VCE Biology Questions Thread

hey, what is the difference between coding strand

Hi NG900! Let me see if I can be of any help!
So, firstly, monoclonal antibodies are identical lab-made antibodies produced by plasma cell clones, which can be used as an immunotherapy treatment (antibody therapy). They can be both used to activate the immune response (induce/amplify to treat cancer) or suppress the immune response (prevent or reduce to treat autoimmune diseases). I'm assuming your question is referring to how they work, not the production process, but correct me if I'm wrong.
Here are some examples of how they can be used in the body (but not limited to):

Antibody-dependent cell-mediated cytotoxicity - Activation immunotherapy:

• Bind to cancer cells and interact with immune system cells, particularly NK cells (natural killer cells), causing them to recognise the cancer cell coated in antibodies as foreign.
• Helps them kill the cancer cells.

Complement activation - Activation immunotherapy:

• Bind to cancer cells and interact with complement proteins (remember, these are proteins found in the body that opsonise, cause lysis, and attract phagocytes to invading pathogens).
• This interaction aids in helping the complement proteins recognise the cancer cells as foreign, creating membrane attack complexes to kill the cells or enhancing the functions of other immune cells.

Checkpoint inhibition - Activation immunotherapy:

• Immune checkpoints -> Regulate immune system, and when activated, suppress the immune system. This is important for normal bodily functioning, but cancer cells can secrete molecules that stimulate these checkpoints, reducing the ability for the immune system to recognise and destroy them.
• Monoclonal antibodies -> Block immune checkpoints, meaning immune system can function at a grater capacity and destroy the cancer cells more easily.

Cytokine inhibition - Suppression immunotherapy:

• Cytokines = Messenger molecules used by immune system to coordinate an immune response.
• Monoclonal antibodies -> Bind to and inhibit cytokines to suppress the immune response.

B cell and T cell depletion and inhibition - Suppression immunotherapy:

• They bind to autoreactive (cell that recognises self-tissue/self-antigens as non-self) B and T cells -> This can act as a means of inhibiting these cells, or stimulate other immune cells to destroy these autoreactive B and T cells.

Now, how effective are monoclonal antibodies in comparison to tradition treatments.

Cancer treatment (activation immunotherapy):

• Benefit -> More specific and targeted in attack, unlike traditional treatments (chemo and radiotherapy) that target all rapidly dividing cells (means other cells of the body are impacted, such as hair and cells lining gut - results in hair loss, nausea, etc.) This is due to their variable regions that bind with cancer antigens specifically, meaning their is a lower chance of other cells in the body being effected by the treatments and lower side effects.
• Benefit -> Can be used to stimulate the immune system to recognise and destroy cancer cells, unlike traditional treatments that directly kill cancer cells.
• Con -> Still has a wide range of side effects, such as fatigue, fever, nausea, shortness of breath. However, it is still generally less than traditional treatments and does depend on the type immunotherapy being used.
• Con -> Only available as a treatment for very specific types of cancers, and is still used in conjunction with other traditional treatments.

Autoimmune disease treatments (suppression immunotherapy):

• Benefit -> Prevents overall immunodeficiency, which is occurs with traditional treatments that try to reduce the symptoms of the patient by suppressing their whole immune system (immunosuppression). This causes the individual to be more prone to developing cancer and infections. Monoclonal antibodies prevent this because only specific autoreactive cells are being targeted, meaning the rest of immune system can function normally.
• Cons -> Same as cancer treatment cons. It is still used in conjunction with traditional treatments due to not being widely available, and can have some side effects.

I hope that helps. Let me know if you were actually asking about the production process of monoclonal antibodies, not their uses (wasn't 100% what you were asking, that's all).

Now, with your second question, the specific type of cell is indeed helper T lymphocytes. This because these are the cells that are presented with the foreign antibodies by antigen presenting cells (aka dendritic cells, macrophages, and B cells). Obviously, these cells will also identify that their is something foreign in the body, but the helper T lymphocyte is required to actually recognise this and stimulate a specific adaptive immune response against the transplanted organ. Not sure if that makes sense, but that's how I interpret the question and their answer.

chimichurri
From a chemistry point of view (what I've learnt in VCE chem), enzymes lower the amount of activation energy required for the reaction to take place by weakening the bonds that hold together substrate, which means its much easier for the substrate to break down into its respective products, or for bonds to form between the substrates to form the product. This is because less energy is needed to break weaker bonds, and therefore the reaction rate will increase.

Re: Enzymes, _sophiestudies_ Answer is really good!

I’d suggest that we don’t really need to know anything more complex than this for VCE - but I think I know what you are talking about with the whole ‘bringing reactants together’.

I believe there is a khan academy video where he talked about the reaction between an Alkene and water. (An Alkene being a carbon chain with a Carbon=Carbon double bond in the middle)

The enzyme/catalyst moves or bends the hydrogens away from the double bond - allowing for the water molecule to attack it (performing a nucleophilic attack). This - without the catalyst - is harder; because the hydrogens would get in the way of the water molecule. This is called a hydration/addition reaction in Chem.

While you don’t need to know that for bio - I found it quite interesting last year.

Another example is that of ATP synthase. It acts like a windmill - using the flow of H+ ions to provide energy to attach a phosphate group to ADP - forming ATP.

So overall, perhaps:
An enzyme lowers activation energy by stimulating conditions favourable to the reaction - and weakening intramolecular forces.