VCE Biology Question Thread

[Scooby]

Ah good pickup! Completely misunderstood that.
Would Humoral fall under Natural Active Acquired Immunity?

"Active" and "passive" are terms used to describe different kinds of acquired immunity. They aren't relevant when describing an adaptive immune response itself

[Scooby]

Ive answered this before so I had a skim through...

Well Humoral and Cell-Mediated responses fall under the 3rd line of defence also known as the specific/adaptive immunity

Humoral:
-B-lymphocytes are the major cells involved.
- Produced in the Bone Marrow (thus the name B-lymphocytes) They aren't named after bone marrow
-Each B-Cell has its individual antibody/antigen complex What do you mean by this?
-Production of antibodies
B-Cells differentiate (clonal expansion) Clonal expansion and differentiation aren't the same process into
- B-Plasma cells (effector cells): secrete antibodies
- B-memory cells: remain in the body so when the antigen is encountered again, a response can rapidly be reenacted.

Cell-Mediated:
-Cell mediated response occurs when a pathogen is already in the cell. This level of immunity is carried out by T cells.
-T-Cells made in the Bone Marrow however matured in the Thymus (hence its name  T-Cells)
T-Cells include; Helper T cells (Th), Cytotoxic T cells (Tc) and Suppressor T cells.
-Helper T cells active cytotoxic cells and present antigens to immature B cells. Helper T cells activate B cells by releasing cytokines - they don't present antigens to B cells. It's actually the other way around (but you won't need to know that)
-Cytotoxic cells detect/recognise cells with infection, are able to destroy these foreign cells with contact What do you mean by contact?
-Lastly Suppressor T cells, literally suppress the immune responses once the antigen has been removed

Antibodies; are proteins that bind and neutralise antigens. Are quite highly specific (like an enzyme-substrate complex).

[Reus]

- Produced in the Bone Marrow (thus the name B-lymphocytes) They aren't named after bone marrow

I know. They got their name from the discovery in the Bursa of Fabricius (some bird). Easier to recognise B-cells are made in the Bone marrow that way.

Each B-Cell has its individual antibody/antigen complex What do you mean by this?

I meant that each antibody is specific.

B-Cells differentiate (clonal expansion) Clonal expansion and differentiation aren't the same process into

Does clonal expansion and selection not come under differentiation?

This level of immunity is carried out by T cells.

I don't see whats wrong with saying this level of immunity is carried out by T cells? (as quoted from TSSM Topic 9 booklet.)

Helper T cells activate B cells by releasing cytokines - they don't present antigens to B cells. It's actually the other way around (but you won't need to know that)

Helper T cells active cytotoxic cells and present antigens to immature B cells. Once again TSSM booklet.

What do you mean by contact?

To depict its significance, as a killer cell. I've also learnt that it 'punches holes'? And again TSSM.

Are quite highly specific (like an enzyme-substrate complex).

Oops I see how 'quite' isn't the right terminology

[Scooby]

Does clonal expansion and selection not come under differentiation?

Clonal selection - only a B cell specific to the antigen that triggered the adaptive immune response is activated
Clonal expansion - that B cell proliferates rapidly to produce a number of clones
Differentiation - process by which a cell becomes more specialised (eg. differentiation of some B cell clones into plasma cells)

I don't see whats wrong with saying this level of immunity is carried out by T cells? (as quoted from TSSM Topic 9 booklet.)

Nah, nothing's wrong with it. It just doesn't really make sense. Humoral and cell-mediated responses aren't different "levels." I'm just being pedantic here

Helper T cells active cytotoxic cells and present antigens to immature B cells. Once again TSSM booklet.

Yeah, TSSM is wrong (in saying that helper T cells present antigens to B cells)

To depict its significance, as a killer cell. I've also learnt that it 'punches holes'? And again TSSM.

Yeah, perforin released by cytotoxic T cells causes those infected cells to lyse

[Reus]

Thanks for the clarification. 

[eagles]

Hello!

I've read that mast cells secrete histamine upon an allergic reaction and that histamine is a chemical neurotransmitter.

However, aren't neurotransmitters only released between neurons, or at neuron-muscle junctions, or between a neuron and a gland?

Since mast cells are not neurons, would it then be more correct to state that histamine acts as a neurontransmitter?

Thanks

[Scooby]

Hello!

I've read that mast cells secrete histamine upon an allergic reaction and that histamine is a chemical neurotransmitter.

However, aren't neurotransmitters only released between neurons, or at neuron-muscle junctions, or between a neuron and a gland?

Since mast cells are not neurons, would it then be more correct to state that histamine acts as a neurontransmitter?

Thanks

You're right. Histamine can function as a neurotransmitter, but in the case of it being secreted by a mast cell, it isn't

[eagles]

Thanks for clarifying.

Since allergies come under the third line of defence, would we classify the hypersensitivity response as humoral or cell-mediated?

[vox nihili]

Thanks for clarifying.

Since allergies come under the third line of defence, would we classify the hypersensitivity response as humoral or cell-mediated?

Depends on the individual response. There are cell mediated and there are humoral hypersensitivities.

[Jason12]

what are booster vaccines and how do they 'wake up' memory cells? What do the cells do when they 'wake up?'

[eagles]

A booster vaccine is an extra administration of a vaccine after an earlier dose. After initial immunisation, a booster injection is a re-exposure to the pathogen. Its purpose is to increase the individual's immunity against that antigen after a specified period.

After initial exposure, next exposure to pathogen will stimulate T helper cells to stimulate B-cells. B-cells will undergo faster clonal selection and expansion due to previous exposure to pathogen. Booster vaccine creates a stronger and faster response in the production of B plasma cells (and its specific antibodies) and B memory cells.

Essentially, memory of the pathogen is retained and 'boosted' when we have recurring bouts of vaccines.

[Jason12]

Blood groups? Or blood types? If so, no.

blood groups with what type of antigens they have attached

[soNasty]

this should help a bit!

[Reus]

(Image removed from quote.)
this should help a bit!

blood groups with what type of antigens they have attached

I (my school) never learnt this :/ Is this even on the study design?

[vox nihili]

I (my school) never learnt this :/ Is this even on the study design?

Not to my knowledge.