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Chapter 2: The Chemical Level of Organization

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1 Chapter 2: The Chemical Level of Organization

2 KEY CONCEPT All Matter is made up of atoms
Atoms join together to form chemicals with different characteristics Chemical characteristics determine physiology at the molecular and cellular level

3 Atomic Particles Proton: Neutron: Electron: positive, 1 mass unit
neutral, 1 mass unit Electron: negative, low mass

4 Isotopes 2 or more elements with equal numbers of protons but different numbers of neutrons

5 Elements in the Human Body
Table 2–1

6 Molecules and Compounds
atoms joined by strong bonds Compounds: atoms joined by strong or weak bonds

7 States of Matter Solid: Liquid: Gas: constant volume and shape
constant volume but change shape Gas: change volume and shape

8 Chemical reactions & Physiology?
Energy: the power to do work Work: a change in mass or distance

9 Forms of Energy Kinetic energy - energy of motion
Potential energy - stored energy Chemical energy - potential energy stored in chemical bonds

10 KEY CONCEPT When energy is exchanged, heat is produced, but cells cannot capture it or use it for work

11 Break Down, Build Up Decomposition reaction (catabolism):
AB A + B Synthesis reaction (anabolism): A + B AB Exchange reaction (reversible): AB A + B

12 KEY CONCEPT Reversible reactions seek equilibrium, balancing opposing reaction rates Add or remove reactants: reaction rates adjust to reach a new equilibrium

13 How do enzymes control metabolism?

14 Activation Energy Chemical reactions in cells cannot start without help Activation energy gets a reaction started Figure 2–7

15 How Enzymes Work Figure 2–21

16 KEY CONCEPT Most chemical reactions that sustain life cannot occur unless the right enzymes are present

17 Organic and Inorganic Molecules
molecules based on carbon and hydrogen Inorganic: molecules not based on carbon and hydrogen

18 Why is water so important to life?

19 Properties of Water (1 of 2)
Solubility: water’s ability to dissolve a solute to make a solution Reactivity: most body chemistry uses or occurs in water

20 Properties of Water (2 of 2)
High heat capacity: water’s ability to absorb and retain heat Lubrication: to moisten and reduce friction

21 KEY CONCEPT Most of our body weight is water
Water is the key structural and functional component of cells and their control mechanisms, the nucleic acids

22 Electrolytes Inorganic ions conduct electricity in solution
Electrolyte imbalance seriously disturbs vital body functions Fluid balance Blood pressure Muscular contractions

23 pH pH: the concentration of hydrogen ions (H+) in a solution Neutral pH: a balance of H+ and OH— pure water = 7.0

24 Acids and Bases Acid (acidic): pH lower than 7.0
high H+ concentration, low OH— concentration Base (basic): pH higher than 7.0 low H+ concentration, high OH— concentration

25 pH Scale Has an inverse relationship with H+ concentration:
more H+ ions mean lower pH, less H+ ions mean higher pH Figure 2–9

26 KEY CONCEPT pH of body fluids measures free H+ ions in solution
Excess H+ ions (low pH): damages cells and tissues, alters proteins interferes with normal functions Excess OH— ions (high pH) also problem Normal blood pH – 7.35 to 7.45 Incompatibile with life – 6.8 to 7.8

27 Acid and Alkaline Acidosis: Alkalosis:
excess H+ in body fluid (low pH) Loss of bicarbonate Blood level < 7.2 Alkalosis: excess OH— in body fluid (high pH) Blood level > 7.5

28 Nucleic Acids Large organic molecules, found in the nucleus, which store and process information at the molecular level DNA and RNA

29 Deoxyribonucleic Acid (DNA)
Determines inherited characteristics Directs protein synthesis Controls enzyme production Controls metabolism Ribonucleic Acid (RNA) Codes intermediate steps in protein synthesis

30 KEY CONCEPT DNA in the cell nucleus contains the information needed to construct all of the proteins in the body

31 Nucleotides Building blocks of DNA Have 3 molecular parts:
sugar (deoxyribose) phosphate group nitrogenous base (A, G, T, C)

32 DNA Bases Figure 2–22b, c

33 Complementary Bases Complementary base pairs:
purines pair with pyrimidines: DNA: adenine (A) and thymine (T) cytosine (C) and guanine (G) RNA: uracil (U) replaces thymine (T)

34 Nucleic Acids Long chains of nucleotides form RNA and DNA RNA and DNA
Figure 2–23

35 RNA and DNA RNA: DNA: Single strand Double helix
Joined at bases by hydrogen bonds

36 Forms of RNA Messenger RNA (mRNA) Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

37 ADP and ATP Adenosine diphosphate (ADP): Adenosine triphosphate (ATP):
2 phosphate groups di = 2 Adenosine triphosphate (ATP): 3 phosphate groups tri = 3 Energy for muscular contractions

38 KEY CONCEPT Body recycles/renews all chemical components at intervals ranging from minutes to years Metabolic turnover lets your body: Grow Change Adapt

39 SUMMARY (1 of 2) Atoms, molecules, and chemical bonds control cellular physiology Metabolism and energy work within the cell Importance of organic and inorganic nutrients and metabolites

40 SUMMARY (2 of 2) Role of water and solubility in metabolism and cell structure Chemistry of acids and bases, pH and buffers Structure and function of carbohydrates, lipids, proteins, and nucleic acids

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