bio mod 7

Question 1

disease

Answer 1

condition that impairs regular function of an organism and produces specific symptoms

Question 2

infectious disease

Answer 2

caused by pathogens which infect hosts and can be spread directly or indirectly

Question 3

pathogen

Answer 3

disease causing agent which live and reproduce at expense of host, can cause damage by releasing toxins or damaging tissue directly

Question 4

Direct transmission

Answer 4

Direct contact between infected and new host (touching, bodily fluids, airborne droplets immediately passed on)

Question 5

Indirect transmission

Answer 5

Indirect contacted due to pathogen spending time in the environment (on contaminated objects/materials or airborne droplets)

Question 6

Vector transmission

Answer 6

Use of an immediate host
Eg mosquito acquires and transfers disease by stinging or being a parasite

Question 7

Prions

Answer 7

Non-cellular misfolded proteins
(Cruetz-Jakob,kuru)

Question 8

Viruses

Answer 8

DNA or RNA in a protein coat
(influenza, COVID-19, smallpox)

Question 9

Bacteria

Answer 9

Cellular prokaryote
(tuberculosis, cholera, tetanus)

Question 10

Fungi

Protozoans

Answer 10

Cellular eukaryotes
(athletes foot)

(malaria, Giardia)

Question 11

Koch’s postulates

Answer 11

1 pathogen must be present in only infected organisms

2 Pathogen must be able to be isolated and cultured

3 samples must cause same disease

4 pathogen must be able to be re-isolated again

Question 12

Physical defence barriers

Answer 12

Skin blocks pathogen and removes them by shedding

Mucous membranes trap pathogens

Pathogens are swept from respiratory tract by cilia

Question 13

Chemical and biological defence barriers

Answer 13

Stomach acid has pH which kills eaten pathogens

Lysosomes in tears kill pathogens

Microflora prevent pathogen growth by competing for space and resources

Question 14

Inflammatory response

Answer 14

Increased blood flow including white blood cells

Vasodilation allows white blood cells to diffuse across membrane to infected side

Chemokines attract more white blood cells to destroy pathogen

Question 15

Phagocytosis

Answer 15

1. Microbe detected by phagocyte
2. Microbe is engulfed via endocytosis
3. Microbe is enclosed in a membrane.
4. Phagolysosome is formed by fusion of lysosome and phagosome
5. Lysozymes breakdown microbe

Question 16

Fever response

Answer 16

Body temperature increased by hypothalamus to inhibit virus reproduction

Bodies response to high temperature is vasoconstriction, shivering etc

Question 17

Antigen

Answer 17

Substance that stimulates immune response specific to particular pathogens

Question 18

Clonal selection

Answer 18

Large number of B & T cells specific to invading pathogen are produced

Question 19

What do Antibodies do

Answer 19

Neutralise pathogen ability to harm body cells,
Tag pathogen to be noticed by phagocytes
Activate compliment system

Question 20

Compliment system

Answer 20

Immune response enhancing proteins that perforate cell membranes of antibody targets causing them to burst

Question 21

Antigen specific immune response

Answer 21

Achieved by activating only B and T cells with receptors matching the antigen

Question 22

MHC class 2 antigens

Answer 22

Antigen that displays to other cells so they can identify the specific antigen

Question 23

MHC class 1 antigen

Answer 23

On surface of almost all cells

Recognised by killer T cells which enables body to defend against intracellular pathogens and cancer cells

Question 24

Antibody mediated response

Answer 24

Many B-cell variants are made, B cells with “correct” antibodies are activated which turns them into plasma cells or memory B cells

Question 25

T cells

Answer 25

Cytotoxic T cells destroy infected cells and cancer cells Helper T cells activate cytotoxic T cells and other helper T cells Memory T cells remain to allow effective secondary response Suppress cells turn off immune response

Question 26

B cells

Answer 26

Makes antibodies or changes into memory cells When specific antigen is encountered again, B cells change into plasma cells

Question 27

Apoptosis

Answer 27

Program cell death trapping pathogen in wall of dead tissue

Question 28

Lymphatic system

Answer 28

System of vessels that carry lymph and white blood cells around the body. Lymph nodes filter bacteria, viruses and fungi out and destroy them with white blood cells The spleen is part of this system and filters old or broken cells and macrophages destroy them.

Question 29

Active immunity

Answer 29

Natural: Microbes antibody and person gets sick , body produces antibodies and becomes immune Artificial: Antigens are presented in vaccine in person gains immunity after recognising and making antibodies

Question 30

Passive immunity

Answer 30

Natural: passed from mother to fetus via placenta or milk to infant because baby doesn’t make antibodies Artificial : snake anti-venom introduced via injection

Question 31

Primary and secondary response

Answer 31

Primary response produces appropriate number of antibodies to deal with new antigen Secondary response is fast and stronger due to immunological memory

Question 32

Vaccine

Answer 32

Introduction of harmless foreign antigens deliberately introduced to trigger bodies immune response

Question 33

Herd immunity

Answer 33

Gained by large number of people being vaccinated, which protects others

Question 34

Epidemiology

Answer 34

Study of distribution of diseases to identify causes sources and methods of control

Question 35

Incidence and prevalence

Answer 35

Number of new cases during a given time period Number of total cases at a specific time

Question 36

Transmissibility infectivity and reservoir

Answer 36

Effectiveness of pathogen spread How likely pathogen is to cause infection Any place pathogen lives before infecting new host

Question 37

Hygiene practices

Answer 37

Actions performed to prevent pathogen spread such as hand washing regular disinfectant, cleaning and coughing into arm

Question 38

Public health campaign

Answer 38

Organised efforts to promote awareness and behaviour for improving health outcomes such as targeted messaging and community education programs