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Description
Flashcards by Laura García Penabad, updated more than 1 year ago
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Created by Laura García Penabad
almost 3 years ago
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| Question | Answer |
| What are the levels of organisation in living organisms, starting from the smallest? | organelles, cells, tissues, organs, systems |
| Why do many multicellular organisms need transport systems? | Many cells are to far from the external environment Diffusion is too slow over large distances (over 1mm is far) |
| Write the equation for the rate of diffusion | |
| What is the concentration gradient? | An unequal distribution of molecules, so there is an area of higher concentration, and an area of lower concentration |
| What is equilibrium? | An equal distribution of molecules, so that the flow is equal in all directions |
| Why does equilibrium cause a problem for cells? | To stay living, cells require a constant flow of molecules into, and out of the cell |
| Name 4 specialised surfaces for exchange in humans | Lungs, small intestine, placenta, kidneys |
| What 3 features do all humans specialised surfaces for exchange have to increase the rate of diffusion? | Large surface area, short exchange distance, maintain concentration gradient |
| Explain the meaning of surface area: volume | It is a comparison between the amount of surface that can exchange with the environment, and the total living volume of the organism |
| Explain why SA:V is an important restrictor on the shape of organisms | There needs to be enough exchanging surface are to meet the demands for the flow of energy and matter of all cells of the organism |
| What is the equation for calculating the surface area of a cube? | 6 x (side length) ² |
| What is the equation for calculating the volume of a cube? | (Side length) ³ |
| What is the equation for calculating surface area to volume ratio? | Surface area / volume |
| Draw a diagram of the human gas exchange system | |
| What organs does air pass through (in order) when breathing in? | Trachea, bronchi, bronchiole, alveoli |
| Name two organs found in the thorax cavity | Lungs, heart |
| What is the mechanism for breathing in? | - The diaphragm & external intercostal muscles contract - Volume of thorax & lungs increases - The air pressure decreases in the lungs (lower than atmosphere) - Air moves into the lungs |
| What is the mechanism for breathing out? | - Internal intercostal muscles contract (pulling ribs inwards) - The lungs decrease in volume - The air pressure increases in the lungs (higher than the atmosphere) - Air moves out of the lungs |
| What is the function of the rings of cartilage found in the trachea and bronchi? | Prevent them from collapsing when breathing in (due to decrease in pressure) |
| What is the function of breathing? | Renew the alveoli air - maintain the concentration gradient between the alveoli air and the blood - maintain the flow of exchange between the organism and the air |
| Name four adaptation of the alveolus (and it’s capillaries) that allow quick gas exchange | Short diffusion distance: Alveolus and capillaries are one cell thick large surface area: Alveolus has many folds Allows gases to dissolve: Alveolus is moist (has a water layer) Maintenance of a concentration gradient: flowing blood in capillaries |
| Name the gases that are exchanged in the alveolus and in what direction they diffuse | Oxygen: air in the alveolus to blood Carbon dioxide: from blood into the air in the alveolus |
| What is the function of increasing the breathing rate during exercise? | Increase the flow of oxygen to muscle tissue Increase the excretion of carbon dioxide |
| Why does a faster breathing rate increase the rate of exchange in the alveoli? | Maintenance of a larger concentration gradient of gases - rate of diffusion (in the alveoli) increases |
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