Assignment: Eukaryotic Cells

Transfection: One of the methods of gene transfer where the genetic material is deliberately introduced into the animal cell in view of studying various functions of proteins and the gene. This mode of gene transfer involves creation of pores on the cell membrane enabling the cell to receive the foreign genetic material. Transfection can be carried out using calcium phosphate (i.e. tricalcium phosphate), by electroporation, by cell squeezing or by mixing a cationic lipid with the material to produce liposomes which fuse with the cell membrane and deposit their cargo inside. The choice of methods of DNA transfer depends upon the target cells in which transformation will be performed.

This can occur through vesicles that are formed by throttling the plasma membrane and then penetrating into the cell (endocytosis), or they merge with it to free their contents (exocytosis) outside. There are three types of endocytosis known: • phagocytosis - very common among unicellular protists, who use it to feed themselves; in the human body, some types of white blood cells incorporate cells and foreign substances into phagocytosis. • pinocytosis - a constant activity of pinocytosis is carried out by the endothelium, the tissue that covers the blood capillaries and which allows the cells of the surrounding tissues to withdraw fluids from the blood. • Receptor-mediated endocytosis - a quick and efficient method for withdrawing substances that can be found in the environment even at low concentrations. Finally, exocytosis is important for the secretion of many substances, including digestive enzymes produced by the pancreas and materials for the construction of the plant cell wall.

Throughout the urea cycle, the amino acid, arginine, is changes into ornithine- this is another amino acid when hydrated, that is when water was added. During this reaction, urea is the product formed (Nelson and Cox 2008). Figure 1 shows the urea cycle, occurs specifically in the mitochondria and cytosol in the liver. (Nelson and M.Cox 2008). Urea is made in the liver by means of enzymes in the urea cycle.

The membrane permeability of Beta vulgaris is affected by ethanol solution Introduction Cell membranes are the semi-permeable membrane that surrounds all cells. It separates the extracellular environment from the intercellular environment. It is a phospholipid bilayer which contains various proteins, lipids and carbohydrates all serving different purposes. It is this structure which allows for the transport of nutrients, proteins and water. (Nature.com, 2014).

While some common foods that are high in tyrosine are cheese, milk, and tofu. The samples experimented on in the lab also had contents of tryptophane and tyrosine. The skim, 2% milk and the powdered protein contained both Tryptophane and tryrosine while the Gelatin contained Tyrosine. To see the specific amounts per 100grams, refer to Table 2 in the results section.

When oxygen is breathed in, the red blood cells in the lungs have a low concentration of oxygen and a high concentration of carbon dioxide. Once the new oxygen molecules come into contact with the red blood cells they diffuse into the cells and down the concentration gradient and the carbon dioxide diffuses out of the red blood cells and out of the lungs. Both osmosis and simple diffusion of CO2 are processes that involve the movement of materials across a membrane. As for osmosis, it requires water in order to experience this movement where as simple diffusion of CO2 doesn’t require any additional help. Aquaporins are integral proteins that aid in the transfer of water across membranes via a channel.

Potassium ions diffuse out the cell due to the concentration gradient, creating a potential difference across the membrane. Other ions, such as sodium, are unable to cross the membrane and thus remain concentrated on one side. Consequently, the increased negative charge created inside the cell attracts potassium ions back across the membrane into the cell. This force is called electrostatic pressure. When the potential difference across the membrane is around -70mV, the electrical gradient exactly balances the chemical gradient and equilibrium is reached.

An enzyme is a biological catalyst (protein) which speeds up the rate of chemical reactions without changing the chemical reaction at the end. A chemical reaction is when a substance is changed into a different substance. To begin a reaction, you need energy which in this case is called activation energy. A reaction in a chemical reaction is called a substrate when it is being acted upon by an enzyme that speeds up the rate of a reaction. In addition, the region on the enzyme where the substrate binds is the active site.

The detergent attaches to the cell membrane and capture the protein and lipids of the cell membrane causing the cell to rupture. Then, the cell contents and DNA are released to the outside of the cell. The lysis buffer added causes the double stranded DNA in the cell to become single stranded DNA by disrupting the hydrogen bond between the bases. Next, acid is added to neutralize back the DNA to form double stranded DNA again. After centrifuge, the supernatant is collected as that is the plasmid while the pellet is the debris including protein and lipids.

The first one has REC8 in the protein complex, while the second and third groups have Rad21L and Rad21Scc1 resectively (Uhlmann, 2011). The Rad21L containing group is thought to act as a foundation for lateral-element formation because only Rad21L recruits SYCP1. When the recombination is complete, Rad21L gets dissociated from the complex as a result of phosphorylation. This dissociation can result in synaptonemal-complex disassembly. Thereafter, the meiotic cohesin complexes containing Rad21Scc1 is bound to the chromosomes (Figure 1.8) (Uhlmann,

Even though transport proteins are involved in facilitated diffusion, it is still considered passive transport because the solute is moving down its concentration gradient. Facilitated diffusion speeds up the transport of a solute by providing an efficient passage through the membrane, but it does not alter the direction of transport. Active transport requires energy to move a solute against its concentration gradient. As in most other cellular work, ATP will most often provide this energy, usually by transferring its terminal phosphate group directly to the transport protein. With ATP, the donated phosphate group induces the transport protein to change its shape in a manner that translocates the solute bound to the protein across the membrane.

Macromolecules are usually used to refer to large biological polymer which are made up of small monomers linked together. All living things contain organic macromolecules, which is divided into four main groups: Lipids, proteins, carbohydrates and nucleic acids. (D 'Onofrio, 2009-2015) Characteristic for these organic molecules is that they are made up of only a small number of elements: carbon, hydrogen, oxygen, and to smaller amounts nitrogen, phosphorus and sulfur. Carbohydrates are better known as sugars and starches. There are three main categories in which carbohydrates can be divided into: Monosaccharides, disaccharides and polysaccharides.