What is Schwann cells?
Schwann cell, also called neurilemma cell, any of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons. Schwann cells are named after German physiologist Theodor Schwann, who discovered them in the 19th century.
How do Schwann cells work?
The way Schwann cells work is because Schwann cells are a variety glial cell that keep peripheral nerve fibres (both myelinated and un myelinated) alive. In myelinated axons, Schwann cells form the myelin sheath.
Drug Trials
Which drugs come form plants and microorganisms?
These are the drugs which come from plants :
- Opium poppy (heroin, morphine, codeine)
- Blue agave (Tequila)
- Coca leaves (cocaine)
- Ephedra sinica (Sudafed, meth)
- Psilocybin mushroom (shrooms)
- Willow bark (aspirin)
- Sassafras root (ecstasy)
- Penicillium mold (penicillin)
These are the drugs which come form micro organisms :
- Belladonna alkaloids
- Cinchona alkaloids
- Cocaine alkaloids
- Ergot alkaloids
- Opium alkaloids
- Rauwolfia alkaloids
- Xanthine alkaloids
Why drugs need to be tested before they are prescribed?
The reason why drugs need to be tested is similar to why most things are tested; it is to make sure the drug doesn’t cause any harm to the body and if the drug actually work for the reason why they are being prescribed.
Describe the main steps in the development and testing of a new drug? Give reasons for different parts of drug testing? (2 questions in 1 answer)
New drugs have to be tested otherwise it could be harmful towards a human. The way they would test it is by testing the drug on a computer model and human cells grown in the laboratory. This is the common part were most drugs fail the test as the drug either damage the cells or don’t work. This is an important part of the drug testing because if it was testing straight onto a human the human would be risking his life potentially. If the drug pass this part of the drug testing it would later on be tested on human volunteers. This is the part of the testing were side effects become known. This is also another important part of drug testing as the drug is now being tested on a real human being and this would let the doctors would know much more clearly the outcome of this drug. So Drug development is an expensive procedure and takes quite a while before you can prescribe i.
Antibodies
Explain what an antibody is in your own words?
An antibody is when the blood from the blood is formed to neutralize the antigen (a toxin or other foreign substance in the body). Antibodies come together to fight off an antigen which the body recognizes as usual. Examples of antigens are viruses, bacteria, unfamiliar substances in the blood. The leukocyte (white blood cell) goes around the blood and body fluids and is part of the antibodies which form to fight off the pathogen; there are 2 types of white blood cells which are T and B cells, the B cells are the ones which produce the antibodies.
What is the antibody role in preventing reinfection in diseases?
The antibody has no role what so ever in controlling viral infectious diseases. However the antibody does have a major sort of role with the resolution of bacterial infectious diseases. There are some cells around the body which help with the bacterial infection like phagocoyte white is capable of absorbing the bacteria. Another cell is the macrophage which can engulfs and digest unfamiliar substances (these are a type of white blood cells).
Transpiration
The process of transpiration is when water moves through plants from the roots to the leaves, then changes to vapor as it leaves the plant. Transpiration cools the plant and also provides it with nutrients, carbon dioxide and water. Water is necessary for plants but only a small amount of water taken up by the roots is used for growth and metabolism.
The rate of transpiration is dependent on a few different factors:
Temperature
As the temperature increases, the transpiration rate goes up. The openings in the plant that release the vapor are called stoma, and when the temperature is warm, the stoma are open. Colder temperatures cause the stoma to close.
Relative humidity
Because it is difficult for vapor to be released into damp air, the less humid it is, the higher the rate of transpiration.
Wind and air movement
The transpiration rate increases with increased air movement. One reason is because air movement is constantly bringing drier air close to the plant, which relates to relative humidity.
Soil and moisture availability
If the soil does not have enough water, the transpiration rate decreases.
Type of plant
The transpiration rate differs depending on the type of plant. Cacti, for example, conserve water and have low transpiration rates.
The process of transpiration is a very important procedure for plants. It creates a negative pressure gradient that helps draw water and minerals up through the plant from its roots. It also helps to keep the plants cool during hot weathers – a method of evaporation cooling.
Xylem – The vascular tissue in plants which conducts water and dissolved nutrients upwards from the root and also helps to form the woody element in the stem.
Stomata – Any of the minute pores in the epidermis (the outer layer of a tissue in a plant) of the leaf or stem of a plant, forming a slit of variable width which allows movement of gases in and out of the intercellular (located or occurring between cells) spaces.
Transpiration and water loss from leaves happen because of the way that leaves are adapted for efficient photosynthesis. The flat, thin shape of a leaf, its spongy mesophyll (the inner tissue of a leaf, containing many chloroplast) layer and stomata are adaptations that also allow water loss from the leaf.
Stem Cells Research
The google definition of Stem Cells :
‘An undifferentiated cell of a multi cellular organism which is capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation.’
The google reason why stem cells are controversial is :
The stem cell controversy is the consideration of the ethics of research involving the development, use, and destruction of human embryos. Most commonly, this controversy focuses on embryonic stem cells. Not all stem cell research involves the human embryos.
Ms Critchley Science Lichens Project
Task 1 :
Use a light microscope
State why microscopes are useful in the study of cell biology
Calculate total magnification
To calculate magnification the formula you have to do: length of magnified divided by the length of object
The invention of the microscope has opened up a whole new dimension in science. By using microscope scientists were able to discover the existence of microorganisms, study the structure of cells, and see the tiniest parts of fungi, plants, and animals.
Task 2 : Describe the difference between magnification and resolution.
Magnification is the ability to make small objects seem larger, such as making a microscopic organism visible.Resolution is the ability to distinguish two objects from each other. Light microscopy has limits to both its resolution and its magnification.
Task 3 : Describe the advantages and disadvantages of using a light and electron microscope.
Advantage :
Light microscopes advantage is that it can show a useful magnification only up to 1000 to 2000 times.
Electron microscopes have certain advantages over optical microscopes: The biggest advantage is that they have a higher resolution and are therefore also able of a higher magnification (up to 2 million times).
Disadvantage :
Light microscope disadvantages include limited resolution, lower magnification and poorer surface view of the specimen. Compound light microscope require the user to adjust to optical inversion, meaning the specimen will appear to be displaced in the opposite direction it is moved.
Electron microscopes have a range of disadvantages as well: They are extremely expensive. Sample preparation is often much more elaborate. It is often necessary to coat the specimen with a very thin layer of metal (such as gold).
Task 4 : Structures in prokaryotic cells :
The Prokaryotic Cell. Prokaryotes are unicellular organisms that lack organelles or other internal membrane-bound structures . Therefore, they do not have a nucleus, but, instead, generally have a single chromosome: a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid. Bacterial (prokaryotic) cells do not contain a nucleus however Eukaryotic cells do contain a nucleus.
Task 5 : The Comparison between prokaryotic cells and eukaryotic cells :
Prokaryotic – A prokaryote is a single-celled organism that lacks a membrane-bound nucleus (karyon), mitochondria, or any other membrane-bound organelle. Prokaryotes can be divided into two domains, Archaea and Bacteria.
Eukaryotic – An organism whose cells contain a nucleus surrounded by a membrane and whose DNA is bound together by proteins into chromosomes. The cells of eukaryotes also contain an endoplasmic reticulum and numerous specialized organelles not present in prokaryotes, especially mitochondria, Golgi bodies, and lysosomes.
Comparison – Both organisms are composed of cells, the basic unit of life, with each cell surrounded by a cell membrane. The biggest difference between prokaryotes and eukaryotes is that eukaryotes has a nucleus while prokaryotes doesn’t. They also have other membrane structures called organelles.
Explaination how Lichens can be environmental indicators.
Lichens can be used as air pollution indicators, especially of the concentration of sulfur dioxide in the atmosphere. Lichens are plants that grow in exposed places such as rocks or tree bark. They need to be very good at absorbing water and nutrients to grow there.
Natural Selection
Natural Selection is the process by which random evolutionary changes are chosen for by nature in a normal, same, orderly, non-random way. An example is the Main Land Tortoise and Island Tortoises. A Tortoise from the main land might have possibly traveled on a raft to get the the island. Once it arrived it laid its eggs. After thousands of years, because of random changes caused by decent with modification eventually transformed the island creatures and the main land creatures so much that they can no longer be considered the same species. The Tortoises wasn’t only randomly different to ancestors but they were specially adapted to their environment.
Hotel Rwanda – Scene of Close Analysis
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