Macromolecules

Macromolecules are large molecules composed of thousands of covalently connected atoms All living things are made up of four classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids

Monomers and Polymers A polymer is a long molecule consisting of many similar building blocks These small building-block molecules are called monomers Carbohydrates, Proteins, Nucleic acids Monomer Polymer

dehydration reaction -two monomers bond together to build a polymer. Water is lost (done by enzymes)done by enzymes) Polymer synthesis Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Hydrolysis - Polymers are broken down into monomers. Water is added. (done by enzymes) Polymer breakdown

Carbohydrates Carbohydrates polymers made of sugar monomers. Serve as a fuel source for the body Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Monosaccharides Monosaccharides –single sugar molecule Glucose (C 6 H 12 O 6 ) is the most common monosaccharide Monosaccharides are classified by: – The location of the carbonyl group and he number of carbons in the carbon skeleton Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-3 Dihydroxyacetone Ribulose Ketoses Aldoses Fructose Glyceraldehyde Ribose Glucose Galactose Hexoses (C 6 H 12 O 6 ) Pentoses (C 5 H 10 O 5 ) Trioses (C 3 H 6 O 3 )

Can be found as chains or rings. Monosaccharides serve as a major fuel for cells and for building carbohydrates. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Monosaccharides (a) Linear and ring forms(b) Abbreviated ring structure

Fig. 5-4a (a) Linear and ring forms

Glycosidic Linkage Glycosidic linkage – covalent bond formed between two monosaccharides (dehydration) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Polysaccharides Polysaccharides – many monosaccharides linked together (carbohydrate) Polysaccharides can store sugars: Starch in plants glycogen in animals (liver cells) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

More Linear More Branched

Structural Polysaccharides Cellulose – a polysaccharide used to give plant cell walls their shape and structure (we can’t digest it). Cellulose is made of glucose just like starch. However, starch is made of alpha (  ) glucose and cellulose is made of beta (  ) glucose.

Hydrogen bonding holds the strands together.

Digesting Carbohydrates Enzymes that digest starch by hydrolyzing  linkages can’t hydrolyze  linkages in cellulose Cellulose in humans passes through the digestive tract as fiber Some bacteria can digest fiber and live in the stomachs of animals like cows.

Chitin- a structural polysaccharide found in the exoskeleton of arthropods and the cell walls of fungi. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structural Polysaccharides

Lipids Lipids – used by the body as storage, insulation, water proofing and membranes (fats, oils, steroids, phospholipids) Hydrophobic – don’t like water, because they have nonpolar covalent bonds. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fats Fats - constructed from one glycerol and 3 fatty acids attached by an ester linkage. (triglycerol/ tryglyceride) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Saturated vs. Unsaturated Saturated fats - have the maximum number of hydrogen atoms possible and no double bonds (animal fats, solid at room temp) (Clog arteries). Unsaturated fats have one or more double bonds (plant and fish oils, liquid at room temp). Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings SaturatedUnsaturated

Adipose Cells adipose cells – store fat. Adipose tissue also cushions vital organs and insulates the body (cellulite)

Phospholipids Phospholipid- two fatty acids and a phosphate group are attached to glycerol The two fatty acid tails are hydrophobic, but the phosphate group and its attachments form a hydrophilic (likes water) head Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Membranes When phospholipids are added to water, they self- assemble into a bilayer, with the hydrophobic tails pointing toward the interior. This makes up a cell membrane. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Steroids Steroids are lipids characterized by a carbon skeleton consisting of four rings Cholesterol, an important steroid, is a component in animal cell membranes, and can act as a hormone.

Proteins Proteins –polymers made of polypeptides that are made of amino acid monomers. Protein are used for structural support, storage, muscles, transport, cellular communications, movement, and defense against foreign substances

Amino Acid Amino acids are organic molecules with carboxyl and amino groups Amino acids differ in their properties due to differing side chains, called R groups (only 20 types of amino acids. Amino group Carboxyl group

Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine (Ile or I) Methionine (Met or M) Phenylalanine (Phe or F) Tryptophan (Trp or W) Proline (Pro or P)

=polypeptides =Peptide bonds =proteins =amino acids

Peptide bond Amino end (N-terminus) Peptide bond Side chains Backbone Carboxyl end (C-terminus) (a) (b)

Protein Structure and Function A protein consists of one or more polypeptides twisted, folded, and coiled into a unique shape. This shape determines its function. Primary, secondary, tertiary, quaternary

Primary Structure Primary structure, the order of the amino acids in a protein (like the order of letters in a long word)like

Secondary Structure secondary structure – a pattern of folds and/ or coils of the amino acid chain resulting from hydrogen bonds between the amino acidsacids

Tertiary Structure Tertiary structure is random folding, twisting, and clumping that takes place due to interactions between R groups. (hydrogen bonds, ionic bonds, hydrophobic interactions, and van der Waals interactions) interactions

Quanternary Structure Quaternary structure - two or more polypeptide chains combine (ex. Hemoglobin is 4 chains)ex Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Structure and Function A slight change in primary structure can affect a protein’s structure and ability to function Sickle-cell disease, an inherited blood disorder, results from a single amino acid substitution in the protein hemoglobin. The misshaped blood cell does not hold enough oxygen.

Structure and Function Denature - the loss of a protein’s structure (proteins can regain their shape) Changes in pH, salt concentration, temperature, or other environmental factors can cause a protein to denature. (will not function properly) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig Normal protein Denatured protein Denaturation Renaturation

Enzymes Enzymes- are a type of protein that acts as a catalyst to speed up chemical reactions Enzymes can perform their functions repeatedly, to allow your body to do things like digest, or copy DNA, or build muscle.Enzymes

Lock and Key Enzymes match the shape of their substrates (reactants) to put them together or break them apart. Active sight is where this action takes place. Enzyme = lock substrate = key

Enzyme Denature An enzyme will denature at certain temperature’s or pH’s.

Chaperonins Chaperonins are protein molecules that assist the proper folding of other proteins

X-ray crystallography Scientists use X-ray crystallography to determine a protein’s structure Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Nucleic acids nucleic acid – polymers made of nucleotide monomers. They store genetic information (DNA) Nucleic acids determine the primary structure proteins.

Nucleotides Nucleotides – a base, sugar, and phosphate Nucleoside – base and sugar The phosphate and sugar make up the outside of DNA the base makes up the inside One side of DNA

Bases Two types of bases: Pyrimidines – one ring, Purines two rings (cytosine, thymine, uracil) (adenine, guanine) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

3’ to 5 ’ end orientation The phosphates attach to the 5 th and 3 rd carbon of each sugar. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

DNA Sequence The order the bases are in determine the primary structure of the protein the DNA codes for. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

You should now be able to: 1.List and describe the four major classes of molecules 2.Describe the formation of a glycosidic linkage and distinguish between monosaccharides, disaccharides, and polysaccharides 3.Distinguish between saturated and unsaturated fats. 4.Describe the four levels of protein structure Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

You should now be able to: 5.Distinguish between the following pairs: pyrimidine and purine, nucleotide and nucleoside, ribose and deoxyribose, the 5 end and 3 end of a nucleotide Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings