Reviewing Knowledge in Biology, Free Paper Sample

The stereoscopic microscope can be used to view objects that are relatively large or in situations where high magnification is not required. Its stereoscopic capability permits depth and it can therefore be used to view specimens in three dimensions. The stereoscopic microscope is also used in situations where the objects being viewed are too thick to transmit light.

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The organelles of these cells are membrane-bound, with the nucleus being bound by nuclear membrane and placed centrally within the cell. The primary mode of movement is by cilia, which are tiny hairs located around the cell membrane or by flagella, which are long hair like strands also located outside the organism

Plant cells have rigid outer cell wall that is made up of cellulose and chloroplasts that contain chlorophyll. Animals on the other hand have their cells bound by a cell membrane and lack chloroplasts since they do not need to make their own food. Plant cells lack centrioles which are primary to cell division they however have their own cell division path. The chloroplasts contain chlorophyll that are necessary in the process of photosynthesis. The cellulose cell wall serves to protect the organelles from damage as well as serve to maintain the structure of the cell.

The observations match my earlier predictions. Have been able to identify the nucleus which is centrally positioned, the mitochondria and a host of other organelles.

Multicellular organisms consist of two or more types of cells with specialized structure and function. If any one of the cell types of the organism is isolated, it is not capable of perpetuating the species in nature. Colonial organisms consist of a predictable number of cells of similar types and with a predictable structure. They tend to live in groups and depend on each other. Volvox is considered multicellular since its individual cells are interconnected by cytoplasmic strands to form a sphere.

Applying own knowledge

Evolution to organismal complexity can be attributed to increased specialization. An example of would be the amoeba cells or the trichonympha that have clearly specialized structures for movement pseudopodia in the amoeba and flagella for trichonympha. The Volvox cell also displays some simple specializations.

Unicellular organisms are in greater abundance as compared to multicellular organisms. There are millions of species of bacteria in the world today with more yet to be discovered. Unicellular organisms are also able to reproduce faster than multicellular organisms this greatly improves their chances of survival. Unicellular organisms have been discovered in locations that were previously considered uninhabitable. Finally, multicellular organisms themselves evolved from unicellular organisms.

Enzyme (proteins)-secreting cells of the pancrease- (e)

Insect flight-muscles (b)

Cells lining the respiratory passages - (f)

White-blood-cells that engulf and destroy invading bacteria (i)

Leaf-cells of cacti (d)

This can be defined as an aggregate organism. This is so because the spirilla and bacilla cells are not permanently fused to the organisms but depend on it their existence. This indicates before forming into a unicellular organism, cells initially formed aggregated relationships that later merged into a single functional unit.

Pleodorina should not be classified as multicellular since the somatic cells become reproductive when isolated from the colony. For an organism to be multicellular, it should not be capable of perpetuating the species when in isolation.