4.1 Flashcards

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1
Q

Pathogen

A

A microorganism that can cause disease

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2
Q

Name types of pathogen

A

Virus
Bacteria
Fungi
Protoctista

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3
Q

Bacteria

A

Organism that can reproduce every twenty minutes

They can cause disease by damaging cells or releasing toxins in the host body

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4
Q

Virus

A

Organisms that invade cells and take over their genetic machinery
They can make copies of itself causing the host cell to burst open and spread the virus
eg. flu, cold,measles

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5
Q

Fungi

A

Can cause disease in plants and animals

They release spores which can cause redness and irritation

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6
Q

Protoctista

A

Organisms that cause harm by entering host cells and feeding on the contents as they grow

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7
Q

Describe callose deposition

A
  • Plants produces callose
  • During stress, callose gets deposited between plant cell walls and plasma membranes
  • This makes it harder for pathogens to enter cells and limits the spread of viruses
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8
Q

How are communicable diseases spread?

A

Directly or indirectly

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9
Q

Direct transmission

A

Passing a pathogen from host to host with no intermediate

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10
Q

Indirect transmission

A

Passing a pathogen from host to host via a vector or intermediate

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11
Q

Examples of direct transmission

A
Droplet infection 
Sexual intercourse
Touching
Faecal - oral transmission 
Transmission by spores
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12
Q

Give examples of non specific animal defences against pathogens

A
Skin
Mucous membranes 
Blood clotting
Inflammation
Wound repair
Expulsion reflexes
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13
Q

How does skin act as a defence?

A

Acts as a physical barrier by blocking pathogens

Acts as a chemical barrier by producing chemicals that are antimicrobial

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14
Q

How does mucous membranes act as a defence?

A

Protects body openings that are exposed to the environment by secreting mucus

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15
Q

How does inflammation act as a defence?

A

Causes swelling and isolates any pathogens that entered the damaged area

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16
Q

How does wound repair act as a defence?

A

The skin can repair itself to reform a barrier against pathogen entry

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17
Q

How do expulsive reflexes act as a defence?

A

They’re automatic.
For example, coughing and sneezing are attempts to expel foreign objects such as pathogens when they irritate our nostrils or throat

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18
Q

Why are primary defences non-specific?

A

They work in the same way for all pathogens

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19
Q

Active immunity

A

Immunity when your immune system makes its own antibodies after being stimulated by an antigen

Provides long term protection and produces memory cells

20
Q

Passive immunity

A

Immunity when you’re given antibodies made by a different organism

Immediate short term protection but doesn’t produce memory cells

21
Q

Types of immunity including sub groups

A

> Active immunity

  • natural active
  • artificial active

> Passive immunity

  • natural passive
  • artificial passive
22
Q

Structure and function of an antibody

A

A Y shaped molecule consisting of four polypeptide chains held together a disulfide bridge

They attach to the antigen on a pathogen in order to clear an infection

23
Q

Describe the primary immune response

A

Slow as pathogens enter for the 1st time
Activates B and T lymphocytes cells
Person will display symptoms

24
Q

Describe the secondary immune response

A

Fast as pathogens enter for the 2nd time
Activates memory cells (memory T lymphocytes are activated)
Person will not display symptoms

25
Q

Artificial immunity

A

Immunity provided through medical intervention

26
Q

Natural immunity

A

Immunity achieved through normal life processes

27
Q

Vaccination

A

The administration of antigens so that the body produces memory cells in order to achieve immunity to a particular disease

Helps control disease and prevent epidemics

28
Q

Phagocyte

A

A type of white blood cell that carries out phagocytosis

They’re found in the blood and tissues

They carry out a non specific immune response

29
Q

Neutrophils

A

A type of phagocyte that is the first white blood cell to respond to the pathogen inside the body

They’re are made in the bone marrow and travel in the blood

30
Q

T lymphocyte

A

A type of white blood cell covered with receptors

31
Q

B lymphocyte

A

A type of white blood cell covered with antibodies

32
Q

Stages of the immune response (brief)

A

1) Phagocytes engulf pathogens

2) Phagocytes activate T lymphocytes such as the T helper cells, T killer cells and T regulatory cells
(Some of which become memory cells)

3) T lymphocytes activate B lymphocytes, which divide into plasma cells
4) Plasma cells make more antibodies to a specific antigen

33
Q

T helper cells

A

Release substances to activate B lymphocytes and T killer cells

34
Q

T killer cells

A

Attach to and kill cells infected with a virus

35
Q

T regulatory cells

A

Suppress the immune response from other WBCs

36
Q

Opsonins

A

A group of antibodies that bind to the antigens on a pathogen

37
Q

Aggulitinins

A

Cross links pathogens to clump them together so they’re non infective

38
Q

Anti-toxins

A

Antibodies that bind to potentially toxic molecules released by pathogenic cells in order to make them harmless

39
Q

Describe a autoimmune disease

A

When an organism’s immune system isn’t able to recognise self antigens and treats the self antigens as foreign antigens.
This means it launches a immune response against the organisms own tissues

40
Q

What is lupus?

A

An autoimmune disease caused by the immune system attacking cells in the connective tissue

This damages the tissues and causes painful inflammation

As well as affecting the skin,joints,heart and lungs

41
Q

How do vaccines prevent epidemics?

A

A herd vaccination can be used to provide immunity to all or most of the population at risk

If enough people are immune the dose can not spread as there’s no one to catch it from so the disease becomes rare

Preventing the mass outbreak of a disease

42
Q

Why does the flu vaccine change every year?

A

The antigens on the surface of the influenza virus change regularly to form new strands of the virus

This means that the memory cells will no longer recognise the flu strands because the antigens are different

43
Q

Sources of new medicine

A

Natural compounds found in plants,animals or microorganisms

Accidental discovery

Observations of wildlife

44
Q

Benefits of antibiotics

A

Useful
Kills or inhibits the growth of bacteria
Treats bacterial infections
Targets bacterial cells without damaging body cells

45
Q

Risk of antibiotics

A

ANTIBIOTIC RESISTANCE

Genetic mutations make some bacteria naturally resistant to an antibiotic

This means the bacteria can live longer and reproduce more

The allele for resistance may be passed on and become more common which means it’s difficult to treat those infected with the bacteria

46
Q

Describe MRSA as an example of antibiotic resistance

A

Causes serious wound infections and is resistant to several antibodies including meticillin