20 Facts on Carbohydrat

1. Carbohydrate is one of the four macro-molecules .
2. The main function of carbohydrates is to store energy. They are the main energy source in living organisms.
3. Carbohydrates contain carbon, oxygen and hydrates only.
4. Monosaccharide can be divided into Aldoses and ketoses. Aldoses are the sugars that contain an aldehyde group at the end such as glucose. Differently, ketoses have a ketone group (most likely at C2) , one of the examples of ketoses is Fructose. 
5. Sugars are usually seen in pentatoses ( 5 carbons ) or hexoses (6 carbons ). In order to become stable, they generally would form a ring at where the carbonyl group is at. 
6. Fructose and glucose are both hexoses, even though fructose forms a ring of five carbons with one extra carbon attaches on the C5.
7. Sugars are not plain 2D diagrams but in real life it can be presented into two ways -- "chair" and "boat".However chair form is more stable.
8. Glycosidic bonds are formed when two sugars combine though a process of condensation (dehydration synthesis) . In which the water is produced in order to link two carbohydrates together. 
9. Opposite to condensation is the synthesis of hydrolysis. The process of separate two sugars by adding in the water.
10. Disaccharides means the molecule combined from two monosaccharides. Examples of disaccharides are : maltose,  a starch formed by two glucose (C1-4). Sucrose, commonly known as table sugar in which is formed by glucose and fructose. Lactose, it is found in the milk and formed from galactose with glucose.
11. The shape of α linkage looks like two molecules are "holding hands" and "pointing". Examples: Maltose, Sucrose.
12. The shape of β linkage is looks more similar as a straight line rather than α linkage. Example: Lactose.
13. Carbohydrate polymers ( such as starch, glycogen and cellulose ) are formed from many monosaccharides connected together with glycosidic linkages. 
14. Amylose is a glucose polymer with α(1-4) linkages. It normally presents in a single helix shape.
15. Amylopection is a glucose polymer with mainly α(1-4) linkage, but few of α(1-6) linkages in which is able to produce multiple chains. 
16. The polymer of energy storage in animals is called glycogen, in which is a glucose polymer with α(1-4) linkages and α(1-6) linkages. However, it contains more α(1-6) linkages than amylopectin so it is able to form more branches than amylopectin.
17. In order for the plant cells to keep its shape, the cell walls of plant cells contains cellulose. Cellulose has long chains of glucose with β(1-4) linkages in which stabilizes its shape. 
18. Humans are unable to digest cellulose in the plants ( such as grass or vegetables) due to the lack of the appreciate enzyme to breakdown the β linkages. Unlike humans, animals such as sheep or cow has the symbolic enzymes in the intestinal tract that allows them to digest the plants.
19. Oligosaccharides means few monosaccharides are joined together either in linear or branched chains. They covalently attached to proteins or to membrane lipids.
20. Selectins are integral proteins of the plasma membrane with lectin-like domain that protrude on the outer surface of mammalian cells. 

Notes on Restriction Endonuleases, Gel Electrophoresis, Plasmid and Transformation

Compare & Contrast : Replication, Transcription and Translation

Five of the Great Scientists in the Genetics Field

Hugo De Vries (February 16,1848 - May 21, 1935)
De Vries is one of the first geneticists. Both De Vries and Mendel had worked on the research of the discovery of the law of heredity with the unawareness of each other. He is also known suggesting the concept of the genes. In which himself called this particle contains inheritance traits as pangenes.  He introduced the theory of mutation, in which he believed species evolve one from another through sudden changes in traits. 

Thomas Hunt Morgan ( September 25, 1866 - December 4, 1945)

Morgan was initially again the theory of chromosomes contain inheritance traits. He worked with his students in Columbia University, together they studied the reproduction of the Drosophila melanogaster (a common seen type of fruit flies). He then became a big supporter of the idea of the chromosomes passes down the inheritance traits. Morgan and his students provided proofs for the chromosomal theory of inheritance. They also worked out the evidence for genetic linkage in which is the concept that there are more than one genes located on the same chromosome. Their research also include non-disjunction and chromosomal crossing over.

Walter S.Sutton (April 5, 1877 - November 10, 1916)

Sutton is an American scientist who applied Medal's Law of inheritance to the chromosomes and concluded the chromosomes are the basis of inheritance. He observed each chromosome in the grasshoppers' cell are clearly different. The chromosomes reduce the number of chromosomes in gametes. Sutton published his work in 1903. However, he never finished his research. He entered medical school and became a surgeon, then served in WWI as a doctor. He died at age of 39.

Rosalind Franklin (July, 25,1920-April 16,1958)
She is the first person who took a clear picture of the structure of DNA with X-ray diffraction technique. In which later it has helped Watson and Crick with the building the 3D molecular structure of DNA. Her picture of DNA has shown a clear "X" shape. This discovery prompted Watson and Crick that DNA is not a straight ladder but instead it is a twisted double helix. The Double Helix structure is "protecting" the hydrogen bonds in DNA from denaturing by the water. Unfortunately, she died 4 years earlier before the Nobel Prize in 1962 most likely due to the frequent exposure to X-ray.


Barbara McClintock (June 16, 1902 - September 2, 1992) 
McClintock awarded the Nobel Prize of 1983 in Physiology or Medicine for her discovery of the transposition of corn chromosomes. She realized the maize (corn) husks have different colors and the corn kernels have spots. She worked on her observation at the Cold Spring Harbor Laboratory. McClintock then found the existence of "jumping" genes, she is the first one who recognized this element. She concluded from her work that the small segment of DNA "jumps" between different chromosomes, and this action leads to activate or deactivate of certain traits.




Bibliography 

"Barbara McClintock." National-Academies.org | Where the Nation Turns for Independent, Expert Advice. Web. 12 Feb. 2012. <http://www.nas.edu/history/members/mcclintock.html>. 

"Hugo De Vries :: DNA from the Beginning." DNA from the Beginning - An Animated Primer of 75 Experiments That Made Modern Genetics. Web. 11 Feb. 2012. <http://www.dnaftb.org/6/bio.html>. 

"Rosalind Franklin Biography | Genius of Britain | Athena." Athena - Engage Your Mind | Expand Your World. Web. 10 Feb. 2012. <http://www.athenalearning.com/programs/genius-britain/rosalind-franklin-bio>. 

"Thomas Hunt Morgan :: DNA from the Beginning." DNA from the Beginning - An Animated Primer of 75 Experiments That Made Modern Genetics. Web. 12 Feb. 2012. <http://www.dnaftb.org/10/bio.html>. 

"Walter Stanborough Sutton :: DNA from the Beginning." DNA from the Beginning - An Animated Primer of 75 Experiments That Made Modern Genetics. Web. 11 Feb. 2012. <http://www.dnaftb.org/8/bio-2.html>.