chapter 15 biochemistry. energy of life sun energy is converted to chemical energy by plants 6co 2 +...
TRANSCRIPT
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
Crim
e S
cene
Sus
pect
1
Sus
pect
2
Sus
pect
3
Sus
pect
4
Source: http://www.copernico.bo.it/subwww/webnewbio/webbiotec/html/K5_DNA%20Fingerprinting.html
DNA Manipulation
Recombinant Genetics