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Organic Molecules of Life

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Presentation on theme: "Organic Molecules of Life"— Presentation transcript:

1 Organic Molecules of Life

2 Organic molecules : are compounds created by living organisms
contain the elements carbon and hydrogen

3 Carbon atoms: need four electrons to fill their outer electron shell
Must form four bonds with other elements. These are covalent bonds. Most often bond with Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur, and other Carbon atoms 6 P 6 N

4 These can include: Single bonds (one electron shared) Double bonds
(two electrons shared) Or triple bonds (three electrons shared)

5 Carbon Atoms: Can bond with other atoms of carbon to form long chains
These chains can be: Straight Branched Rings

6 Isomers Molecules with the same formula Atoms are arranged differently
Carbons are branched in various ways

7 Functional groups: Are special groups of atoms that stay together and act as a single unit can bond with the carbon chains determine how the entire molecule will react.

8 The functional groups you need to know are:

9 Hydroxyl Group one oxygen and one hydrogen usually written as -OH

10 Carboxyl Group one carbon with a double bond to an oxygen AND a single bond to a hydroxyl group usually written as COOH or O=C–OH Creates an organic acid (carboxylic) Oxygen Carbon Oxygen Hydrogen

11 Amino Group one nitrogen bonded to two hydrogen
usually written as NH2 or H–N–H Hydrogen Nitrogen Hydrogen

12 Phosphate Group: One phosphorus bonded to two hydroxyl groups, and two other oxygens (one has a double bond) Usually written as –P or OH O P O Phosphorus

13 Biological molecules can be made up of thousands of atoms

14 These large molecules are built from basic units called
monomers. One monomer

15 The monomers are linked together to form the large molecules called
polymers. Polymer – chain of repeating monomer units

16 Making and Breaking Polymer Bonds
Monomers When two monomers are put together to form larger molecules, a water molecule is created. Polymer

17 This process is called:
Dehydration Synthesis. (Dehydration means to lose water Synthesis means to build or put things together)

18 When polymers are broken apart, it is done by adding a water molecule.

19 (hydro- for water, -lysis for breaking apart)
This is called Hydrolysis (hydro- for water, lysis for breaking apart)

20 Types of Organic Molecules
There are four categories of organic molecules in organisms: Carbohydrates Lipids Proteins Nucleic acids

21 Carbohydrates

22 What are Carbohydrates?
Organic compounds Commonly called starches and sugars Used as: An energy source Energy storage Cellular structures

23 Chemical Composition Contains only three elements:
Carbon Hydrogen Oxygen Ratio of hydrogen to oxygen is 2: (just like water) Example: C6H12O6 Basic Unit is called a saccharide

24 Types of Carbohydrates
Monosaccharides Simple, single (mono-) sugar unit Building block of all other carbohydrates Name usually ends in –ose Used as energy source

25 Examples of Monosaccharides
Glucose – blood sugar Fructose – fruit sugar Galactose – one monomer in lactose (milk) Isomers of C6H12O6

26 Examples of Monosaccharides
Ribose and Deoxyribose 5 - Carbon sugars in RNA and DNA

27 Types of Carbohydrates
Disaccharides Double sugar units synthesized from monosaccharides All are isomers of C12H22O11 Formed by dehydration synthesis (requires enzymes)

28 Examples of Disaccharides
Sucrose – table sugar Glucose + Fructose Maltose – seed sugar Glucose + Glucose Lactose – milk sugar Glucose + Galactose

29 Types of Carbohydrates
Polysaccharides Large, complex chains of many (poly-) repeating sugar units Polymers Bonded together by dehydration synthesis Used by living things as a sugar storage or for structures

30 Examples of Polysaccharides
Amylose – plant starch Used as sugar storage in seeds, roots, stems Glycogen – animal starch Used as sugar storage by humans in the liver Cellulose Very tough polymer Used as a main component of cell walls Indigestible by humans Chitin Used in exoskeletons (crab shells, insects)

31 Digesting Polysaccharides
Broken apart by hydrolysis with the help of enzymes

32 Lipids

33 What are Lipids? Three elements: Carbon Hydrogen Oxygen
Ratio of H:O much greater than 2:1 Example: Oleic acid C18H34O3 Insoluble in water Greasy, slippery texture Three main groups: Fats oils and waxes At room temperature: Liquid – oils/Solid – fats and waxes Phospholipids Steroids

34 What are the Functions of Lipids?
Fats, Oils and Waxes: Long term energy storage More than twice as much energy stored than carbohydrates fats- 9 Calories/gram; carbohydrates- 4 Cal/g In plants: stored in and around seeds Peanut oil, corn oil, olive oil In animals: stored under the skin and around internal organs Used as insulation and shock absorber

35 What are the Functions of Lipids?
Phospholipids Structural Part of Cell membranes Steroids Part of cell membranes, transport of lipids, regulate body functions (hormones)

36 Chemical Composition Fats Oils, Waxes
Fatty Acid Glycerol One or more fatty acids attached to a Glycerol backbone Fatty Acids: Long chains of carbon with a carboxyl group at the end Glycerol: C3H8O3 Formed by dehydration synthesis NOT a polymer Glycerol Lipid

37 Formation of a Triglyceride:

38 Types of Fats Saturated
All carbons of the fatty acid have single bonds All carbons are “filled” with hydrogen Solid at room temperature Associated with heart disease risk Examples: Bacon grease, butter

39 Types of Fats Unsaturated
Carbons share one or more double or triple bonds with other carbons Monounsaturated – only one double bond Polyunsaturated – many double or triple bonds Liquid at room temperature Examples: corn oil, olive oil

40 Phospholipids Phosphate group replaces fatty acid on one end
Used as the main component of cellular membranes


42 Steroids: Four Fused Rings
lipids with four fused hydrocarbon rings Includes: Cholesterol - found in animal cell membranes Testosterone, estrogen, progesterone - sex hormones Vitamin D An anabolic steroid is a synthetic testosterone.

43 Proteins

44 Protein Functions Structural parts Carriers Regulators
cell membrane, muscles, hair, nails, pigments Regulators Hormones, enzymes Carriers Transport materials in, out and around cells Identification Allow cells to recognize each other Immune system antibodies

45 Composition of Proteins
Elements: carbon, hydrogen, oxygen and NITROGEN Very large, complex Hemoglobin: C3032H4816O872N780S8Fe4 Monomers (building blocks) are amino acids 20 common amino acids 9 are essential 11 are non essential

46 The R group is different for each of the twenty amino acids

47 Peptide Bonds Chains of amino acids are called peptides
Amino acids are joined by dehydration synthesis This occurs between the carboxyl end of one amino acid and the amino end of another amino acid. The resulting bond is called a Peptide bond

48 Primary Structure The sequence of amino acids in a protein is called the Primary Structure The sequence is unique for each protein and is determined by the DNA

49 Secondary Structure Hydrogen bonds are formed between the chains of amino acids causing different shapes.

50 Secondary Structure Two shapes are common – a helix and a sheet.
Sheet and Helix

51 Tertiary Structure The 3-D arrangement of the molecule caused by weak bonds between the R groups The most important structure format Determines the function of the protein

52 Quaternary Structure More than one protein molecule can combine to create a macromolecule This is the quaternary structure of the protein This creates either globular (hemoglobin) or fibrous (collagen) proteins

53 Nucleic Acids

54 Nucleic Acids are: The largest molecules in living things
The DNA of humans has about 6 billion monomers Some reptiles have 20 times more units The largest DNA known is a flower with 5 trillion units

55 The two most important Nucleic Acids:
DNA (deoxyribonucleic acid) RNA (ribonucleic acid)

56 Functions of Nucleic Acids
DNA make up chromosomes and their genes that carry hereditary information found in the nucleus, mitochondria and chloroplasts (plants) RNA functions in the synthesis of proteins for the cell found in cell parts: nucleoli, ribosomes, and throughout the cytoplasm

57 General Structure of Nucleic Acids
Polymers, with many repeating units called nucleotides Nucleotides have three subunits: a five carbon sugar a phosphate group a nitrogenous base (a base that contains nitrogen) Phosphate group Nitrogenous Base Five Carbon Sugar

58 Structure of DNA The sugar backbone is deoxyribose

59 Structure of DNA The base can be one of four: Adenine Guanine Thymine

60 Structure of DNA The bases pair up –
A (adenine) always pairs with T (thymine) G (guanine) always pairs with C (cytosine)

61 Structure of DNA

62 Structure of DNA Two polymer chains of nucleotides are connected by weak hydrogen bonds and are twisted into a double helix

63 Structure of DNA Sequence of nitrogenous bases codes for specific amino acids Amino acid sequence determines the protein made in the cell and the cellular activity

64 Relationship Between Proteins and Nucleic Acids

65 Structure of RNA Ribose is its sugar backbone

66 Structure of RNA The base can be one of four: Adenine Guanine Cytosine
Uracil Thymine is replaced by Uracil

67 Structure of RNA Only a single polymer chain is created in RNA, but strands of RNA have complex, folded structures that compliment their function.

68 Enzymes

69 What are Enzymes? Large, Complex Proteins
Function as Organic Catalysts Allow reactions to occur at lower temperatures ( 37° C) Used temporarily Unchanged by the reaction Can be reused Specific to one reaction

70 What are Enzymes? Bind to reactants called substrates
Enzyme names usually end in –ase and can be named for their substrate: Protease – proteins Lipase – lipids Maltase – maltose ATPase – ATP Acetylcholinesterase - acetylcholine

71 How Do Enzymes Work? Reduces energy needed to begin reaction (Activation energy) Without catalyst With catalyst Activation Energy Energy Energy Time Time

72 How Do Enzymes Work? Lock and Key Model Products Substrate Active Site
Substrate attaches to enzyme at active site Enzyme Substrate Complex Formed Reaction takes place and products are released

73 How Do Enzymes Work? Induced Fit Model Product
Enzyme substrate complex formed Substrate Enzyme Enzyme Enzyme Substrate attaches to active site Enzyme changes shape to match substrate – Stressed molecule may help to weaken bonds Enzyme resumes original shape after product formed

74 How Do Enzymes Work? Coenzymes sometimes needed
Non proteins – minerals, vitamins Smaller molecules Part of the enzyme structure or work along side the enzyme Enzyme and substrate do not match Coenzyme fills in needed shape Coenzyme

75 Denaturation: If the shape changes, the enzyme cannot function properly

76 Factors Affecting Enzymes
Temperature Enzyme activity increases with temperature Optimum temperature for each enzyme Higher temperatures denature (change the shape) of the enzyme’s active site Rate of reaction decreases quickly after optimum temperature Optimum temperature

77 Factors Affecting Enzymes
pH Enzymes are pH dependent Some work at low pH (acid) Some at high pH (basic) Surrounding solutions will activate or deactivate enzyme by changing the shape of the active site Extremely high or low pH values generally result in complete loss of activity for most enzymes pH for Optimum Activity Enzyme pH Optimum Lipase (pancreas) 8.0 Lipase (stomach) Lipase (castor oil) 4.7 Pepsin Trypsin Urease 7.0 Invertase 4.5 Maltase Amylase (pancreas) Amylase (malt) Catalase

78 Factors Affecting Enzymes
Concentration: Increasing amount of enzyme: rate increases then levels off substrate levels fall and reduces efficiency Increasing amount of substrate: enzyme is saturated and no additional reactions can occur Presence of Inhibitors Bind to enzyme and change shape or compete with the substrate

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