Let us make an in-depth study of the structure and functions of cell. After reading this article you will learn about: Comparison of Prokaryotic Cells and Eukaryotic Cells and 2. Structure and Components of a Human Cell.
Cell and diagram of a cell highlighting the membrane bound organelles mentioned in the table above. Nucleus Our DNA has the blueprints for every protein in our body, all packaged into a neat double helix. The processes to transform DNA into proteins are known as transcription and translation, and happen in different compartments within the cell.
The first step, transcription, happens in the nucleus, which holds our DNA. A membrane called the nuclear envelope surrounds the nucleus, and its job is to create a room within the cell to both protect the genetic information and to house all the molecules that are involved in processing and protecting that info.
This membrane is actually a set of two lipid bilayers, so there are four sheets of lipids separating the inside of the nucleus from the cytoplasm. The space between the two bilayers is known as the perinuclear space.
Though part of the function of the nucleus is to separate the DNA from the rest of the cell, molecules must still be able to move in and out e.
Proteins channels known as nuclear pores form holes in the nuclear envelope. The nucleus itself is filled with liquid called nucleoplasm and is similar in structure and function to cytoplasm.
It is here within the nucleoplasm where chromosomes tightly packed strands of DNA Cell and diagram all our blueprints are found. Cartoon showing a close up the nucleus and highlighting structures specific to the nucleus.
A nucleus has interesting implications for how a cell responds to its environment. Thanks to the added protection of the nuclear envelope, the DNA is a little bit more secure from enzymes, pathogens, and potentially harmful products of fat and protein metabolism.
Since this is the only permanent copy of the instructions the cell has, it is very important to keep the DNA in good condition.
If the DNA was not sequestered away, it would be vulnerable to damage by the aforementioned dangers, which would then lead to defective protein production. The nuclear envelope also keeps molecules responsible for DNA transcription and repair close to the DNA itself - otherwise those molecules would diffuse across the entire cell and it would take a lot more work and luck to get anything done!
While transcription making a complementary strand of RNA from DNA is completed within the nucleus, translation making protein from RNA instructions takes place in the cytoplasm.
Before an RNA can exit the nucleus to be translated, it must get special modifications, in the form of a cap and tail at either end of the molecule, that act as a stamp of approval to let the cell know this piece of RNA is complete and properly made.
Cartoon showing mRNA preparing to leave the nucleus and enter the cytoplasm. Nucleolus Within the nucleus is a small subspace known as the nucleolus. It is not bound by a membrane, so it is not an organelle. This space forms near the part of DNA with instructions for making ribosomes, the molecules responsible for making proteins.
Ribosomes are assembled in the nucleolus, and exit the nucleus with nuclear pores. In our analogy, the robots making our product are made in a special corner of the blueprint room, before being released to the factory.
A diagram representing the cell as a factory. The cell membrane is represented as the "factory walls. The ribosome is represented as the "production room" and the final protein made by the ribosome is represented as the "product. Reticulum comes from the Latin word for net. Basically, an endoplasmic reticulum is a plasma membrane found inside the cell that folds in on itself to create an internal space known as the lumen.
This lumen is actually continuous with the perinuclear space, so we know the endoplasmic reticulum is attached to the nuclear envelope. There are actually two different endoplasmic reticuli in a cell: The rough endoplasmic reticulum is the site of protein production where we make our major product - the toy while the smooth endoplasmic reticulum is where lipids fats are made accessories for the toy, but not the central product of the factory.
Rough Endoplasmic Reticulum The rough endoplasmic reticulum is so-called because its surface is studded with ribosomes, the molecules in charge of protein production. When a ribosome finds a specific RNA segment, that segment may tell the ribosome to travel to the rough endoplasmic reticulum and embed itself.
The protein created from this segment will find itself inside the lumen of the rough endoplasmic reticulum, where it folds and is tagged with a usually carbohydrate molecule in a process known as glycosylation that marks the protein for transport to the Golgi apparatus.
The rough endoplasmic reticulum is continuous with the nuclear envelope, and looks like a series of canals near the nucleus. Proteins made in the rough endoplasmic reticulum as destined to either be a part of a membrane, or to be secreted from the cell membrane out of the cell.
Without an rough endoplasmic reticulum, it would be a lot harder to distinguish between proteins that should leave the cell, and proteins that should remain. Thus, the rough endoplasmic reticulum helps cells specialize and allows for greater complexity in the organism. Smooth Endoplasmic Reticulum The smooth endoplasmic reticulum makes lipids and steroids, instead of being involved in protein synthesis.
These are fat-based molecules that are important in energy storage, membrane structure, and communication steroids can act as hormones. The smooth endoplasmic reticulum is also responsible for detoxifying the cell. It is more tubular than the rough endoplasmic reticulum, and is not necessarily continuous with the nuclear envelope.Learn Easier With A Cell Diagram.
Learn Easier With A Cell Diagram: If you plan to teach biology, no matter how young or old are your students, you should know that images will help them understand and remember the information easier. Cell theory, first developed in by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells.
A plant cell diagram, like the one above, shows each part of the plant cell including the chloroplast, cell wall, plasma membrane, nucleus, mitochondria, ribosomes, etc.
A plant cell diagram is a great way to learn the different components of the cell . One can observe the golgi apparatus in the labeled animal cell parts diagram.
Printable animal cell diagram to help you learn the organelles in an animal cell in preparation for your test or quiz. 5th grade science and biology. Learn Easier With A Cell Diagram. Learn Easier With A Cell Diagram: If you plan to teach biology, no matter how young or old are your students, you should know that images will help them understand and remember the information easier. Jul 11, · Nerve cells, bone cells and liver cells, for example, all develop in ways that enable them to better perform their specific duties. The most important structures of plant and animal cells are shown in the diagrams below, which provide a clear illustration of how much these cells have in barnweddingvt.coms:
The golgi apparatus is situated near the cell nucleus and besides the stacked sacs, it also contains large number of vesicles. Diagram of the human cell illustrating the different parts of the cell.
Cell Membrane The cell membrane is the outer coating of the cell and contains the cytoplasm, substances within it and the organelle. Mar 13, · The cell membrane, also known as the plasma membrane, is a double layer of lipids and proteins that surrounds a cell and separates the cytoplasm (the contents of the cell) from its /5().