1. Chemistry, Matter, and Life
Chapter 2
Chemistry, Matter, and Life

2. Chemistry Science that deals with composition and properties of matter
Used to understand normal and abnormal functioning of body

3. Elements Make up all matter 92 occur in nature
Identified by names or chemical symbols (abbreviations of modern or Latin names)
Identified by number (based on structure of subunits or atoms)
Described and organized in periodic table

4. Atoms Subunits of elements Smallest complete units of matter
Cannot be broken down or changed by ordinary chemical and physical means

5. Atomic Structure
Nucleus
Protons (+ charge)
Neutrons (no charge)
Electrons (– charge)

6. Representation of the oxygen atom.
ZOOMING IN • How does the number of protons in this atom compare with the number of electrons?

7. Checkpoint 2-1: What are atoms?
Checkpoint 2-2: What are three types of particles found in atoms?

8. Energy Levels
Distances from nucleus where electrons orbit
Higher energy levels can hold more electrons
Electrons in farthest level give atom its characteristics (positive or negative charge)
Valence of element is number of electrons lost or gained by atoms of element in chemical reactions

9. Molecules and Compounds
Formed when two or more atoms unite on the basis of their electron structures
Can be made of like atoms or atoms of different elements
Compounds
Composed of two or more elements
Smallest subunits of a compound

10. Checkpoint 2-3: What are molecules?

11. The Importance of Water
Most abundant compound in body
Critical in all physiologic processes in body tissues
Deficiency (dehydration) can threaten health
Universal solvent
Stable liquid at ordinary temperatures
Participates in chemical reactions in body

12. Checkpoint 2-4:What is the most abundant compound in the body?

13. Mixtures: Solutions and Suspensions
Solution components
Indistinguishable from one another
Evenly distributed throughout (homogeneous)
Suspension components
Separate from solvent
Settle out (heterogeneous or non-uniform)
Colloid components
Evenly distributed throughout

14. Checkpoint 2-5: Both solutions and suspensions are types of mixtures
Checkpoint 2-5: Both solutions and suspensions are types of mixtures. What is the difference between them?

15. Chemical Bonds
Atoms interact chemically to alter neutrality of atoms and form bonds.

16. Ionic bonding.

17. Ionic Bonds Electrons transferred between atoms form ionic bonds.
Electrolytes— ionic bonds form compounds that release ions when they are in solution
Influence homeostasis (stable condition of normal organism)
Conduct electronic current

18. Checkpoint 2-6: What happens when an electrolyte goes into solution?

19. Covalent Bonds A chemical bond in which atoms share electrons
Non-polar covalent bond
Polar covalent bond

20. Checkpoint 2-7: How is a covalent bond formed?

21. Compounds: Acids, Bases and Salts
Compounds are chemical substances with specific
properties
Acid can donate hydrogen ion (H+)
Base (alkali) can accept hydrogen ion (H+)
Salt is formed by a reaction between an acid and a base

22. The pH Scale
Represents relative concentrations of hydrogen and hydroxide ions in a solution
Scale from 0 (most acidic) to 14 (most basic)
Each unit represents a 10-fold change
Body fluids usually pH

23. The pH scale.
ZOOMING IN • What happens to the amount of hydroxide ion (OH–) present in a solution when the amount of hydrogen ion (H1) increases?

24. Buffers
Chemicals that prevent sharp changes in hydrogen ion concentration and maintain relatively constant pH in body fluids

25. Checkpoint 2-8: The pH scale is used to measure acidity and alkalinity of fluids. What number is neutral on the pH scale? What kind of compound measures lower than this number? Higher?
Checkpoint 2-9: What is a buffer?

26. Isotopes and Radioactivity
Elements can exist in several forms (isotopes).
Same number of protons and electrons
Different number of neutrons
Different atomic weights
May be stable or unstable (radioactive)

27. Use of Radioactive Isotopes
Radioisotopes are the rays given off by some radioactive
elements.
Can penetrate and destroy cancer cells
Can aid in diagnosis
X-rays
Tracers

28. Checkpoint 2-10: Some isotopes are stable; others break down to give off atomic particles. What word is used to describe isotopes that give off radiation?

29. Chemistry of Living Matter
Living matter contains 26 of 92 natural elements.
96% of body weight—four elements
4% of body weight—nine elements
0.1% of body weight—13 elements

30. Organic Compounds Chemical compounds that characterize living things
Contain carbon, hydrogen, and oxygen
Carbohydrates
Lipids
Proteins

31. Checkpoint 2-11: Where are organic compounds found?
Checkpoint 2-12: What element is the basis of organic chemistry?

32. Carbohydrates
Monosaccharides (simple sugars)
Glucose
Disaccharides
Polysaccharides
Starch
Glycogen

33. Examples of carbohydrates.
ZOOMING IN • What are the building blocks of disaccharides and polysaccharides?

34. Lipids
Triglycerides
Glycerol (glycerin)
Phospholipids
Steroids
Cholesterol
Steroid hormones
Sex hormones

35. Lipids.
ZOOMING IN • How many carbon atoms are there in glycerol?

36. Checkpoint 2-13: What are the three main categories of organic compounds?

37. Proteins
Amino acids
Enzymes
Catalysts
Substrates

38. Proteins.
ZOOMING IN • What part of an amino acid contains nitrogen?

39. Diagram of enzyme action.
ZOOMING IN • How does the shape of the enzyme before the reaction
compare with its shape after the reaction?

40. Checkpoint 2-14: Enzymes are proteins that act as catalysts
Checkpoint 2-14: Enzymes are proteins that act as catalysts. What is a catalyst?