The Cell

The basic units of structure for all living organisms are cells. All living things are made up of cells. Every person, animal and plant, as well as tiny organisms that can only be seen under a microscope are made up of cells. Living organisms may be made up of billions and billions of cells or a single cell.

The introduction of the term cell is credited to a physicist named Robert Hooke. The invention of the microscope helped Hooke describe the cells of the bark of a tree and other plant cells. The term cell was introduced by Hooke in 1665, because they reminded him of the tiny rooms or cells used by monks.

Cells are the basic units of life because cells make up all living things. Cells come from other cells, meaning they can reproduce to create new cells of the same kind.

All animal cells are surrounded by a structure called cell membrane. The cell membrane is like a boundary between the inside and outside of cells. Cell membranes have different functions depending on the type of cell the membrane surrounds. Some membrane control what enters or leaves the cell.

The cytoplasm of a cell is inside the cell membrane and is a liquid area that contains different fluids that help keep the cell working. The fluids contain enzymes, fats, sugars and acids. The waste products of a cell are also dissolved within the cytoplasm before exiting the cell.

The nucleus of a cell is usually found in its center. The nucleus could be considered the brain of the cell. The molecules of DNA are found in the nucleus of a cell which determines the characteristics of the organism, such as what it will look like.

DNA molecules contain the instructions for life. For a plant, it may be its size, for people it may be eye or hair color and much more. Nearly all cells have a nucleus. It also controls the eating, movement, and reproduction of the cell.

A plant cell is a little different than an animal cell. A cell wall is only found in plant cells but not animal cells. The cell wall of a plant is found on the outside of its cell membrane. The cell wall provides all plants protection and support, and it also helps plants keep their shape. Cell walls also have tiny holes to allow the movement of nutrients and waste. Bacteria, fungi, and some protozoa also have cell walls.

Chloroplasts are also only found only in plant cells. Chloroplasts produce the food for the plant cells. In addition, the process of photosynthesis depends on the chloroplasts. The chloroplasts help the plant turn light energy from the Sun into food for the plant. There are green chlorophyll molecules in every chloroplast. Oxygen is also released through plants by the chloroplasts.

Vacuoles are a part of both plant and animal cells. Inside a fluid, vacuoles store the food and nutrients the cell needs to survive. They also store waste products of the cell to prevent contamination to the rest of the cell. The waste will then be sent out of the cell. The vacuoles in plant cells are larger than in animal cells because they hold large amounts of water and food.

Mitochondria also provides plant and animal cells with energy through a process known as cellular respiration. The mitochondria take in nutrients, breaks them down, and turns them into energy using molecules.

In summary, cells of plants and animals have many parts and functions which are the basic units and parts of the organism.

A: Cell membrane
B: Nucleus
C: Cytoplasm
D: Cell wall

A: Mitochondria
B: Cytoplasm
C: Chloroplasts
D: Vacuoles

A: Mitochondria
B: Chloroplasts
C: Vacuoles
D: Cell wall

A: Nucleus
B: Cell membrane
C: Mitochondria
D: Vacuoles

A: Cytoplasm
B: Chloroplast
C: Cell membrane

A: Oxygen
B: Vacuoles
C: Mitochondria
D: Cell wall

Related Topics
Function of Nucleolus
Animal Cells
The Function of Endoplasmic Reticulum
Cell Theory Timeline
The Cell and Cell Structure Quiz
Plant Cells
Discovery of the Cell
Function of Cytoplasm
The Function Of Golgi Bodies

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