Biology Exam Revision : Cell Membrane

Essentially, the nucleus is vital for the cell’s survival. The nucleus controls and gives instructions to all organelles and inhabitants of the cell(Doc. 2). It is a dense, ball shaped configuration that contains the DNA of the cell.

My analogy is a hospital to an animal cell. The nucleus directs all of the cells’ activities. The nucleus is similar to a boss in a hospital in that it takes charge of these activities.

The protein-synthesizing machinery in mitochondria and chloroplasts resemble prokaryotes. This is shown through their ribosomal RNA and the structure of the ribosomes. The ribosomes are similar in size and structure to bacterial ribosomes. fMat is always the first amino acid that is in the mitochondria and chloroplasts transcripts. The antibiotics that act by blocking protein synthesis in bacteria also block protein synthesis in mitochondria and chloroplasts. These antibiotics do not interfere with protein synthesis in the cytoplasm of the eukaryotes. The inhibitors that effect the protein synthesis of eukaryotic ribosomes do not change the protein synthesis of the bacteria, mitochondria, or chloroplasts.

Nucleus – The nucleus is the largest organelle in the cell. It acts as the control system for almost all the activities of the cell. It stores the cell 's hereditary material, or DNA

The Transport of Substances Across the Plasma Membrane The plasma membrane or, the cell surface membrane, is made almost entirely of protein and lipid. The plasma membrane controls the movement of substances into and out of a cell. It is partially permeable so some substances cross more easily than others.

Nearly all animal cells have a nucleus, with the only exception being the red blood cell. The nucleus has two major functions, which are housing the DNA and controlling the cell’s activities. In the centre of the nucleus is the nucleolus. This doesn’t have a membrane, but holds itself together. In the nucleolus, ribosomes are created through the mixture of RNA and proteins. These proteins are originally found in the cytoplasm, outside the nucleus, but they travel through the pores in the nuclear envelope, through the chromatin and into the nucleolus. The structure of the nucleolus allows easy

They are very important in the synthesis and packaging of proteins. Some of those proteins might be used in the cell and some are sent out. The ribosomes are attached to the membrane of the ER. As the ribosomes builds the amino acid chain, the chain is pushed into the ER. When the protein is complete, the rough ER pinches off a vesicle. That vesicle, a small membrane bubble, can move to the cell membrane or the Golgi apparatus

Inside the nucleus is the nucleolus which produces ribosomes. The ribosomes then transport out of the nucleolus and to the rough endoplasmic reticulum for a process called protein synthesis. (Plant Cell Anatomy, n.d.)

The cell membrane consists of eight distinctive parts that each have their own unique structure and function. The phospholipid bilayer is an integral part of the cell membrane because it is the external layer of the cell membrane and composes the barriers that isolate the internal cell components and organelles from the extracellular environment. It is composed of a series of phospholipids that have a hydrophobic region and a hydrophilic region. These regions are composed of the hydrophilic heads and the hydrophobic tails of the phospholipids, this organization of the polar heads and nonpolar tails allows the heads of the cell to form hydrogen bonds with water molecules while the tails are able to avoid water. The phospholipid bilayer also has many important functions within the cell, it gives the cell shape, provides protection, and it is selectively permeable which allows it to only let very specific molecules pass through its surface. The phospholipid bilayer is an important structure because it prevents harmful and unwanted molecules from entering the cell and isolates organelles which helps to maintain the internal environmental homeostasis of the cell.

Next, SMS and cells have “ribosomes.” The function of the ribosome is to make proteins for the cell. The school has several cooks. They make food (and proteins) for students.

Choice B is incorrect because too much carbohydrates lead to the cause of coliform bacteria to die, not acidophilic bacteria. Acidophilic bacteria means acid loving bacteria, so the heightened ph would not kill them, it would make more of them grow. If more of them grow, the LPS that causes inflammation is not circulating, because they would only circulate if the bacteria dies.

Ribosomes are the structures in which proteins are made. Cells that are active in protein synthesis are often crowded with ribosomes. Ribosomes are composed of RNA and protein. Some ribosomes are attached to the membranes, and some are free in the cytoplasm. Ribosomes are among the smallest of organelles. They are no larger than 25 nanometers in diameter. A nanometer is equal to one billionth of a meter.

As you could see, I am a sphere shaped organelle that is surrounded by a nuclear membrane. The nucleoplasm that is found within me helps separate the nucleolus from this membrane. This nucleolus, or better known as Leo, helps in creating RNA and ribosomes and is the site for DNA to be wrapped in Chromatin. Now you may think that this bit of info. is nice to know, You may be wondering what can i do for the cell? Not only do i contain the cell’s DNA which

Nucleus- “the brain” or control center of the cell. The Nucleus, a membrane-bound structure of a cell, plays two crucial roles in controlling the cell. The nucleus carries the cell's genetic information that determines if the organism will develop, for instance, into a tree or a human; and it directs most cell activities including growth, metabolism, and reproduction by controlling protein synthesis. The presence of a nucleus distinguishes the more complex eukaryotic cells of plants and animals from the simpler prokaryotic cells of bacteria and cyanobacteria that lack a nucleus. The nucleus is the most predominate structure in the cell. It is typically round and occupies 10% of the cells total volume. The nucleus is wrapped in a

A membrane is the cell’s gatekeeper. This phospholipid bilayer says what molecules can move in or out of the cell. The cell membrane is also responsible for maintaining homeostasis. The cell membrane is semipermeable. They can control what molecules come in or out. There are two ways that molecules can move across the membrane. Passive mechanisms like diffusion dont use any energy while active transport uses energy to move molecules.