Year 8 General Science - Unit 1: Humans as Organisms

Vocabulary practice flashcards covering laboratory hazard symbols, food groups and biochemical tests, digestive organs and enzymes, pathogenic microbes and immune defences, the skeletal system and antagonistic muscle mechanics, and human evolution from Year 8 General Science Unit 1.

Pathogen

Any disease-causing microorganism, which can include certain species of bacteria, viruses, or fungi.

Bacteria

Tiny, single-celled microbes that lack a nucleus, can multiply rapidly by cell division, and may possess a flagellum for movement; responsible for diseases like food poisoning and cholera.

Virus

The smallest type of microbe, which cannot survive or reproduce on its own and must invade host cells to multiply, causing diseases such as influenza and measles.

Fungi

The largest type of microbe, existing as single-celled or multicellular organisms composed of thread-like hyphae; includes yeasts, moulds, and mushrooms, and can cause conditions like athlete's foot and ringworm.

Hyphae

Thin, thread-like structures that form the primary growth structure of most fungi.

Flagellum

A microscopic, tail-like projection found on some single-celled organisms, such as bacteria, that assists in movement.

Phagocyte

A type of non-specific white blood cell involved in the second line of defence that engulfs and digests invading foreign pathogens.

Lymphocyte

A specialized white blood cell involved in the third line of defence that produces specific Y-shaped antibodies targeted against particular pathogens.

Antibody

A Y-shaped chemical substance produced by lymphocytes that binds specifically to antigens on a pathogen, clumping them together to immobilize them and mark them for destruction by phagocytes.

Digestion

The bodily process of breaking down large food molecules mechanically and chemically into smaller molecules that can be absorbed into the bloodstream.

Enzyme

A biological chemical substance that speeds up the rate of chemical reactions in the body without being consumed or altered in the process.

Catalase

An enzyme present in the liver that breaks down the toxic metabolic byproduct hydrogen peroxide into harmless water and oxygen according to the equation: $\text{Hydrogen Peroxide} \rightarrow \text{Water} + \text{Oxygen}$.

Peristalsis

The coordinated wave of muscular contractions that transports food down the oesophagus toward the stomach.

Biuret Solution

A chemical test reagent used to identify proteins in food samples, producing a characteristic purple color if protein is present.

Benedict's Solution

A chemical reagent used to detect glucose in food, which changes from blue to green, yellow, or red after heating in a boiling water bath.

Iodine Solution

A chemical reagent used to test for starch in food samples, turning from orange-brown to a blue-black colour in the presence of starch.

Food Intolerance

A non-immediate adverse bodily reaction to certain foods occurring over a prolonged period, causing fatigue or illness, believed to involve antibody production against food proteins.

Food Allergy

An immediate and often severe immune reaction occurring rapidly after consuming a specific food, causing symptoms such as rashes, severe headaches, or difficulty breathing.

Bone Marrow

The tissue found inside certain bones that produces both red blood cells and white blood cells.

Calcium

An essential mineral stored in bones that provides strength, hardness, and structural rigidity to the skeleton.

Tendon

A band of tough, flexible connective tissue that attaches skeletal muscle to bone.

Antagonistic Muscle Pair

A set of two opposing muscles (such as the biceps and triceps) where one contracts to pull a bone while the other relaxes, coordinating movement across a joint.

Synovial Joint

A moveable skeletal junction enclosed by a synovial capsule and lubricated by synovial fluid, with bone ends cushioned by cartilage and held together by ligaments.

Bipedalism

The evolved physical adaptation and form of locomotion in which an organism habitually walks upright on two legs.

Common Ancestor

An ancestral species from which two or more distinct descendant lineages (such as humans and chimpanzees) have diverged and evolved over time.

Flammable Hazard Symbol

A safety symbol indicating substances that readily ignite; requires keeping containers sealed and strictly avoiding use near naked flames or heat sources.

Corrosive Hazard Symbol

A safety symbol warning that a chemical causes skin burns and irreversible eye damage; requires gloves, lab coat, eye protection, and immediate rinsing with copious water upon contact.

Toxic Hazard Symbol

A safety symbol warning of substances that can cause life-threatening effects even in small quantities or upon short exposure; must be handled with extreme care under supervision.

Hazard to Environment Symbol

A safety symbol indicating that a substance is harmful to aquatic or terrestrial organisms and must not be poured down the drain or released directly into the environment.

Explosive Hazard Symbol

A safety symbol indicating materials that may explode upon exposure to heat, sparks, friction, or shock; requires protective distance and clothing.

Risk of Electric Shock Symbol

A safety sign warning of high electrical voltage; requires keeping equipment dry, inspecting for damaged wiring, and disconnecting from the mains power supply prior to servicing.

Health Hazard Symbol

A safety symbol designating chemicals that can cause severe, prolonged systemic health consequences through ingestion, inhalation, or skin contact.