BIO.A.2 The Chemical Basis for Life
Topic Summary for :
Organic chemistry is the study of compounds with bonds between carbon atoms. Carbon atoms have four valence electrons, allowing them to form strong covalent bonds with many other elements, including hydrogen, oxygen, phosphorus, sulfur, and nitrogen. Living organisms are made up of molecules made of carbon and these other elements.
One carbon atom can bond to another to form chains and rings.
Carbon can form millions of different large and complex structures.
Many of the carbon molecules in living things are so large they are called macromolecules. Macromolecules form by polymerization, in which smaller units called monomers join together to form polymers. Biochemists sort the macromolecules in living things into groups based on their chemical composition.
Carbohydrates (starches and sugars) are composed of carbon, hydrogen, and oxygen. Carbohydrates are the main energy source for living things. Plants and some animals also use carbohydrates for structural purposes. Molecules with one sugar monomer are monosaccharides. A disaccharide is made of two monosaccharides.
Lipids (fats, oils, and waxes) are made mostly of carbon and hydrogen atoms. Lipids can be used to store energy and form parts of biological membranes and waterproof coverings. Steroids manufactured by the body are lipids as well.
Nucleic acids contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. They are polymers of nucleotides. A nucleotide has three parts: a 5-carbon sugar, a phosphate (–PO4) group, and a nitrogenous base. Nucleic acids store and transmit hereditary (genetic) information. There are two kinds of nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Proteins are made up of nitrogen, carbon, hydrogen, and oxygen. Proteins are polymers of amino acids. An amino acid molecule has an amino group (–NH2) on one end and a carboxyl group (–COOH) on the other end. Proteins control the rate of reactions, regulate cell processes, form cellular structures, carry substances into or out of cells, and help fight disease.
• More than 20 different amino acids are found in nature. Any amino acid can bond with any other.
• Covalent bonds called peptide bonds link amino acids together to form a polypeptide.
• Amino acids are assembled into polypeptide chains according to instructions coded in DNA.
Topic Summary for :
Organic chemistry is the study of compounds with bonds between carbon atoms. Carbon atoms have four valence electrons, allowing them to form strong covalent bonds with many other elements, including hydrogen, oxygen, phosphorus, sulfur, and nitrogen. Living organisms are made up of molecules made of carbon and these other elements.
One carbon atom can bond to another to form chains and rings.
Carbon can form millions of different large and complex structures.
Many of the carbon molecules in living things are so large they are called macromolecules. Macromolecules form by polymerization, in which smaller units called monomers join together to form polymers. Biochemists sort the macromolecules in living things into groups based on their chemical composition.
Carbohydrates (starches and sugars) are composed of carbon, hydrogen, and oxygen. Carbohydrates are the main energy source for living things. Plants and some animals also use carbohydrates for structural purposes. Molecules with one sugar monomer are monosaccharides. A disaccharide is made of two monosaccharides.
Lipids (fats, oils, and waxes) are made mostly of carbon and hydrogen atoms. Lipids can be used to store energy and form parts of biological membranes and waterproof coverings. Steroids manufactured by the body are lipids as well.
Nucleic acids contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. They are polymers of nucleotides. A nucleotide has three parts: a 5-carbon sugar, a phosphate (–PO4) group, and a nitrogenous base. Nucleic acids store and transmit hereditary (genetic) information. There are two kinds of nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Proteins are made up of nitrogen, carbon, hydrogen, and oxygen. Proteins are polymers of amino acids. An amino acid molecule has an amino group (–NH2) on one end and a carboxyl group (–COOH) on the other end. Proteins control the rate of reactions, regulate cell processes, form cellular structures, carry substances into or out of cells, and help fight disease.
• More than 20 different amino acids are found in nature. Any amino acid can bond with any other.
• Covalent bonds called peptide bonds link amino acids together to form a polypeptide.
• Amino acids are assembled into polypeptide chains according to instructions coded in DNA.