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Major Elements in Biological Molecules: Nucleic acids

By: HWC, Views: 6608

DNA and RNA are nucleic acids (polymers of nucleotides). Two polymers with complementary nucleotide sequences can pair with each other. This pairing endows nucleic acids with the ability to store, transmit, and retrieve genetic information. Two strands of DNA pair by hydrogen bonding. A compon...

Mutations and translation

By: HWC, Views: 3194

A mutation, which may arise during replication and/or recombination, is a permanent change in the nucleotide sequence of DNA. Damaged DNA can be mutated either by substitution, deletion or insertion of base pairs. Mutations, for the most part, are harmless except when they lead to cell death or t...

Subunits of DNA And Semi Conservative Replication

By: HWC, Views: 3051

Adenine is a purine with a double-ring structure. In double-stranded DNA, adenine base-pairs with thymine. Guanine is a purine with a double-ring structure. In double-stranded DNA, guanine base-pairs with cytosine. Thymine is a pyrimidine with a single-ring structure. In double-stranded DNA, th...

DNA close up Animation

By: HWC, Views: 535

A section from a DNA double helix The backbone of each DNA strand consists of alternating deoxyribose sugars and phosphate groups. The two strands run in opposite directions. One runs from the 5' to 3' direction, the other in the 3' to 5' direction. Think of the deoxyribose units o...

Peptide Bond Formation Animation

By: HWC, Views: 497

During protein synthesis, peptide bonds link amino acids together in the order specified by DNA instructions. In this case, the first two amino acids in the protein are methionine and alanine. Here are ball-and-stick models of these amino acids. Peptide bond formation is a type of condensatio...

Polymerase chain reaction PCR - Animation

By: HWC, Views: 478

Polymerase chain reaction (PCR) is a method that amplifies fragments of DNA. The purpose of PCR is to create copies of a specific region of DNA. To use this technique, researchers must know the base sequences at either end of the region of interest. They use this information to create...

Structure of Amino Acid, Peptide Bonds & Polypeptides

By: HWC, Views: 6131

Here are the molecular formulas of three different amino acids. All amino acids share this backbone. The main difference between every amino acid is the side groups seen here, and these side groups give each of the amino acids their different characteristics. But before we get into that, let's ...

Acids and bases - definition

By: HWC, Views: 6592

Acids and bases are found all around your house. For example, if you open your pantry or refrigerator, you might see a lot of acids. Fruit juice, soda pop, vinegar, and milk are all examples of acids. The word acid actually comes from a Latin term meaning ''sour.'' Many materials, like sugar for ...

Appendicitis Animation

By: Administrator, Views: 9505

Appendectomy. The appendix and cecum are brought through the incision to the surface of the abdomen. The base of the appendix is clamped and ligated, and the appendix is then removed. McBurney’s point is the common location of pain in children and adolescents with appendicitis.