Communication and Homeostasis Flashcards
Responding to the environment helps organisms…
Survive.
Animals increase their chances of survival by …
Responding to changes in their external environment, e.g by avoiding harmful environments.
Animals also respond to their internal environment …
to make sure conditions are always optimal for their metabolism.
Plants also increase their chances of survival by…
responding to changes in their environment.
Any change in the internal or external environment is called a …
stimulus
Receptors detect a stimuli and effectors
produce a response.
Receptors detect…
stimuli.
Receptors are specific…
they only detect one particular stimulus.
There are many different types of receptors that each detect a …
different type of stimulus.
some receptors are…
cells
Photoreceptors are receptor cells…
that connect to the nervous system.
Some receptors are proteins on …
cell surface membranes.
Glucose receptors are proteins found in …
the cell membranes of some pancratic cells.
Effectors are cells that bring about …
a response to a stimulus, to produce an effect.
Give an example of an effector cell.
Effectors include muscle cells and cells found in the glands, e.g the pancreas.
To produce a response…
receptors need to communicate with effectors and effectors may need to communicate with other cells.
This communication happens via …
cell signalling.
Cell signalling can occur between…
adjacent cells or between distance cells.
An example of cell signalling in the nervous system…
Cells in the nervous system communicate by secreting chemicals called neurotransmitters., which sends signals to adjacent cells, such as other nerve cells or muscle cells.
How does the hormonal system work?
The hormonal system works by releasing chemicals called hormones, which travel in the blood and act as signals to distant cells.
Cell surface receptors allow…
cells to recognise the chemicals involved in cell signalling.
Changes in the external environment…
can affect your internal environment- the blood and tissue fluid that surrounds your cells.
What is Homeostasis?
Homeostasis involves control systems that keep your internal environment roughly constant (within certain limits).
Keeping your internal environment constant is…
vital for cells to function normally and to stop them from being damaged.
Why is it important to maintain the right core temperature?
This is because temperature affects enzyme activity, and enzymes control the rate of metabolic reaction.
What happens to enzymes when body temperature is too high?
If body temperature is too high, enzymes may become denatured. over 40 degrees.
Describe how enzymes break down due to denaturing.
The enzymes molecules vibrate too much, which breaks the hydrogen bonds that hold them in their 3D shape.
The shape of the enzyme’s active site is changed and it no longer works as a catalyst. This means metabolic rates are less efficient.
What happens when temperatures are too low?
If the body temperature is too low enzyme activity is reduced, slowing the rate of metabolic reactions.
What is so important at 37 degrees?
The highest rate of enzyme activity happens at the optimum temperature of 37 degrees.
It is also important to maintain the right concentration of glucose in the blood so…
there is always enough for respiration.
