1. How and why was the cell theory developed

Only a few cells are large enough to be seen by the naked aye. Our knowledge of cells began with the invention of lens in the 1600's and grew along with advances in microscope technology.

About 150 years passed before scientist begin to organize observations of Hooke and van Leeuwenhoek into a unified theory. IN 1838 a German botanist Matthias Schleiden, concluded that all plants were composed of cells. A year later German zoologist came to the same conclusion about animals. In 1855 a German physician, Rudolph Virchow, while studying how disease effects living things, determined that cells come only from other cells. The observations of these three scientist taken together are known as the cell theory This theory has three parts:

1.All living things are composed of one or more cells

2.In organisms, Cells are organisms basic units of structure and function

3.Cells come only from existing cells

2.Explain why cells must remain small. Give examples to support your ideas

There are two limits that affect how efficiently cells work and that govern cell size. One limit is related to the exchange of materials between the inside and the outside of the cell, and the other limit is related to the distribution of materials within the cell. A cell’s surface provides the only opportunity for interaction with it’s environment. All information and materials entering or leaving the cell, including wastes, must pass through "doors" in the cell’s membrane . The efficiency of such an exchange depends on the ratio of the cell’s surface area to its volume. The surface area of a cell is the measurement of the exterior of the cell. Large cells have far less membrane surface per unit of volume with which to supply materials to the cell’s interior and to rid it of wastes. You can understand surface-area-to-volume ratios by thinking of a cube sized cell split into 8 little cubes and then 64 tiny cubes. A cell with six times as much surface area per unit as volume per unit can move materials in and out of a cell more efficiently than a cell with a smaller surface-area-to-volume ratio. A second limit governing the size of cells has to do with transport within the cell itself. As cell size increases, it takes longer for information and materials to reach their destination. Small cells, therefore, function more efficiently than larger cells.

3. Compare eukaryotic cells with prokaryotic cells.(Discuss similarities and differences)

A prokaryotic cell is a mostly bacterial cell, it differs from eukaryotic cell in many aspects. It is not only surrounded by plasmatic membrane but also by a cell wall outside of it which protects it from the outer environment. The other major difference is the absence of nucleus, also it does not contain Lysosomes . Its characteristics are closer to a plant cell rather than an animal cell. It is more primitive than an animal cell. Its evolutionary older than plant or animal cells. It does not have an endoplasmic Reticulum or an golgi complex. It also does not have mitochondria or vacuoles. It does not have micro tubules. However it has Cilia and flagella.

These organisms contain prokaryotic cells: Prokaryotes are different kinds of bacteria: including pathogenic bacteria streptococcus, staphylococcus, etc. Eukaryotic are multi cellular organisms which are advanced single cells. Eukaryotic cells have DNA in the nucleus . Eukaryotic cells can also form multi cellular individuals. Prokaryotic cells have naked DNA. They belong to the kingdom Maricra. They live independent and are more primitive than others.

4. Explain how being multi cellular is different than living in a colony. Use examples..

In most multi cellular organisms the cells are organized into tissues. A tissue is a group of similar cells that can carry out a common function. Several types of tissue that interact to perform a specific function form an organ. An organ system is made up of a group of organs that work together to perform a set of related tasks.

Since in a complex organisms there is a number of cells and each cell performs its own function the organism can perform these functions much more faster because there is more cells to perform that function., but an individual cell has to perform all these functions at the same time which makes the process much slower and less efficient. In other words they have specialized tissues and organs made of the same kind of cell which makes them much more efficient than other cells.

5.Define the levels of organization used to define life from protons to galaxies.

Protons make up atoms along with neutrons and electrons. A single proton is an hydrogen ion. A proton and a neutron makes up an original hydrogen atom. Atoms make up molecules when they are put together. Molecules make up cells. Single celled organisms are called protozoan. Cells make up a tissue. Tissues make up organs. Organs make up organ systems. Organ systems make up an organism. Organisms are a population. They make up communities. Communities make up the ecosystems. Ecosystems make up Biomes. Biomes make up realms. Realms make up the Biosphere. The biosphere makes up all the area where living things are which is about 7-8 miles deep to 30,000 feet high. The biosphere belongs to the planet Earth. Earth belongs to the solar system. The solar system belong to a galaxy( the Milky Way galaxy). Milky Way galaxy belongs to a galaxy cluster. A galaxy cluster belongs to a super galaxy.