10)Movement of materials across membranes. Active transport. Group translocation.

Active transport is the movement of a substance against its concentration gradient (from low to high concentration). In all cells, this is usually concerned with accumulating high concentrations of molecules that the cell needs, such as ions, glucose, and amino acids. If the process uses chemical energy, such as fromadenosine triphosphate (ATP), it is termed primary active transport. Secondary active transport involves the use of an electrochemical gradient. Active transport uses energy, unlike passive transport, which does not use any type of energy. Active transport is a good example of a process for which cells require energy. Examples of active transport include the uptake of glucose in the intestines in humans and the uptake of mineral ions into root hair cells of plants. Many crucial processes in the life of cells depend upon active transport. Included in the illustration above is the sodium-potassium pump which is a vital cell process. Active transport mechanisms may draw their enegy from the hydrolysis of ATP, the absorbance of light, the transport of electrons, or coupling with other processes that are moving particles down their concentration gradients.

A vital active transport process that occurs in the electron transport process in the membranes of both mitochondria and chloroplasts is the transport of protons to produce a proton gradient. This proton gradient powers the phosphorylation of ATP associated with ATP synthase.

Group translocation is a form of active transport that can occur in prokaryotes. In this case of group translocation, a substance becomes chemically altered during its transport across a membrane so that once inside, the cytoplasmic membrane becomes impermeable to that substance and it remains within the cell. An example of group translocation in bacteria is the phosphotransferase system. A high-energy phosphate group from phosphoenolpyruvate is transferred by a series of enzymes to glucose. The final enzyme both phosphorylates the glucose and transports it across the membrane as glucose 6-phosphate.

The opening slide of this animation depicts a phospholipid bilayer cytoplasmic membrane, a cell wall, glucose and glucose 6-phosphate molecules, phosphoenolpyruvate, and a phosphotransferase transport system. Clicking on “play” labels the various parts of the illustration. Subsequently clicking on “continue” plays the animation and shows a high-energy phosphate group from phosphoenolpyruvate being transferred by a series of enzymes to glucose. The final enzyme then phosphorylates the glucose and transports it across the membrane as glucose 6-phosphate.

11.The emergence of microbiology. Discovery and description of microorganisms. Studies of Antony Van Leeuvenhoek. experimentations mainly of Girolamo Fracastoro, Robert Hooke, Francesco Redi, Lazzaro Spallanzani, Theodor Schwan.

Microorganisms were first discovered by two remarkable geniuses, Robert Hooke and

Antoni van Leeuwenhoek, between 1665 and 1678.

Priority in the discovery of microorganisms by a Dutch amateur naturalist Antonio Levenguk .A cloth merchant Leeuwenhoek fond grinding of glasses and brought the art to perfection by designing a microscope would allow the subjects discussed 300 times. By studying the different objects under a microscope (rain water, infusions, plaque, blood, feces, semen), A. Leeuwenhoek saw the smallest animals, whom he called animalkulyus. His observations A. Leeuwenhoek regularly reported to the Royal Society, and the v1695 was compiled in the book "Secrets of Nature, open Anthony Leeuwenhoek."

 In Micrographia (1665), Hooke presented the first published depiction of a microganism, the microfungus Mucor. Later, Leeuwenhoek observed and described microscopic protozoa and bacteria. These important revelations were made possible by the ingenuity of Hooke and Leeuwenhoek in fabricating and using simple microscopes that magnified objects from about 25-fold to 250-fold. After a lapse of more than 150 years, microscopy became the backbone of our understanding of the roles of microbes in the causation of infectious diseases and the recycling of chemical elements in the biosphere.

Robert Hooke first used the microscope for the study of plant and animal tissues. Studying the cut made ​​from cork and core elder, R. Hooke said that the composition of their introduces a number of very small structures, similar in shape to the cell honeycomb. He gave them the name of the cell or cells

 he did make a major contribution to microbiology in 1668 by disproving the Theory of Spontaneous Generation (also known as abiogenesis). He did this by proving maggots come from flies laying eggs. This took two separate experiments due to skeptics.

The first time around Redi put rotten meat in six jars. He covered three of the jars and left three open to the air. The three open to the air produced maggots because the flies could lay their eggs there. The covered jars did not because flies were not able to enter the jars. However, supporters of Spontaneous Generation claimed that it was lack of open air to the meat not egg-laying flies.

In response to the skeptics, Redi prepared a second trial. This time he covered three jars with a fine net and left the other three open to the air again. This left the jars covered by the net open to the air but prevented flies from entering the jars. Just as he had proved earlier when flies were prevented from entering the jars to lay eggs no maggots appeared. Francesco Redi performed some of the key early experiments showing thatspontaneous generation of life did not take place. His experiments showed that maggots would only occur in rotting meat if flies could land on it 

Lazzaro Spallanzani repeated John Needham's experiment in which nutrient fluids (Chicken broth) was put into a sealed flask then heated. The nutrient medium could be stored and microoganisms did not arise from it. This experiment disproved the Spontaneous Generation and paved the way for Pasteur's research. Spallanzani was largely criticised under claims that microorganisms needed oxygen to survive. He was also a pioneer in the fertilization an experiment which he produced with frogs.

Girolamo FracastoroIn his main work "On Contague about contagious diseases and treatment," he suggested that epidemics are caused by tiny particles ("seed"), carried by the patient through direct, indirect (or visual) contact. "Seeds" in terms of it closer to the atomistic or chemical elements than to the living beings.

The name for syphilis is derived from Fracastoro's 1530 epic poem in three books, Syphilis sive morbus gallicus ("Syphilis or The French Disease"), about a shepherd boy named Syphilus who insulted the sun god of Haiti and was punished by that god with a horrible disease. The poem suggests using mercury and "guaiaco" as a cure. His 1546 book (De contagione -- "On Contagion") also gave the first description for typhus. The collected works of Fracastoro appeared for the first time in 1555.

1836: Theodor Schwann (1810-1882) helped develop the cell theory of living organisms, namely that that all living organisms are composed of one or more cells and that the cell is the basic functional unit of living organisms.