| The movement of particles from an area of higher concentration to an area of lower concentration, resulting in the equal distribution of particles. | Diffusion |
| How do substances move in and out of cells through the cell membrane? | Substances move through the cell membrane by diffusion. |
| A semipermeable membrane that surrounds the cell, controlling the passage of substances in and out. | Cell Membrane |
| Where does diffusion commonly occur in the body? | Diffusion commonly occurs in various places in the body. |
| The process by which gases move between the lungs and the bloodstream. | Gas Exchange |
| Give an example of diffusion during gas exchange in the body. | Diffusion happens in the lungs during gas exchange. |
| Tiny sacs in the lungs where gas exchange occurs. | Alveoli |
| What surrounds the alveoli in the lungs? | Alveoli are surrounded by tiny blood vessels called capillaries. |
| Tiny blood vessels connecting arteries and veins, facilitating the exchange of substances between blood and tissues. | Capillaries |
| What is the role of capillaries during gas exchange in the lungs? | Capillaries facilitate the exchange of gases (oxygen and carbon dioxide) between the alveoli and the blood. |
| The amount of a specific gas present in a given space or substance. | Gas Concentration |
| How does oxygen move during gas exchange in the lungs based on concentration? | Oxygen diffuses from the alveoli into the blood where the oxygen concentration is lower. |
| A waste gas produced by cells during cellular respiration. | Carbon Dioxide |
| How does carbon dioxide move during gas exchange in the lungs based on concentration? | Carbon dioxide diffuses from the blood into the alveoli, later to be breathed out. |
| A waste product produced by body cells as a result of protein metabolism. | Urea |
| What is an example of diffusion involving urea? | The movement of urea is an example of diffusion. |
| The liquid component of blood in which blood cells are suspended. | Blood Plasma |
| Where does urea diffuse after moving out of cells? | Urea diffuses into the blood plasma. |
| A semipermeable membrane that enclose cells, controlling the movement of substances in and out. | Cell Membrane |
| Why can urea diffuse through cell membranes? | Urea particles can pass through cell membranes. |
| The amount of urea present in a specific area or substance. | Concentration of Urea |
| What is the concentration of urea like in body cells compared to the blood? | The concentration of urea is higher in body cells than in the blood. |
| Organs responsible for filtering waste products from the blood to produce urine. | Kidneys |
| Where does urea travel after diffusing into the blood? | Urea travels to the kidneys. |
| Liquid waste product formed by the kidneys, containing urea and other substances. | Urine |
| How is urea removed from the body? | Urea is removed from the body in urine. |
| Substances that, like urea, need to be moved in and out of organisms. | Water, Dissolved Food Molecules, and Mineral Ions. |
| Besides urea, name other substances that undergo movement in and out of organisms. | Water, Dissolved Food Molecules, and Mineral Ions. |
| The combined area of all sides of an object. | Surface Area |
| The space occupied by an object, calculated as height × width × depth. | Volume |
| The ratio of an object's surface area to its volume. | Surface Area to Volume Ratio |
| What is the formula for the surface area to volume ratio? | Surface Area : Volume. |
| How many sides does a cube have, and what is the area of each side in the example given? | A cube has 6 sides, and each side has an area of 4 cm². |
| What is the volume of the cube in the example, and how is it calculated? | The volume is 8 cm³, calculated as 2 cm × 2 cm × 2 cm. |
| The ratio of the surface area to the volume for the cube. | Surface Area to Volume Ratio Calculation for Cube |
| What is the surface area to volume ratio for the cube, and how is it simplified? | The ratio is 24:8, which simplifies to 3:1. |
| The larger an object, the smaller its surface area to volume ratio. | Relationship Between Size and Surface Area to Volume Ratio |
| How does the surface area to volume ratio change with the size of an object? | The larger the object, the smaller its surface area to volume ratio. |
| Organisms consisting of only one cell, such as bacteria and amoebas. | Single-Celled Organisms |
| What is the surface area to volume ratio of single-celled organisms like? | Single-celled organisms have a large surface area to volume ratio. |
| The external area of a single-celled organism. | Surface Area in Single-Celled Organisms |
| Why do single-celled organisms have a large surface area? | To facilitate efficient exchange of substances through diffusion. |
| The amount of internal content within a single-celled organism. | Volume in Single-Celled Organisms |
| Why is the volume of single-celled organisms relatively small? | To maintain a high surface area to volume ratio. |
| The efficiency of substances diffusing in and out of an organism. | Surface Area to Volume Ratio in Diffusion |
| How does the large surface area to volume ratio impact diffusion in single-celled organisms? | It allows molecules to efficiently diffuse in and out of the organism. |
| The process of substances taking in and waste products getting rid of through diffusion. | Substances Exchange in Single-Celled Organisms |
| How do single-celled organisms acquire necessary substances and eliminate waste products? | Through diffusion across their outer surface. |
| The benefits of efficient substance exchange for the organism. | Advantage of Large Surface Area to Volume Ratio in Single-Celled Organisms |
| Why is a large surface area to volume ratio advantageous for single-celled organisms? | It enables effective diffusion for acquiring nutrients and eliminating waste. |
| Organisms composed of multiple cells, such as plants and animals. | Multicellular Organisms |
| What is the surface area to volume ratio of multicellular organisms like? | Multicellular organisms have smaller surface area to volume ratios. |
| Structures adapted for specific functions in multicellular organisms. | Specialised Structures in Multicellular Organisms |
| Why do multicellular organisms have specialised structures for exchanging materials? | To compensate for the slower diffusion rate through their outer surface. |
| Surfaces adapted for efficient exchange of substances in multicellular organisms. | Exchange Surfaces in Multicellular Organisms |
| What adaptations do exchange surfaces in multicellular organisms have to increase the rate of diffusion? | Large surface area, thin membrane, good blood supply, and ventilation. |
| An adaptation to increase the number of particles that can diffuse simultaneously. | Large Surface Area in Exchange Surfaces |
| Why is a large surface area important for exchange surfaces in multicellular organisms? | It enhances the rate of diffusion by accommodating more particles. |
| An adaptation to reduce the distance molecules must travel during diffusion. | Thin Membrane in Exchange Surfaces |
| How does a thin membrane aid the exchange of substances in multicellular organisms? | It shortens the distance molecules need to travel, facilitating faster diffusion. |
| Adaptations that maintain a favorable concentration gradient for efficient diffusion. | Good Blood Supply and Ventilation in Exchange Surfaces |
| Why do exchange surfaces in animals have a good blood supply and ventilation? | To ensure a larger concentration gradient, promoting a faster rate of diffusion. |
| A system allowing the movement of substances throughout the body. | Transport System in Multicellular Organisms |
| Why do multicellular organisms need a transport system? | To move substances, such as oxygen, around the body efficiently. |
| The transport system in humans, comprising the heart and blood vessels. | Circulatory System in Humans |
| What is the circulatory system in humans responsible for? | Moving substances, like oxygen, from one part of the body to another. |
| The process of exchanging gases, typically oxygen and carbon dioxide, between an organism and its environment. | Gas Exchange |
| What are the primary gases involved in gas exchange in the lungs? | Oxygen and carbon dioxide. |
| Small, air-filled sacs in the lungs where gas exchange occurs. | Alveoli |
| What is the role of alveoli in the lungs? | Alveoli are specialised for gas exchange. |
| The total area of the alveoli available for gas exchange. | Surface Area in Alveoli |
| Why is the surface area of alveoli crucial for efficient gas exchange? | A larger surface area allows for more efficient gas exchange. |
| The thickness of the alveoli membrane, which is only one cell thick. | Single-Cell Thickness in Alveoli |
| How does the single-cell thickness of alveoli aid in gas exchange? | It reduces the distance gases must diffuse, facilitating faster exchange. |
| The network of blood vessels surrounding the alveoli. | Blood Supply in Alveoli |
| Why is a good blood supply important in the alveoli for gas exchange? | It ensures efficient transport of gases to and from the alveoli. |
| Structural features that enable rapid and efficient gas diffusion. | Adaptations for Quick Gas Diffusion |
| How do the adaptations of alveoli contribute to quick and efficient gas diffusion? | They provide a large surface area, single-cell thickness, and a good blood supply. |
| The movement of gases from an area of high concentration to an area of low concentration. | Gas Diffusion |
| What is the primary mechanism for gas exchange in the alveoli? | Gas diffusion between the blood and the alveoli. |
| The ability to quickly and effectively exchange gases. | Efficiency in Gas Exchange |
| Why is efficiency crucial in the process of gas exchange in the lungs? | Efficient gas exchange ensures an adequate supply of oxygen and removal of carbon dioxide. |
