Chapter 24 The Chemistry of Life – Flashcards
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| What are the two major types of cells that occur in nature? |
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| two major cell types occur in nature: the cells of bacteria, known as prokaryotic cells, and the cells of all other organisms, known as eukaryotic cells. |
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| What compound is reduced during photosynthesis? What compounds are formed? |
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| Photosynthesis uses the energy from sunlight to reduce carbon dioxide to compounds that contain C-H bonds, mainly in the form of glucose(C6H12O6). |
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| Photosynthesis |
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| a light-capturing system within the chloroplast that converts light energy into chemical energy. |
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| Where is glucose found abundantly in nature? |
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| glucose is abundant in plants and animals. |
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| How can the cyclic forms of two simple sugars be linked? |
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| the cyclic forms of two simple sugars can be linked by means of a condensation reaction. |
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| Carbohydrates |
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| monomers and polymers of aldehydes and keytones that have numerous hydroxyl groups attached; they are made up of carbon, hydrogen, and oxygen. |
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| Monosaccharides |
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| the simplest carbohydrate molecules are also called simple sugars or... |
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| Disaccharides |
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| a carbohydrate formed from two monosaccharides. Ex: table sugar (sucrose). |
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| Polysaccharides |
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| the polymers produced by the linkage of many monosaccharide monomers. |
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| What is the general structure of an amino acid? |
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| amino acids have a skeleton that consists of a carboxyl group and an amino group, both of which are covalently bonded to a central carbon atom. The remaining two groups on the central carbon atom are hydrogen and an R group that constitutes the amino acid side chain. |
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| Which functional groups are always involved in amide bonds between amino acids? |
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| the amide bond between amino acids always involve the central amino and central carboxyl groups. The side chains are not involved in the bonding. |
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| What determines the differences in the chemical and physiological properties of peptides and proteins? |
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| differences in the chemical and physiological properties of peptides and proteins result from differences in the amino acid sequence. |
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| How do enzymes affect the rates of reactions in living things? |
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| enzymes increase the rates of chemical reactions in living things. |
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| Amino acid |
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| any compound that contains an amino group(-NH2) and a carboxyl group(-COOH) in the same molecule. |
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| Peptide |
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| any combination of amino acids in which the amino group of one amino acid is united with the carboxyl group of another amino acid. |
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| Peptide bond |
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| the amide bond between the carboxyl group of one amino acid and the nitrogen in the amino group of the next amino acid in the peptide chain. |
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| Protein |
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| a peptide with more than about 100 amino acids. |
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| Enzymes |
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| proteins that act as biological catalysts. |
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| Substrates |
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| the molecules on which an enzyme acts. |
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| Active site |
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| the place on a enzyme where a substrate binds. |
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| What physical property distinguishes lipids from other classes of biological molecules? |
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| Lipids tend to dissolve readily in organic solvents, such as ether and chloroform, rather than in highly polar solvents such as water. This property sets them apart from most biological substances such as carbohydrates and proteins. |
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| How do phospholipid molecules arrange themselves in water? |
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| in water, phospholipids spontaneously form a spherical double layer, called a lipid bilayer, in which the hydrophobic tails of phospholipid molecules are sandwiched between two layers of hydrophilic heads. |
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| Lipids |
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| fats, oils, and other water-insoluble compounds. |
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| Triglyceride |
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| an ester in which all three hydroxyl groups on a glycerol molecule have been replaced by long-chain fatty acids (C12-C24). Ex: fats |
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| Saponification |
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| the hydrolysis of oils or fats by boiling with an aqueous solution of an alkali-metal hydroxide. |
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| Phospholipids |
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| lipids that contain phosphate groups. |
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| Waxes |
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| esters of long-chain fatty acids and long-chain alcohols. |
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| What are the functions of DNA and RNA? |
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| DNA stores the information needed to make proteins and governs the reproduction and growth of cells and new organisms. RNA has a key role in the transmission of the information stored in DNA and in the synthesis of proteins. |
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| How long a base sequence of DNA is required to specify one amino acid in a peptide chain? |
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| Three bases of DNA arranged in a specific sequence are required to specify one amino acid in a peptide or protein chain. |
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| What are gene mutations? |
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| substitutions, additions, or deletions of one or more nucleotides in the DNA molecule are called gene mutations. |
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| What forms the basis for a method of identifying a person from biological samples? |
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| the variation in the DNA of individuals forms the basis for a method of identifying a person from samples of his or her hair, skin cells,or body fluid. |
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| What is recombinant DNA technology? |
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| recombinant DNA technology consists of methods for cleaving a DNA chain, inserting a new piece of DNA into the gap created by the cleavage, and resealing the chain. |
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| Nucleic acid |
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| these nitrogen-containing compounds are polymers that are found primarily in cell nuclei. Two kinds of nucleic acids are found in cells -deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). |
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| Nucleotides |
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| the monomers that make up the DNA and RNA polymers. |
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| Gene |
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| a segment of DNA that carries the instructions for making one peptide chain. |
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| What is the function of ATP in living cells? |
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| in living cells, ATP is the energy carrier between the spontaneous reactions that release energy and nonspontaneous reactions that use energy. |
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| How does a cell obtain the energy and building blocks needed for the construction of new biological compounds? |
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| the degradation of complex biological molecules such as carbohydrates, lipids, proteins, and nucleic acids during catabolism provides the energy and the building blocks for the construction of new biological compounds needed by the cell. |
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| What happens in a cell during anabolism? |
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| In anabolism, the products and the energy of catabolism are used to make new cell parts and compounds needed for cellular life and growth. |
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| How do nitrogen-fixing bacteria provide plants with a useable form of nitrogen? |
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| Nitrogen-fixing bacteria reduce atmospheric nitrogen(N2(g)) to ammonia(NH3(g)), a water-soluble form of nitrogen that can be used by plants. |
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| Adenosine triphosphate (ATP) |
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| a molecule that transmits energy in the cells of living organisms. |
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| Metabolism |
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| the entire set of chemical reactions carried out by an organism. |
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| Catabolism |
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| the reactions in living cells in which substances are broken down and energy is produced. |
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| Anabolism |
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| the synthesis reactions of metabolism |
