An extension of the Easy Peasy All-in-One Homeschool Nucleic Acids Nucleic acids are macromolecules containing hydrogen, oxygen, nitrogen, carbon and phosphorus.
Each nucleotide in DNA contains one of four possible nitrogenous bases: Adenine and guanine are purines, meaning that their structures contain two fused carbon-nitrogen rings.
Cytosine and thymine, in contrast, are pyrimidines and have a single carbon-nitrogen ring. RNA nucleotides may also bear adenine, guanine and cytosine bases, but instead of thymine they have another pyrimidine base called uracil U. As shown in the figure above, each base has a unique structure, with its own set of functional groups attached to the ring structure.
In molecular biology shorthand, the nitrogenous bases are often just referred to by their one-letter symbols, A, T, G, C, and U. These two are very similar in structure, with just one difference: Polynucleotide chains A consequence of the structure of nucleotides is that a polynucleotide chain has directionality — that is, it has two ends that are different from each other.
DNA sequences are usually written in the 5' to 3' direction, meaning that the nucleotide at the 5' end comes first and the nucleotide at the 3' end comes last. This makes a chain with each sugar joined to its neighbors by a set of bonds called a phosphodiester linkage.
Properties of DNA Deoxyribonucleic acid, or DNA, chains are typically found in a double helix, a structure in which two matching complementary chains are stuck together, as shown in the diagram at left.
The sugars and phosphates lie on the outside of the helix, forming the backbone of the DNA; this portion of the molecule is sometimes called the sugar-phosphate backbone.
The nitrogenous bases extend into the interior, like the steps of a staircase, in pairs; the bases of a pair are bound to each other by hydrogen bonds.
Structural model of a DNA double helix. This is referred to as antiparallel orientation and is important for the copying of DNA. So, can any two bases decide to get together and form a pair in the double helix?
The answer is a definite no. Because of the sizes and functional groups of the bases, base pairing is highly specific: A can only pair with T, and G can only pair with C, as shown below. This means that the two strands of a DNA double helix have a very predictable relationship to each other.
This allows each base to match up with its partner: The A-T pairs are connected by two hydrogen bonds, while the G-C pairs are connected by three hydrogen bonds.
When two DNA sequences match in this way, such that they can stick to each other in an antiparallel fashion and form a helix, they are said to be complementary.
Hydrogen bonding between complementary bases holds DNA strands together in a double helix of antiparallel strands. Thymine forms two hydrogen bonds with adenine, and guanine forms three hydrogen bonds with cytosine.
Image modified from OpenStax Biology. A nucleotide in an RNA chain will contain ribose the five-carbon sugarone of the four nitrogenous bases A, U, G, or Cand a phosphate group.
Here, we'll take a look at four major types of RNA: The transcript carries the same information as the DNA sequence of its gene.
Once an mRNA has been produced, it will associate with a ribosome, a molecular machine that specializes in assembling proteins out of amino acids.Nucleic acids are formed when nucleotides come together through phosphodiester linkages between the 5' and 3' carbon atoms.
A Nucleic acid sequence is the order of nucleotides within a DNA (GACT) or RNA (GACU) molecule that is determined by a series of letters.
Nucleic Acids 1. Introduction. The first isolation of what we now refer to as DNA was accomplished by Johann Friedrich Miescher circa He reported finding a weakly acidic substance of unknown function in the nuclei of human white blood cells, and named this material "nuclein".
The Nucleic Acids The nucleic acids are the building blocks of living organisms. You may have heard of DNA described the same way. Guess what? DNA is just one type of nucleic leslutinsduphoenix.com other types are RNA, mRNA, and tRNA.
-two amino acids join together to form a dipeptide -adjacent carboxyl and amino groups bond together -linked together to make proteins by removing a molecule of water in a process called condensation, or dehydration synthesis. Nucleic acid definition is - any of various complex organic acids (such as DNA or RNA) that are composed of nucleotide chains.
any of various complex organic acids (such as DNA or RNA) that are composed of nucleotide chains. The Nucleic Acids The nucleic acids are the building blocks of living organisms. You may have heard of DNA described the same way. Guess what? DNA is just one type of nucleic leslutinsduphoenix.com other types are RNA, mRNA, and tRNA.