Grade 8 Integrated Science Revision

Vocabulary practice flashcards based on Grade 8 Science notes covering Cell Structure, Nutrition, Transport, and Atomic basics.

Cell

The basic structural and functional unit of a living organism.

Cell wall

Provides support, protection and maintains cell shape.

Cell membrane

Controls substances entering and leaving the cell.

Cytoplasm

Site of most chemical reactions.

Nucleus

Controls cell activities and contains genetic material.

Chloroplast

Contains chlorophyll and is the site of photosynthesis.

Vacuole

Contains cell sap and helps maintain turgidity.

Mitochondria

Site of aerobic respiration and energy release.

Animal Cell characteristics

Contains cell membrane, cytoplasm, nucleus and mitochondria, but lacks a cell wall, chloroplasts and a large permanent vacuole.

Photosynthesis

The process by which green plants manufacture glucose using carbon dioxide and water in the presence of light and chlorophyll.

Photosynthesis Word Equation

$$Carbon\,dioxide + Water \rightarrow Glucose + Oxygen$$

Conditions necessary for photosynthesis

Light, chlorophyll, carbon dioxide, water, and a suitable temperature.

Starch test

Iodine solution turns blue-black when starch is present.

Balanced diet

A diet containing all essential nutrients in the correct proportions.

Carbohydrates

Major nutrients used for energy.

Proteins

Major nutrients used for growth and tissue repair.

Diffusion

Movement of particles from a region of higher concentration to lower concentration until they become evenly distributed.

Osmosis

Movement of water molecules from a region of higher water concentration to lower water concentration through a selectively permeable membrane.

Turgid

The state of plant cells when they gain water.

Flaccid/plasmolysed

The state of plant cells when they are placed in a concentrated solution and lose water.

Respiration

A chemical process in cells that releases energy from food.

Aerobic respiration

Respiration that occurs in the presence of oxygen: $Glucose + Oxygen \rightarrow Carbon\,dioxide + Water + Energy$

Anaerobic respiration (in muscles)

Respiration that occurs when oxygen is absent or insufficient: $Glucose \rightarrow Lactic\,acid + Energy$

Respiration vs. Breathing

Breathing is the physical movement of air, while respiration is a chemical process in cells.

Red blood cells

Carry oxygen using haemoglobin, have a biconcave shape, and lack a nucleus when mature.

White blood cells

Defend the body against pathogens by destroying them or producing antibodies.

Platelets

Help blood clot.

Plasma

Liquid part of blood that transports nutrients, carbon dioxide, urea and other substances.

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that carry blood towards the heart.

Capillaries

Blood vessels that allow exchange of substances between blood and tissues.

The Heart

A muscular organ that pumps blood around the body.

Right ventricle

Chamber that pumps deoxygenated blood to the lungs.

Left atrium

Chamber that receives oxygenated blood from the lungs.

Left ventricle

Chamber that pumps oxygenated blood to the rest of the body.

Valves

Structures that prevent the backward flow of blood.

Double circulation

Process where blood passes through the heart twice during one complete circulation: 1. Heart to lungs to heart 2. Heart to body to heart.

Element

A pure substance made of one type of atom, such as Oxygen, iron, or carbon.

Compound

A substance formed when two or more elements chemically combine in fixed proportions, such as water ($H_2O$) or sodium chlor ($NaCl$).