Chapter 2. What is life? Reproduction. All living things are made of cells

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1 What is life? Chapter 2 The Nature of Life All living things are made of cells Composed of one or more cells ossess inherited information (DNA) Reproduce Develop respond to the environment Assimilate and use energy Maintain a relatively constant internal environment (homeostasis) Evolve ossess inherited information (DNA) Figure 1.3cx Growth and development Reproduction 1

2 Living things sense their environment Figure 1.3dx Energy utilization Energy source Carbon source Energy flows though Biological Systems Autotrophs SUN C 2 Heterotrophs - consumers - decomposers THER RGANISMS (CHEMICAL ENERGY) RGANIC MLECULES Living things evolve Complexity and organization Homeostasis 2

3 The Chemistry of Life Matter Elements Atoms Table 2.1 Figure 2.10 Electron configurations of the first 18 elements Fig

4 Molecules Chemical Bonds Molecule Compound Covalent bonds Non-polar polar Table Salt, an Ionically Bonded Molecule Slide number: Table Salt, an Ionically Bonded Molecule Slide number: 3 Na Cl Na Cl Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display. Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display Table Salt, an Ionically Bonded Molecule Slide number: Table Salt, an Ionically Bonded Molecule Slide number: 5 Na Cl Na Cl Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display. Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display. 4

5 02.09 Table Salt, an Ionically Bonded Molecule Slide number: Table Salt, an Ionically Bonded Molecule Slide number: 7 () ( ) () ( ) Na Cl NaCl Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display. Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display. Hydrogen Bonds Figure 3.9 The ph of some aqueous solutions Water will dissociate into ions Acids more H than H - Bases more H - than H Neutral H = H - ph can play a significant role in plant growth ENERGY 5

6 Kinetic energy is energy that is actually doing work otential and kinetic energy otential energy is stored energy First law of Thermodynamics 1) Energy cannot be created or destroyed, only changed in form. Sound (out) Chemical energy Heat (IN) (out) Kinetic (out) Second Law of Thermodynamics When energy is transformed, the amount of useful energy decreases (heat is the most useless form of energy) ****(Quality changes not quantity)***** H--H 6 = =C= =C= H--H H--H H--H =C= =C= =C= =C= H--H H--H =C= Solar energy Waste heat Chemical energy (photosynthesis) Waste heat Chemical energy (food) Waste heat Mechanical energy (moving, thinking, living) Waste heat C 6 H C 2 and 6 H 2 0 energy 6

7 Some important terms rganic Molecules Macromolecule- a large molecule made up of smaller molecules (building blocks or subunits) olymer- a long molecule consisting of many similar or identical monomers Monomer- building block (subunit) of a polymer The synthesis and breakdown of polymers Class Monomer olymer Carbohydrates Lipids Monosaccharides e.g. glucose None polysaccharide None roteins Amino acids polypeptide Nucleic acids Nucleotides polynucleotide The structure and classification of some monosaccharides 03_21 Formation of sucrose Slide number: 4 CH 2 H CH 2 H H H H H H CH 2 H H H Glucose Fructose Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display. 7

8 03_21 Formation of sucrose Slide number: 5 03_21 Formation of sucrose Slide number: 7 CH 2 H CH 2 H CH 2 H CH 2 H CH 2 H CH 2 H H H H H H H H CH 2 H H H H H H H H CH 2 H H 2 H H H H H CH 2 H Glucose Fructose Glucose Fructose Sucrose Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display. Copyright The McGraw-Hill Companies, Inc. ermission required for reproduction or display. Storage polysaccharides The arrangement of cellulose in plant cell walls Lipids 8

9 Examples of saturated and unsaturated fats and fatty acids Saturated and unsaturated fatty acids Figure 3.8C The structure of a phospholipid amino group H H N C C H H R H H N C C H H CH 2 H side-chain tyrosine carboxyl group roteins are made of amino acids 20 different types FUR LEVELS F STRUCTURE IN RTEIN ala leu pleated sheet ser folded polypeptide chain glu glu ala his gln ile ser tyr ala ser glu glu random coil rimary structure Secondary structure Tertiary structure H H N C C H H CH 2 C H 2 N glutamine two or more polypeptide chains Quaternary structure 9

10 a NUCLETIDE G nitrogenous base C sugar (deoxyribose) phosphate group T A G c A T G c T A T A b Fig DNA double helix The human body contains about 100 trillion cells. There is a nucleus inside each human cell (except red blood cells). Each nucleus contains 46 chromosomes, arranged in 23 pairs. ne chromosome of every pair is from each parent. The chromosomes are filled with tightly coiled strands of DNA. Genes are segments of DNA that contain instructions to make proteins the building blocks of life. The genes in each cell are coded by sequences of nucleotides In their DNA molecules. G T A C C A T G 10