Human Body

1. Human Body Chapter 2 Basic Chemistry

2. Chemistry in the Human Body • The food that we eat is composed of chemicals • The medicines that we take are composed of chemicals • The entire body is composed of chemicals • Chemical rxns underlie all body processes

3. Concepts of Matter and Energy • Matter= the “stuff” of the universe • Anything that occupies space and has mass • Matter exists in solid, liquid, and gaseous state • Ex. Solids= bones and teeth • Ex. Liquids= blood plasma and interstitial fluid • Ex. Gases= air that we breathe

4. Changes in Matter • Physical Changes- do not alter the basic nature of a substance. • Ice melting to become water, cutting food into smaller pieces

5. Changes in Matter • Chemical Changes- do alter the composition of a substance • Fermenting grapes to make wine, digestion of food

6. Energy • No mass and does not take up space • It can only be measured by its effects on matter • The ability to do work or to put matter into motion

7. Types of Energy • Kinetic Energy-when energy is actually doing work • Potential Energy- inactive or stored energy • All forms of energy exhibit both kinetic and potential work capacites.

8. Forms of Energy • Chemical Energy- energy that is stored in the bonds of chemical substances **All body activities are “run” by the chemical energy harvested from the foods we eat.

9. Forms of Energy 2. Electrical Energy-energy that results from the movement of charged particles. -An electrical current is generated when charged particles (ions) move across cell membranes

10. Forms of Energy 3. Mechanical Energy- is directly involved in moving matter. -As the muscles in your legs shorten, they pull on your bones, causing your limbs to move.

11. Forms of Energy 4. Radiant Energy- energy that travels in waves, energy of the electromagnetic spectrum. -includes x-rays, ultraviolet waves -Ultraviolent waves are responsible for the suntan we get at the beach but also stimulate our bodies to make vitamin D.

12. Energy Form Conversions • Ex. The chemical of foods is trapped in the bonds of high energy molecules called ATPs. • ATPs energy can be transformed into the electrical energy of a nerve impulse or mechanical energy of shortening muscles.

13. Energy Form Conversions • Energy conversions are very inefficient. • Some initial energy is lost as heat(ex. Light bulb is losing some energy as heat and not all of it is used as light energy. • Humans have a high body temp. that influences the rxns in the body

14. Composition of Matter • All matter is composed of a limited number of fundamental substances called ELEMENTS. • Element-a unique substance that cannot be broken down or decomposed into simpler substances by ordinary chemical methods.

15. Composition of Matter • A complete listing of elements appears in the Periodic Table. • The most abundant elements in the Human Body are listed in Table 2.1. • The building block of matter=ATOM • Atoms of each element will differ from those of all the other atoms.

16. Composition of Matter • Atomic Symbol=a one or two letter chemical shorthand that is used to identify each element. • Ex. O=oxygen, Ca=Calcium, Ag=Silver (sometimes the symbol is taken from the Latin name of the elements)

17. Atomic Structure Subatomic Particles • Protons-are found in the nucleus of the atom and carry a positive charge. • Neutrons- are found in the nucleus of the atom and carry a neutral charge. • Electrons- are found in the energy shells orbiting the nucleus and carry a negative charge.

18. Atomic Structure • Atomic Number= the number of protons • Atomic Mass Number= the number of the protons + the number of neutrons

19. Isotopes • Almost all elements have at least two or more structural variations. • Isotopes have the same number of protons and electrons but different numbers of neutrons. • Isotopes of the same element will have the same atomic number but different mass numbers.

20. Molecules • A molecule is formed when two or more atoms are combined chemically. • Ex. O+O=O2 • When two or more atoms of different elements join together a Compound is formed. • Ex. H+ O= H2O

21. Chemical Rxns • Occur whenever atoms combine with or dissociate from other atoms. • A chemical bond is not a physical structure but an energy relationship that involves the interactions between the electrons of the reacting elements.

22. Chemical Bonds • Ionic Bonds-form when electrons are completely transferred from one atom to another. • Atoms are neutral but when they gain or lose electrons they become charged. • Ions=charged particles

23. Chemical Bonds • Covalent Bonds- when electrons are shared between atoms. **The point of bonds is for atoms to become stable***

24. Hydrogen Bonds • Extremely weak bonds formed when a Hydrogen atom gives an electron to another element.

25. Patterns of Chemical Rxns • Chemical rxns involve the making or breaking of bonds between atoms. Three Types of Rxns • Synthesis Rxns • Decomposition Rxns • Exchange Rxns

26. Synthesis Rxns • Occur when two or more atoms or molecules combine to form a larger, more complex molecule. • Always involve bond formation • Energy absorbing rxns • Underlie all anabolic activities that occur in body cells. Really important for growth and repair of worn out and damaged cells.

27. Decomposition Rxns. • Occur when a molecule is broken down into smaller molecules, atoms, or ions. • Synthesis rxns in reverse • As bonds are broken energy is released • Underlie all catabolic processes that occur in the body.

28. Exchange Rxns