Download Chapter 2 Chemical Principles

Chapter 2
Principles of Biochemistry
• Both living and nonliving things are made
up of atoms.
• Water, bacteria, humans
• Atoms – molecules-organelles-cell-tissueorgan-organ system-organism
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Electron are arranged in shells
Shell #1 – maximum of 2eShell #2 – maximum of 8eShell #3 – maximum of 8eDo not have maximum #of electrons in
their outer most shell
• Unstable – atoms interact
Chemical bonds
Formation of molecules
• Ionic bond – atoms gain or lose electrons
• NaCl – table salt
• Ion atom – gained or lost e-
• Atoms get together and share electrons
• Electrons orbit around the nuclei of both
atoms
• Hydrogen bonds – water molecules are
held together
• H2O – covalent bonds are formed
between atoms.
• Electrons are not shared equally
• Electron stays close to the O – lot more
protons than H atom
• O in water – slightly negative
• H in water – slightly positive
• Water is a good solvent
• NaCl goes into solution readily
(dissociates, ionizes)
• Play an important role in chemical reaction
that take place in cell.
• Dehydration synthesis
• hydrolysis
Acids, bases and salts
• Acids ionize – H+ and a negative ion
• HCl ---------H+ + Cl• Bases ionize –OH- (hydroxide ion) and a
positive ion.
• NaOH ------ Na+ + OH• Salt – positive ion and a negative ion.
Neither of which is a H+ ion or OH• NaCl --- Na+ +Cl-
Carbohydrates
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C, H, O
2 to 1 ratio of oxygen to hydrogen
Monosaccharides – simple sugars
Glucose C6H12O6
Maine source of energy in cells.
Ribose – one of the molecules found in
RNA
Sucrose – glucose and a unit of fructose
Sugarcane
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Lactose – milk sugar
Glucose + galactose
Maltose – breakdown product of starch
2 glucose
Polysaccharides – many units of simple
sugars
Cellulose – plant cell wall
Glycogen – glucose is stored - in animals
Starch – glucose is stored – plant cells
Polymers of glucose
Lipids
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C, H, O
No 2 to 1 ratio
Simple lipids – triglycerides
Glycerol and 3 fatty acids
Energy storage molecule
phospholipid
Proteins
• C, H, O, N, S
• Building blocks – amino acids
• 20 different amino acids
• Hemoglobin – polypeptide chains
• Specific AA sequence
• Valine-histidine-leucine-glutamic acid
valine
• Sickle cell anemia
• Shape of the protein changes
• RBCs sickle shaped
• Not flexible – trouble getting through the
capillaries
• Health problems
• Egg – protein albumin (egg white)
• Semisolid and transparent
• Hot frying pan – albumin is solid and
white.
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Nucleic acids – deoxyribonucleic acid
(DNA) ribonucleic acid (RNA)
Building blocks – nucleotides
Pentose, phosphate group, nitrogen base
Purines – adenine, guanine
Pyrimidines – cytosine, thymine, uracil
DNA – double helix
Deoxyribose
DNA nuceotides – A, G, C, T no U
RNA
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Single stranded
Ribose
A,G,C,U – no T
Messenger RNA – mRNA
Ribosomal RNA – rRNA
Transfer RNA – tRNA
Each plays a different role in protein
synthesis