chapter 15 biochemistry. energy of life sun energy is converted to chemical energy by plants 6co 2 +...

Chapter 15Biochemistry

Energy of Life

• Sun energy is converted to chemical energy by plants

6CO2 + 6H2O C6H12O6 + 6O2

• Building energy molecules = anabolism

• Breaking down molecules for energy = catabolism

Molecules of Life: Carbohydrates

• Formed from C, H, and O

• Types:– Sugars = monosaccharides

• Names end in –ose

– Starches = polysaccharide• Plant starch = amylose, large granules• Animal starch = glycogen, small

granules

– Cellulose = polysaccharide• Different linkages than starches

Molecules of Life: Fats

• Called lipids

• Types:– Fatty acids (triglycerides)– Steroids: cholesterol, sex hormones– Fat-soluble vitamins– Waxes

• Classified by degree of saturation

• Insoluble in water

• Usually less dense than water

Molecules of life: Proteins

• Vital: present in all body tissues

• Combinations of amino acids– 9 are essential amino acids– All have 3-letter abbreviations

• How many combinations can you make from threonine (Thr), proline (Pro), cysteine (Cys), and leucine (Leu)?

Molecules of life: Protein Structure

• Primary– Amino acid sequence: long chain

• Secondary– Pleated sheet– α- helix

• Tertiary– 3-dimensional folding of chain

• Quaternary– Multiple separate tertiary structures

bonded together

Molecules of life: Protein Structure

Molecules of life: Protein Structure

α-helix Pleated sheet

Both due to hydrogen bonding!

Molecules of life: Protein Structure

• Linking proteins together– Primary = peptide bonds (amide linkage)– Secondary

• Hydrogen bonds

– Tertiary, Quaternary• Ionic bonds (“salt bridge”)• Disulfide bond (covalent)• Dispersion forces

– Most important for non-polar side-chains

Molecules of life: Protein Structure

Molecules of Life: Special Proteins

• Enzymes– Catalyze reactions– Lower activation energy:

bring reactants into precise proximity

– Increase reaction rate– Lower necessary

temperature– Not used up in reaction!– Some for catabolism,

some for anabolism

Molecules of Life: Nucleic Acids

• Nucleotides:– Sugar

• Ribose (in RNA)• Deoxyribose (in DNA)

– Phosphate• PO4

3- polyatomic ion bonded to sugar

• Backbone of the DNA

– Amine base• Purines: adenine (A), guanine (G)• Pyrimidines: cytosine (C), thymine (G),

uracil (U) in RNA• Purines bond with pyrimidines• Linked by hydrogen bonding

Molecules of Life: Nucleic Acids

Molecules of Life: Nucleic Acids

Molecules of Life: Nucleic Acids

• Double helical structure• DNA synthesis

– Unzipped by enzymes for replication– “Semi-conservative replication”– Sets of nucleotides copied into new strand

Molecules of Life: Nucleic Acids• Protein Synthesis

– Transcription• mRNA: “negative” copy of DNA in

nucleus

– Translation• tRNA: amino acids make protein

structure

Molecules of Life: Nucleic Acids

DNA Analysis

• Paternity Testing– 50% of DNA from each parent

• DNA fingerprinting– Compare evidence to known

samples

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Sus

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1

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2

Sus

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3

Sus

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4

Source: http://www.copernico.bo.it/subwww/webnewbio/webbiotec/html/K5_DNA%20Fingerprinting.html

DNA Manipulation

Recombinant Genetics