Ch12: Immunity

Question 1

What are the 3 stages of the immune systems?

Answer 1

1) Recognition of non-self cells

2) Activation Phase

3) Effector phase

Question 2

Describe what occurs in the recognition of non-self cells stage

Answer 2

Pattern recognising receptors (PRRs) recognise microbe associated molecular patterns (MAMPs) of microbes

Question 3

Where are MAMPs located? And what does their necessity suggest?

Answer 3

These are located on the surface of cells

They are usually vital to the microbes survival SO they are NOT subject to much change (receptors do NOT have to change = more efficient)

Question 4

What does pneumonic: Pussy rider revolver (PRR) refer to?

Answer 4

Pattern Recognising Receptors

Question 5

What does pneumonic: major amazing molecular pussy

Answer 5

Microbe associated molecular patterns

Question 6

What are some examples of common MAMPs? (Hint: for bacterium and virus vectors)

Answer 6

Bacterium: have flagellin (protein)
Virus vectors = have coat proteins + ssRNAs

Question 7

Describe what occurs in the activation phase:

Answer 7

cells mobilise to fight pathogen:
-When the MAMPs bind to PRRs there is;

• secretion of DEFENSINS –> disrupt cell membrane of pathogen = causing cell lysis and death
• CYTOKINES: bind to surface of pathogen to signal infection + cause further immune response (cascade) = recognised by primary immune system cells

Question 8

Describe what occurs in the effector phase:

Answer 8

• includes defensins: disrupt cell membrane = cause cell lysis + death
• Macrophages: engulf (phagocytose) pathogens into a vacuole (PHAGOSOME) to mix digestive enzymes + break it down
  • Some of these macrophages act as APC (antigen presenting cells), presenting the antigen on their surface to PRIME other immune cells

Question 9

What part of the immune system are the; recognising, activation and effector phases a part of

Answer 9

INNATE immune system

Question 10

What can the effector phase activate (different kind of immune system)

Answer 10

Can activate ADAPTIVE immune system

Question 11

What implies convergent evolution between fungi, plants and animals?

Answer 11

Cell death

Question 12

Define immune system

Answer 12

natural system of innate + adaptive defences in charge of providing resistance to disease

Question 13

Define the innate immune system, what kind of response does the 2nd line of defence cause?

Answer 13

1st barrier of defence:
- skin + mucous membranes

Second line of internal defence it activated when the first line is compromised
- Phagocytic cells (macrophages + mast cells) and other non-specific cells + chemicals
- Causes an INFLAMMATORY response

Question 14

Define the adaptive immune system

Answer 14

3rd line of defence:
- Uses lymphocytes to destroy infection and circulate antibodies
- System needs to be primed (be exposed) to form a memory + produce a stronger attack

Question 15

Compare innate and acquired immunity

Answer 15

INNATE:
- Non-specific response
- Rapid
- Acute (short-term)

ACQUIRED:
- Specific
- Takes longer
- Long-term

Question 16

What are some physical barriers in plants

Answer 16

Plants have wax of their epidermis to serve as a barrier as well as bark, they can also have a cuticle layer

Question 17

Properties of chitin, keratin and mucous

Answer 17

Chitin: exoskeleton serves as support + strength
Keratin: fur, scales = epidermal layer

Mucous: can have antimicrobial properties + trap pathogens;
- in lungs = cilia which push the mucous to the stomach OR removal via coughing

Question 18

How does the stomach and eyes defend against pathogens

Answer 18

Stomach: acidic environment + digestive enzymes = kill pathogens

Eyes: have eyelids or membranes covering the eye and preventing pathogens from entering - tears also have antimicrobial properties

Question 19

What do cytokines do?

Answer 19

They attract more immune cells and thus increase inflammation

Question 20

Define and describe inflammation. What leads this process, and what do they cause?

Answer 20

The isolation of damaged cells to prevent spread of damage

This is led by MAST cells (vertebrates) that release cytokines, attacinting immune cells (which also release cytokines = cascade)
- increasing blood flow to the area of inflammation as blood vessels become more permeable (clots at site = promotes healing

Question 21

Plant immune response: What are the 3 steps after detection?

Answer 21

When a pathogen breaks the physical barrier, membrane bound pattern recognition receptors detect the flagellin (bacterium) and release immune cells to respond

1) Stomatal closure
2) Produce antimicrobial chemicals
3) Strengthen cell wall

Question 22

Describe the process of coevolution that occurs between bacterium and plant cells

Answer 22

Bacterium inject cells with EFFECTOR molecules t stop the effect of immune cells (STOP response)
- Plants release RESISTANCE proteins that detect effector molecules + cause pathogen related (fight against) genes to be produced or induce cell death

Question 23

What is a respond to a herbivore attack that plants have as a defnce?

Answer 23

They release VOLATILES: which attract parasites to kill the herbivores

Question 24

Define: Cell-mediated Immunity:

Answer 24

adapted cellular response to prevent infection

Question 24

Explain how Major Histocompatibility class (MHC) cells work with macrophages:

Answer 24

MHCs enter the macrophage and bring the antigen to the cells surface (APC)

Question 25

How do T cells (Lymphocytes) play a role in acquired immunity? What kind of cells specialise from T cells? What happens when an infection is cleared?

Answer 25

T cells detect the antigen on the APC and undergo mitosis for SPECIALISATION:

Helper T cells: assist in growth and differentiation of cytotoxic T cells

Cytotoxic T cells: kill damaged cells

Memory T cells: for later infection, cells proliferate easier to form cytotoxic T cells

When an infection is cleared: Suppressor T cells prevent further damage to healthy cells (host tissue)

Question 26

Define humoral immunity

Answer 26

Adaptive respond to pathogens of the humoral fluid (blood + lymph)

Question 27

Describe the process B cells undertake when they detect antigens:

Answer 27

Detect antigens on surface of bacterial cells:

They proliferate + differentiate into PLASMA cells that produce lots of antigens to fight infection and MEMORY B cells that are able to later recognise reinfection, release small amounts of antibodies + immediately proliferate into PLASMA cells (to produce antibodies)

Question 28

What are the 3 defence mechanisms of antibodies?

Answer 28

NOC:
1) Neutralisation: antibodies bind to antigens to prevent them from entering + infecting cells

2) Opsonisation: antibodies tag these antigens (antigen-antibody complex) by binding to them, for ENGULFMENT by PHAGOCYTES (macrophages, neutrophils, etc)

3) Complement: activate complement system, where PROTEINS tag antigens which enhances opsonisation + destroys pathogens