Year 9 Science Semester 2 Exam Revision Guide

Ultraviolet Waves

Used in sterilization and fluorescent lights.

Antibodies

Proteins that identify and neutralize pathogens.

Passive Immunity

Immunity acquired through antibodies from another source.

Second Line of Defence

General immune response to all pathogens.

Third Line of Defence

Specific immune response involving B and T cells.

Trophic Level

Position of an organism in a food chain.

Trophic Levels

Levels in a food chain representing energy transfer.

Energy Transfer

Movement of energy through trophic levels.

Visible Light

The light spectrum visible to the human eye.

X-rays

Used for medical imaging of bones.

Gamma Rays

Used in cancer treatment and nuclear reactions.

Infectious Disease

Disease caused by pathogens entering the body.

Non-Infectious Disease

Disease caused by lifestyle or genetic factors.

Immune System

Body's defense against pathogens and infections.

Active Immunity

Immunity developed after exposure to a pathogen.

First Line of Defence

Physical and chemical barriers preventing infection.

Decomposers

Organisms that break down dead matter, recycling nutrients.

Ecosystem

Community of living organisms and their environment.

Biotic Factors

Living components of an ecosystem, like plants and animals.

Abiotic Factors

Non-living components, such as water and soil.

Invasive Species

Non-native species that disrupt local ecosystems.

Carbon Cycle

Process of carbon exchange among Earth's systems.

Food Web

Complex network of feeding relationships in an ecosystem.

Big Bang Theory

Universe originated from a singular explosive event.

Steady State Theory

Universe has no beginning or end; matter is continuously created.

Cosmological Theory

Widely accepted explanation of the universe's origin.

Speed of Light

Approximately 3 × 10^8 metres per second.

Distance from Sun to Earth

About 1.5 × 10^8 kilometres.

Doppler Effect

Change in frequency due to relative motion.

Redshift

Light wavelength stretches, indicating universe expansion.

Radio Waves

Used in communication technologies like radios.

Microwaves

Used for cooking and satellite transmissions.

Infrared Waves

Used in thermal imaging and remote controls.

Resilience

Ecosystem's ability to recover from disturbances.

Deforestation

Clearing forests, impacting carbon storage and cycle.

Urbanization

Expansion of cities affecting land use and ecosystems.

Chemical Change

Transformation of substances into different chemical entities.

Physical Change

Change affecting form but not chemical identity.

Exothermic Reaction

Releases energy, usually in the form of heat.

Endothermic Reaction

Absorbs energy from surroundings during the process.

pH Scale

Measure of acidity or basicity of a solution.

Photosynthesis

Process converting light energy into chemical energy.

Chlorophyll

Green pigment essential for photosynthesis in plants.

Chloroplast

Organelle where photosynthesis occurs in plant cells.

Respiration

Process of converting glucose into energy in cells.

Aerobic Respiration

Respiration using oxygen to produce energy.

Anaerobic Respiration

Respiration occurring without oxygen, producing less energy.

Neutralisation

Reaction between acid and base producing salt and water.

Ocean Acidification

Decrease in ocean pH due to increased CO2 absorption.

Ion Concentration

Amount of ions present in a solution.

Symbiotic Relationship

Interaction between two different organisms living together.

Energy Storage

Process of storing energy produced during respiration.

Chemical Equation

Symbolic representation of a chemical reaction.

Balanced Equation

Chemical equation with equal numbers of each atom.

Variables in Experiment

Factors that can change in a scientific experiment.

Controlled Variables

Factors kept constant to ensure valid results.

Independent Variable

Factor manipulated to observe its effect.

Dependent Variable

Factor measured in response to changes made.