Communicable Disease

Question 1

What is tuberculosis?

Answer 1

A bacterial infection that kills cells and tissues; most commonly in the lungs

Question 2

What is bacterial meningitis?

Answer 2

Infection of the meninges (membranes surrounding the brain and spinal cord) causing them to become swollen, damaging the brain

Question 3

What is ring rot?

Answer 3

Caused by bacteria, ring of decay in the vascular tissue of a potato or tomato, accompanied by leaf wilting

Question 4

What is HIV/AIDS?

Answer 4

A virus which attacks cells in the immune system and compromises the immune response

Question 5

What is influenza?

Answer 5

A virus which attacks the respiratory system causing muscle pain and headaches

Question 6

What is tobacco mosaic virus?

Answer 6

A virus which causes mottling and discolouration of leaves

Question 7

What is black Sigatoka?

Answer 7

A fungus causing leaf spots on banana plants

Question 8

What is blight?

Answer 8

A protist which affects tomato leaves and potato tubers

Question 9

What is ringworm? (Cattle)

Answer 9

Growth of fungus in the skin, spores erupt through the skin creating a rash

Question 10

What is athletes foot?

Answer 10

Growth of fungus under the skin on the foot

Question 11

What is malaria?

Answer 11

Caused by a protist; parasite in the blood causing headache and fever and may progress to death

Question 12

What is fungi?

Answer 12

A pathogen
Often lives in the skin of an animal where they grow hyphae to form a mycelium.
Specialised hyphae can grow to the surface of the skin to release spores.

Question 13

What are bacteria?

Answer 13

A type of pathogen

They multiply quickly and cause disease by releasing toxins or damaging cells

Question 14

What are viruses?

Answer 14

A type of pathogen
They invade cells and take over the genetics of the cell
They cause the host cell to replicate copies of the virus
The host cell eventually bursts

Question 15

What are 4 means of transmission?

Answer 15

• direct physical touch(person to person/person to surface)
• oral transmission(eg. Cholera or salmonella)
• droplet infection through coughing and sneezing (eg. Tuberculosis and influenza)
• transmission by spores

Question 16

What are some social factors effecting transmission?

Answer 16

• overcrowding
• poor ventilation
• poor diet
• homelessness

Question 17

What is a vector?

Answer 17

Another organism that is used by the pathogen to gain entry to the primary host

Question 18

Explain the transmission of malaria

Answer 18

• Female anopheles mosquito sucks blood of an infected person
• plasmodium migrates to salivary glands
• uninfected person is bitten
• plasmodium migrated to the liver
• plasmodium migrated to blood
• person becomes infected

Question 19

How does climate effect the spread of disease?

Answer 19

Many protoctists bacteria and fungi can grow and reproduce more rapidly in warm and moist conditions. In cooler climates the pathogens may be damaged

Question 20

Explain the process of keratinisation?

Answer 20

Keratinocytes are made at the base of the epidermis and migrate to the surface of the skin. As they migrate they dry out and the cytoplasm is replaced by keratin

Question 21

Explain the process of blood clotting?

Answer 21

Damage to the blood vessel causes exposure to collagen which releases clotting factors
Platelets form a plug at the cut
Prothrombin is converted to thrombin which causes soluble fibrinogen in the blood to become insoluble fibrinogen
The fibres attach to platelets creating a mesh

Question 22

How do mucous membranes act as a primary defence in the body?

Answer 22

Epithelial layer contains goblet cells which secrete mucus aswell as extra mucus-secreting glands under the epithelium.
Mucus traps pathogens
The ciliated cells of the epithelium have cilia which waft the mucus up to the oesophagus where it is swallowed
HCl in the stomach kills the bacteria

Question 23

Explain inflammation

Answer 23

Presence of microorganisms is detected by mast cells which release histamine
Histamine causes vasodilation which causes capillary walls to become more permeable to white blood cells
Increased tissue fluid leads to swelling

Question 24

What are opsonins?

Answer 24

They are protein molecules which attach to antigens on the surface of a pathogen. They act as binding sites for phagocytes

Question 25

What are neutrophils? Explain their function

Answer 25

A type of phagocyte with a multi-lobed nucleus and many lysosomes They bind to opsonins and engulf the pathogen through endocytosis Lysosome fuses with the phagosome to release lyric enzymes which digest the pathogen

Question 26

What are macrophages?

Answer 26

They are larger than neutrophils When they engulf a pathogen they don’t fully digest it Antigen from the surface is saved and presented on the surface of the cell so that other cells in the immune system can recognise - becomes an antigen presenting cell

Question 27

What are the types of T lymphocytes?

Answer 27

T helper cells- release cytokines that stimulate B cells to develop phagocytes for phagocytosis T killer cells- attach and kill host body cells that display the foreign antigen T memory cells- provide long term immunity T regulator cells- shut down the immune response after the pathogen has been successfully removed

Question 28

What are the types of B lymphocytes?

Answer 28

Plasma cells- circulate in the blood manufacturing and releasing antibodies B memory cells- remain in the body for a number of years providing immunological memory

Question 29

What are monokines?

Answer 29

A type of cytokine released by macrophages | Stimulate B cells o differentiate into plasma cells and release antibodies

Question 30

What are interleukins?

Answer 30

A type of cytokine released by T cells and macrophages which stimulate clonal expansion (proliferation) and differentiation of B and T cells

Question 31

What are the steps to the specific immune response?

Answer 31

``` Clonal selection-T and B lymphocytes detect the antigens on pathogens contact occurs between the antigen and the lymphocytes Clonal expansion(proliferation)- mitosis occurs when the correct lymphocytes have been activated, t helper cells stimulate B cells to divide Differentiation occurs- clones of the lymphocytes develop into a range of useful cells ```

Question 32

Explain the structure of an antibody

Answer 32

Y shaped, consisting of 4 polypeptide chains Light polypeptide chains make up the outer top branches of the Y Heavy polypeptide chains make up the middle/bottom of the Y Disulfide bridges hold the chains together Hinge region allows flexibility The variable region is at the top The constant region is made up of the polypeptide chains

Question 33

What are agglutinins?

Answer 33

Type of antibody which can ‘crosslink’ / bind to two pathogens antigen because of the two binding sites

Question 34

What are antitoxins?

Answer 34

Bind to toxins released by pathogenic cells, rendering them harmless

Question 35

What is the primary immune response?

Answer 35

Antibodies are produced in response to first infection, takes a number of days for the number of antibodies in the blood rise to a level that can combat the infection

Question 36

What is the secondary immune response?

Answer 36

B memory and T memory cells circling the blood can recognise the specific antigen and can produce antibodies more quickly, concentration of antibodies increases faster and to a higher concentration.

Question 37

Explain herd vaccination

Answer 37

Once enough people have been vaccinated a disease can no longer be spread throughout the population

Question 38

What is ring vaccination?

Answer 38

Involves vaccinating all people in the immediate vicinity of a bee case of disease/infection

Question 39

What are the different forms of antigenic material used in vaccines?

Answer 39

- whole live microorganisms that have similar antigens to the more harmful pathogen - a weakened version of the pathogen - a dead pathogen - antigens from the pathogen - harmless versions of a toxin

Question 40

What is the result of genetic mutations to pathogens?

Answer 40

Their antigens can change which means the pathogen can be transmitted, an epidemic may arise

Question 41

What is active natural immunity?

Answer 41

Immunity provided by antibodies in the body as a result of infection

Question 42

What is natural passive immunity?

Answer 42

Antibodies provided via the placenta or breast milk- baby becomes immune

Question 43

What is artificial active immunity?

Answer 43

Immunity provided by antibodies made in the immune system as a result of a vaccine

Question 44

What is passive artificial immunity?

Answer 44

Immunity provided by the injection of antibodies made by another individual

Question 45

What is is penicillin?

Answer 45

A fungus discovered by Fleming to kill bacteria

Question 46

What is synthetic biology?

Answer 46

The development of new molecules(particularly enzymes) which mimic other biological systems

Question 47

What is personalised medicine?

Answer 47

Genomes are screened to identify potential medicinal compounds from the DNA sequences