Intermediate filaments play similar roles in the cell: providing a supporting framework within the cell. Provide support for microfilaments and microtubules by holding them in place. There are several types of intermediate filament, each constructed from one or more proteins characteristic of it. • keratins are found in epithelial cells and also form hair and nails; • nuclear lamins form a meshwork that stabilizes the inner membrane of the
Ribosomes Ribosomes are small spherical organelles, composed of two subunits, which can be found on the Rough Endoplasmic Reticulum (and also in the cytoplasm and in mitochondria, and other places). Attached to a network of membranes. Where protein synthesis takes place. Ribosomes translate genetic information in the form of mRNA into proteins. Rough ER (Endoplasmic Recticulum) The Endoplasmic Reticulum (ER) is found near the Nucleas and is made up of a number of flattened sacs called Cisternae, which are continuous with the Nuclear Envelope.
It can also be called nuclear envelope. The nuclear envelope has two membranes, each with the typical unit membrane structure. They enclose a flattened sac and are connected at the nuclear pore sites. The outermost membrane is continuous with the RER and has ribosomes attached. The space between the outer and inner membranes can fill with newly synthesized proteins just as the rough endoplasmic reticulum does.
| | | A) | endoplastic reticulum | | | B) | microtubules | | | C) | cytoplasm | | | D) | mitochondria | | | | | | Feedback: The cell's chemical processes take place in a semifluid material called the cytoplasm. This material provides an ideal environment for organelles because of its fluidity. | | 7 CORRECT | | This shows an example of endoplasmic reticulum. What is the significance of its structure? | | | A) | provides a location for DNA production | | | B) | helps decrease surface area | | | C) | allows selective permeability of cell membrane | | | D) | facilitates breakdown of chemical bonds | | | | | | Feedback: The pleats and folds of the endoplasmic reticulum provides a large surface area where cellular functions, such as breaking chemical bonds, can take place.
It control movement in and out of the Nucleus. The nucleolus is found in the nucleus and contains most of the cells genetic material. The chromatin is made up of DNA and proteins. Osmosis is the net movement of water through a semipermeable membrane from areas of a high concentration to areas of low concentrations. Diffusion is the net movement of a substance by the random movement of particles from areas of high concentrations to areas of low concentrations to reach equilibrium.
7. A distinctive feature of eukaryotes is the organization of their chromosomal DNA which is tightly packaged with proteins into a membrane-bound structure called a _______. 8. The delivery system of eukaryotic cells called the ______ complex can collect, package, modify, and transport molecules. 9.
There are two types of chromosomes (male or female) X and Y, also known as the sex chromosomes. The chemical responsible for inherited characteristics and gender. They are found within DNA and protein seen in a dividing cell. Cytoplasm: The cytoplasm refers to all cell material outside the nucleus but within the cell boundary. This is a gel like fluid where chemical reactions take place.
The membrane also contains proteins that can serve multiple functions such as transportation, communication and structure (Childs). Nucleus Function – The nucleus is the control center of the cell. The nucleus contains DNA, which holds the genetic material that is used to build and process the cell itself. The nucleus is responsible for genetic coding as well as regulating the genetic expression (Campbell, 2005, pg.107). Structure – The nucleus is encapsulated and protected by the nuclear envelope, which is a double lipid bilayer.
When the MRNA and tRNA bind the amino acid is deposited and binds with an adjacent amino acid forming a polypeptide chain and eventually (after modification by other organelles) forms a protein codes for proteins. A piece of DNA coding for a protein is called a gene. When the protein is produced, we say that the gene is expressed different form of the gene are called alleles which are codes which produce different proteins that lead to characteristics of an organism in general. Proteins are the expressed traits of organisms. Sometimes single proteins other times groups of proteins which account for the phenotype of an organism All organisms begin life a single cell.
The number of Golgi bodies in a cell varies according to its function. Animal cells contain 10-20 Golgi per cell. The Golgi apparatus is also responsible for producing lysosomes. Cell membrane: The electron microscope shows the cell membrane to be a lipid--*protein sandwich. The lipids are small, fatty molecules in two layers with larger protein molecules inserted at intervals partly or completely through the bi-layer.