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IMPORTANTÉ > Immunity (4) > Flashcards

Immunity (4) Flashcards

1
Q

what do phagocytes do after phagocytosis

A

They produce cytokines; which act as cell-signalling molecules, informing other phagocytes of the infection; stimulates them to site of inflammation/infection.

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2
Q

name two viral pathogens + two bacterial pathogens in animals

A

virus: HIV and INFLUENZA
bacterial: TUBERCULOSIS and BACTERIAL MENINGITIS ​

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3
Q

what occurs when the skin is cut

((two parts))

A

Blood clots rapidly to seal a wound and prevent entry of pathogens. POSITIVE FEEDBACK: clotting cascade.

The clot dries out forming a hard scab.

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4
Q

what is an autoimmune disease

+ 5 examples

A

When the body’s own cells become antigens (self-antigens). Tf the body’s immune system attacks its own cells.

  • Rheumatoid arthritis- synovial fluid + membranes of joints attacked*
  • Multiple sclerosis- myelin sheath of nerve axons attacked*
  • Lupus- many tissues attacked*
  • Diabetes Type 1*
  • Eczema*
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5
Q

A graft of tissue, such as skin, from a different person is usually rejected by the body. Which immune system cells cause this

A

The graft is rejected by T-lymphocytes because they circulate in the blood and can gather at the graft site.

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6
Q

why is the is the second exposure to an antigen much larger than during a vaccination/first exposure

A

The vaccination/first exposure is the primary exposure, which takes time because the immune system goes through clonal selection, clonal expansion/proliferation and differentiation.

The second exposure already has long-lasting memory cells from the first infection, meaning there is a more rapid and larger response as the memory cells act as cell-signalling molecules.

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7
Q

function of immunoglobulins?

A

Identify and neutralise foreign material, eg. b**acteria & viruses.

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8
Q

how are ringworm + athlete’s foot transmitted and what are their symptoms

A

DIRECT (AF: skin to skin, R: housing and bedding) & INDIRECT

AF: itchiness, R: inflammation, scaly patches, itchiness

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9
Q

how is a new vaccine created against a new strain of influenza virus

A

WHO + CDC laboratories collect samples of different strains, and test the effectiveness of different influenza vaccines against them. Each year the most effective is chosen, so governments/health authorities implement a programme of vaccination.

Some people can be given a vaccine to prevent the strain causing an epidemic in another country & spreading globally.

The antigen is either inactive/dead/attenuated.

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10
Q

describe the second exposure to an antigen/pathogen

A
  • Memory cells replicate rapidly on encountering the antigen
  • Response is much greater- more rapid elimination of Ag/Pg
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11
Q

how do phagocytes (macrophages, neutrophils + dendritic cells) pass from the blood into the tissue fluid

A
  1. Lobed/narrow nucleus
  2. They can squeeze between pores/gaps/fenestrations in the capillary walls/endothelium
  3. Cells can change shape
  4. Histamines from mast cells make the capillary walls/endothelium leaky
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12
Q

how do the following actively defend plants from pathogens:

  • Hypersensitivity*
  • Systemic Acquired Resistance*
  • General toxins*
A

Hypersensitivity- immediate death of tissues surrounding the site of infection by a pathogen

SAR: signalling molecule travels to uninfected areas + gives protection.

Toxins- plant produces chemicals that when broken down, produce a toxic product eg. cyanide

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13
Q

what are immunoglobulins secreted from and where are they secreted into

A

By B lymphocytes (B cells) into the blood.

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14
Q

why are personalised medicines necessary?

A

Genes determine how the body responds to certain drugs- making them more or less effective for different people.

Personalised drugs are tailored to an individual’s DNA; genetic information is used to predict how a person will respond; the most effective drug will be prescribed.

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15
Q

how is black sigatoka transmitted + its symptoms?

A

INDIRECT transmission eg. wind, rain, water, irrigation

large brown patches

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16
Q

how are HIV & influenza transmitted and what are their symptoms

A

HIV = direct transmission eg. bodily fluids

depressed immune system, AIDS

influenza = indirect transmission by droplet infection

runny nose, fever, coughing, sneezing

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17
Q

name the 5 passive physical barriers present in plants all the time

+ what is the difference between animal/plant disease defence

A

-waxy cuticle

-bark

-cellulose cell walls

-casparian strip

-closing stomata

Plants do not heal diseased tissue, they seal it off & discard it.

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18
Q

which ROUTINE VACCINES are offered to everybody in the UK

A

MMR- measles, mumps, rubella- attenuated virus given

Meningitis C- bacterial

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19
Q

what is IMMUNITY (3 marks)

A

The ability of an organism to resist a particular infection or toxin by the action of specific antibodies and sensitised white blood cells. Either:

NATURAL- produced by own antibodies or from antibodies mother-foetus/newborn

ARTIFICIAL- administrated medically

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20
Q

Define autoimmune disease (2 marks)

A

A disease in which the body produces antibodies that attack its own tissues, leading to the deterioration and sometimes destruction of such tissue.

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21
Q

how is bacterial meningitis transmitted and what are the symptoms

A

DIRECT + INDIRECT transmission eg. kissing, coughing, sneezing, (respiratory secretions)

Symptons = fever, headache, neck stiffness, light sensitivity

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22
Q

what is the specific/adaptive immune response

A

A pathogen and antigen-specific immune response with both cell-mediated and humoral components. Characterised by immunological memory.

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23
Q

name the parasite that causes malaria + the vector for the malarial parasite

A

Plasmodium is the parasite eg. Plasmodium vivax**, Plasmodium malariae etc.

female Anopheles is the vector

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24
Q

how is tobacco mosaic virus transmitted and what are the symptoms

A
  • DIRECT transmission: contact between plants*
  • INDIRECT transmission: farm machinery, tobacco products*

Yellow streaking, stunted growth.

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25
name a *bacterial pathogen in plants* + what are the _symptoms_
(bacterial plant infection) *RINGROT in potatoes* _discolouration, oozing, wilting leaves_
26
define an OPSONIN
Any substance that **binds** to **foreign microorganisms or cells**, making them more **susceptible** to **phagocytosis.** ## Footnote *They act as cell-signalling molecules.*
27
why do some vaccines have to be changed every year?
The *antigens* on the CSM *change regularly* eg. the _influenza virus_, forming *new strains.* Therefore the *memory cells* from one vaccination with one strain will *not recognise* the new strain with *different antigens;* strains are *_immunologically different._*
28
why is there a HINGE REGION on an immunoglobulin
_to allow movement of variable regions, therefore increasing antigen-binding potential_
29
*which cells carry out PHAGOCYTOSIS*
Specialised **phagocytic white cells i.e. phagocytes- *neutrophils, macrophages + dendritic cells.***
30
differences between types of immunity- *active + passive* Exposure? Time/how rapid? How long protection will last? Memory cells produced?
**ACTIVE** **REQUIRES EXPOSURE TO ANTIGEN** **TAKES A WHILE FOR PROTECTION TO DEVELOP** **LONG-TERM** **M CELLS PRODUCED** * passive* * no exposure to antigen* * protection is immediate* * short-term* * m cells are not produced*
31
what happens in an inflammatory response after the *mast cell histamines* make capillary walls *leaky*
**Fluid, platelets & antimicrobial proteins enter tissue** from the capillary. *Clotting begins.* Further **cytokines secreted** by mutliple cells- attract **phagocytes** from blood. **Phagocytosis** by **neutrophils + macrophages** of pathogens and cell debris at the site.
32
why does the government aim to vaccinate a large % of the population
**Herd immunity- helps to prevent epidemics** i.e. mass outbreaks of disease. *-Those not vaccinated are unlikely to become infected because they will not come into contact with anyone who has the disease.*
33
what is the **SPECIFIC immune reponse**
* *Recognises & targets a specific antigen only* * *Involves lymphocytes (specialised leucocytes), which are produced in the bone marrow and differentiate in the _bone marrow; B lymphocytes_ + _thymus: T lymphocytes_* * Interleukins/cytokines. * Humoral + Cell-mediated parts.
34
what are the _types of transmission_ & the 5 factors *affecting transmission* of communicable disease in plants
_DIRECT transmission - eg. touching_ **INDIRECT TRANSMISSION - wind, water, soil, animals, humans** 1. *poor _____ nutrition* 2. *susceptibility to disease* 3. *over-crowding* 4. *abiotic conditions* 5. *climate change*
35
what is **ACTIVE** immunity
An organism's **own memory cells are produced** and **antibodies** are obtained from organism's **own B cells**. i.e. the immune system has been stimulated by an antigen
36
what is the _inflammatory reponse_
A **localised response to pathogens/irittants/damage** resulting in inflammation at the site of the wound *i.e. heat, pain, swelling/oedema, redness.* ## Footnote *The heat prevents pathogens reproducing.*
37
what is the difference between a *primary* and _secondary_ immune response?
*PR: The response of the immune system the **first time** it is **exposed** to an antigen**.*** _SR: The response of the immune system the **second** and **subsequent times** it is **exposed** to an antigen._
38
How do antibodies act as **ANTI-TOXINS**
They *combine with toxins secreted by bacteria* to render them **harmless** eg. Tetanus + Diphtheria toxins
39
what kind of protein is an *immunoglobulin* how many *antigens* can an antibody bind to
* Y-shaped GLOBULAR protein* * two antigen molecules per antibody*
40
explain how *production of callose, tyloses + phtoalexins* help actively defend the plant from pathogens
**CALLOSE-** *Closes plasmodesmata, blocking passage between cytoplasms to inhibit pathogen entry. Deposited in sieve pores to block transport of phloem sap to entire plant.* **TYLOSES-** ingrowths in _xylem vessels_. (blocks xylem lumen) **PHYTOALEXINS**- cell-signalling molecules produced as a response to breakdown products of cellulose by bacteria + fungal cellulases. They stimulate production of _chitinase enzymes_ to digest fungi cell wall. _Disrupt cell membrane_ & _delay reproduction_ of bacteria.
41
in which *natural compounds* are many medicinal drugs found? give 3 examples
**Plants, animals, microorganisms** (only a small proportion have been investigated) ## Footnote * Penicillin obtained from **fungus*** * Some cancer drugs made using **soil bacteria*** * Alzheimer's disease drugs produced from **daffodils***
42
*what is natural _active_ immunity*
**EXPOSURE TO A DISEASE:** immune system makes its own **antibodies + memory cells**
43
what is *immunisation* and **vaccination**
A programme that can involve *both artificial active immunity & artificial passive immunity* ***Artificial active immunity only.***
44
what is *immunological memory*
The ability of the immune system to **respond rapidly** in the future to **antigens encountered** in the **past.**
45
name the human cells in which the malaria parasite reproduces
Hepatocytes + erythrocytes
46
*WHAT ARE ANTIBIOTICS FOR*
Chemicals that **kill or inhibit the growth of bacteria.** Used in drugs to treat **bacterial** infections- do not harm human body cells or viral cells because they **do not have a cell wall**, unlike bacteria (*peptidoglycan*). The antigen is either **inactive/dead/attenuated**.
47
What causes the measles vaccine to be less effective in children from less economically developed countries?
Their diet it protein deficient
48
what happens in the _first exposure_ to a pathogen
**CLONAL SELECTION** Clones of lymphocytes that are *complementary bind to antigens,* all other lymphocytes are *blind* **CLONAL EXPANSION/PROLIFERATION** Those that are *complementary increase in number- plasma cells.* **CLONAL DIFFERENTIATION** Some clones *differentiate into memory cells.*
49
what is *artificial* **active** immunity
Immune system produces own antibodies and memory cells after exposure to a vaccine.
50
what is *natural* **passive** immunity
Antibodies are provided by natural means, i.e. from the **placenta or breast milk.** from mother to baby
51
*what are interleukins*
A group of **cytokines** (**cell-signalling proteins** + other signal molecules) **secreted by leucocytes** and regulate **proliferation, differentiation & activation** of the cells of the specific immune system.
52
name two potential problems with antibiotics
**Side effects/severe allergic reactions** in some people. **Antibiotic resistance**.
53
name a *protoctista + a fungal pathogen in plants*
PROCTISTA = ***blight*** *(in tomatoes, potatoes etc.)* *FUNGAL =* _**black sigatoka** eg. in bananas_
54
how is _malaria transmitted_ + what are the *symptoms*
by a **_vector_** _i.e. *Plasmodium,* in a **mosquito**_ *tiredness, fever, decreased O2, death*
55
Outline *ANTIBIOTIC RESISTANCE*
* **genetic resistance in a population** * **natural resistance** * **antibiotic kills all** * **resistant survive** * **lack of competition = thrive** * **allele passed for resistance passed on (artificial selection)** * **resistant spreads, (frequency)** * **'superbugs' antibiotic redundant**
56
why are booster vaccines given
to make sure memory cells are produced (after several years)
57
what is *clonal selection*
A model for how **B and T cells** are **selected** to target **specific antigens** invading the host.
58
Define PHARMING + *Nanotechnology* in synthesis of medicines
Using **animals** to **mass-****grow drugs**/make many copies. ***Particles** used to **deliver drugs** to **pathogens or tumours.***
59
give 5 examples of primary physical+chemical defences
1. *Nasal cavity-* hairs & mucus trap microorganisms, the mucus is wafted away or digested. Other *MUCOUS MEMBRANES-* urethra, lungs, vagina, alimentary canal 2. *Tear glands-* clean eyes with tear solution containing **lysozyme** 3. *Skin-* Impervious unless broken, friendly bacteria outcompete, sebum + fatty acid secretions kill many bacteria 4. *Stomach-* Acidic juices kill many bacteria 5. *Large intestine-* bacteria outcompete pathogenic bacteria
60
name 2 ways in which the body forcibly removes pathogens
***EXPULSIVE REFLEXES*** *Coughing + sneezing.* Caused by pathogens in the linings of the airways eg. in the mucus in the upper respiratory tract.
61
what is *cell-mediated immunity*
An immune response involving the **activation of macrophages, specific T cells + cytokines against antigens.**
62
*Describe the structure of an antibody*
***4 polypeptide chains:* two heavy** two light The heavy chains are held at a HINGE REGION by INTERCHAIN DISULFIDE BONDS The phagocyte binds to the *constant region*, whilst the *variable region* binds to the **specific complementary antigens** on a pathogen via the *antigen-binding site.*
63
what is an ANTIGEN
An *identifying chemical* on the **surface of a cell or macromolecule** that **induces** an immune response. eg. *allergens, pathogens & foreign bodies i.e. non-self antigens.*
64
name two *fungal pathogen + a protoctista pathogen in animals*
**ATHLETE's FOOT and RINGWORM** **MALARIA from PLASMODIUM**
65
explain how antibodies act as **AGGLUTININS**
Antibodies **bind to two identical antigens or two or more pathogens,** causing them to **CLUMP** together -tf difficult for them to spread/easy for phagocytes to engulf them
66
what is the difference between ***Innate*** and *Acquired* immunity
***INNATE immunity: non-specific rapid response to a range of pathogens*** **primary defences- prevent entry of pathogen into body** **secondary defences- internal, killing pathogen when it has entered system** *ACQUIRED immunity: **specific** immune response, targeted at one particular pathogen*
67
*briefly describe* the _SPECIFIC/ADAPTIVE immune response_
**humoral** B cells activated by T cells B cells secrete antibodies into the blood plasma, they bind to antigens. **cell-mediated** Helper T cells bind to an APC eg. macrophage, and are activated Helper T cells divide/proliferate Helper T cells activate B cells, cytotoxic T cells & produce T memory cells Cytotoxic T cells destroy infected body cells
68
name 6 *active defence mechanisms* in plants
1. **HYPERSENSITIVITY** (immediate death of tissues) 2. **production of CALLOSE** (closes plasmodesmata) 3. **production of TYLOSES** (xylem vessel blockages) 4. **production of PHYTOALEXINS** cell-signalling molecules 5. **Systemic Acquired Resistance** cell-signalling molecules 6. **General toxins**
69
how does the skin/wound heal _after_ a scab has formed
**Epithelial cells** below the scab start to grow, sealing the wound **permanently.** *damaged capillaries regrow* ***Collagen fibres** are deposited to give new tissue strength.* *Scab falls off once epidermis normal and wound is healed.*
70
*Describe the stages of the clotting mechanism*
**Platelets** gather near the wound and release **clotting factors**, stimulating the conversion of **prothrombin to thrombin**, which splits **fibrinogen to form fibrin.** **FIBRIN FIBRES** form a **mesh** over the wound, **trapping RBCs + platelets-** stopping the bleeding. Clot hardens-scab- new cells grow for repair- **enzyme plasmin** released to dissolve clot.
71
name the 5 _PASSIVE chemical defence mechanisms_ in plants
* *secretion of **toxins*** * *secretion of enzyme **inhibitors*** * *sticky **resin** in bark* * *secretion of **growth** substance, promoting growth of microorganisms that **compete** with the pathogen* * ***receptors** on cell surface detecting pathogen, **activate** plant defences*
72
explain how antibodies act as **OPSONINS**
The antibodies _cover_ the pathogen(s) to _facilitate phagocytosis_ bc the phagocytes can _bind_ to their _constant_ regions (receptors). By attaching to bacteria, they _mark_ the pathogen for phagocytes. *If binding to viruses, they prevent the virus binding to a host.*
73
what is _tobacco mosaic virus_
*A viral pathogen in plants.*
74
what is the function of a *vaccine*
They contain **antigens** (free or attached to a dead or weakened pathogen) so that the body **produces memory cells against a particular pathogen- without** the pathogen causing disease/symptons of it. Vaccination *causes* immunisation, i.e. the process by which you develop immunity.
75
**PASSIVE immunity?**
**Antibodies** are **not** produced by organism's own B cells, but obtained otherwise. **Memory cells not** produced.
76
how is _tuberculosis transmitted_ and what are the *symptoms*
*_INDIRECT transmission by_ droplet infection* -causes a respiratory disorder
77
Describe the process by which a *pathogen* is destroyed once recognised
**PHAGOCYTOSIS of pathogen/foreign cell** 1. ***Endocytosis** of pathogen, enabled by cytoskeleton, forming **pseudopodia**.* 2. *This forms a **phagosome**, which is a **vacuole** containing bacteria.* 3. *Phagosome fuses with a **lysosome**, which contains **hydrolytic enzymes**, forming a **phagolysosome**.* 4. *These begin to hydrolyse the pathogen into monomers eg. amino acids, fatty acids.* 5. *The antigens of the pathogen are **presented on the surface** of the phagocyte- becomes an APC.* 6. *Waste products released by **exocytosis**.*
78
After CLONAL SELECTION, what happens to the clones and what are their roles
*expansion/proliferation* **they differentiate into PLASMA CELLS;** carry out cell function, secreting antibodies **and MEMORY CELLS;** they have a long life-span, replicate occassionally and induce a rapid second immune response and the proliferation of _many_ plasma cells
79
how is _synthetic biology_ used in antibiotic production
* Technology is used to _design/produce_ _artificial proteins, cells + microorganisms_ * eg. *engineering bacteria to destroy cancer cells while leaving healthy body cells intact*
80
*what are the 3 types of T cell + their functions*
**T helper cell :** *receptors* on surface membrane *bind to APC.* T cells produce *interleukins* that stimulate *proliferation* of B cells & all T cells. ## Footnote **T killer/cytotoxic cell** **T regulator**
81
what is the function of MACROPHAGES + MAST CELLS when the body is wounded eg. skin broken
**MACROPHAGES RELEASE CYTOKINES - cell-signalling molecules-** alerting other phagocytes to the pathogen(s) in the site of infection. **MAST CELLS RELEASE HISTAMINES - type of cytokine-** making nearby capillary walls leaky (for phagocytes).
82
_what is artificial PASSIVE immunity_
*Antibodies injected into _bloodstream_*
83
how is *blight* transmitted and what are the symptoms
_INDIRECT transmission eg. *spores* in the wind_ rotting flesh, foul smelling
84
what are the factors that *increase* the chance of infection of *tuberculosis*
* **not vaccinated** against TB * **weakened** immune system * **overcrowding** * **poor ventilation** of housing * homelessness * **lifestyle**- poor diet/ lack of protein/ malnourished/smoking/alcoholism * close/prolonged **contact** with **infected** individuals * close contact with people from/visiting, **area** where TB is common * consumption of **milk/beef** from infected cattle/in developing countries

IMPORTANTÉ (15 decks)

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