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Molecules of Life Chapter 3. Molecules Inorganic compound Nonliving matter Salts, water Organic compound Molecules of life Contains Carbon (C) and Hydrogen.

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Presentation on theme: "Molecules of Life Chapter 3. Molecules Inorganic compound Nonliving matter Salts, water Organic compound Molecules of life Contains Carbon (C) and Hydrogen."— Presentation transcript:

1 Molecules of Life Chapter 3

2 Molecules Inorganic compound Nonliving matter Salts, water Organic compound Molecules of life Contains Carbon (C) and Hydrogen (H) Carbon backbone

3 Carbon Chemistry Cell is mostly water The rest of the cell consists mostly of carbon-based molecules Carbon is a versatile atom four electrons in an outer shell that holds eight can share its electrons with other atoms to form up to four covalent bonds Structures may vary


5 Organic Molecules Many molecules of life are macromolecules (macromolecules contain many molecules joined together) Monomers :Simple organic molecules that exist individually Polymers :Large organic molecules form by combining monomers PolymerMonomer CarbohydrateMonosaccharide ProteinAmino acid LipidsTriglycerides Nucleic acidNucleotide

6 Polymers Are Built of Monomers All polymers are assembled the same way Covalent bond is formed by removing an hydroxyl group (OH) from one subunit and a hydrogen (H) from another subunit Amounts to the removal of a molecule of water (H 2 O) Dehydration synthesis


8 Polymers Are Built of Monomers Process of disassembling polymers into component monomers is essentially the reverse of dehydration synthesis Molecule of water is added to break the covalent bond between the monomers Hydrolysis


10 Molecules of Life 4 main classes of biological molecules 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids

11 Carbohydrates

12 Some Functions: Quick fuel Short-term energy storage Structure of organisms Cell to cell recognition Consist of C, H, and O atoms 1:2:1 ratio “ Saccharides” 3 major classes: Monosaccharides Disaccharides Polysaccharides

13 Monosaccharides “simple sugars”; “one monomer of a sugar” Dissolve easily in water hydrophilic Glucose C 6 H 12 O 6 Fructose Form of glucose

14 Disaccharides Short chain of two sugar monomers Two Monosaccharides Lactose, sucrose, maltose Lactose = glucose + galactose

15 Polysaccharide “Complex” carbohydrate Contain many C-H bonds Good for storing energy These bond types are the ones most often broken by organisms to obtain energy Glycogen Polysaccharide of glucose Storage form of glucose in animals Starch Storage form of glucose in plants Cellulose Found in the cell walls of plants


17 Lipids

18 Cells use lipids to store energy Hydrophobic Functions: Energy Storage Cushioning and Insulation Found in the plasma membrane 3 main types: Fats & Oils Phospholipids Steroids

19 Fats Dietary fat consists largely of the molecule triglyceride Combination of glycerol and three fatty acids

20 Fats Unsaturated fatty acids Have less than the maximum number of hydrogens bonded to the carbons Saturated fatty acids Have the maximum number of hydrogens bonded to the carbons Most animal fats have a high proportion of saturated fatty acids, which can be unhealthy Example: butter Most plant oils tend to be low in saturated fatty acids Example: corn oil

21 Phospholipids Glycerol, two fatty acids and a phosphate group Plasma membrane Nonpolar tail Polar heads

22 Proteins

23 Why Proteins?? VERY important functions in cells Keratin and collagen have structural roles Enzymes speed up chemical reactions of metabolism Responsible for transport of substances within the body Transport substances across cell membranes Hormones that regulate cellular function Insulin

24 Proteins Made from amino acids 20 various kinds Amino acids linked to one another by peptide bonds Two amino acids bound by a peptide bond is a dipeptide Three or more is a polypeptide chain

25 Protein Polypeptide Peptide / Dipeptide Amino Acids

26 Proteins Amino acids are small molecules with a simple basic structure, a carbon atom to which three groups are added an amino group (-NH 2 ) a carboxyl group (-COOH) a functional group (R) The functional group gives amino acids their chemical identity

27 Protein Structure Protein’s final shape and chemical behavior arise from: Chain bends, folds, coils, etc.

28 Proteins Primary structure sequence of amino acids in the polypeptide chain determines all other levels of protein structure

29 Proteins Secondary structure Forms because regions of the polypeptide that are non-polar are forced together folded structure may resemble coils, helices, or sheets

30 Proteins Tertiary structure final 3-D shape of the protein final twists and folds that lead to this shape are the result of polarity differences in regions of the polypeptide

31 Proteins Quaternary structure spatial arrangement of proteins comprised of more than one polypeptide chain

32 Protein The shape of a protein affects its function Changes to the environment of the protein may cause it to unfold or denature Increased temperature or lower pH affects hydrogen bonding, which is involved in the folding process Denatured protein is inactive

33 Nucleic Acids

34 Proteins Denaturing When proteins lose their shape

35 Nucleotides and Nucleic Acids Nucleic acids Can be single stranded or double stranded DNA  Deoxyribonucleic acid  genetic information RNA  Ribonucleic acid  used to build proteins

36 Nucleotides and Nucleic Acids Nucleic acids Built by nucleotides Phosphate Pentose sugar Nitrogen-containing base

37 DNA Composition DNA is built from four different kinds of nucleotides One of four bases determines the nucleotide: A - Adenine G - Guanine T - Thymine C – Cytosine DNA consists of two strands of nucleotides twisted into a double helix

38 GAGA….a nucleotide repeat!! Base pairs Bases can only pair up with their corresponding “mate” 2 kinds: A – T G – C Amount of A = T Amount of G = C Can line up in any order

39 DNA Composition Nucleotides linked together by covalent bonds Bases of one strand linked to the other by hydrogen bonds The two strands run in opposite directions

40 DNA into RNA RNA a big player!! Single strand Sugar, phosphate group, and a N-containing base Bases are: A, C, G, and URACIL (U)


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