Search results
Results from the WOW.Com Content Network
The site was updated in 2014 to replace the Standard Grade section with National 4 and National 5 sections. Gaelic versions of these were also made available. Until 2014, in the Higher section, Biology, English, Geography, Maths, Chemistry, History, Modern Studies, Physics and the Scotland-only subject Scottish Gaelic were available.
A past paper is an examination paper from a previous year or previous years, usually used either for exam practice or for tests such as University of Oxford, [1] [2] University of Cambridge [3] College Collections. Exam candidates find past papers valuable in test preparation.
The Department for Education has drawn up a list of core subjects known as the English Baccalaureate for England based on the results in eight GCSEs, which includes both English language and English literature, mathematics, science (physics, chemistry, biology, computer science), geography or history, and an ancient or modern foreign language.
Although the active site occupies only ~10–20% of the volume of an enzyme, [1]: 19 it is the most important part as it directly catalyzes the chemical reaction. It usually consists of three to four amino acids, while other amino acids within the protein are required to maintain the tertiary structure of the enzymes.
The citric acid cycle is an 8-step process involving 18 different enzymes and co-enzymes. During the cycle, acetyl-CoA (2 carbons) + oxaloacetate (4 carbons) yields citrate (6 carbons), which is rearranged to a more reactive form called isocitrate (6 carbons).
Ribbon diagram of a protease (TEV protease) complexed with its peptide substrate in black with catalytic residues in red.(. A protease (also called a peptidase, proteinase, or proteolytic enzyme) [1] is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. [2]
The rate acceleration conferred by enzymatic catalysis is often enormous—as much as 10 17-fold increase in rate over the uncatalysed reaction in the case of orotate decarboxylase (78 million years without the enzyme, 18 milliseconds with the enzyme). [63] The molecules bound and acted upon by enzymes are called substrates.
(The enzymes that digest polysaccharides, by contrast, are primarily produced by the walls of the intestines.) The cells are filled with secretory granules containing the precursor digestive enzymes. The major proteases, the pancreatic enzymes which work on proteins, are trypsinogen and chymotrypsinogen. Elastase is also produced. Smaller ...