lysosomes contain
lysozymes
Pathogens are made of biological molecules, such as proteins and carbohydrates, which are formed by condensation reactions.
$$
Lysozymes break down the pathogen by catalysing a/an…
hydrolysis reaction
What are the two methods of direct transmission of pathogens between animals?
direct contact and droplets
What are the two methods of indirect transmission of pathogens between animals?
Ingestion of contaminated food or water and vectors.
Name four vectors which may transfer a pathogen from an infected individual.
Organisms, water, air and spores.
Name three factors which can increase the chances of transmission of a communicable disease between animals.
overcrowding, malnutrition and a weakened immune system
Name four factors which can increase the chances of transmission of a communicable disease between humans.
Population density of an area
A lack of trained healthcare workers
A lack of health education
Climate change
What are the two methods of indirect transmission of pathogens between plants?
vectors and soil contamination
Name three factors which can increase the chances of transmission of a communicable disease between plants.
overcrowding in soil, mineral deficiency, damp and warm growing conditions, growing crops susceptible to disease
State five ways farmers and growers control the transmission of a communicable disease between plants.
crop rotation
cleaning equipment
controlling insect vectors
leaving more space between growing plants
removing plant material from soil after harvesting
a virus affects tomatoes and pepper plants. the vector are bumblebees
there are no varieties of tom that are resistant, however some pepper varieties have become resistant, suggest why (2)
some pepper varieties may have different defence mechanisms (1) such as the production of different chemical compounds (1)
as a result some varieties may produce compounds that prevent the growth of the virus > so resistant
What is meant by the term ‘‘personalised medicine’’?
using information about a person’s genes to choose treatment which will work best for the individual.
What is the term for immunity in which T lymphocytes respond to a foreign antigen?
cell mediated immunity
what feature of a pathogen such as tb (bacteria) could be altered by a mutation, making a vaccine ineffective (1)
shape of proteins/glycoproteins/antigens on cell surface membrane
What are interleukins and what is their function?
What are interleukins and what is their function?
list vulnerable groups of people whom you would advise doctors prescribe antibiotics although theyre not yet showing symptoms
babies/infants
elderly
immuno-comprimised/on immunosuppressant drugs
HIV positive
known to have been exposed to the infection named
discuss the implications of the over-use of antibiotics when people do not show symptoms (4)
antibiotic is a selection pressure.
bacterial gene pool has variation.
only some bacteria have resistance/some more resistant than others .
when exposed to antibiotic most resistant survive.
surviving bacteria continue to reproduce to make a RESISTANT POPULATION.
over many generations there is an increase in the PROPORTION of resistant bacteria (under continued antibiotic pressure)
antibiotic becomes ineffective and a new one is needed
ignore: increase in number of resistant bacteria
What is meant by the term autoimmune disease?
An autoimmune disease occurs when the body produces antibodies which are complementary to antigens on self cells.
Give one example of a common autoimmune disease.
arthritis
Biologists think the cause of autoimmune disease may be…
genetic
