Science AT2: Disease, Immune Response, and Materials

Comprehensive practice flashcards covering neurology, pathogen types, immune system lines of defence, chemical bonding, atomic structure, hydrocarbons, and alternative materials.

What are the main structural parts of a neuron?

The nucleus, cell body, dendrite, axon, myelin sheath, axon terminals, and synapse.

What alternative name is given to a neuron based on how it transmits signals?

An electrochemical messenger.

How does an impulse travel through a neuron and across a synapse?

The message begins at the dendrites as an electrical signal, passes through the cell body towards the axon, causes neurotransmitters to be released across the synapse to the next neuron, where it is transformed back into an electrical signal.

How is a disease defined?

An illness or condition of the body affecting how an organism or parts of an organism or organs function.

What is a pathogen, and what types of organisms or agents are included?

Any organism or agent that causes or can cause disease or illness to its host, including bacteria, viruses, fungi, protozoa, and parasites.

What is the difference between an infectious and a non-infectious disease?

Infectious diseases are caused by pathogens and can be passed directly or indirectly from one living thing to another, whereas non-infectious diseases are not caused by pathogens, cannot be transmitted between organisms, and arise from genetics, lifestyle, nutrition, or the environment.

Which listed infectious diseases are caused specifically by viruses?

Measles, influenza, chickenpox, AIDS/HIV, and hepatitis.

What causes the non-infectious diseases scurvy, Down syndrome, and cystic fibrosis?

Scurvy is caused by nutrition, while Down syndrome and cystic fibrosis are caused by genetics.

What seven methods of infectious disease transmission are represented by the acronym DIVA FLS?

Direct contact, Indirect contact, Vectors, Air/droplets, Food/water, Liquids/bodily fluids, and Sexual contact.

What distinguishes an endemic, an epidemic, and a pandemic?

An endemic persists at a consistent level in a community; an epidemic is a temporary occurrence spreading rapidly in a specific community or region affecting a significantly higher number than expected; a pandemic is an epidemic spread over several countries or continents affecting a very large amount of people.

What is the difference between an antigen and an antibody?

An antigen comes with the pathogen as a foreign marker (a 'bad guy tag'), while an antibody recognizes the antigen and attaches itself onto the pathogen like a marker so the immune system can dispose of it.

What four physical and chemical barriers make up the body's first line of defence?

Skin (physical barrier blocking pathogens), nose hairs and mucus (filter and trap pathogens), stomach acid (kills swallowed microorganisms), and earwax (traps particles and pathogens).

What four symptoms occur during vasodilation in the second line of defence?

Swelling (fluids and immune cells move into surrounding tissue), heat (more blood flow than usual), redness, and pain (inflammation stimulates nerves).

What is pus composed of during wound healing?

Dead pathogens, dead or damaged body cells, and dead immune cells.

What are the roles of B cells and plasma cells in the third line of defence?

B cells recognize specific antigens and divide to produce plasma cells, which manufacture specific antibodies.

What are the functions of helper T cells and suppressor T cells?

Helper T cells recognize antigens and release chemical signals to stimulate/activate B cells, T cells, and phagocytes; suppressor T cells stop or slow the immune response to ensure the immune system does not continue attacking.

How do vaccines stimulate immunity against a pathogen?

A vaccine introduces a harmless form or antigen of a pathogen, causing B cells to recognize it, divide into plasma cells, produce specific antibodies, and form memory cells so the body can quickly fight off future infections.

What is the difference between finite and renewable resources?

Finite resources are used faster than they can be replaced and will eventually run out (e.g., limestone, fossil fuels, metal ores), whereas renewable resources are replaced at the same rate they are used (e.g., wood, cotton).

How are atomic number and mass number defined?

Atomic number is the number of protons in an atom, while mass number is the combined number of protons and neutrons.

What distinguishes a cation from an anion?

A cation has a positive charge because it lost electrons, whereas an anion has a negative charge because it gained electrons.

What are the key properties of ionic bonding?

Occurs between a metal and non-metal, involves electrostatic attraction between positive and negative ions, forms a giant regular lattice, has a high melting point, is brittle, and conducts electricity when dissolved but not when solid.

What are the key properties of covalent bonding?

Occurs between two non-metals via shared pairs of electrons, typically has low melting and boiling points, and usually does not conduct heat or electricity.

What structure gives metallic bonding its strength, malleability, and electrical conductivity?

The attraction between a giant lattice of positive metal ions and a surrounding sea of delocalised electrons.

What seven diatomic molecules are remembered by the mnemonic 'Have No Fear Of Ice Cold Beer'?

Hydrogen ($\text{H}_2$), Nitrogen ($\text{N}_2$), Fluorine ($\text{F}_2$), Oxygen ($\text{O}_2$), Iodine ($\text{I}_2$), Chlorine ($\text{Cl}_2$), and Bromine ($\text{Br}_2$).

How does fractional distillation separate crude oil into fractions?

Crude oil is heated into vapour and enters a fractionating column that is hot at the bottom and cooler at the top; hydrocarbons condense at different heights based on their differing boiling points.

What fraction of crude oil boils at > 350^\text{ }^\bullet\text{C} and what is its primary use?

Bitumen, which is used for road surfacing.

What is the general chemical formula for an alkane?

$$\text{C}_n\text{H}_{2n+2}$$

What are the products and flame characteristics of complete versus incomplete combustion of hydrocarbons?

Complete combustion has enough oxygen, releases more energy, produces $\text{CO}_2$ and water, and burns with a blue flame; incomplete combustion lacks enough oxygen, produces carbon monoxide, soot, or water, and burns with a yellow/orange flame.

What is bioaccumulation in relation to microplastics?

The build-up of microplastics in organisms when they are absorbed faster than the organism can get rid of them.

What are the pros and cons of using bioplastics as an alternative material?

Pros: made from renewable resources and are biodegradable; Cons: uses land and water resources, and not all types break down easily.