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9 Cards in this Set
- Front
- Back
- 3rd side (hint)
a) Outline the need for communication systems in multicellular organisms
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Multicellular organisms need communication systems in order to respond to changes in their internal and or their external environment. They also need to be able to coordinate activities between organs.
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- response - internal - external
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b) How do cells communicate with each other?
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Through a process called cell signalling.
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c) Name two examples of cell signalling.
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Hormonal and neuronal systems.
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d) Define the term "negative feedback".
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Negative feedback is a process by which any changes in a parameter brings about a response that reverses that change, so that it returns to its original set of conditions.
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reversal
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d) Define the term "positive feedback".
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Positive feedback is a process in which any changes in a parameter leads to a response that increases that change.
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increase
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d) Define the term "homeostasis".
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Homeostasis is th maintenance of an external environment in a constant state despite changes to the external environment.
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- maintain - despite
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e) What are the principles of homeostasis?
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A stimulus is detected by a receptor (I. e. sensory receptor). The receptor then uses a communication pathway (cell signalling) in order to send a signal to an effector (hepatocyte, muscle cell etc). Once an effector receives this signal, the effector carries out a response that reverses that change.
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- stimulus - receptor - communication pathway - effector - reversal
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e) What things need to maintain homeostasis?
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- Body temperature
- Blood glucose concentration - Blood pressure |
Blood, body
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f) What is an ectotherm?
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An ectotherm is an organism that relies on external sources of heat in order to regulate its body temperature.
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external, temperature
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