Science 8 Final Exam Review

Vocabulary flashcards covering Year 8 Science topics including cells, human organ systems, light and optics, and water systems.

Characteristics of Living Things

The six essential traits include Energy, Growth, Adaptations, Response to environment, Reproduce, and Produce waste.

Basic Unit of Life

Cells; they are the smallest living organisms capable of performing all essential functions required for life.

Right Atrium

The chamber of the heart that receives deoxygenated blood returning from the body and pumps it into the right ventricle.

Right Ventricle

The chamber that pumps deoxygenated blood out to the lungs through the pulmonary artery for gas exchange.

Left Atrium

The chamber that receives freshly oxygenated blood returning from the lungs and pumps it into the left ventricle.

Left Ventricle

A chamber with a thick, muscular wall that pumps oxygenated blood out to the rest of the body via the aorta.

Epiglottis

The structure that acts as a trapdoor to the trachea to keep food from entering the windpipe.

Adaptations

A body part (structure) or behavior that helps an organism survive in its specific environment.

Gas Exchange

A process occurring via diffusion across one-cell-thick walls where $O_2$ moves from alveoli into capillaries and $CO_2$ moves from capillaries into alveoli.

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that carry blood into the heart.

Aorta

The main artery through which oxygen-rich blood exits the heart to reach the body.

Chloroplasts

Organelles referred to as the "solar panels" of the cell that carry out photosynthesis to convert light into food.

Cell wall

A rigid outer structural boundary made of cellulose that provides protection, strength, and shape to plant cells.

Central vacuole

A clear liquid gel found in plant cells used for the storage of water and nutrients.

Circulatory System

The system responsible for carrying oxygen and nutrients to all cells in the body.

Digestive System

The system that allows the body to digest and absorb nutrients from a variety of foods.

Respiratory System

The system responsible for bringing in fresh oxygen while simultaneously removing unwanted carbon dioxide.

Excretory System

The system that detoxifies blood and removes harmful waste before it reaches poisonous levels.

Nervous System

The system that gathers and interprets sensory information and responds by sending electrical messages throughout the body.

Nucleus

The control center or "brain" of the cell that houses genetic material ($DNA$) and directs cellular processes.

Cell membrane

A semi-permeable barrier that allows some materials in while keeping harmful materials out.

Mitochondria

The "powerhouse" of the cell where cellular respiration occurs to turn sugar energy into chemical energy.

Cytoplasm

A jelly-like material found throughout the cell that holds organelles in place.

Vacuole (Animal Cell)

Small membrane-bound sacs used to store nutrients, water, and waste materials until they are expelled or processed.

Ribosomes

The protein-producing structures within a cell.

Selectively Permeable

A membrane property of being choosy; it allows substances like water and oxygen to pass easily while blocking large or harmful molecules.

Diffusion

The movement of particles from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water molecules across a membrane.

Trachea

The vessel or tube that allows outside air to reach the lungs.

Bronchi

The two main structures that branch off the trachea and enter the lungs.

Bronchioles

The smaller branches stemming from the bronchi that carry gases directly to the alveoli.

Alveoli

The air sacs where the diffusion of $O_2$ and $CO_2$ takes place in the lungs.

Diaphragm

The muscle responsible for inhalation and exhalation; it contracts to pull air in and expands to force air out.

Levels of Organization

Similar cells form tissue; tissues combine to form an organ; organs coordinate to form an organ system; organ systems keep the organism alive.

Transparent

A material property allowing almost all light to pass through unobstructed so objects on the other side are clearly seen.

Translucent

A material property that scatters or partially diffuses light, making objects on the other side appear blurry.

Opaque

A material property that completely blocks, absorbs, or reflects light, allowing no light to pass through.

Law of Reflection

The scientific principle stating that the angle of incidence is equal to the angle of reflection.

Concave Mirror

A mirror that curves inward like a cave and converges (brings together) incoming parallel light rays to a single focal point.

Convex Mirror

A mirror that curves outward like a dome and diverges (spreads apart) incoming parallel light rays.

Convex Lens

A lens thicker in the middle than at the edges that converges parallel light rays toward a single real focal point.

Concave Lens

A lens thinner in the middle than at the edges that diverges parallel light rays, making them spread apart.

Refraction

The bending of light when it passes obliquely from one transparent medium into another medium with a different optical density.

Rods

Highly sensitive photoreceptor cells in the retina that detect black, white, and gray, functioning well in low light.

Cones

Photoreceptor cells in the retina that allow for fine detail detection and color vision in bright light environments.

Luminous

Objects that create and emit their own light energy, such as the Sun or a flashlight.

Non-luminous

Objects that do not generate light but are visible because they reflect light from a source into our eyes.

Pixel

The smallest individual unit or picture element that makes up a digital image.

Ray Diagram

A simplified drawing using straight arrows to model the path that light travels.

Optical Device

Any technological device that uses light, such as binoculars, glasses, or microscopes.

Primary Colours of Light

Red, Green, and Blue.

Secondary Colours of Light

Magenta, Yellow, and Cyan.

Bioluminescence

Light produced by a chemical reaction occurring inside a living organism.

Incandescence

Light produced by heating a high-resistance tungsten filament.

Fluorescence

Light produced as a substance absorbs and reacts with $UV$ rays.

Phosphorescence

Light that is absorbed and stored, then released over a long period of time.

Earth's Water Coverage

Approximately $74\%$ of the surface is covered in water, consisting of $97\%$ saltwater and $3\%$ freshwater.

Potable Water

Water that is safe for human consumption.

Distillation

A purification method where a mixture is boiled to create vapor, leaving waste behind, and the vapor is condensed into pure liquid.

Acid Rain

Precipitation made acidic ($\text{low pH}$) by air pollution that can reduce organism populations.

Currents

Water movements caused by temperature differences, salinity differences, or surface wind conditions.