Question

Question about: Sensory Reception

This is my homework I need help with. There is no more information I can provide with. Please help! Thanks!!

All organisms interact with their environment by receiving and processing information from the environment and then responding to that information.

Describe the difference in sensory reception between a single-celled organism and a multicelled animal.

Draw a representation to show how the human body detects two different types of sensory signals. Label the structures in your illustration.

Answer 1

Single celled organism have only one cell which performs multiple functions. This cell is used for all functions. Now, this cell senses the environment around it. They move materials into and out of the cell by regulation of the cell membrane and its functioning. Most multicellular organisms have most of their cells protected from the external environment, having them surrounded by an aqueous internal environment. This hemostasis is done by that single cell. Unicellular organisms sense the chemicals and are attracted towards it. Once that chemical produces a stimulus more than the threshold then all the organisms of the chemical change their gene expression together and this is known as quorum sensing.

The bacterium Escherichia coli accumulates in high concentrations of sugars and some amino acids. This is also true of the ciliate protozoan Paramecium, which accumulates in areas with high concentrations of folate or biotin—compounds that are released by bacteria, the food of these animals. However, Paramecium disperses when it encounters quinine or potassium hydroxide.
As in multicellular organisms, perception of chemicals often involves the possession of receptor proteins in the cell membrane that activate second-messenger systems within the cell. However, unlike with multicellular organisms, the second messengers of single-celled organisms cause changes in the effector mechanisms of the cell, such as the flagellum or cilium, that modify the cell’s movement.

Multicellular organisms have receptors which sense the stimulus.
A stimulus forces a response.
For eg- Our tongue has numerous taste buds or papillae which respond to various different taste present in the food. The taste is sensed by the papillae and then the brain senses the taste and if it is too bitter or sour response can be seen on our face.
In case of eyes when we see any dog running towards us then this is a stimulus for us then our sense the stimulus send the message to brain and our muscles respond towards it by contracting and relaxing and we start running.