defence against disease

Question 1

pathogen & types

Answer 1

an organism that causes disease by invading a body and living there parasitically

bacteria (tuberculosis)
viruses (Covid-19)
prions (degeneration in the nervous system of mammals, mad cow disease)
fungi (ringworm)
protists (malaria)

Question 2

primary defence

Answer 2

skin
- seals entire body
- sebaceous glands produce oils that keep low pH prevents growth of bacteria
- 3 layers (epidermis, dermis and hypodermis = outer, thick between, inner w fat and energy)

mucous membranes
- line body cavities
- produce mucus that traps pathogens and is expelled by coughing, tears, urine

Question 3

commensal bacteria

Answer 3

present naturally and can outcompete pathogens for nutrients or space, dont harm host

Question 4

blood clotting

Answer 4

1 platelets & plug
2 release clotting factors
3 thromboplastin converts prothrombin to thrombin w calcium ions
4 thrombin converts fibrinogen to insoluble fibrin
5 mesh by fibrin, traps more platelets and red blood cells
6 blood clot
7 over time dries and forms a scab

Question 5

what happens to pathogens entered with food

Answer 5

low pH and hydrochloric acid of the gastric secretion of stomach kill them

Question 6

innate immune system

Answer 6

rapid, non-specific defense responses encountered in daily life

uses phagocytosis and physical and chemical barriers of primary defense system to prevent entry and limit spreading of pathogens

responds to any potential pathogen

Question 7

phagocytosis

Answer 7

the process of a pathogen being surrounded and engulfed by a cell to a membrane bound vesicle

steps
1. recognize pathogen and bind
2. chain of reaction and formation of pseudopodia which encircles the target and seals it = phagosome
3. phagosome maturation
4. fusion with lysosomes form phagolysosomes that contain digestive enzymes
5. microbial components digested by enzymes and released from cell!

Question 8

adaptive immune system

Answer 8

slower, stronger and long lasting effects
- specific, directed towards a specific pathogen
- immunological memory (remembers encountered pathogens with memory B cells and has a faster elimination on second infection)

Question 9

lymphocytes

Answer 9

mediate adaptive immune system
- T mature in thymus
- B mature in bone marrow

travel through lymphatic system, some remain in circulation while some concentrate in lymphoid organs

Question 10

lymphatic system

Answer 10

part of the immune system
- keeps body fluid levels in balance
- defends body against infections

composed of
- lymph (fluid)
- lymphoid organs (tonsils, lymph nodes, spleen)
- lymphatic vessels

Question 11

humoral immunity

Answer 11

an immune response created by the antibodies of B-lymphocytes

they are diverse, recognize many antigens and produce highly specific antibodies

Question 12

cell mediated immunity

Answer 12

an immune response by T-lymphocytes

• helper Ts help immune system by activating other components
• cytotoxic T lymphocytes kill the infected cells

Question 13

activation of T cells

Answer 13

antigen-presenting cells present fragments of a pathogen to specific T-cells activating it

leads to
- increase in the number of helper Ts that recognize the antigen
- activation of Bs specific to it
- activation of cytotoxic Ts specific to it

Question 14

activation of B cells

Answer 14

receptor on surface recognizes and binds to antigen
active helper T stimulates
=> integrated events

once activated
- undergoes mitotic divisions to clone itself > many cells that recognize the antigen
- the multiplications differentiate to plasma and memory B cells

Question 15

plasma cells and memory cells (B)

Answer 15

plasmas produce thousands of antibodies specific to the same antigen

memory cells help immune system to remember encountered antigens
- small %
- long-lived
- in lymph nodes and blood
- dormant until infected again, become plasma cells
> faster, effective = secondary immune response

Question 16

HIV-1

Answer 16

retrovirus with RNA as genetic info that weakens immune system by attacking helper Ts
- causes AIDS

transmitted by
- blood transfusion
- breastfeeding
- sexual intercourse
- shared needles

Question 17

stages of HIV infection

Answer 17

1 acute
- multiplication of HIV and destruction of helper Ts
- high in blood, increased risk of transmission

2 chronic
- low multiplication
- no obvious symptoms
- can last years

3 final stage
- body is unable to fight opportunistic infections (is immunocompromised = weakened immune system)
- suffering from a range of conditions
- leads to AIDS

antiretroviral therapy can slow down the progression of HIV allowing patients to live longer and healthier lives

Question 18

types of antibiotics

Answer 18

bacteriostatic (inhibit growth or replication)

bactericidal (kill)

broad spectrum (used to treat many bacterial infections)

narrow spectrum (only work in case of certain bacteria)

Question 19

how do antibiotics kill/inhibit bacteria

Answer 19

interfering w protein synthesis
disturbing cell wall synthesis
interfering w DNA replication or metabolism

Question 20

zoonosis & how spread

Answer 20

infectious disease that spreads from non-vertebrate animals to humans by

• handling wild animals
• consumption of wild animal
• poaching
• animal markets
• deforestation

Question 21

types of vaccines

Answer 21

live-attenuated - weak form of a whole pathogen

inactivated - inactivated form of a pathogen

DNA - use plasmids containing DNA sequence that encodes for an antigen

RNA - strand of mRNA that codes for an antigen