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Description
Flashcards by sophiebowen4, updated more than 1 year ago
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Created by sophiebowen4
over 8 years ago
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| Question | Answer |
| All living things need to maintain a certain limited set of conditions inside their cells because they rely on the action of enzymes, these include: | -A suitable temperature -A suitable pH -An aqueous environment that keeps the substrates and products in solution -Freedom from toxins and excess inhibitors |
| Define STIMULUS | A stimulus is any change in the environment that causes a response |
| Define RESPONSE | A response is any change in behaviour or physiology as a result of a change in the environment. |
| A slow environmental change such as the seasons will result in... | A gradual response such as adapting its coat to the seasons. |
| The environment of internal cells and tissues in animals is... | Tissue fluid |
| How is the composition of tissue fluid maintained by the blood? | Blood flows throughout the body and transports substances to and from the cells. Any wastes or toxins accumulating in the tissue fluid are likely to enter the blood and be carried away. In order to prevent their accumulation in the blood they must be carried away. In order to prevent their accumulation they need to be excreted. |
| Why is it important to monitor concentrations of waste and all substances? | This ensures that the body does not excrete too much of any useful substance but removes enough of the wastes to maintain good health. It also ensures that all of the cells of the body are supplied with the substrates they need. |
| Why is a multicellular organism more efficient than a single-celled organism? | Cells can be differentiated meaning they can be specialised to perform particular functions. Groups of cells specialised in this way form tissues and organs. As a result the cells that monitor the blood may be in a different part of the body and well away from the cells that monitor and release a substance into the blood or well away from the organ that removes that substance from the blood. |
| What makes a good communication system? | A good communication system will: -Cover the whole body -Enable cells to communicate with each other -Enable specific communication -Enable rapid communication -Enable both short-term and long-term responses |
| How do cells communicate with each other? | Cells communicate with each other by a process known as cell signalling. This is a process in which one cell will release a chemical that is detected by another cell. The second cell will respond to the signal released by the first cell. |
| What are the two major communication systems that work by cell signalling? | The NEURONAL system and the HORMONAL system |
| What is the neuronal system? | The neuronal system is an interconnected network of neurones that signal to each other across synapse junctions. The neurones can conduct a signal very quickly and enable rapid responses to stimuli that may be changing quickly. |
| What is the hormonal system? | The hormonal system uses the blood to transport its signals. Cells in an endocrine organ release the signal ( a hormone ) directly into the blood. It is carried out all over the body but it is only recognised by specific target cells. The hormonal system enables longer-term responses to be coordinated. |
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