Microbiology: Basic and Clinical Principles PDF

Microbiology: Basic and Clinical Principles Second Edition Chapter 2 Biochemistry Basics Presented by Janet Dowding, Ph.D....

Microbiology: Basic and Clinical Principles Second Edition Chapter 2 Biochemistry Basics Presented by Janet Dowding, Ph.D. St. Petersburg College Copyright © 2023 Pearson Education, Inc. All Rights Reserved Clinical Case Copyright © 2023 Pearson Education, Inc. All Rights Reserved From Atoms to Macromolecules (1 of 2) After reading this section, you should be able to: Define the term atom and identify an atom’s parts. Determine the atomic mass, atomic number, and chemical symbol of an element using the periodic table. Explain the difference between an anion and a cation and state how they are formed. Describe isotopes and their importance in medicine. Distinguish between a molecule, compound, and isomer. Interpret and write a molecular formula. Copyright © 2023 Pearson Education, Inc. All Rights Reserved From Atoms to Macromolecules (2 of 2) After reading this section, you should be able to: Differentiate between organic and inorganic compounds and identify selected functional groups. Compare acids and bases and discuss their effects on pH. Explain what the pH scale reflects and list its features. Define the term buffer and state why buffers are important in biological systems. Copyright © 2023 Pearson Education, Inc. All Rights Reserved What Are Atoms? (1 of 4) Atoms are the smallest units of elements, which are pure substances that make up ordinary matter. Copyright © 2023 Pearson Education, Inc. All Rights Reserved What Are Atoms? (2 of 4) The center of an atom is called the atomic nucleus and contains protons and neutrons Around the nucleus is a cloud of electrons Copyright © 2023 Pearson Education, Inc. All Rights Reserved What Are Atoms? (3 of 4) Protons are positively charged particles Neutrons are noncharged (neutral) particles Electrons are negatively charged particles Copyright © 2023 Pearson Education, Inc. All Rights Reserved What Are Atoms? (4 of 4) Atoms can vary their number of neutrons and/or electrons, but protons remains constant Number of protons is a defining feature and equal to the element’s atomic number Each element has a unique atomic number Elements are organized by their atomic number in the periodic table The periodic table of elements includes the chemical symbol, atomic number, and atomic mass Copyright © 2023 Pearson Education, Inc. All Rights Reserved Figure 2.2 The Periodic Table Copyright © 2023 Pearson Education, Inc. All Rights Reserved The Periodic Table Atomic mass is the mass of the protons and neutrons in the atom (electrons have negligible mass) Atomic mass is the average mass of 6.022  1023 atoms, or one mole, of the element Copyright © 2023 Pearson Education, Inc. All Rights Reserved Ions and Isotopes: Variations of Atoms (1 of 2) Two forms of atoms are ions and isotopes All elements exist as a variety of isotopes, while only certain elements form ions Copyright © 2023 Pearson Education, Inc. All Rights Reserved Ions and Isotopes: Variations of Atoms (2 of 2) Ions are charged atoms that have an unequal number of protons and electrons Cations are atoms that have lost electrons and consequently have an overall positive charge Anions are atoms that have gained electrons and consequently have an overall negative charge Copyright © 2023 Pearson Education, Inc. All Rights Reserved Figure 2.3 Ion Formation Copyright © 2023 Pearson Education, Inc. All Rights Reserved Isotopes Isotopes are elements with the same number of protons but different numbers of neutrons All elements exist as a mixture of isotopes – Isotopes are denoted by their atomic mass – For example, carbon atoms: ▪ 99% are C-12 with 6 protons and 6 neutrons ▪