Photosynthesis occurs in the chloroplast of a plant cell Tomography: process used to make a tomogram picture which is a two-dimensional slice of a three-dimensional object. A computer can then be used to build a three-dimensional image of the object by stacking the tomograms together. Cells come in many shapes and sizes. Some cells are covered by a cell wall, other are not, some have slimy coats or elongated structures that push and pull them through their environment.
Some cells have a thick layer surrounding their cell. This layer is called the capsule and is found in bacteria cells. In our body there are many different kinds of cells. We are made up of about different types of cells. Our body also has non-living materials such as hair, finger nails, and the hard part of teeth enamel.
All these materials are made up of dead cells or other minerals. Have you ever wondered what the inside of a cell looks like? If you think about the rooms in our homes, the inside of any animal or plant cell has many similar room-like structures called organelles. Each organelle is a place where specific jobs are done. Plant and animal cells have many of the same organelles.
But in some cases, the organelles in cells are different. For example, in plant cells, there are more types of organelles than are found in animal cells. And fungal cells have organelles not found in any other cell type. Below are some names and descriptions of organelles commonly found in certain cells. There is also an interactive cell viewer and game that can be used to learn about the parts of animal, plant, fungal, and bacterial cells.
Archaea cells are very similar to bacterial cells, so have not been included separately. Plasma membrane - The membrane enclosing a cell is made up of two lipid layers called a "bilipid" membrane. The lipids that are present in the plasma membrane are called "phospholipids. These lipid layers are made up of a number of fatty acid building blocks. The fatty acid that makes up this membrane has two different parts to it- a small water loving head- hydrophilic head.
Hydro stands for water and philic means liking or loving. The other part of this fatty acid is a long water-repelling or water hating tail. This tail is hydrophobic- Hydro stands for water and phobic means fear. The plasma membrane is arranged in such a way so that the tails face each other on the inside and the heads face towards the outside of the membrane.
This channel is made up of certain proteins that control the movement of molecules, including food and water, into the cell. Cell wall and plasmodesmata - In addition to cell membranes, plants have cell walls. Cell walls provide protection and support for plants. In land plants, the cell wall is mostly made of cellulose. Unlike cell membranes, materials cannot get through cell walls. This would be a problem for plant cells if not for special openings called plasmodesmata.
These openings are used to communicate and transport materials between plant cells because the cell membranes are able to touch and therefore exchange needed materials. Cell wall septum and pores - Fungal cells have both cell membranes and cell walls, like plant cells. Cell walls provide protection and support. Fungal cell walls are largely made of chitin, which is the same substance in insect exoskeletons. Because materials cannot get through cell walls, fungal cells have special openings called pores.
Materials can be moved between fungal cells through the pores. Some fungal cells also have a septum plural is septa that are special internal walls between cells that are found in long tube-shaped strings or strands called hyphae. DNA Deoxyribonucleic Acid contains all the information for cells to live, perform their functions and reproduce.
Inside the nucleus is another organelle called the nucleolus. The nucleolus is responsible for making ribosomes. The circles on the surface of the nucleus are the nuclear pores. These are where ribosomes, and other materials move in and out of the nucleus.
Nucleoid - Bacteria don't have a nucleus to hold their nuclear DNA. Instead, their DNA is found in the nucleoid. This structure has no protective membrane, but is tightly packed DNA material and also has some RNA and proteins in it. Endoplasmic reticulum ER - It is a network of membranes throughout the cytoplasm of the cell.
There are two types of ER. When ribosomes are attached it is called rough ER and smooth ER when there are no ribosomes attached. The rough endoplasmic reticulum is where most protein synthesis occurs in the cell. A cell consists of three parts: the cell membrane , the nucleus , and, between the two, the cytoplasm. Within the cytoplasm lie intricate arrangements of fine fibers and hundreds or even thousands of miniscule but distinct structures called organelles.
Every cell in the body is enclosed by a cell Plasma membrane. The cell membrane separates the material outside the cell, extracellular, from the material inside the cell, intracellular. It maintains the integrity of a cell and controls passage of materials into and out of the cell. All materials within a cell must have access to the cell membrane the cell's boundary for the needed exchange. The cell membrane is a double layer of phospholipid molecules.
Proteins in the cell membrane provide structural support, form channels for passage of materials, act as receptor sites, function as carrier molecules, and provide identification markers.
They have their own genetic material, separate from the DNA in the nucleus, and can make copies of themselves. The nucleus is surrounded by a membrane called the nuclear envelope, which protects the DNA and separates the nucleus from the rest of the cell. The plasma membrane is the outer lining of the cell. It separates the cell from its environment and allows materials to enter and leave the cell.
These organelles can float freely in the cytoplasm or be connected to the endoplasmic reticulum see above. Other chapters in Help Me Understand Genetics. Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. What is a cell? From Genetics Home Reference.
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