BIOCHEM 1 & 2

An organism is a living thing such as an animal, plant, fungus, protist, or bacteria. All living organisms share the same characteristics and abilities which are: obtaining and using energy, maintaining a stable internal state, the ability to grow, the ability to reproduce, and responding to stimuli in the environment. All organisms obtain energy, some in different ways such as sunlight and ingesting other organisms. Organisms and cells function best at certain temperature, ph levels, and other conditions, so they must keep their levels from falling to low or raising too high with the process called homeostasis. All organisms consist of cells whether it is unicellular or multicellular. Both unicellular and multicellular organisms have the ability to grow and reproduce which consist of cell division. Lastly all organisms are able to respond to a change in an environment, but in order to do this organisms must be able to sense their environment. The four characteristics of all cells are the plasma membrane, cytoplasm, DNA, and ribosomes. The plasma membrane forms the outside layer of a cell and separates the cell from its environment. The DNA stores genetic information which allows the cell to pass it on to future generations. The cytoplasm fills the cell’s internal volume and is composed of mostly water. The ribosomes decode the genetic information in mRNA and assemble amino acids into proteins. There are two main types of cells which are Prokaryotic and Eukaryotic cells. Prokaryotes are unicellular organisms that lack membrane-bound organelles while Eukaryotes are organisms whose cells have a nucleus enclosed within membranes.