Lecture slides I (F18).pdf - Welcome to Introduction to Biochemistry BIOC*2580 Fall 2018 Molecules we study in biochemistry small molecules sugars amino

Fall 2018 Welcome to Introduction to Biochemistry BIOC*2580

__________________ sugars, amino acids, nucleotides, carboxylic acid derivatives act as building blocks for macromolecules __________________ Proteins – chains of amino acids Polysaccharides – chains of simple sugars Nucleic acids – chains of nucleotides Molecules we study in biochemistry

A macromolecule myoglobin is a protein that stores O 2 in muscle tissue C N S O

How large is a protein molecule? Most proteins: 10,000 to 100,000 g mol-1Protein size is expressed in _______________ 1 Dalton (Da) = 1 g mol-1(mass of H atom) 1 kDa = 1000 gmol-1 Myoglobin is 16.5 kDa –small protein P-glycoprotein is 170 kDa –large protein

The building block principle of macromolecular structure Understand the building blocks Understand the macromolecules repeated simple bonds building blocks

Proteins are made of amino acids Understand amino acids Understand proteins amide bonds amino acids

Proteins are made of amino acids linear chains of amino acidslinked by peptide bonds (type of amide bond) Each protein has: unique sequence of different amino acids a well definedsize and structure Proteins have diverse functions including: catalyzing reactions (enzymes) forming complex subcellular structures

Basic amino acid structure Each amino acid has an _________ group and a ____________ group Each amino acid has a different ____________ 20 different amino acids are found in proteins (see Lehninger p79 (75))

Peptide bonds ____________involves removal ofH2O from the units being linked _________ The C=O group of the amide is thepoint of weakness allowing H2O attack

Large numbers of amino acids can be linked together to form a peptide chain The combination of different side chains R1, R2, R3, etc gives each protein its unique properties there are 153 amino acids in myoglobin (16.5 kDa) ______________ – a chain with many amino acids, usually a complete protein Greek poly = many ______________ – a chain with a few amino acids, usually a fragment Greek oligo = a few

The____________is the central backbone atom The___________is the first atom of the side chain, the g-carbonis the second, etc Functional groups may be linked to different core atoms:

The 20 natural amino acids Amino acids share a common backbone, but differ in the side chain You need to be able to reproduce the structures of the amino acids and know their 1- and 3-letter codes You need to be able to associate particular properties with each amino acid ______________ ______________ _________________________ Amino acids can be grouped according to structures or by similar properties

“inverted pyramid” 6 5 4 3 2 6 with very non- polar side chains 5 with moderately non-polar side chains 4 with polar but uncharged side chains 3 with positively charged side chains (very polar) 2 with negatively charged side chains (very polar)

6 with very non-polar side chains 5 with moderately non-polar side chains

4 with polar but uncharged side chains 3 with positively charged side chains (very polar)

4 nucleotides in DNA (second half of the course) 2 with negatively charged side chains (very polar) Do not need to memorize the structures of the nucleotide bases for the midterm. They will be tested in the final exam.