Experiments with blood transfusions, the transfer of blood or blood components into a person's blood stream, have been carried out for hundreds of years. Many patients have died and it was not until 1901, when the Austrian Karl Landsteiner discovered human blood groups, that blood transfusions became safer.
Mixing blood from two individuals can lead to blood clumping or agglutination. The clumped red cells can crack and cause toxic reactions. This can have fatal consequences. Karl Landsteiner discovered that blood clumping was an immunological reaction which occurs when the receiver of a blood transfusion has antibodies against the donor blood cells.
Karl Landsteiner's work made it possible to determine blood groups and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930.
What is blood made up of?
An adult human has about 4–6 liters of blood circulating in the body. Among other things, blood transports oxygen to various parts of the body.
Blood consists of several types of cells floating around in a fluid called plasma.
The red blood cells contain hemoglobin, a protein that binds oxygen. Red blood cells transport oxygen to, and remove carbon dioxide from, the body tissues.
The white blood cells fight infection.
The platelets help the blood to clot, if you get a wound for example.
The plasma contains salts and various kinds of proteins.
What are the different blood groups?
The differences in human blood are due to the presence or absence of certain protein molecules called antigens and antibodies. The antigens are located on the surface of the red blood cells and the antibodies are in the blood plasma. Individuals have different types and combinations of these molecules. The blood group you belong to depends on what you have inherited from your parents.
There are more than 20 genetically determined blood group systems known today, but the AB0 and Rh systems are the most important ones used for blood transfusions. Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals.
Nobel Laureate Karl Landsteiner was involved in the discovery of both the AB0 blood group (in 1901) and Rh blood group (in 1937).
AB0 blood grouping system
According to the AB0 blood group system there are four different kinds of blood groups: A, B, AB or 0 (null).
Blood group A If you belong to the blood group A, you have A antigens on the surface of your red blood cells and B antibodies in your blood plasma.
Blood group B If you belong to the blood group B, you have B antigens on the surface of your red blood cells and A antibodies in your blood plasma.
Blood group AB If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and no A or B antibodies at all in your blood plasma.
Blood group 0 If you belong to the blood group 0 (null), you have neither A or B antigens on the surface of your red blood cells but you have both A and B antibodies in your blood plasma.
The discovery of the relationship between magnetism and electricity was, like so many other scientific discoveries, stumbled upon almost by accident. The Danish physicist Hans Christian Oersted was lecturing one day in 1820 on the possibility of electricity and magnetism being related to one another, and in the process demonstrated it conclusively by experiment in front of his whole class! By passing an electric current through a metal wire suspended above a magnetic compass, Oersted was able to produce a definite motion of the compass needle in response to the current. What began as conjecture at the start of the class session was confirmed as fact at the end. Needless to say, Oersted had to revise his lecture notes for future classes! His serendipitous discovery paved the way for a whole new branch of science: electromagnetics.
Detailed experiments showed that the magnetic field produced by an electric current is always oriented perpendicular to the direction of flow. A simple method of showing this relationship is called the left-hand rule. Simply stated, the left-hand rule says that the magnetic flux lines produced by a current-carrying wire will be oriented the same direction as the curled fingers of a person's left hand (in the "hitchhiking" position), with the thumb pointing in the direction of electron flow:
The magnetic field encircles this straight piece of current-carrying wire, the magnetic flux lines having no definite "north" or "south' poles.
While the magnetic field surrounding a current-carrying wire is indeed interesting, it is quite weak for common amounts of current, able to deflect a compass needle and not much more. To create a stronger magnetic field force (and consequently, more field flux) with the same amount of electric current, we can wrap the wire into a coil shape, where the circling magnetic fields around the wire will join to create a larger field with a definite magnetic (north and south) polarity:
The amount of magnetic field force generated by a coiled wire is proportional to the current through the wire multiplied by the number of "turns" or "wraps" of wire in the coil. This field force is called magnetomotive force (mmf), and is very much analogous to electromotive force (E) in an electric circuit.
An electromagnet is a piece of wire intended to generate a magnetic field with the passage of electric current through it. Though all current-carrying conductors produce magnetic fields, an electromagnet is usually constructed in such a way as to maximize the strength of the magnetic field it produces for a special purpose. Electromagnets find frequent application in research, industry, medical, and consumer products.
As an electrically-controllable magnet, electromagnets find application in a wide variety of "electromechanical" devices: machines that effect mechanical force or motion through electrical power. Perhaps the most obvious example of such a machine is the electric motor.
Another example is the relay, an electrically-controlled switch. If a switch contact mechanism is built so that it can be actuated (opened and closed) by the application of a magnetic field, and an electromagnet coil is placed in the near vicinity to produce that requisite field, it will be possible to open and close the switch by the application of a current through the coil. In effect, this gives us a device that enables elelctricity to control electricity:
Relays can be constructed to actuate multiple switch contacts, or operate them in "reverse" (energizing the coil will open the switch contact, and unpowering the coil will allow it to spring closed again).
REVIEW:
When electrons flow through a conductor, a magnetic field will be produced around that conductor.
The left-hand rule states that the magnetic flux lines produced by a current-carrying wire will be oriented the same direction as the curled fingers of a person's left hand (in the "hitchhiking" position), with the thumb pointing in the direction of electron flow.
The magnetic field force produced by a current-carrying wire can be greatly increased by shaping the wire into a coil instead of a straight line. If wound in a coil shape, the magnetic field will be oriented along the axis of the coil's length.
The magnetic field force produced by an electromagnet (called the magnetomotive force, or mmf), is proportional to the product (multiplication) of the current through the electromagnet and the number of complete coil "turns" formed by the wire.
Biochemistry is the study of the structure, composition, and chemical reactions of substances in living systems. Biochemistry emerged as a separate discipline when scientists combined biology with organic, inorganic, or physical chemistry and began to study such topics as how living things obtain energy from food, the chemical basis of heredity, and what fundamental changes occur in disease. Biochemistry includes the sciences of molecular biology; immunochemistry; neurochemistry; and bioinorganic, bioorganic, and biophysical chemistry.
Has a Wide Range of Applications
Biochemistry is applied to medicine, dentistry, and veterinary medicine. In food science, biochemists research ways to develop abundant and inexpensive sources of nutritious foods, determine the chemical composition of foods, develop methods to extract nutrients from waste products, or invent ways to prolong the shelf life food products. In agriculture, biochemists study the interaction of herbicides with plants. They examine the structure-activity relationships of compounds, determine their ability to inhibit growth, and evaluate the toxicological effects on surrounding life.
Biochemistry spills over into pharmacology, physiology, microbiology, and clinical chemistry. In these areas, a biochemist may investigate the mechanism of a drug action; engage in viral research; conduct research pertaining to organ function; or use chemical concepts, procedures, and techniques to study the diagnosis and therapy of disease and the assessment of health.
Work in the field of biochemistry is often related to toxicology. Rogene Henderson, senior scientist and supervisor of the Biochemical Toxicology Group at Lovelace Respiratory Research Institute, does research to understand ways in which organic compounds in the body are changed by enzymes into toxic metabolites. Henderson focuses on determining the health effects of inhaled pollutants. She develops chemical analytical techniques to detect pollutants and their metabolites in body tissues and fluids, uses mathematics to describe the relationships between the air and body concentrations of these chemicals or their metabolites, and determines how these concentrations change with time.
Is Interacting With Scientists from Many Disciplines
Real-world problems seldom come neatly packaged for one discipline to study, says Henderson. For example, our institute collaborated with the Department of Energy to investigate the health effects of an increased number of diesel-powered cars on the road. To address this problem, we needed engineers, aerosol scientists, veterinarians, analytical chemists, pathologists, and mathematicians as well as biochemists to work as a team. In another scenario, Henderson explains that she often interacts with people outside of her organization, for example, those who sponsor her work. She adds, Much of my work is related to regulation of air pollutants, and the research that I do is often audited by those who have an interest in the regulatory process.
David Green, senior research investigator in cardiovascular drug discovery, echoes the sentiment that interaction with others is an integral part of the job. Green specializes in enzymology; he identifies and characterizes enzymes as drug discovery targets. Green states, My projects vary, but a common element is working with people from different disciplines physiology or medicinal chemistry, for example to find a compound that can be used in clinical trials. Green says that he finds interacting with other scientists the best part of his job.
The underlying principle of biochemistry is understanding the structure of living systems. By understanding the structure of something, a scientist has a vital start to understanding its function. As an associate professor of chemistry at the Massachusetts Institute of Technology, Jamie Williamson undertook the study of the structures of virus-producing proteins in order to supply other researchers with the information needed to develop ways (drugs) to control the action of the proteins and, hence, the virus.
Williamson says, This exchange of information is one of the most gratifying things about being a researcher. The information and insight that you possess makes you a valuable scientist. So, the more you share your information, the better. Green explains, The desire to discover truths about nature and provide products that can improve the quality of peoples lives is what has driven me in my work.
Studying the cell and chemistry of life results in valuable contributions being made in medicine, industry, and society. This knowledge is used in fighting illness and improving the quality of life, making the field interesting, challenging, rewarding, and full of opportunity. Williamson explains, Biochemistry is a vast, huge field. Although we already understand much about how cells work, we really have just scratched the surface. The field is wide open.
Work Description
Biochemists study the chemical components and processes of living systems plants, insects, viruses, microorganisms, and mammals to explain how and why chemical reactions occur. Their work contributes to many fields of science.
Working Conditions
Biochemists work in modern research laboratories that stimulate creative work. Often they interact with scientists and specialists from other fields because their research is tied to another discipline. Biochemistry´s application to other fields and its focus on improving the quality of our lives means that laboratory research is guided by strict guidelines. The results often are presented to others who have an outside interest in the work.
Places of Employment
Colleges and universities employ the majority of biochemists as teachers or researchers in schools of arts and sciences, medicine, engineering, pharmacy, dentistry, veterinary medicine, and agriculture. The Department of Agriculture, the National Institutes of Health, and the Environmental Protection Agency are just a few of the government agencies that employ biochemists specializing in basic research analyzing food, drugs, air, water, waste, or animal tissue. Industries that produce pharmaceuticals, agricultural chemicals, foods, feeds, and consumer products also employ biochemists in research as well as in areas outside the lab such as marketing, management, science information, technical writing, and editing. Drug companies employ biochemists to research the causes of disease and to develop drugs to combat these diseases. Biotechnology companies employ biochemists in research quality control, clinical research, manufacturing, and information systems with applications to the environment, energy, human health care, agriculture, and animal health. Some biochemists work in hospitals.
Glycolysis literally means "splitting sugars." In glycolysis, glucose (a six carbon sugar) is split into two molecules of a three-carbon sugar. Glycolysis yields two molecules of ATP (free energy containing molecule), two molecules of pyruvic acid and two "high energy" electron carrying molecules of NADH. Glycolysis can occur with or without oxygen. In the presence of oxygen, glycolysis is the first stage of cellular respiration. Without oxygen, glycolysis allows cells to make small amounts of ATP. This process is called fermentation.
10 Steps of Glycolysis
Step 1
The enzyme hexokinase phosphorylates (adds a phosphate group to) glucose in the cell's cytoplasm. In the process, a phosphate group from ATP is transferred to glucose producing glucose 6-phosphate.
The enzyme phosphoglucoisomerase converts glucose 6-phosphate into its isomer fructose 6-phosphate. Isomers have the same molecular formula, but the atoms of each molecule are arranged differently.
The enzyme aldolase splits fructose 1, 6-bisphosphate into two sugars that are isomers of each other. These two sugars are dihydroxyacetone phosphate and glyceraldehyde phosphate.
The enzyme triose phosphate isomerase rapidly inter-converts the molecules dihydroxyacetone phosphate and glyceraldehyde phosphate. Glyceraldehyde phosphate is removed as soon as it is formed to be used in the next step of glycolysis.
Net result for steps 4 and 5: Fructose 1, 6-bisphosphate (C6H10O6P2) ↔ 2 molecules of Glyceraldehyde phosphate (C3H5O3P1)
Step 6
The enzyme triose phosphate dehydrogenase serves two functions in this step. First the enzyme transfers a hydrogen (H-) from glyceraldehyde phosphate to the oxidizing agent nicotinamide adenine dinucleotide (NAD+) to form NADH. Next triose phosphate dehydrogenase adds a phosphate (P) from the cytosol to the oxidized glyceraldehyde phosphate to form 1, 3-bisphosphoglycerate. This occurs for both molecules of glyceraldehyde phosphate produced in step 5.
B. Triose phosphate dehydrogenase + 2 P + 2 glyceraldehyde phosphate (C3H5O3P1) → 2 molecules of 1,3-bisphosphoglycerate (C3H4O4P2)
Step 7
The enzyme phosphoglycerokinase transfers a P from 1,3-bisphosphoglycerate to a molecule of ADP to form ATP. This happens for each molecule of 1,3-bisphosphoglycerate. The process yields two 3-phosphoglycerate molecules and two ATP molecules.
2 molecules of 1,3-bisphoshoglycerate (C3H4O4P2) + phosphoglycerokinase + 2 ADP → 2 molecules of 3-phosphoglycerate (C3H5O4P1) + 2 ATP
Step 8
The enzyme phosphoglyceromutase relocates the P from 3-phosphoglycerate from the third carbon to the second carbon to form 2-phosphoglycerate.
2 molecules of 3-Phosphoglycerate (C3H5O4P1) + phosphoglyceromutase → 2 molecules of 2-Phosphoglycerate (C3H5O4P1)
Step 9
The enzyme enolase removes a molecule of water from 2-phosphoglycerate to form phosphoenolpyruvic acid (PEP). This happens for each molecule of 2-phosphoglycerate.
2 molecules of 2-Phosphoglycerate (C3H5O4P1) + enolase → 2 molecules of phosphoenolpyruvic acid (PEP) (C3H3O3P1)
Step 10
The enzyme pyruvate kinase transfers a P from PEP to ADP to form pyruvic acid and ATP. This happens for each molecule of PEP. This reaction yields 2 molecules of pyruvic acid and 2 ATP molecules.
2 molecules of PEP (C3H3O3P1) + pyruvate kinase + 2 ADP → 2 molecules of pyruvic acid (C3H4O3) + 2 ATP
Summary
In summary, a single glucose molecule in glycolysis produces a total of 2 molecules of pyruvic acid, 2 molecules of ATP, 2 molecules of NADH and 2 molecules of water.
Although 2 ATP molecules are used in steps 1-3, 2 ATP molecules are generated in step 7 and 2 more in step 10. This gives a total of 4 ATP molecules produced. If you subtract the 2 ATP molecules used in steps 1-3 from the 4 generated at the end of step 10, you end up with a net total of 2 ATP molecules produced. For a detailed view of the 10 steps, see: Details of the 10 Steps of Glycolysis.
The periodic table of the chemical elements (also known as the periodic table or periodic table of the elements) is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasingatomic number, the number of protons in an atom's atomic nucleus. While rectangular in general outline, gaps are included in the horizontal rows (known as periods) as needed to keep elements with similar properties together in vertical columns (known as groups), e.g. alkali metals, alkali earths, halogens, noble gases.[1]
The following is the periodic table as defined by the IUPAC:
Group #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Period
1
1 H
2 He
2
3 Li
4 Be
5 B
6 C
7 N
8 O
9 F
10 Ne
3
11 Na
12 Mg
13 Al
14 Si
15 P
16 S
17 Cl
18 Ar
4
19 K
20 Ca
21 Sc
22 Ti
23 V
24 Cr
25 Mn
26 Fe
27 Co
28 Ni
29 Cu
30 Zn
31 Ga
32 Ge
33 As
34 Se
35 Br
36 Kr
5
37 Rb
38 Sr
39 Y
40 Zr
41 Nb
42 Mo
43 Tc
44 Ru
45 Rh
46 Pd
47 Ag
48 Cd
49 In
50 Sn
51 Sb
52 Te
53 I
54 Xe
6
55 Cs
56 Ba
*
72 Hf
73 Ta
74 W
75 Re
76 Os
77 Ir
78 Pt
79 Au
80 Hg
81 Tl
82 Pb
83 Bi
84 Po
85 At
86 Rn
7
87 Fr
88 Ra
**
104 Rf
105 Db
106 Sg
107 Bh
108 Hs
109 Mt
110 Ds
111 Rg
112 Cn
113 Uut
114 Uuq
115 Uup
116 Uuh
117 Uus
118 Uuo
* Lanthanides (Lanthanoids)
57 La
58 Ce
59 Pr
60 Nd
61 Pm
62 Sm
63 Eu
64 Gd
65 Tb
66 Dy
67 Ho
68 Er
69 Tm
70 Yb
71 Lu
** Actinides (Actinoids)
89 Ac
90 Th
91 Pa
92 U
93 Np
94 Pu
95 Am
96 Cm
97 Bk
98 Cf
99 Es
100 Fm
101 Md
102 No
103 Lr
This common arrangement of the periodic table separates the lanthanides (lanthanoids) and actinides (actinoids) (the f-block) from other elements. The wide periodic table incorporates the f-block. The extended periodic table adds the 8th and 9th periods, incorporating the f-block and adding the theoretical g-block.
Element categories in the periodic table
Metals
Metalloids
Nonmetals
Unknown chemical properties
Alkali metals
Alkaline earth metals
Inner transition metals
Transition metals
Post-transition metals
Other nonmetals
Halogens
Noble gases
Lanthanides
Actinides
Atomic number colors show state of matter at standard conditions (0 °C and 1 atm):
Solids
Liquids
Gases
Unknown
Borders show natural occurrence:
Primordial
From decay
Synthetic
Although there were precursors, the current presentation's invention is generally credited to Russian chemist Dmitri Mendeleev, who developed a version of the now-familiar tabular presentation in 1869 to illustrate recurring ("periodic") trends in the properties of the then-known elements.[2] The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behavior.[3]
Since the periodic table accurately predicts the abilities of various elements to combine into chemical compounds, use of the periodic table is now ubiquitous within the academic discipline of chemistry, providing a useful framework to classify, systematize, and compare many of the many different forms of chemical behavior. The table has found many applications not only in chemistry and physics, but also in such diverse fields as geology, biology, materials science, engineering, agriculture, medicine, nutrition, environmental health, and astronomy. Its principles are especially important in chemical engineering.
One of the strengths of Mendeleev's presentation is that the original version accurately predicted of the properties of then-undiscovered elements expected to fill gaps in his arrangement. For example: "eka-aluminium", expected to have properties intermediate betweenaluminium and indium, was discovered with said properties in 1875 and named gallium. No gaps remain in the current 118-element periodic table; all elements from hydrogen to plutonium except technetium, promethium and neptunium exist in the Earth in macroscopic or recurrently produced trace quantities. The three said exceptions do exist naturally, but only in trace amounts as the result of rare nuclear processes from decay of heavy elements. Every element through Copernicium, element 112, has been isolated, characterized, and named, and elements 113 through 118 have been synthesized in laboratories around the world.
While plutonium is now included among the 91 regularly occurring natural elements, and technetium, promethium, and neptunium also occur naturally in transient trace amounts, these four elements were first identified and characterized from technologically produced samples. Numerous synthetic radionuclides of various naturally occurring elements have been produced as well.
Production of additional synthetic elements beyond atomic number 118 is being pursued; whether the next elements will neatly fill an eighth period or require modifications to the overall patterns of the present periodic table remains unknown.
Blood Groups 
The white blood cells fight infection.
