Edexcel International A Level Biology - Immunity

<p>Transmissibility (D)</p> Signup and view all the answers

<p>Pathogens can lead to diseases but are not synonymous with them. (A)</p> Signup and view all the answers

<p>To induce artificial active immunity through the introduction of antigens (C)</p> Signup and view all the answers

<p>It stimulates the production of memory cells that recognize antigens (A)</p> Signup and view all the answers

<p>Antigenic variation due to mutation of pathogens (B)</p> Signup and view all the answers

<p>Either killed or weakened pathogens, or antigens alone (C)</p> Signup and view all the answers

<p>Memory cells are able to initiate a faster immune response upon re-exposure (B)</p> Signup and view all the answers

<p>It plays an important role in preventing pathogen entry after skin damage. (B)</p> Signup and view all the answers

<p>They compete with pathogens for resources, limiting their numbers. (B)</p> Signup and view all the answers

<p>To create an acidic environment that is unfavourable to many pathogens. (C)</p> Signup and view all the answers

<p>It damages bacterial cell walls, causing them to burst. (A)</p> Signup and view all the answers

<p>Some may enter before a blood clot forms due to exposed tissue. (D)</p> Signup and view all the answers

<p>HIV (B)</p> Signup and view all the answers

<p>Helper T cells (A)</p> Signup and view all the answers

<p>By attaching to a receptor molecule (B)</p> Signup and view all the answers

<p>It is used as a template to produce DNA (D)</p> Signup and view all the answers

<p>Asymptomatic or chronic stage (B)</p> Signup and view all the answers

<p>Decreased ability to fight infections (D)</p> Signup and view all the answers

<p>By mixing blood during delivery (A)</p> Signup and view all the answers

<p>When the immune system is severely compromised (A)</p> Signup and view all the answers

<p>Opportunistic infections (A)</p> Signup and view all the answers

<p>Type of diet (C)</p> Signup and view all the answers

<p>HIV is a virus and AIDS is the disease caused by HIV. (A)</p> Signup and view all the answers

<p>Through body openings and breaks in the skin (A)</p> Signup and view all the answers

<p>They carry and transmit pathogens between hosts. (D)</p> Signup and view all the answers

<p>Eating undercooked food or contaminated drinks (A)</p> Signup and view all the answers

<p>Tuberculosis (C)</p> Signup and view all the answers

<p>Transfusion of untainted blood (D)</p> Signup and view all the answers

<p>Cell surface membranes and bacterial cell walls (A)</p> Signup and view all the answers

<p>Being produced by the organism's own body cells (C)</p> Signup and view all the answers

<p>They transfer antigens to lymphocytes (B)</p> Signup and view all the answers

<p>Y-shaped molecules consisting of heavy and light chains (C)</p> Signup and view all the answers

<p>It allows for binding to antigens, giving specificity (C)</p> Signup and view all the answers

<p>Hinge region (A)</p> Signup and view all the answers

<p>Plasma cells (B)</p> Signup and view all the answers

<p>All antibody classes (D)</p> Signup and view all the answers

<p>The binding of lymphocytes to non-self antigens (B)</p> Signup and view all the answers

<p>It activates the immune response when recognized as non-self (B)</p> Signup and view all the answers

An illness or disorder that affects the body or mind, leading to poor health.

Specific characteristics or changes in the body that indicate a particular disease.

Illnesses caused by pathogens that can be spread from one person to another.

Microorganisms that cause disease, such as bacteria, fungi, or viruses.

Not all viruses cause disease in humans.

A type of white blood cell that plays a key role in the immune system by activating B cells to produce antibodies.

A single-stranded RNA virus that infects helper T cells, weakening the immune system.

The enzyme used by HIV to convert its RNA into DNA, allowing it to integrate into the host's genome.

The stage of HIV infection where the virus begins actively replicating within the body, often causing flu-like symptoms.

The stage of HIV infection where the virus replicates at a slower rate and individuals may experience no symptoms.

The final stage of HIV infection, characterized by a severely weakened immune system and susceptibility to opportunistic infections.

The process by which HIV enters helper T cells, replicates its genetic material, and produces new viruses that infect other cells.

The transmission of HIV from a mother to her child during pregnancy, labor, or breastfeeding.

A term often used to describe the late stage of HIV infection, where the immune system is severely compromised and vulnerable to opportunistic infections.

A virus that weakens the immune system, making the body susceptible to infections.

Infections that exploit a weakened immune system, often occurring in individuals with compromised immune systems like those with AIDS.

Living organisms that transmit pathogens from one host to another.

The entry point of a pathogen into the body.

A way for pathogens to enter the body through the mouth, eyes, or urinary tract.

A way for pathogens to enter the body through cuts or wounds in the skin.

A mode of pathogen transmission through inhaling droplets released by coughing, sneezing, or talking from an infected person.

The skin acts as a physical barrier against pathogens, preventing their entrance into the body. If the skin is damaged, it exposes the underlying tissue, making it vulnerable to infection.

The normal microorganisms that live on the skin and in the gut are called flora. They compete with pathogens for resources, limiting their numbers and reducing their ability to cause infection.

The stomach contains hydrochloric acid, creating an acidic environment that is unfavorable to most pathogens. This helps prevent the entry of harmful microorganisms into the body.

Lysozyme is an enzyme found in secretions like tears, saliva, and mucus. It breaks down bacterial cell walls, leading to their destruction. This helps protect against bacterial infections.

Blood clotting is a crucial process for preventing pathogen entry after skin damage. The blood clot acts as a barrier to stop pathogens from entering the bloodstream.

Intentionally introducing weakened or dead pathogens, less harmful strains, antigens alone, or genetic material encoding antigens into the body to stimulate the immune system and induce immunity.

Vaccines cause the immune system to produce memory cells, which provide long-term immunity against the specific pathogen. Upon re-exposure, the immune system rapidly generates a stronger, faster response, preventing disease development.

Changes in the antigens of a pathogen, often due to mutations, can make existing vaccines less effective. This necessitates frequent modifications or updates to vaccines to ensure continued protection.

A secondary immune response is triggered when the body is re-exposed to an antigen it has encountered before, leading to a faster and stronger response due to the presence of memory cells.

The introduction of antibodies from an external source, such as through the transfer of serum, plasma, or immunoglobulin preparations, provides temporary passive immunity without stimulating the recipient's immune system.

Unique markers found on cell surface membranes, bacterial cell walls, or viral surfaces, enabling cell-to-cell recognition.

Antigens produced by an organism's own body cells, not triggering an immune response.

Antigens not produced by the organism's own body cells, triggering an immune response.

Cells that engulf pathogens and present their antigens on their surface to activate the immune response.

A type of white blood cell that engulfs and destroys pathogens through phagocytosis, and acts as an antigen presenting cell.

Proteins secreted by plasma cells, specifically designed to bind to antigens and neutralize them.

The specific region of an antibody where it binds to an antigen, providing specificity for that antigen.

The part of an antibody molecule that remains constant within a particular class, determining its overall function.

The portion of an antibody molecule that varies between antibodies, specifically targeting different antigens.

Specialized white blood cells that produce and secrete antibodies, playing a vital role in the humoral immune response.

The flexible region of an antibody molecule that allows the antigen binding site to be positioned at different angles.