The cell is the basic unit structurally and functionally sentient beings. As the structural integrity means living things made up of cells. Living things consisting of a single cell called a single-celled creatures (unicellular = monoseluler) and the living creatures that consist of many cells are called multicellular creatures.
Cell as a functional unit means that all the functions of life / activities of life (metabolism, reproduction, irritability, digestive, and other excretions) on single cell creatures and multicellular take place in the body that carried out by the cell.
The extent of the problem in this paper are:
1. Identify prokaryotic cells and eukaryotic cells
2. Identify the structure and function of cell organelles
3. Identifying differences in animal cells and plant cells
1.3 Objectives Intended
The author's purpose in writing this paper is:
1. Expected to understand the structure and function of plant cell and animal life.
2. Identify differences in the structure and function of plant cell and animal life.
3. As one of the tasks assigned by subject teachers of biology.
1.4 Method Used
Descriptive methods to study engineering literature or literature, that is the knowledge that comes from a good media wrote a book, litelatur and other media that is certainly nothing to do the problems that were discussed in this paper.
CELL STRUCTURE AND FUNCTION
2.1. Structure of prokaryotic and eukaryotic cells
The term cell was first proposed by Robert Hooke, English scientist, in 1665, which means the room is empty. He examined cork under a microscope incision consisting of rooms that are bounded by walls. This is true because cork cells are the cells that have died, so that in the cell is empty, does not contain.
In 1839, a French biologist, Felix Durjadin examines several types of living cells and found that cells fill the cavity constituent called sarcode. Johannes Purkinje (1789-1869) held a change of name Sarcode into protoplasm. Max Schultze (1825-1874), an anatomy suggests protoplasm is the physical basis of life.
Theodore Schwann (1801-1881), a German zoologist, careful study and intensive animal cells, and Mathias Schleiden (1804 1881), German botanist researching plant cells. Based on their observations, the researchers noted that both the body either animal or plant body consists of cells.
The development of knowledge about the cell can not be separated from the development of science in other fields. With the histochemical staining techniques and the use of electron microscopy, revealed that in the cytoplasm, there are a variety of organelles (tiny organs).
All cells have basic properties in general. All cells are limited by the plasma membrane. In it there is a material called semicair cytosol containing organelles. All cells contain chromosomes, which carry genes (DNA, deoxyribose nucleic acid). All cells contain ribosomes which are tiny organelles that function according to the instructions of forming protein gene.
Based on the state of the core, the cells differentiated into two kinds, namely: prokaryotic cells and eukaryotic cells. In the prokaryotic cell, the core material (DNA) contained in the nucleoid is not limited by the nuclear membrane. Examples of prokaryotic cells are bacteria and blue algae that includes Monera. Whereas in eukaryotic cells contained nuclear membrane, which separates the core material (DNA and histone proteins to form chromosomes) from the cytoplasm. Eukaryotic cells found in Plants, Animals, Fungi, and protists.
Bacterial cells is limited by the plasma membrane. Inside are nucleoid (DNA) without being limited by the nuclear membrane, and ribosomes (see Figure 2.1 In the outer plasma membrane of the cell walls are composed by peptidoglycan (complex sugars and proteins). At most bacterial cells are wrapped by a capsule (composed by sugar). bacteria have a flagellum locomotor. At pili are bacterial cell surface that can be used to attach to the substrate. At photosynthetic bacteria and blue-green algae are chlorophyll scattered in the cytoplasm, without a limiting membrane with other cell parts. Thus, the cell prokaryotes have no chlorophyll but not in chloroplasts (plastids in green). prokaryotic cells have a much smaller size (approximately one-tenth) of the eukaryotic cell.
Figure 2.1 prokaryotic bacteria cells (Campbell et al, 2006).
In plant cells, animal cells, and other eukaryotic cells, in addition to the plasma membrane limiting the cell with the outside environment, also contained in a membrane system (internal) which restrict the organelles inside the cell to the cytoplasm (see Figure 2.2). Nucleus (core) bounded by the nuclear membrane so that the ingredients in it apart from the cytoplasm. Vacuoles separated from the cytoplasm because it is limited by a membrane (tonoplas). Similarly, in other membranous organelles, which are separated from each other so that each organelle organized chemical reactions separately. In other words, eukaryotic cells have undergone kompartementasi, is divided into several rooms.
In summary, differences in prokaryotic and eukaryotic cells can be seen in Table 2.1
Table 2.1. Differences in prokaryotic and eukaryotic cells
Description: - (none); + (no)
Based on the number and function of chromosomes, the cells differentiated into two groups, namely somatic cells and reproductive cells. Somatic cells are the cells making up the body, with the chromosome number 2n (diploid). In the process of growth of multicellular creatures somatic cells undergo a process of mitotic division. Reproductive cells for the propagation of living creatures function sexually. This cell is formed through the process of meiosis so as to have n number of chromosomes (haploid).
There are cells that are part of life and there is death. Part of the living cell known as protoplasm, consisting of the nucleus and the cytoplasm. Section off the contents of a cell wall and vacuoles.
The cells in the bodies of animals and plants belonging to the eukaryotic cell, whereas there are eukaryotic microorganisms such as protozoa, protists, and fungi. There are others such as the prokaryotic bacteria and blue algae.
2.2. Structure and function of cell organelles
The cell is the structural and functional unit making up living things that can reproduce themselves. Activity present in the cell occurs in organelles that support certain functions.
The function of the constituent parts of the cell are as follows:
2.2.1. Cell wall
Cell wall is permeable, serves as a protector and giver of body shape. Cells that have a cell wall include: bacteria, fungi, algae (protists), and plants. The living groups have cells with a clear shape and stiff (rigid). On protozoa (protists) and animals do not have cell walls, so that the cell shape is less clear and flexible, not rigid. At certain parts of the cell wall thickening did not take part and have plasmodesmata (Figure 2.3), called the dot (point).
Dots on pine bark
2.2.2. Plasma membrane
Plasma membrane limiting the cell to the external environment, are semi / selectively permeable, controls the income and expenditure of substances into and out of cells by diffusion, osmosis, and active transport. Plasma membrane composed by phospholipids, of protein, cholesterol, dl.
The cytoplasm is the fluid outside the cell nucleus, consisting of water and dissolved substances as well as a variety of live cell organelles. Organelles present in the cytoplasm, among others:
a. Endoplasmic reticulum (ER) of the channels formed by membrane (Figure 2.4). RE divided into two kinds, namely RE RE smooth and rough.
Figure 2.4 endoplasmic reticulum
RE ribosomes on rough there, serves as the site of protein synthesis. While there are subtle at RE ribosome, serves as a lipid synthesis
b. Ribosome consists of two units that are rich in RNA, plays a role in protein synthesis. No ribosomes attached to the rough RE and contained no free in the cytoplasm.
c. Mitochondria have a double membrane, the outer membrane and the inner membrane. Between the two membranes that there is a space between the membranes. Membrane in squiggly called cristae which serves to expand the surface area for the absorption process and the formation energy of oxygen more effectively. On the inside there is a membrane ATP synthase enzyme that serves as the synthesis of ATP. This is the function of mitochondrial aerobic respiration.
Figure 2.5. Mitochondria (Campbell, et al 2006)
d. Lysosomes in the form of small grains / round, contains digestive enzymes that function in intracellular digestion
e. Golgi apparatus (Golgi Apparatus) is a pile of flattened sacs, serve as a synthesis of secretions (such as digestive juices, are found in glandular cells), forming the core of the protein and acid (DNA / RNA), as well as forming the walls and cell membranes.
Round-shaped discs that are found in plants, is divided into three kinds:
- Leukoplas = Amiloplas: colorless plastids, can form and store grain starch / starch.
- Kromoplas is colorless plastids than green, because of the pigment: melanin (black), likopin (red), xantophil (yellow), carotene (orange), phycocyanin (blue), and phycoerythrin (brown).
- Chloroplasts are green plastids, because the leaves contain chlorophyll (chlorophyll), consisting of: chlorophyll a (blue-green color = C55H72O5N4Mg) and chlorophyll b (yellow green color = C55H70O6N4Mg).
Figure 2.6. Chloroplasts (Campbell, et al 2003)
g. Vacuole shaped spherical cavity, contains certain chemical compounds or residual products of cell metabolism, which contain various substances according to cell type. For example, can contain nitrate salts in tobacco plants, tannins in the bark cells, etheric oils in eucalyptus and roses, turpentine in resins, quinine in quinine, nicotine in tobacco, tomato likopersin on, piperine in pepper.
h. Nucleus (nucleus) bounded by the nuclear membrane, containing threads of chromatin and nucleoli (child cell nucleus). Nuclear membrane consists of two layers and have pores. Chromatin threads will shorten the processing time of cell division to form chromosomes. The nucleus regulates all activities that occur within the cell (Figure 2.7).
Figure 2.7. Nucleus and endoplasmic reticulum
coarse (Campbell, et al 2006)
2.3. Differences in plant cells and animal cells
Observation data using light microscopy on cell preparations of plant leaves (Elodea sp) and human cheek epithelial cells obtained results as Table 2.2
Table 2.2. Comparison of Elodea cells and epithelial cells cheek
From Table 2.2 you can find out the similarities between animal cells and plant cells, namely the parts that were found in the epithelial cheek cells and Elodea (sebutkan!) Similarly, you can find out the particular characteristics of plants, namely the parts that were found on the cell Elodea but not found in epithelial cells cheek. With the chloroplast in the plant Elodea cells can synthesize their own food through photosynthesis. Similarly, the cell walls in Elodea cells make cell shape more clearly than in the cheek cells.
If we observe carefully, chloroplasts, and cell nuclei Elode located close to the edge of the cell wall. This is due in the middle of the plant cell contained a large vacuole is located in the middle of the cell (called the central vacuole), whereas in cells.
2.4. The characteristics of living things
In addition there is a difference, between animals and plants also have much in common which is the characteristics of living things. The characteristics of living things such as: require food (nutrients), breathing (respiration), excretion, synthesis, growth and development, regulation, reproduction, irritability, adaptation, interaction with the environment, as well as specific sizes and shapes, made up of cells.
Living things need food and choose foods that suit her body shape. The food will undergo enzymatic fragmentation process to obtain energy in their daily activities, constituent cells, and replace the defective part. Food needed to carry out life activities called nutrients.
Respiration or respiration is the process of simplification of chemical nutrients for energy. Breathing may occur:
* Aerobic (requiring oxygen)
* Anaerobic (not using oxygen, through the fermentation process).
Spending the rest of the chemical compounds that are not useful for the metabolism of living organisms in the body and if there will be toxic (poison).
Changes occur in the body of a compound to another compound for the benefit of constituent body, maintain viability, and maintain the body interacts with the environment. Preparation of chemical compounds in the body for life activity is called synthesis.
e. Growth and development
Growth is a process of increasing the volume and number of cells and the number of chemical compounds in the body that is irreversible (not back to the origin) at a certain period. Development is the growth that followed the change
nature toward maturity. While differentiation is cell growth followed by specialization (special functions) cells.
Setting both in quantity and quality at any time of the metabolic system structures in living things is called by regulation.
Irritability intended as living beings the ability to receive and can afford the excitatory response to that stimulus.
The process of increasing the number of individuals who contribute to the preservation of the offspring is called reproduction.
Adjustment to the state of the environment in a relatively short time is called tolerance, whereas tolerance which takes place in a relatively long time is called adaptation.
To maintain the stability of their lives or sustain life living creatures must compete with other individuals. Competition occurs in getting a place to live, food, and other light.
k. Living things have a certain shape and size, and composed of cells.
Living beings vary greatly in type or shape and size, but every kind of show specific forms and certain sizes. Variation in one species can not eliminate specific form. Living things have in common is composed of cells.
What about viruses? Whether the virus is a living being or inanimate object? Viruses consist of nucleic acids (DNA / RNA) which is bounded by a protein coat, not a cell. Viruses can be crystallized (characteristic of inanimate objects). Viruses possess living creatures, namely: to reproduce and adapt through mutation. However, the virus can live and reproduce only in living bodies. In artificial media virus can not live and reproduce. Therefore, most biologists put a virus as a bridge between the living beings and inanimate objects.
CONCLUSIONS AND RECOMMENDATIONS
Based on the above discussion we can conclude the following:
The first cell once found British scientist Robert Hooke (1665) by examining the cork slice under a microscope consisting of rooms that are bounded by a wall called the cell. In 1839, a French biologist, composer Felix Durjadin find the content in the cell cavities called sarcode. Johannes Purkinje (1789 -
1869) held a change of name sarcode into protoplasm. Theodore Schwann (1801-1881), a German zoologist and Mathias Schleiden (1804-1881), German botanist suggested that the bodies of animals and plants are composed of cells. Robert Brown (1831), a Scottish biologist found the core (nucleus). Max
Schultze (1825-1874), an expert on anatomy suggests protoplasm is the physical basis of life. Rudolf Virchow said cells come from cells Omnis cellula cellula.
Differentiated cells of several forms, which are based on the state of the cell nucleus (eukaryotic and prokaryotic cells), based on the state and function of chromosomes (somatic and reproductive cells), by its nature (a part of life and part of the dead).
Plant cell comprising: cell wall, plasma membrane, cytoplasm, and organelles (rough and smooth endoplasmic reticulum, ribosomes, mitochondria, Golgi apartus, plastids, central vacuole and the nucleus). While the animal cell consists of the cell membrane, cytoplasm and organelles (rough and smooth endoplasmic reticulum, ribosomes, mitochondria, lysosomes, Golgi apparatus, vacuole, and nucleus).
Differences in plant cells and animal cells are plant cells shape remains, consisting of a cell wall containing cellulose, there is a grain of plastids, and a large central vacuole, no lysosomes and centrioles. Whereas animal cell shape varies, there is no point plastids, small vacuoles, lysosomes and centrioles are.
Living beings have the main features as follows: to perform nutrition, transport, respiration, excretion, synthesis, growth and development, regulation, irritability, reproduction, adaptation, interaction, has a certain shape and size, and composed of cells. Virus is a bridge between living things and inanimate objects.
For us and generations to come it is fitting to determine the structure and function of cell organelles in living things, and the difference between animal and plant cells.
To readers that want to know more about this subject can read books or magazines which contain
Alberts B. 1994. Biologi Molekuler Sel, Edisi Kedua. Penerbit PT Gramedia Pustaka Utama, Jakarta.
Departemen Pendidikan dan Kebudayaan. 2004. Kurikulum Sekolah Menengah Kejuruan (GBPP) Mata Pelajaran Biologi. Depdikbud, Jakarta.
Siregar. Ameilia Z. 2008.Biologi Pertanian, Jilid 1. Direktorat Jenderal Manajemen Pendidikan Dasar dan Menengah Departemen Pendidikan Nasional. Jakarta.