Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

OCR A level Biology HJ > Communicable diseases > Flashcards

Communicable diseases Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

whats a disease?

A

a condition that impairs the normal functioning of an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are pathogens?

A

an organism that causes disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the types of pathogens?

A
  • bacteria
  • pathogen
  • fungus
  • protoctista
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are communicable diseases?

A

a disease that can be spread between organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the diseases that bacteria are responsible for? what it affects?

A
  • tuberculosis (TB) - affects animals, typically humans and cattle
  • bacterial meningitis- affects humans
  • ring rot- affects tomatoes and potatoes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the diseases that virus are responsible for? what it affects?

A
  • HIV/AIDS- affects humans
  • Influenza- affects animals including humans
  • Tobacco Mosaic Virus (TMV)- affects plants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the diseases that fungus are responsible for? what it affects?

A
  • Black Sigatoka- affects banana plants
  • Ringworm- affects cattle
  • Athletes foot- affects humans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the diseases that protoctist are responsible for? what it affects?

A
  • potato/tomato late blight- affects tomatoes and potatoes

- Malaria- affects animals including humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the types of transmission of disease?

A

Direct transmission- disease is directly transmitted from one organism to another
=droplet infection (coughing or sneezing tiny droplets of mucus or saliva onto someone)
=sexual intercourse
=touching an infected organism

Indirect transmission- disease is transmitted from one organism to another via an intermediate
Intermediates= air, water, food + another organism (vector) + spores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are some factors affecting transmission?give some examples of diseases transmitted like this?

A

-living conditions
=overcrowded

-social factors
=in humans (income, occupation, area where a person lives) . good healthcare and good health education

-climate change
=some diseases have optimum conditions for spores, wet summers, humid tropical conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

state and explain non specific animal defences against pathogens

A
  • SKIN= acts as both a physical and chemical barrier by producing antimicrobials (which destroy or slow the growth of microorganisms) can lower pH, inhibiting the growth of pathogens -oleic acids and lysosomes
  • MUCOUS MEMBRANES protect body opening that are exposed to the environment (such as nostrils, ears, anus + genitals). some membranes secrete mucus- a sticky substances that traps pathogens and contains antimicrobial enzymes
  • BLOOD CLOTTING - a mesh protein (fibrin) fibres forms to prevent pathogen entry and blood loss. formed by a series of chemical reactions that take place when platelets are exposed to damaged blood cells
  • INFLAMMATION- triggered by damaged tissues releasing molecules which increase the permeability of the blood vessels, so thy start to leak fluid into the surrounding areas. This causes swelling and helps to isolate any pathogens that may have entered damaged tissue. Molecules cause vasodilation, increasing blood flow to affected areas–> makes the area hot + brings white blood cells to the area to fight of any pathogens present
  • WOUND REPAIR- surface is repaired by the outer layer of skin cells dividing and migrating to the edges of the wound closer together. It’s repaired using collagen fibres- too many collagen fibres and they’ll be a scar
  • EXPULSIVE REFLEXES- coughing + sneezing happen when mucous membrane in the nostrils (respiratory tract) are irritated by dust or dirt. this happens automatically to expel these foreign objects or pathogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

state and explain physical plant defences against pathogens

A
  • WAXY CUTICLE- which provides a physical barrier against pathogen entry - it may stop water collecting on the leaf, which could reduce the risk of infection by pathogens that are transferred between plants in water
  • CELL WALL- plant cells surround themselves by cell walls- physical barrier against pathogens which make it past the waxy cuticle
  • CALLOSE- plants produce a polysaccharide called Callose which get deposited between plant cell walls and plasma membranes during times of stress + plant invasion. Callose makes it harder for pathogens to enter cell walls. Callose deposition at the plasmodesmata (small channels in cell walls) may limit the spread of viruses between cells.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

state and explain chemical plant defences

A
  • ANTIMICROBIAL CHEMICALS- including antibiotics which kill pathogens or inhibit their growth
  • SAPONINS-destroy the cell membranes f fungi and other pathogens
  • PHYTOALEXINS- inhibit the growth of fungi and other pathogens
  • other chemicals secreted by plants are toxic to insects- this reduces the amount of insect feeding on plants and therefore reduces the risk of infection by plant viruses carried by insect vectors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

whats the immune response?

A

the bodys reaction to a foregin antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are antigens?

A

antigens are molecules (usually proteins or polysaccharides) found on the surface of cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

whats the difference between the non specific and specific immune response?

A

non specific= happens in the same way for all microorganisms

specific response= antigen-specific - its aimed at specific pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the 4 main stages of the immune response?

A

1- phagocytosis
2- T- lymphocyte activation
3- B lymphocyte activation and plasma cell production
4- antibody production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are opsonins?

A

molecules in the blood that attac to forgein antigens to aid phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

whats a phagosome?

A

a type of vesicle in the cytoplasm of a phagocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

whats a lysosome?

A

an organelle that contains digestive enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

whats a neutrophil?

A

a type of phagocyte. They’re the 1st WBC to respond to a pathogen inside the body. Neutrophils move towards a wound in response to signals from cytokines. The cytokine are released by cells a the site of the wound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are cytokines?

A

proteins that act as messenger molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

whats a phagocyte?

A

a type of white blood cell that carries out phagocytosis (engulfment of pathogens). Found in the blood an din tissues and carry out a non- specific immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe the steps involved in phagocytosis

A

1- a phagocyte recognises the antigen on a pathogen
2-the cytoplasm of the lymphocyte moves round the pathogen, engulfing it. this may be made easier by opsonin
3-the pathogen is now contained in a phagosome in the cytoplasm of a phagocyte
4-a lysosome fuses with the phagosome. The enzymes break down the pathogen.
5-the phagocyte then presents the pathogen’s antigens. It sticks the antigens on its surface to activate other immune system cells. The phagocyte is acting as a APC

25
Q

explain T lymphocyte activation

A
  • a T lymphocyte is another type of white blood cell.
  • its surface is covered with receptors
  • the receptors bind to antigen presented by APCs
  • each T lymphocyte has a different receptor on its surface
  • when the receptor on the surface of a T lymphocyte meets a complementary antigen, it binds to it- so each T lymphocyte will bind to a different antigen
  • this process activates the T lymphocyte and is known as clonal selection
  • the activated T lymphocyte then undergoes clonal expansion- it divides to produce clones of itself
26
Q

what are the different types of T lymphocytes and their functions?

A

-T HELPER CELLS- release substances to activate B lymphocytes and T killer cells
-T KILLER CELLS- attach to and kill cells that are infected with a virus
-T REGULATORY CELLS- supress the immune response from other white blood cells. This helps to stop immune system form mistakenly attacking the host’s body cells
MEMORY CELLS

27
Q

explain B lymphocyte activation and plasma cell production

A
  • B lymphocytes are also a type of WBC.
  • they’re covered with antibodies- proteins that bind antigens to form an antigen- antibody complexes
  • each B lymphocyte has a different shaped antibody on its membrane, so different ones bind to different shaped antigens
  • when the antibody on the surface of a B lymphocyte meets a complementary antigen, it binds to it- so each B lymphocyte will bind to a different antigen.
  • This + substances released from helper T cells, activates the B lymphocyte.
  • this process is an example of clonal selection
  • the activated B lymphocyte then divides, by mitosis, into plasma cells and memory cells
  • this is another example of clonal expansion
28
Q

explain antibody production

A
  • plasma cells are clones of the B lymphocyte
  • they secrete loads of antibody, specific to the antigen into the blood
  • these antibodies will bind to the antigens on the surface of the pathogen to form lots of antigen- antibody complexes.
  • this is the signal for the immune system to attack and destroy the pathogen
29
Q

what is cell signalling + its importance?

A
  • a cell may release (or present) a substance that binds to the receptors on another cell- this causes a response of some kind in the other cell
  • cell signalling is importance in the immune response because it helps to activate all the different types of white blood cells that are needed
30
Q

give an example of cell signalling that occurs in the T helper cells

A
  • T helper cells release interleukins (a type of cytokine) that binds to receptors on B lymphocytes.
  • This activates the B lymphocyte - the T helper cells are signalling to the B lymphocytes that there’s a pathogen in the body
31
Q

describe the structure of antibody

A
  • antibodies are proteins- they’re made up chains of amino acid monomers linked by peptide bonds
  • the variable regions of the antibody form the antigen-binding sites.
  • the shape of the variable region is complementary to a particular antigen
  • the variable regions differ between antibodies
  • the hinge region allows flexibility when the antibody binds to the antigen
  • the constant regions allow binding to receptors on immune system cells, e.g. phagocytes
  • the constant region is the same in all antibodies
  • disulphide bridges hold the polypeptide chains of the protein together
32
Q

what are the 3 roles of antibodies in clearing infection?

A

1-agglutinating pathogens
2-neutralising toxins
3-preventing the pathogen binding to human cells

33
Q

explain how agglutinating pathogens helps antibodies clear infections

A
  • each antibody has 2 binding sites, so an antibody can bind to 2 pathogens at the same time- the pathogens become clumped together
  • phagocytes then bind to the antibodies and phagocytose a lot of pathogens al at once
  • antibodies that behave in this way are known as agglutinins
34
Q

explain how neutralising toxins helps antibodies clear infections

A
  • like antigens, toxins have different shapes
  • antibodies called anti- toxins can bind to the toxins produced by pathogens
  • this prevents the toxins from affecting human cells, so the toxins are neutralised (inactivated)
  • the toxins- antibody complexes are also phagocytosed
35
Q

explain how preventing the pathogen binding to human cells helps

A

when antibodies bind to the antigen on pathogens, they may block the cell surface receptors that the pathogens need t bind to the host cells

-this means he pathogen can’t attach to or infect the host cells

36
Q

explain how immunity arises from the primary immune response

A
  • when a pathogen enters the body for the 1st time, the antigens on its surface activate the immune system= primary immune response
  • its slow because there are’t many B lymphocytes that can make the antibody needed to bind to the pathogen
  • eventually the body will produce enough of the right antibody to overcome the infection
  • meanwhile the infected person will show symptoms of the disease
  • after being exposed to an antigen, both T and B lymphocytes produce memory cells
  • these memory cells remain in the body for a long time
  • memory T lymphocytes remember the specific antigen and will recognise it 2nd time
  • memory B lymphocytes record the specific antibodies needed to bind to the antigen
  • the person is now immune and has the ability to respond quickly to a 2nd infection
37
Q

whats the benefit of the secondary immune response?

A
  • if the same pathogen enters again, the immune system will produce a quicker, stronger immune response
  • clonal selection happens faster
  • memory B lymphocyte divide into plasma cells that produce the right antibody to the antigen
  • memory T lymphocytes are activated and divide into the correct type of T lymphocytes to kill the cell carrying the antigen
  • the secondary response often gets rid of the pathogen before you begin to show any symptoms
38
Q

how do you maintain immunity?

A
  • memory B and T lymphocytes only have a limited lifespan
  • this means that someone who is immune to a particular pathogen won’t always stay immune forever- once all of the memory B and T lymphocytes have died, that person may be susceptible to attack by the pathogen again
  • immunity can be maintained by being continually exposed to the pathogen, so you continue to make more and more memory B and T lymphocytes
39
Q

compare primary and secondary responses

A 
pathogen:
primary response= enters for 1st time
secondary response= enters for 2nd time
speed of response:
primary response= slow
secondary response= fast
cells activated:
primary response= B and T lymphocytes
secondary response= memory cells
symptoms:
primary responses= yes
secondary responses= no

similarities= both are triggered by invasion of the body by a pathogen, both ultimately get rid of the pathogen and both involve the production of antibodies

40
Q

what is active immunity?

A

this is the type of immunity you get when your immune system makes its own antibodies after being stimulated by an antigen

41
Q

what is the difference between the 2 types of artificial immunity?

A

natural= this is when you become immune after catching a disease

artificial= this is when you become immune after you’ve been given a vaccination

42
Q

what is passive immunity?

A

this is the type of immunity you get from being given antibodies made by a different organism- your immune system doesn’t produce any antibodies of its own

43
Q

what is the difference between the 2 types of passive immunity?

A

natural immunity= this is when a baby becomes immune due to the antibodies it receives from its miter, through the placenta and in breast milk

artificial immunity= this is when you become immune after being injected from antibodies from someone lese

44
Q

compare active immunity to passive immunity

A
  • active immunity requires exposure to antigen whereas passive immunity requires no exposure to antigen
  • active immunity takes a while for protection to develop whereas passive immunity is immediate
  • active immunity provides protection for a long term whereas passive immunity provides protection for a short-term
  • active immunity, memory cells are produced whereas in passive immunity memory cells aren’t produced
45
Q

whats an autoimmune disease? + give examples

A

a disease where an organisms immune system isn’t able to recognise self antigens (antigens present on the organisms own cells).
-when this happens, the immune system treats the self antigens as foreign antigens and launches an immune response against the organisms own tissues

Examples= lupus and rheumatoid arthritis

46
Q

explain how vaccinations work

A
  • vaccines contain antigen that cause you body to produce memory cells again a particular pathogen, without the pathogen causing disease
  • this means you become immune without getting any symptoms
  • these antigens may be free or attached to a dead of weakened (attenuated) pathogen.
47
Q

whats the disadvantage of taking vaccines orally instead of injected?

A

it can be broken down by enzymes in the gut or the molecules of the vaccine may be too large to be absorbed into the blood

48
Q

why are booster vaccines given?

A

they’re given later on to make sure that more memory cells are produced

49
Q

whats herd immunity?

A
  • if most people in the community are vaccinates, the disease becomes extremely rare
  • this means that been people who haven’t been vaccinated are unlikely to get the disease, because there’s no one to catch it from
50
Q

whats the difference between vaccination and immunisation?

A
  • vaccination is the admin of antigens (in a vaccine) into the body
  • immunisation is the process by which you develop immunity
  • vaccination causes immunisation
51
Q

what are some routine vaccines that are given?

A
  • the MMR

- the meningitis C vaccine

52
Q

why do we have to change vaccination programmes regularly?

A

some pathogens can change their surface antigen

53
Q

what are antibiotics?

A
  • chemicals that kill or inhibit the growth of bacteria
  • they’re used by humans as drugs to treat bacterial infections
  • they’re useful because they can usually target bacterial cells without damaging human body cells
54
Q

explain antibiotic resitance

A
  • there’s genetic variation in a pop of bacteria
  • genetic mutations make some bacteria resistance to antibiotics
  • its advantageous for the bacteria as its better able to survive in a host who’s being treated with antibiotics to get rid of the infection, and so it lives for longer and reproduces many more times
  • this leads to allele for antibiotic resistance being passed on to lots of offspring
  • its an e.g. of natural selection
  • this is how antibiotic resistance spreads and becomes more common in a population of bacteria over time

1-variation in the pop
2-survival
3-reproduction
4-resistance is more common in the pop

55
Q

what are the problems with antibiotic resistance? name some examples of antibiotic resistance bacteria

A
  • those who become infected with these bacteria cannot get rid of it easily with antibiotics
  • increased use of antibiotics= antibiotic resistance
  • ‘superbugs’ that are more resistance to most known antibiotics are becoming more common
  • this means we are less able to treat some potentially life- threatening bacterial infection

E.g.

  • MRSA
  • Clostridium difficile
56
Q

what are some ways of preventing antibiotic resistance?

A
  • doctors encourages to reduce their use of antibiotics (not for minor infections)
  • advise patients to take all of their prescribed antibiotics to make sure the infection is fully cleared and all the bacteria have been killed

=modifying and developing new antibiotics us difficult

57
Q

what are some sources of medincine?

A
  • many medicinal drugs are manufactured using natural compounds found in plants, animals or microorganisms
  • possible sources of drugs needs to be protected by maintaining the biodiversity (the variety of different species) on earth
  • even organisms that have already been studied could still prove to be useful sources of med as new techniques are developed or identifying, purifying and testing compounds
58
Q

explained personalised medicine

A
  • personalised med is med that are tailored to an individuals DNA
  • more effective drugs can be made
59
Q

explain synthetic biology

A

involves using tech to design and make things like artificial proteins, cells, including medicine which can be applied in med

OCR A level Biology HJ (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions